WorldWideScience

Sample records for quantum-state controlled chemical

  1. Realizing Controllable Quantum States

    Science.gov (United States)

    Takayanagi, Hideaki; Nitta, Junsaku

    -- 4. Mesoscopic superconductivity with unconventional superconductor or ferromagnet. Ultraefficient microrefrigerators realized with ferromagnet-superconductor junctions / F. Giazotto et al. Anomalous charge transport in triplet superconductor junctions by the synergy effect of the proximity effect and the mid gap Andreev resonant states / Y. Tanaka and S. Kashiwaya. Paramagnetic and glass states in superconductive YBa[symbol]Cu[symbol]O[symbol] ceramics of sub-micron scale grains / H. Deguchi et al. Quantum properties of single-domain triplet superconductors / A. M. Gulian and K. S. Wood. A numerical study of Josephson current in p wave superconducting junctions / Y. Asano et al. Tilted bi-crystal sapphire substrates improve properties of grain boundary YBa[symbol]Cu[symbol]O[symbol] junctions and extend their Josephson response to THZ frequencies / E. Stepantsov et al. Circuit theory analysis of AB-plane tunnel junctions of unconventional superconductor Bi[symbol]Sr[symbol]Ca[symbol]Cu[symbol]O[symbol] / I. Shigeta et al. Transport properties of normal metal/anisotropic superconductor junctions in the eutectic system Sr[symbol]RuO[symbol]Ru / M. Kawamura et al. Macroscopic quantum tunneling in d-wave superconductor Josephson / S. Kawabata et al. Quasiparticle states of high-T[symbol] oxides observed by a Zeeman magnetic field response / S. Kashiwaya et al. Experimentally realizable devices for controlling the motion of magnetic flux quanta in anisotropic superconductors: vortex lenses, vortex diodes and vortex pumps / S. Savel'ev and F. Nori. Stability of vortex-antivortex "molecules" in mesoscopic superconducting triangles / V. R. Misko et al. Superconducting network with magnetic decoration - Hofstadter butterfly in spatially modulated magnetic field / Y. Iye et al. Observation of paramagnetic supercurrent in mesoscopic superconducting rings and disks using multiple-small-tunnel-junction method / A. Kanda et al. Guidance of vortices in high

  2. A Scheme of Controlled Quantum State Swapping

    International Nuclear Information System (INIS)

    Zha Xinwei; Zou Zhichun; Qi Jianxia; Song Haiyang

    2012-01-01

    A scheme for controlled quantum state swapping is presented using maximally entangled five-qubit state, i.e., Alice wants to transmit an entangled state of particle a to Bob and at the same time Bob wants to transmit an entangled state of particle b to Alice via the control of the supervisor Charlie. The operations used in this swapping process including C-not operation and a series of single-qubit measurements performed by Alice, Bob, and Charlie.

  3. Quantum state sharing against the controller's cheating

    Science.gov (United States)

    Shi, Run-hua; Zhong, Hong; Huang, Liu-sheng

    2013-08-01

    Most existing QSTS schemes are equivalent to the controlled teleportation, in which a designated agent (i.e., the recoverer) can recover the teleported state with the help of the controllers. However, the controller may attempt to cheat the recoverer during the phase of recovering the secret state. How can we detect this cheating? In this paper, we considered the problem of detecting the controller's cheating in Quantum State Sharing, and further proposed an effective Quantum State Sharing scheme against the controller's cheating. We cleverly use Quantum Secret Sharing, Multiple Quantum States Sharing and decoy-particle techniques. In our scheme, via a previously shared entanglement state Alice can teleport multiple arbitrary multi-qubit states to Bob with the help of Charlie. Furthermore, by the classical information shared previously, Alice and Bob can check whether there is any cheating of Charlie. In addition, our scheme only needs to perform Bell-state and single-particle measurements, and to apply C-NOT gate and other single-particle unitary operations. With the present techniques, it is feasible to implement these necessary measurements and operations.

  4. Controlled teleportation of a 3-dimensional bipartite quantum state

    International Nuclear Information System (INIS)

    Cao Haijing; Chen Zhonghua; Song Heshan

    2008-01-01

    A controlled teleportation scheme of an unknown 3-dimensional (3D) two-particle quantum state is proposed, where a 3D Bell state and 3D GHZ state function as the quantum channel. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional bipartite quantum state

  5. Photodissociation of ultracold diatomic strontium molecules with quantum state control.

    Science.gov (United States)

    McDonald, M; McGuyer, B H; Apfelbeck, F; Lee, C-H; Majewska, I; Moszynski, R; Zelevinsky, T

    2016-07-07

    Chemical reactions at ultracold temperatures are expected to be dominated by quantum mechanical effects. Although progress towards ultracold chemistry has been made through atomic photoassociation, Feshbach resonances and bimolecular collisions, these approaches have been limited by imperfect quantum state selectivity. In particular, attaining complete control of the ground or excited continuum quantum states has remained a challenge. Here we achieve this control using photodissociation, an approach that encodes a wealth of information in the angular distribution of outgoing fragments. By photodissociating ultracold (88)Sr2 molecules with full control of the low-energy continuum, we access the quantum regime of ultracold chemistry, observing resonant and nonresonant barrier tunnelling, matter-wave interference of reaction products and forbidden reaction pathways. Our results illustrate the failure of the traditional quasiclassical model of photodissociation and instead are accurately described by a quantum mechanical model. The experimental ability to produce well-defined quantum continuum states at low energies will enable high-precision studies of long-range molecular potentials for which accurate quantum chemistry models are unavailable, and may serve as a source of entangled states and coherent matter waves for a wide range of experiments in quantum optics.

  6. Control of trapped-ion quantum states with optical pulses

    International Nuclear Information System (INIS)

    Rangan, C.; Monroe, C.; Bucksbaum, P.H.; Bloch, A.M.

    2004-01-01

    We present new results on the quantum control of systems with infinitely large Hilbert spaces. A control-theoretic analysis of the control of trapped-ion quantum states via optical pulses is performed. We demonstrate how resonant bichromatic fields can be applied in two contrasting ways--one that makes the system completely uncontrollable and the other that makes the system controllable. In some interesting cases, the Hilbert space of the qubit-harmonic oscillator can be made finite, and the Schroedinger equation controllable via bichromatic resonant pulses. Extending this analysis to the quantum states of two ions, a new scheme for producing entangled qubits is discovered

  7. Active control of a plasmonic metamaterial for quantum state engineering

    Science.gov (United States)

    Uriri, S. A.; Tashima, T.; Zhang, X.; Asano, M.; Bechu, M.; Güney, D. Ö.; Yamamoto, T.; Özdemir, Ş. K.; Wegener, M.; Tame, M. S.

    2018-05-01

    We experimentally demonstrate the active control of a plasmonic metamaterial operating in the quantum regime. A two-dimensional metamaterial consisting of unit cells made from gold nanorods is investigated. Using an external laser, we control the temperature of the metamaterial and carry out quantum process tomography on single-photon polarization-encoded qubits sent through, characterizing the metamaterial as a variable quantum channel. The overall polarization response can be tuned by up to 33% for particular nanorod dimensions. To explain the results, we develop a theoretical model and find that the experimental results match the predicted behavior well. This work goes beyond the use of simple passive quantum plasmonic systems and shows that external control of plasmonic elements enables a flexible device that can be used for quantum state engineering.

  8. Nonadiabatic quantum state control of many bosons in few wells

    DEFF Research Database (Denmark)

    Tichy, Malte C.; Kock Pedersen, Mads; Mølmer, Klaus

    2013-01-01

    We present a fast scheme for arbitrary unitary control of interacting bosonic atoms in a double well. Assuming fixed interwell tunneling rate and intrawell interaction strength, we control the many-atom state by a discrete sequence of shifts of the single-well energies. For strong interactions......, resonant tunneling transitions implement beam-splitter U(2) rotations among atom number eigenstates, which can be combined and, thus, permit full controllability. By numerically optimizing such sequences of couplings at avoided level crossings, we extend the realm of full controllability to a wide range...... of realistic interaction parameters, while we remain in the simple control space. We demonstrate the efficiency and the high achievable fidelity of our proposal with nonadiabatic population transfer, NOON-state creation, a cnot gate, and a transistorlike, conditional evolution of several atoms....

  9. Quantum Logic Networks for Probabilistic and Controlled Teleportation of Unknown Quantum States

    Institute of Scientific and Technical Information of China (English)

    GAO Ting

    2004-01-01

    We present simplification schemes for probabilistic and controlled teleportation of the unknown quantum states of both one particle and two particles and construct efficient quantum logic networks for implementing the new schemes by means of the primitive operations consisting of single-qubit gates, two-qubit controlled-not gates, Von Neumann measurement, and classically controlled operations. In these schemes the teleportation are not always successful but with certain probability.

  10. Controlled quantum-state transfer in a spin chain

    International Nuclear Information System (INIS)

    Gong, Jiangbin; Brumer, Paul

    2007-01-01

    Control of the transfer of quantum information encoded in quantum wave packets moving along a spin chain is demonstrated. Specifically, based on a relationship with control in a paradigm of quantum chaos, it is shown that wave packets with slow dispersion can automatically emerge from a class of initial superposition states involving only a few spins, and that arbitrary unspecified traveling wave packets can be nondestructively stopped and later relaunched with perfection. The results establish an interesting application of quantum chaos studies in quantum information science

  11. Controllable gaussian-qubit interface for extremal quantum state engineering.

    Science.gov (United States)

    Adesso, Gerardo; Campbell, Steve; Illuminati, Fabrizio; Paternostro, Mauro

    2010-06-18

    We study state engineering through bilinear interactions between two remote qubits and two-mode gaussian light fields. The attainable two-qubit states span the entire physically allowed region in the entanglement-versus-global-purity plane. Two-mode gaussian states with maximal entanglement at fixed global and marginal entropies produce maximally entangled two-qubit states in the corresponding entropic diagram. We show that a small set of parameters characterizing extremally entangled two-mode gaussian states is sufficient to control the engineering of extremally entangled two-qubit states, which can be realized in realistic matter-light scenarios.

  12. Universality in exact quantum state population dynamics and control

    International Nuclear Information System (INIS)

    Wu, Lian-Ao; Segal, Dvira; Brumer, Paul; Egusquiza, Inigo L.

    2010-01-01

    We consider an exact population transition, defined as the probability of finding a state at a final time that is exactly equal to the probability of another state at the initial time. We prove that, given a Hamiltonian, there always exists a complete set of orthogonal states that can be employed as time-zero states for which this exact population transition occurs. The result is general: It holds for arbitrary systems, arbitrary pairs of initial and final states, and for any time interval. The proposition is illustrated with several analytic models. In particular, we demonstrate that in some cases, by tuning the control parameters, a complete transition might occur, where a target state, vacant at t=0, is fully populated at time τ.

  13. Optimal and robust control of quantum state transfer by shaping the spectral phase of ultrafast laser pulses.

    Science.gov (United States)

    Guo, Yu; Dong, Daoyi; Shu, Chuan-Cun

    2018-04-04

    Achieving fast and efficient quantum state transfer is a fundamental task in physics, chemistry and quantum information science. However, the successful implementation of the perfect quantum state transfer also requires robustness under practically inevitable perturbative defects. Here, we demonstrate how an optimal and robust quantum state transfer can be achieved by shaping the spectral phase of an ultrafast laser pulse in the framework of frequency domain quantum optimal control theory. Our numerical simulations of the single dibenzoterrylene molecule as well as in atomic rubidium show that optimal and robust quantum state transfer via spectral phase modulated laser pulses can be achieved by incorporating a filtering function of the frequency into the optimization algorithm, which in turn has potential applications for ultrafast robust control of photochemical reactions.

  14. On-chip generation of high-dimensional entangled quantum states and their coherent control.

    Science.gov (United States)

    Kues, Michael; Reimer, Christian; Roztocki, Piotr; Cortés, Luis Romero; Sciara, Stefania; Wetzel, Benjamin; Zhang, Yanbing; Cino, Alfonso; Chu, Sai T; Little, Brent E; Moss, David J; Caspani, Lucia; Azaña, José; Morandotti, Roberto

    2017-06-28

    Optical quantum states based on entangled photons are essential for solving questions in fundamental physics and are at the heart of quantum information science. Specifically, the realization of high-dimensional states (D-level quantum systems, that is, qudits, with D > 2) and their control are necessary for fundamental investigations of quantum mechanics, for increasing the sensitivity of quantum imaging schemes, for improving the robustness and key rate of quantum communication protocols, for enabling a richer variety of quantum simulations, and for achieving more efficient and error-tolerant quantum computation. Integrated photonics has recently become a leading platform for the compact, cost-efficient, and stable generation and processing of non-classical optical states. However, so far, integrated entangled quantum sources have been limited to qubits (D = 2). Here we demonstrate on-chip generation of entangled qudit states, where the photons are created in a coherent superposition of multiple high-purity frequency modes. In particular, we confirm the realization of a quantum system with at least one hundred dimensions, formed by two entangled qudits with D = 10. Furthermore, using state-of-the-art, yet off-the-shelf telecommunications components, we introduce a coherent manipulation platform with which to control frequency-entangled states, capable of performing deterministic high-dimensional gate operations. We validate this platform by measuring Bell inequality violations and performing quantum state tomography. Our work enables the generation and processing of high-dimensional quantum states in a single spatial mode.

  15. Controlled teleportation of high-dimension quantum-states with generalized Bell-state measurement

    Institute of Scientific and Technical Information of China (English)

    Zhan You-Bang

    2007-01-01

    In this paper a scheme for controlled teleportation of arbitrary high-dimensional unknown quantum states is proposed by using the generalized Bell-basis measurement and the generalized Hadamard transformation. As two special cases, two schemes of controlled teleportation of an unknown single-qutrit state and an unknown two-qutrit state are investigated in detail. In the first scheme, a maximally entangled three-qutrit state is used as the quantum channel, while in the second scheme, an entangled two-qutrit state and an entangled three-qutrit state are employed as the quantum channels. In these schemes, an unknown qutrit state can be teleported to either one of two receivers, but only one of them can reconstruct the qutrit state with the help of the other. Based on the case of qutrits, a scheme of controlled teleportation of an unknown qudit state is presented.

  16. Polarization control of spontaneous emission for rapid quantum-state initialization

    Science.gov (United States)

    DiLoreto, C. S.; Rangan, C.

    2017-04-01

    We propose an efficient method to selectively enhance the spontaneous emission rate of a quantum system by changing the polarization of an incident control field, and exploiting the polarization dependence of the system's spontaneous emission rate. This differs from the usual Purcell enhancement of spontaneous emission rates as it can be selectively turned on and off. Using a three-level Λ system in a quantum dot placed in between two silver nanoparticles and a linearly polarized, monochromatic driving field, we present a protocol for rapid quantum state initialization, while maintaining long coherence times for control operations. This process increases the overall amount of time that a quantum system can be effectively utilized for quantum operations, and presents a key advance in quantum computing.

  17. Heat-machine control by quantum-state preparation: from quantum engines to refrigerators.

    Science.gov (United States)

    Gelbwaser-Klimovsky, D; Kurizki, G

    2014-08-01

    We explore the dependence of the performance bounds of heat engines and refrigerators on the initial quantum state and the subsequent evolution of their piston, modeled by a quantized harmonic oscillator. Our goal is to provide a fully quantized treatment of self-contained (autonomous) heat machines, as opposed to their prevailing semiclassical description that consists of a quantum system alternately coupled to a hot or a cold heat bath and parametrically driven by a classical time-dependent piston or field. Here, by contrast, there is no external time-dependent driving. Instead, the evolution is caused by the stationary simultaneous interaction of two heat baths (having distinct spectra and temperatures) with a single two-level system that is in turn coupled to the quantum piston. The fully quantized treatment we put forward allows us to investigate work extraction and refrigeration by the tools of quantum-optical amplifier and dissipation theory, particularly, by the analysis of amplified or dissipated phase-plane quasiprobability distributions. Our main insight is that quantum states may be thermodynamic resources and can provide a powerful handle, or control, on the efficiency of the heat machine. In particular, a piston initialized in a coherent state can cause the engine to produce work at an efficiency above the Carnot bound in the linear amplification regime. In the refrigeration regime, the coefficient of performance can transgress the Carnot bound if the piston is initialized in a Fock state. The piston may be realized by a vibrational mode, as in nanomechanical setups, or an electromagnetic field mode, as in cavity-based scenarios.

  18. Uhrig dynamical control of a three-level system via non-Markovian quantum state diffusion

    International Nuclear Information System (INIS)

    Shu, Wenchong; Zhao, Xinyu; Jing, Jun; Yu, Ting; Wu, Lian-Ao

    2013-01-01

    In this paper, we use the quantum state diffusion (QSD) equation to implement the Uhrig dynamical decoupling to a three-level quantum system coupled to a non-Markovian reservoir comprising of infinite numbers of degrees of freedom. For this purpose, we first reformulate the non-Markovian QSD to incorporate the effect of the external control fields. With this stochastic QSD approach, we demonstrate that an unknown state of the three-level quantum system can be universally protected against both coloured phase and amplitude noises when the control-pulse sequences and control operators are properly designed. The advantage of using non-Markovian QSD equations is that the control dynamics of open quantum systems can be treated exactly without using Trotter product formula and be efficiently simulated even when the environment is comprised of infinite numbers of degrees of freedom. We also show how the control efficacy depends on the environment memory time and the designed time points of applied control pulses. (paper)

  19. Controlled teleportation of a multipartite quantum state via driven QED cavity

    International Nuclear Information System (INIS)

    Cao Haijing; Song Heshan

    2007-01-01

    We propose a scheme for teleporting a multipartite quantum state via driven QED cavity technologies. The combined state of Bell states is employed as a quantum channel. By adopting QED cavity technologies, our scheme does not involve the Bell-state measurements and can be perfectly realized by communicators' single particle measurements, possible C-not transformation and classical communication. The probability of successful teleportation can reach 1.0. The theoretical scheme is experimentally feasible via current technologies

  20. All optical quantum control of a spin-quantum state and ultrafast transduction into an electric current.

    Science.gov (United States)

    Müller, K; Kaldewey, T; Ripszam, R; Wildmann, J S; Bechtold, A; Bichler, M; Koblmüller, G; Abstreiter, G; Finley, J J

    2013-01-01

    The ability to control and exploit quantum coherence and entanglement drives research across many fields ranging from ultra-cold quantum gases to spin systems in condensed matter. Transcending different physical systems, optical approaches have proven themselves to be particularly powerful, since they profit from the established toolbox of quantum optical techniques, are state-selective, contact-less and can be extremely fast. Here, we demonstrate how a precisely timed sequence of monochromatic ultrafast (~ 2-5 ps) optical pulses, with a well defined polarisation can be used to prepare arbitrary superpositions of exciton spin states in a semiconductor quantum dot, achieve ultrafast control of the spin-wavefunction without an applied magnetic field and make high fidelity read-out the quantum state in an arbitrary basis simply by detecting a strong (~ 2-10 pA) electric current flowing in an external circuit. The results obtained show that the combined quantum state preparation, control and read-out can be performed with a near-unity (≥97%) fidelity.

  1. Controllable Quantum States Mesoscopic Superconductivity and Spintronics (MS+S2006)

    Science.gov (United States)

    Takayanagi, Hideaki; Nitta, Junsaku; Nakano, Hayato

    2008-10-01

    distance on the magnetization configuration of submicron-sized ferromagnetic rings / Tetsuya Miyawaki. A wide GaAs/GaAlAs quantum well simultaneously containing two dimensional electrons and holes / Ane Jensen. Simulation of the photon-spin quantum state transfer process / Yoshiaki Rikitake. Magnetotransport in two-dimensional electron gases on cylindrical surface / Friedland Klaus-Juergen. Full counting statistics for a single-electron transistor at intermediate conductance / Yasuhiro Utsumi. Creation of spin-polarized current using quantum point contacts and its detection / Mikio Eto. Density dependent electron effective mass in a back-gated quantum well / S. Nomura. The supersymmetric sigma formula and metal-insulator transition in diluted magnetic semiconductors / I. Kanazawa. Spin-photovoltaic effect in quantum wires / A. Fedorov -- Quantum interference. Nonequilibrium transport in Aharonov-Bohm interferometer with electron-phonon interaction / Akiko Ueda. Fano resonance and its breakdown in AB ring embedded with a molecule / Shigeo Fujimoto, Yuhei Natsume. Quantum resonance above a barrier in the presence of dissipation / Kohkichi Konno. Ensemble averaging in metallic quantum networks / F. Mallet -- Coherence and order in exotic materials. Progress towards an electronic array on liquid helium / David Rees. Measuring noise and cross correlations at high frequencies in nanophysics / T. Martin. Single wall carbon nanotube weak links / K. Grove-Rasmussen. Optical preparation of nuclear spins coupled to a localized electron spin / Guido Burkard. Topological effects in charge density wave dynamics / Toru Matsuura. Studies on nanoscale charge-density-wave systems: fabrication technique and transport phenomena / Katsuhiko Inagaki. Anisotropic behavior of hysteresis induced by the in-plane field in the v = 2/3 quantum Hall state / Kazuki Iwata. Phase diagram of the v = 2 bilayer quantum Hall state / Akira Fukuda -- Trapped ions (special talk). Quantum computation with trapped

  2. Optimal control of fast and high-fidelity quantum state transfer in spin-1/2 chains

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiong-Peng [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Shao, Bin, E-mail: sbin610@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Hu, Shuai; Zou, Jian [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Wu, Lian-Ao [Department of Theoretical Physics and History of Science, The Basque Country University (EHU/UPV), PO Box 644, 48080 Bilbao (Spain); Ikerbasque, Basque Foundation for Science, 48011 Bilbao (Spain)

    2016-12-15

    Spin chains are promising candidates for quantum communication and computation. Using quantum optimal control (OC) theory based on the Krotov method, we present a protocol to perform quantum state transfer with fast and high fidelity by only manipulating the boundary spins in a quantum spin-1/2 chain. The achieved speed is about one order of magnitude faster than that is possible in the Lyapunov control case for comparable fidelities. Additionally, it has a fundamental limit for OC beyond which optimization is not possible. The controls are exerted only on the couplings between the boundary spins and their neighbors, so that the scheme has good scalability. We also demonstrate that the resulting OC scheme is robust against disorder in the chain.

  3. Quantum-state discrimination

    International Nuclear Information System (INIS)

    Roa, Luis; Retamal, Juan Carlos; Saavedra, Carlos

    2002-01-01

    A proposal for a physical implementation of a quantum-state discrimination protocol using an ion in a linear trap is studied, where two nonorthogonal quantum states are codified using two electronic states of the ion. In addition, a protocol is given for discriminating superpositions of nonorthogonal entangled states between ions inside widely separated optical cavities. The discrimination protocol is extended to the case of N linearly independent nonorthogonal quantum states lying in a space of 2N-1 dimensions

  4. Metrics of quantum states

    International Nuclear Information System (INIS)

    Ma Zhihao; Chen Jingling

    2011-01-01

    In this work we study metrics of quantum states, which are natural generalizations of the usual trace metric and Bures metric. Some useful properties of the metrics are proved, such as the joint convexity and contractivity under quantum operations. Our result has a potential application in studying the geometry of quantum states as well as the entanglement detection.

  5. Threshold quantum state sharing based on entanglement swapping

    Science.gov (United States)

    Qin, Huawang; Tso, Raylin

    2018-06-01

    A threshold quantum state sharing scheme is proposed. The dealer uses the quantum-controlled-not operations to expand the d-dimensional quantum state and then uses the entanglement swapping to distribute the state to a random subset of participants. The participants use the single-particle measurements and unitary operations to recover the initial quantum state. In our scheme, the dealer can share different quantum states among different subsets of participants simultaneously. So the scheme will be very flexible in practice.

  6. Quantum states of light

    CERN Document Server

    Furusawa, Akira

    2015-01-01

    This book explains what quantum states of light look like. Of special interest, a single photon state is explained by using a wave picture, showing that it corresponds to the complementarity of a quantum. Also explained is how light waves are created by photons, again corresponding to the complementarity of a quantum. The author shows how an optical wave is created by superposition of a "vacuum" and a single photon as a typical example. Moreover, squeezed states of light are explained as "longitudinal" waves of light and Schrödinger's cat states as macroscopic superposition states.

  7. Geometry of Quantum States

    International Nuclear Information System (INIS)

    Hook, D W

    2008-01-01

    A geometric framework for quantum mechanics arose during the mid 1970s when authors such as Cantoni explored the notion of generalized transition probabilities, and Kibble promoted the idea that the space of pure quantum states provides a natural quantum mechanical analogue for classical phase space. This central idea can be seen easily since the projection of Schroedinger's equation from a Hilbert space into the space of pure spaces is a set of Hamilton's equations. Over the intervening years considerable work has been carried out by a variety of authors and a mature description of quantum mechanics in geometric terms has emerged with many applications. This current offering would seem ideally placed to review the last thirty years of progress and relate this to the most recent work in quantum entanglement. Bengtsson and Zyczkowski's beautifully illustrated volume, Geometry of Quantum States (referred to as GQS from now on) attempts to cover considerable ground in its 466 pages. Its topics range from colour theory in Chapter 1 to quantum entanglement in Chapter 15-to say that this is a whirlwind tour is, perhaps, no understatement. The use of the work 'introduction' in the subtitle of GQS, might suggest to the reader that this work be viewed as a textbook and I think that this interpretation would be incorrect. The authors have chosen to present a survey of different topics with the specific aim to introduce entanglement in geometric terms-the book is not intended as a pedagogical introduction to the geometric approach to quantum mechanics. Each of the fifteen chapters is a short, and mostly self-contained, essay on a particular aspect or application of geometry in the context of quantum mechanics with entanglement being addressed specifically in the final chapter. The chapters fall into three classifications: those concerned with the mathematical background, those which discuss quantum theory and the foundational aspects of the geometric framework, and

  8. Set discrimination of quantum states

    International Nuclear Information System (INIS)

    Zhang Shengyu; Ying Mingsheng

    2002-01-01

    We introduce a notion of set discrimination, which is an interesting extension of quantum state discrimination. A state is secretly chosen from a number of quantum states, which are partitioned into some disjoint sets. A set discrimination is required to identify which set the given state belongs to. Several essential problems are addressed in this paper, including the condition of perfect set discrimination, unambiguous set discrimination, and in the latter case, the efficiency of the discrimination. This generalizes some important results on quantum state discrimination in the literature. A combination of state and set discrimination and the efficiency are also studied

  9. Symmetric extendibility of quantum states

    OpenAIRE

    Nowakowski, Marcin L.

    2015-01-01

    Studies on symmetric extendibility of quantum states become especially important in a context of analysis of one-way quantum measures of entanglement, distilabillity and security of quantum protocols. In this paper we analyse composite systems containing a symmetric extendible part with a particular attention devoted to one-way security of such systems. Further, we introduce a new one-way monotone based on the best symmetric approximation of quantum state. We underpin those results with geome...

  10. Quantum state transfer with untunable couplings

    International Nuclear Information System (INIS)

    Gagnebin, P. K.; Skinner, S. R.; Behrman, E. C.; Steck, J. E.

    2007-01-01

    We present a general scheme for implementing bidirectional quantum state transfer in a quantum swapping channel. Unlike many other schemes for quantum computation and communication, our method does not require qubit couplings to be switched on and off. The only control variable is the bias acting on individual qubits. We show how to derive the parameters of the system (fixed and variable) such that perfect state transfer can be achieved. Since these parameters vary linearly with the pulse width, our scheme allows flexibility in the time scales under which qubits evolve. Unlike quantum spin networks, our scheme allows the transmission of several quantum states at a time, requiring only a two qubit separation between quantum states. By pulsing the biases of several qubits at the same time, we show that only eight bias control lines are required to achieve state transfer along a channel of arbitrary length. Furthermore, when the information to be transferred is purely classical in nature, only three bias control lines are required, greatly simplifying the circuit complexity

  11. Quantum States as Ordinary Information

    Directory of Open Access Journals (Sweden)

    Ken Wharton

    2014-03-01

    Full Text Available Despite various parallels between quantum states and ordinary information, quantum no-go-theorems have convinced many that there is no realistic framework that might underly quantum theory, no reality that quantum states can represent knowledge about. This paper develops the case that there is a plausible underlying reality: one actual spacetime-based history, although with behavior that appears strange when analyzed dynamically (one time-slice at a time. By using a simple model with no dynamical laws, it becomes evident that this behavior is actually quite natural when analyzed “all-at-once” (as in classical action principles. From this perspective, traditional quantum states would represent incomplete information about possible spacetime histories, conditional on the future measurement geometry. Without dynamical laws imposing additional restrictions, those histories can have a classical probability distribution, where exactly one history can be said to represent an underlying reality.

  12. Statistical representation of quantum states

    Energy Technology Data Exchange (ETDEWEB)

    Montina, A [Dipartimento di Fisica, Universita di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy)

    2007-05-15

    In the standard interpretation of quantum mechanics, the state is described by an abstract wave function in the representation space. Conversely, in a realistic interpretation, the quantum state is replaced by a probability distribution of physical quantities. Bohm mechanics is a consistent example of realistic theory, where the wave function and the particle positions are classically defined quantities. Recently, we proved that the probability distribution in a realistic theory cannot be a quadratic function of the quantum state, in contrast to the apparently obvious suggestion given by the Born rule for transition probabilities. Here, we provide a simplified version of this proof.

  13. Criteria for reachability of quantum states

    Energy Technology Data Exchange (ETDEWEB)

    Schirmer, S.G.; Solomon, A.I. [Quantum Processes Group and Department of Applied Maths, Open University, Milton Keynes (United Kingdom)]. E-mails: S.G.Schirmer@open.ac.uk; A.I.Solomon@open.ac.uk; Leahy, J.V. [Department of Mathematics and Institute of Theoretical Science, University of Oregon, Eugene, OR (United States)]. E-mail: leahy@math.uoregon.edu

    2002-10-11

    We address the question of which quantum states can be inter-converted under the action of a time-dependent Hamiltonian. In particular, we consider the problem as applied to mixed states, and investigate the difference between pure- and mixed-state controllabilities introduced in previous work. We provide a complete characterization of the eigenvalue spectrum for which the state is controllable under the action of the symplectic group. We also address the problem of which states can be prepared if the dynamical Lie group is not sufficiently large to allow the system to be controllable. (author)

  14. Quantum State Description Complexity (Invited Talk)

    OpenAIRE

    Vazirani, Umesh V.

    2011-01-01

    Quantum states generally require exponential sized classical descriptions, but the long conjectured area law provides hope that a large class of natural quantum states can be described succinctly. Recent progress in formally proving the area law is described.

  15. Quantum States Transfer by Analogous Bell States

    International Nuclear Information System (INIS)

    Mei Di; Li Chong; Yang Guohui; Song Heshan

    2008-01-01

    Transmitting quantum states by channels of analogous Bell states is studied in this paper. We analyze the transmitting process, constructed the probabilitic unitary operator, and gain the largest successful transfer quantum state probability.

  16. Quantum state of the multiverse

    OpenAIRE

    Robles Pérez, Salvador; González-Díaz, Pedro F.

    2010-01-01

    A third quantization formalism is applied to a simplified multiverse scenario. A well-defined quantum state of the multiverse is obtained which agrees with standard boundary condition proposals. These states are found to be squeezed, and related to accelerating universes: they share similar properties to those obtained previously by Grishchuk and Siderov. We also comment on related works that have criticized the third quantization approach. © 2010 The American Physical Society.

  17. Quantum state of the multiverse

    International Nuclear Information System (INIS)

    Robles-Perez, Salvador; Gonzalez-Diaz, Pedro F.

    2010-01-01

    A third quantization formalism is applied to a simplified multiverse scenario. A well-defined quantum state of the multiverse is obtained which agrees with standard boundary condition proposals. These states are found to be squeezed, and related to accelerating universes: they share similar properties to those obtained previously by Grishchuk and Siderov. We also comment on related works that have criticized the third quantization approach.

  18. Engineering arbitrary pure and mixed quantum states

    International Nuclear Information System (INIS)

    Pechen, Alexander

    2011-01-01

    Controlled manipulation by atomic- and molecular-scale quantum systems has attracted a lot of research attention in recent years. A fundamental problem is to provide deterministic methods for controlled engineering of arbitrary quantum states. This work proposes a deterministic method for engineering arbitrary pure and mixed states of a wide class of quantum systems. The method exploits a special combination of incoherent and coherent controls (incoherent and coherent radiation) and has two properties which are specifically important for manipulating by quantum systems: it realizes the strongest possible degree of their state control, complete density matrix controllability, meaning the ability to steer arbitrary pure and mixed initial states into any desired pure or mixed final state, and it is all-to-one, such that each particular control transfers all initial system states into one target state.

  19. Multipartite fully nonlocal quantum states

    International Nuclear Information System (INIS)

    Almeida, Mafalda L.; Cavalcanti, Daniel; Scarani, Valerio; Acin, Antonio

    2010-01-01

    We present a general method for characterizing the quantum correlations obtained after local measurements on multipartite systems. Sufficient conditions for a quantum system to be fully nonlocal according to a given partition, as well as being (genuinely) multipartite fully nonlocal, are derived. These conditions allow us to identify all completely connected graph states as multipartite fully nonlocal quantum states. Moreover, we show that this feature can also be observed in mixed states: the tensor product of five copies of the Smolin state, a biseparable and bound entangled state, is multipartite fully nonlocal.

  20. Multiparty Quantum Secret Sharing of Quantum States Using Entanglement States

    International Nuclear Information System (INIS)

    Ying, Guo; Da-Zu, Huang; Gui-Hua, Zeng; Ho, Lee Moon

    2008-01-01

    A multi-partite-controlled quantum secret sharing scheme using several non-orthogonal entanglement states is presented with unconditional security. In this scheme, the participants share the secret quantum state by exchanging the secret polarization angles of the disordered travel particles. The security of the secret quantum state is also guaranteed by the non-orthogonal multi-partite-controlled entanglement states, the participants' secret polarizations, and the disorder of the travelling particles. Moreover, the present scheme is secure against the particle-number splitting attack and the intercept-and-resend attack. It may be still secure even if the distributed quantum state is embedded in a not-so-weak coherent-state pulse

  1. Control in the Chemical Industry

    Science.gov (United States)

    Jones, R. G.

    1974-01-01

    Discusses various control techniques used in chemical processes, including measuring devices, controller functions, control valves, and feedforward and feedback actions. Applications of control to a real chemical plant are exemplified. (CC)

  2. Global Controllability of Chemical Reactions

    OpenAIRE

    Drexler, Dániel András; Tóth, János

    2015-01-01

    Controllability of chemical reactions is an important problem in chemical engineering science. In control theory, analysis of the controllability of linear systems is well-founded, however the dynamics of chemical reactions is usually nonlinear. Global controllability properties of chemical reactions are analyzed here based on the Lie-algebra of the vector fields associated to elementary reactions. A chemical reaction is controllable almost everywhere if all the reaction rate coefficients can...

  3. Quantum state discrimination and its applications

    International Nuclear Information System (INIS)

    Bae, Joonwoo; Kwek, Leong-Chuan

    2015-01-01

    Quantum state discrimination underlies various applications in quantum information processing tasks. It essentially describes the distinguishability of quantum systems in different states, and the general process of extracting classical information from quantum systems. It is also useful in quantum information applications, such as the characterization of mutual information in cryptographic protocols, or as a technique for deriving fundamental theorems on quantum foundations. It has deep connections to physical principles such as relativistic causality. Quantum state discrimination traces a long history of several decades, starting with the early attempts to formalize information processing of physical systems such as optical communication with photons. Nevertheless, in most cases, the problems of finding optimal strategies of quantum state discrimination remain unsolved, and related applications are valid in some limited cases only. The present review aims to provide an overview on quantum state discrimination, covering some recent progress, and addressing applications in some selected areas. This review serves to strengthen the link between results in quantum state discrimination and quantum information applications, by showing the ways in which the fundamental results are exploited in applications and vice versa. (topical review)

  4. Chemical Control of Plant Growth.

    Science.gov (United States)

    Agricultural Research Center (USDA), Beltsville, MD.

    Seven experiments are presented in this Science Study Aid to help students investigate the control of plant growth with chemicals. Plant growth regulators, weed control, and chemical pruning are the topics studied in the experiments which are based on investigations that have been and are being conducted at the U. S. Agricultural Research Center,…

  5. Past Quantum States of a Monitored System

    DEFF Research Database (Denmark)

    Gammelmark, Søren; Julsgaard, Brian; Mølmer, Klaus

    2013-01-01

    A density matrix ρ(t) yields probabilistic information about the outcome of measurements on a quantum system. We introduce here the past quantum state, which, at time T, accounts for the state of a quantum system at earlier times t...(t) and E(t), conditioned on the dynamics and the probing of the system until t and in the time interval [t, T], respectively. The past quantum state is characterized by its ability to make better predictions for the unknown outcome of any measurement at t than the conventional quantum state at that time....... On the one hand, our formalism shows how smoothing procedures for estimation of past classical signals by a quantum probe [M. Tsang, Phys. Rev. Lett. 102 250403 (2009)] apply also to describe the past state of the quantum system itself. On the other hand, it generalizes theories of pre- and postselected...

  6. Quantum correlations and distinguishability of quantum states

    Energy Technology Data Exchange (ETDEWEB)

    Spehner, Dominique [Université Grenoble Alpes and CNRS, Institut Fourier, F-38000 Grenoble, France and Laboratoire de Physique et Modélisation des Milieux Condensés, F-38000 Grenoble (France)

    2014-07-15

    A survey of various concepts in quantum information is given, with a main emphasis on the distinguishability of quantum states and quantum correlations. Covered topics include generalized and least square measurements, state discrimination, quantum relative entropies, the Bures distance on the set of quantum states, the quantum Fisher information, the quantum Chernoff bound, bipartite entanglement, the quantum discord, and geometrical measures of quantum correlations. The article is intended both for physicists interested not only by collections of results but also by the mathematical methods justifying them, and for mathematicians looking for an up-to-date introductory course on these subjects, which are mainly developed in the physics literature.

  7. Quantum correlations and distinguishability of quantum states

    International Nuclear Information System (INIS)

    Spehner, Dominique

    2014-01-01

    A survey of various concepts in quantum information is given, with a main emphasis on the distinguishability of quantum states and quantum correlations. Covered topics include generalized and least square measurements, state discrimination, quantum relative entropies, the Bures distance on the set of quantum states, the quantum Fisher information, the quantum Chernoff bound, bipartite entanglement, the quantum discord, and geometrical measures of quantum correlations. The article is intended both for physicists interested not only by collections of results but also by the mathematical methods justifying them, and for mathematicians looking for an up-to-date introductory course on these subjects, which are mainly developed in the physics literature

  8. Interpreting quantum discord through quantum state merging

    International Nuclear Information System (INIS)

    Madhok, Vaibhav; Datta, Animesh

    2011-01-01

    We present an operational interpretation of quantum discord based on the quantum state merging protocol. Quantum discord is the markup in the cost of quantum communication in the process of quantum state merging, if one discards relevant prior information. Our interpretation has an intuitive explanation based on the strong subadditivity of von Neumann entropy. We use our result to provide operational interpretations of other quantities like the local purity and quantum deficit. Finally, we discuss in brief some instances where our interpretation is valid in the single-copy scenario.

  9. The symmetric extendibility of quantum states

    International Nuclear Information System (INIS)

    Nowakowski, Marcin L

    2016-01-01

    Studies on the symmetric extendibility of quantum states have become particularly important in the context of the analysis of one-way quantum measures of entanglement, and the distillability and security of quantum protocols. In this paper we analyze composite systems containing a symmetric extendible part, with particular attention devoted to the one-way security of such systems. Further, we introduce a new one-way entanglement monotone based on the best symmetric approximation of a quantum state and the extendible number of a quantum state. We underpin these results with geometric observations about the structures of multi-party settings which posses substantial symmetric extendible components in their subspaces. The impossibility of reducing the maximal symmetric extendibility by means of the one-way local operations and classical communication method is pointed out on multiple copies. Finally, we state a conjecture linking symmetric extendibility with the one-way distillability and security of all quantum states, analyzing the behavior of a private key in the neighborhood of symmetric extendible states. (paper)

  10. Unambiguous discrimination of mixed quantum states

    International Nuclear Information System (INIS)

    Zhang Chi; Feng Yuan; Ying Mingsheng

    2006-01-01

    The problem of unambiguous discrimination between mixed quantum states is addressed by isolating the part of each mixed state which has no contribution to discrimination and by employing the strategy of set discrimination of pure states. A necessary and sufficient condition of unambiguous mixed state discrimination is presented. An upper bound of the efficiency is also derived

  11. Preparation of freezing quantum state for quantum coherence

    Science.gov (United States)

    Yang, Lian-Wu; Man, Zhong-Xiao; Zhang, Ying-Jie; Han, Feng; Du, Shao-jiang; Xia, Yun-Jie

    2018-06-01

    We provide a method to prepare the freezing quantum state for quantum coherence via unitary operations. The initial product state consists of the control qubit and target qubit; when it satisfies certain conditions, the initial product state converts into the particular Bell diagonal state under the unitary operations, which have the property of freezing of quantum coherence under quantum channels. We calculate the frozen quantum coherence and corresponding quantum correlations, and find that the quantities are determined by the control qubit only when the freezing phenomena occur.

  12. Chemical control methods and tools

    Science.gov (United States)

    Steven Manning; James. Miller

    2011-01-01

    After determining the best course of action for control of an invasive plant population, it is important to understand the variety of methods available to the integrated pest management professional. A variety of methods are now widely used in managing invasive plants in natural areas, including chemical, mechanical, and cultural control methods. Once the preferred...

  13. Introduction to quantum-state estimation

    CERN Document Server

    Teo, Yong Siah

    2016-01-01

    Quantum-state estimation is an important field in quantum information theory that deals with the characterization of states of affairs for quantum sources. This book begins with background formalism in estimation theory to establish the necessary prerequisites. This basic understanding allows us to explore popular likelihood- and entropy-related estimation schemes that are suitable for an introductory survey on the subject. Discussions on practical aspects of quantum-state estimation ensue, with emphasis on the evaluation of tomographic performances for estimation schemes, experimental realizations of quantum measurements and detection of single-mode multi-photon sources. Finally, the concepts of phase-space distribution functions, which compatibly describe these multi-photon sources, are introduced to bridge the gap between discrete and continuous quantum degrees of freedom. This book is intended to serve as an instructive and self-contained medium for advanced undergraduate and postgraduate students to gra...

  14. Neural-network quantum state tomography

    Science.gov (United States)

    Torlai, Giacomo; Mazzola, Guglielmo; Carrasquilla, Juan; Troyer, Matthias; Melko, Roger; Carleo, Giuseppe

    2018-05-01

    The experimental realization of increasingly complex synthetic quantum systems calls for the development of general theoretical methods to validate and fully exploit quantum resources. Quantum state tomography (QST) aims to reconstruct the full quantum state from simple measurements, and therefore provides a key tool to obtain reliable analytics1-3. However, exact brute-force approaches to QST place a high demand on computational resources, making them unfeasible for anything except small systems4,5. Here we show how machine learning techniques can be used to perform QST of highly entangled states with more than a hundred qubits, to a high degree of accuracy. We demonstrate that machine learning allows one to reconstruct traditionally challenging many-body quantities—such as the entanglement entropy—from simple, experimentally accessible measurements. This approach can benefit existing and future generations of devices ranging from quantum computers to ultracold-atom quantum simulators6-8.

  15. Observability of Quantum State of Black Hole

    CERN Document Server

    David, J R; Mandal, G; Wadia, S R; David, Justin R.; Dhar, Avinash; Mandal, Gautam; Wadia, Spenta R.

    1997-01-01

    We analyze terms subleading to Rutherford in the $S$-matrix between black hole and probes of successively high energies. We show that by an appropriate choice of the probe one can read off the quantum state of the black hole from the S-matrix, staying asymptotically far from the BH all the time. We interpret the scattering experiment as scattering off classical stringy backgrounds which explicitly depend on the internal quantum numbers of the black hole.

  16. Fidelity induced distance measures for quantum states

    International Nuclear Information System (INIS)

    Ma Zhihao; Zhang Fulin; Chen Jingling

    2009-01-01

    Fidelity plays an important role in quantum information theory. In this Letter, we introduce new metric of quantum states induced by fidelity, and connect it with the well-known trace metric, Sine metric and Bures metric for the qubit case. The metric character is also presented for the qudit (i.e., d-dimensional system) case. The CPT contractive property and joint convex property of the metric are also studied.

  17. Optimal control for chemical engineers

    CERN Document Server

    Upreti, Simant Ranjan

    2013-01-01

    Optimal Control for Chemical Engineers gives a detailed treatment of optimal control theory that enables readers to formulate and solve optimal control problems. With a strong emphasis on problem solving, the book provides all the necessary mathematical analyses and derivations of important results, including multiplier theorems and Pontryagin's principle.The text begins by introducing various examples of optimal control, such as batch distillation and chemotherapy, and the basic concepts of optimal control, including functionals and differentials. It then analyzes the notion of optimality, de

  18. Chemical control of flowering time

    DEFF Research Database (Denmark)

    Ionescu, Irina Alexandra; Møller, Birger Lindberg; Sánchez Pérez, Raquel

    2017-01-01

    Flowering at the right time is of great importance; it secures seed production and therefore species survival and crop yield. In addition to the genetic network controlling flowering time, there are a number of much less studied metabolites and exogenously applied chemicals that may influence...... on the genetic aspects of flowering time regulation in annuals, but less so in perennials. An alternative to plant breeding approaches is to engineer flowering time chemically via the external application of flower-inducing compounds. This review discusses a variety of exogenously applied compounds used in fruit...

  19. Quantum state of the black hole interior

    International Nuclear Information System (INIS)

    Brustein, Ram; Medved, A.J.M.

    2015-01-01

    If a black hole (BH) is initially in an approximately pure state and it evaporates by a unitary process, then the emitted radiation will be in a highly quantum state. As the purifier of this radiation, the state of the BH interior must also be in some highly quantum state. So that, within the interior region, the mean-field approximation cannot be valid and the state of the BH cannot be described by some semiclassical metric. On this basis, we model the state of the BH interior as a collection of a large number of excitations that are packed into closely spaced but single-occupancy energy levels; a sort-of “Fermi sea” of all light-enough particles. This highly quantum state is surrounded by a semiclassical region that lies close to the horizon and has a non-vanishing energy density. It is shown that such a state looks like a BH from the outside and decays via gravitational pair production in the near-horizon region at a rate that agrees with the Hawking rate. We also consider the fate of a classical object that has passed through to the BH interior and show that, once it has crossed over the near-horizon threshold, the object meets its demise extremely fast. This result cannot be attributed to a “firewall”, as the trauma to the in-falling object only begins after it has passed through the near-horizon region and enters a region where semiclassical spacetime ends but the energy density is still parametrically smaller than Planckian.

  20. Quantum state transfer and network engineering

    CERN Document Server

    Nikolopoulos, Georgios M

    2013-01-01

    Faithful communication is a necessary precondition for large-scale quantum information processing and networking, irrespective of the physical platform. Thus, the problems of quantum-state transfer and quantum-network engineering have attracted enormous interest over the last years, and constitute one of the most active areas of research in quantum information processing. The present volume introduces the reader to fundamental concepts and various aspects of this exciting research area, including links to other related areas and problems. The implementation of state-transfer schemes and the en

  1. Locking classical correlations in quantum States.

    Science.gov (United States)

    DiVincenzo, David P; Horodecki, Michał; Leung, Debbie W; Smolin, John A; Terhal, Barbara M

    2004-02-13

    We show that there exist bipartite quantum states which contain a large locked classical correlation that is unlocked by a disproportionately small amount of classical communication. In particular, there are (2n+1)-qubit states for which a one-bit message doubles the optimal classical mutual information between measurement results on the subsystems, from n/2 bits to n bits. This phenomenon is impossible classically. However, states exhibiting this behavior need not be entangled. We study the range of states exhibiting this phenomenon and bound its magnitude.

  2. Wigner tomography of multispin quantum states

    Science.gov (United States)

    Leiner, David; Zeier, Robert; Glaser, Steffen J.

    2017-12-01

    We study the tomography of multispin quantum states in the context of finite-dimensional Wigner representations. An arbitrary operator can be completely characterized and visualized using multiple shapes assembled from linear combinations of spherical harmonics [A. Garon, R. Zeier, and S. J. Glaser, Phys. Rev. A 91, 042122 (2015), 10.1103/PhysRevA.91.042122]. We develop a general methodology to experimentally recover these shapes by measuring expectation values of rotated axial spherical tensor operators and provide an interpretation in terms of fictitious multipole potentials. Our approach is experimentally demonstrated for quantum systems consisting of up to three spins using nuclear magnetic resonance spectroscopy.

  3. Majorization uncertainty relations for mixed quantum states

    Science.gov (United States)

    Puchała, Zbigniew; Rudnicki, Łukasz; Krawiec, Aleksandra; Życzkowski, Karol

    2018-04-01

    Majorization uncertainty relations are generalized for an arbitrary mixed quantum state ρ of a finite size N. In particular, a lower bound for the sum of two entropies characterizing the probability distributions corresponding to measurements with respect to two arbitrary orthogonal bases is derived in terms of the spectrum of ρ and the entries of a unitary matrix U relating both bases. The results obtained can also be formulated for two measurements performed on a single subsystem of a bipartite system described by a pure state, and consequently expressed as an uncertainty relation for the sum of conditional entropies.

  4. Single-Atom Gating of Quantum State Superpositions

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Christopher

    2010-04-28

    The ultimate miniaturization of electronic devices will likely require local and coherent control of single electronic wavefunctions. Wavefunctions exist within both physical real space and an abstract state space with a simple geometric interpretation: this state space - or Hilbert space - is spanned by mutually orthogonal state vectors corresponding to the quantized degrees of freedom of the real-space system. Measurement of superpositions is akin to accessing the direction of a vector in Hilbert space, determining an angle of rotation equivalent to quantum phase. Here we show that an individual atom inside a designed quantum corral1 can control this angle, producing arbitrary coherent superpositions of spatial quantum states. Using scanning tunnelling microscopy and nanostructures assembled atom-by-atom we demonstrate how single spins and quantum mirages can be harnessed to image the superposition of two electronic states. We also present a straightforward method to determine the atom path enacting phase rotations between any desired state vectors. A single atom thus becomes a real-space handle for an abstract Hilbert space, providing a simple technique for coherent quantum state manipulation at the spatial limit of condensed matter.

  5. Observer dependence of quantum states in relativistic quantum field theories

    International Nuclear Information System (INIS)

    Malin, S.

    1982-01-01

    Quantum states can be understood as either (i) describing quantum systems or (ii) representing observers' knowledge about quantum systems. These different meanings are shown to imply different transformation properties in relativistic field theories. The rules for the reduction of quantum states and the transformation properties of quantum states under Lorentz transformations are derived for case (ii). The results obtained are applied to a quantum system recently presented and analyzed by Aharonov and Albert. It is shown that the present results, combined with Aharonov and Albert's, amount to a proof of Bohr's view that quantum states represent observers' knowledge about quantum systems

  6. Self-calibrating quantum state tomography

    International Nuclear Information System (INIS)

    Brańczyk, A M; Mahler, D H; Rozema, L A; Darabi, A; Steinberg, A M; James, D F V

    2012-01-01

    We introduce and experimentally demonstrate a technique for performing quantum state tomography (QST) on multiple-qubit states despite incomplete knowledge about the unitary operations used to change the measurement basis. Given unitary operations with unknown rotation angles, our method can be used to reconstruct the density matrix of the state up to local σ z rotations as well as recover the magnitude of the unknown rotation angle. We demonstrate high-fidelity self-calibrating tomography on polarization-encoded one- and two-photon states. The unknown unitary operations are realized in two ways: using a birefringent polymer sheet—an inexpensive smartphone screen protector—or alternatively a liquid crystal wave plate with a tuneable retardance. We explore how our technique may be adapted for QST of systems such as biological molecules where the magnitude and orientation of the transition dipole moment is not known with high accuracy. (paper)

  7. Self-calibrating quantum state tomography

    Energy Technology Data Exchange (ETDEWEB)

    Branczyk, A M; Mahler, D H; Rozema, L A; Darabi, A; Steinberg, A M; James, D F V, E-mail: branczyk@physics.utoronto.ca [CQIQC and IOS, Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario, M5S 1A7 (Canada)

    2012-08-15

    We introduce and experimentally demonstrate a technique for performing quantum state tomography (QST) on multiple-qubit states despite incomplete knowledge about the unitary operations used to change the measurement basis. Given unitary operations with unknown rotation angles, our method can be used to reconstruct the density matrix of the state up to local {sigma}{sub z} rotations as well as recover the magnitude of the unknown rotation angle. We demonstrate high-fidelity self-calibrating tomography on polarization-encoded one- and two-photon states. The unknown unitary operations are realized in two ways: using a birefringent polymer sheet-an inexpensive smartphone screen protector-or alternatively a liquid crystal wave plate with a tuneable retardance. We explore how our technique may be adapted for QST of systems such as biological molecules where the magnitude and orientation of the transition dipole moment is not known with high accuracy. (paper)

  8. On the epistemic view of quantum states

    International Nuclear Information System (INIS)

    Skotiniotis, Michael; Roy, Aidan; Sanders, Barry C.

    2008-01-01

    We investigate the strengths and limitations of the Spekkens toy model, which is a local hidden variable model that replicates many important properties of quantum dynamics. First, we present a set of five axioms that fully encapsulate Spekkens' toy model. We then test whether these axioms can be extended to capture more quantum phenomena by allowing operations on epistemic as well as ontic states. We discover that the resulting group of operations is isomorphic to the projective extended Clifford group for two qubits. This larger group of operations results in a physically unreasonable model; consequently, we claim that a relaxed definition of valid operations in Spekkens' toy model cannot produce an equivalence with the Clifford group for two qubits. However, the new operations do serve as tests for correlation in a two toy bit model, analogous to the well known Horodecki criterion for the separability of quantum states

  9. Scalable on-chip quantum state tomography

    Science.gov (United States)

    Titchener, James G.; Gräfe, Markus; Heilmann, René; Solntsev, Alexander S.; Szameit, Alexander; Sukhorukov, Andrey A.

    2018-03-01

    Quantum information systems are on a path to vastly exceed the complexity of any classical device. The number of entangled qubits in quantum devices is rapidly increasing, and the information required to fully describe these systems scales exponentially with qubit number. This scaling is the key benefit of quantum systems, however it also presents a severe challenge. To characterize such systems typically requires an exponentially long sequence of different measurements, becoming highly resource demanding for large numbers of qubits. Here we propose and demonstrate a novel and scalable method for characterizing quantum systems based on expanding a multi-photon state to larger dimensionality. We establish that the complexity of this new measurement technique only scales linearly with the number of qubits, while providing a tomographically complete set of data without a need for reconfigurability. We experimentally demonstrate an integrated photonic chip capable of measuring two- and three-photon quantum states with statistical reconstruction fidelity of 99.71%.

  10. Probabilistic cloning and deleting of quantum states

    International Nuclear Information System (INIS)

    Feng Yuan; Zhang Shengyu; Ying Mingsheng

    2002-01-01

    We construct a probabilistic cloning and deleting machine which, taking several copies of an input quantum state, can output a linear superposition of multiple cloning and deleting states. Since the machine can perform cloning and deleting in a single unitary evolution, the probabilistic cloning and other cloning machines proposed in the previous literature can be thought of as special cases of our machine. A sufficient and necessary condition for successful cloning and deleting is presented, and it requires that the copies of an arbitrarily presumed number of the input states are linearly independent. This simply generalizes some results for cloning. We also derive an upper bound for the success probability of the cloning and deleting machine

  11. Ancilla-approximable quantum state transformations

    Energy Technology Data Exchange (ETDEWEB)

    Blass, Andreas [Department of Mathematics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Gurevich, Yuri [Microsoft Research, Redmond, Washington 98052 (United States)

    2015-04-15

    We consider the transformations of quantum states obtainable by a process of the following sort. Combine the given input state with a specially prepared initial state of an auxiliary system. Apply a unitary transformation to the combined system. Measure the state of the auxiliary subsystem. If (and only if) it is in a specified final state, consider the process successful, and take the resulting state of the original (principal) system as the result of the process. We review known information about exact realization of transformations by such a process. Then we present results about approximate realization of finite partial transformations. We not only consider primarily the issue of approximation to within a specified positive ε, but also address the question of arbitrarily close approximation.

  12. Quantum-state comparison and discrimination

    Science.gov (United States)

    Hayashi, A.; Hashimoto, T.; Horibe, M.

    2018-05-01

    We investigate the performance of discrimination strategy in the comparison task of known quantum states. In the discrimination strategy, one infers whether or not two quantum systems are in the same state on the basis of the outcomes of separate discrimination measurements on each system. In some cases with more than two possible states, the optimal strategy in minimum-error comparison is that one should infer the two systems are in different states without any measurement, implying that the discrimination strategy performs worse than the trivial "no-measurement" strategy. We present a sufficient condition for this phenomenon to happen. For two pure states with equal prior probabilities, we determine the optimal comparison success probability with an error margin, which interpolates the minimum-error and unambiguous comparison. We find that the discrimination strategy is not optimal except for the minimum-error case.

  13. Ancilla-approximable quantum state transformations

    International Nuclear Information System (INIS)

    Blass, Andreas; Gurevich, Yuri

    2015-01-01

    We consider the transformations of quantum states obtainable by a process of the following sort. Combine the given input state with a specially prepared initial state of an auxiliary system. Apply a unitary transformation to the combined system. Measure the state of the auxiliary subsystem. If (and only if) it is in a specified final state, consider the process successful, and take the resulting state of the original (principal) system as the result of the process. We review known information about exact realization of transformations by such a process. Then we present results about approximate realization of finite partial transformations. We not only consider primarily the issue of approximation to within a specified positive ε, but also address the question of arbitrarily close approximation

  14. Operational geometric phase for mixed quantum states

    International Nuclear Information System (INIS)

    Andersson, O; Heydari, H

    2013-01-01

    The geometric phase has found a broad spectrum of applications in both classical and quantum physics, such as condensed matter and quantum computation. In this paper, we introduce an operational geometric phase for mixed quantum states, based on spectral weighted traces of holonomies, and we prove that it generalizes the standard definition of the geometric phase for mixed states, which is based on quantum interferometry. We also introduce higher order geometric phases, and prove that under a fairly weak, generically satisfied, requirement, there is always a well-defined geometric phase of some order. Our approach applies to general unitary evolutions of both non-degenerate and degenerate mixed states. Moreover, since we provide an explicit formula for the geometric phase that can be easily implemented, it is particularly well suited for computations in quantum physics. (paper)

  15. Quantum state preparation using multi-level-atom optics

    International Nuclear Information System (INIS)

    Busch, Th; Deasy, K; Chormaic, S Nic

    2007-01-01

    One of the most important characteristics for controlling processes on the quantum scale is the fidelity or robustness of the techniques being used. In the case of single atoms localized in micro-traps, it was recently shown that the use of time-dependent tunnelling interactions in a multi-trap setup can be viewed as analogous to the area of multi-level optics. The atom's centre-of-mass can then be controlled with a high fidelity, using a STIRAP-type process. Here, we review previous work that led to the development of multi-level atom optics and present two examples of our most recent work on quantum state preparation

  16. Semiquantum-key distribution using less than four quantum states

    International Nuclear Information System (INIS)

    Zou Xiangfu; Qiu Daowen; Li Lvzhou; Wu Lihua; Li Lvjun

    2009-01-01

    Recently Boyer et al. [Phys. Rev. Lett. 99, 140501 (2007)] suggested the idea of semiquantum key distribution (SQKD) in which Bob is classical and they also proposed a semiquantum key distribution protocol (BKM2007). To discuss the security of the BKM2007 protocol, they proved that their protocol is completely robust. This means that nonzero information acquired by Eve on the information string implies the nonzero probability that the legitimate participants can find errors on the bits tested by this protocol. The BKM2007 protocol uses four quantum states to distribute a secret key. In this paper, we simplify their protocol by using less than four quantum states. In detail, we present five different SQKD protocols in which Alice sends three quantum states, two quantum states, and one quantum state, respectively. Also, we prove that all the five protocols are completely robust. In particular, we invent two completely robust SQKD protocols in which Alice sends only one quantum state. Alice uses a register in one SQKD protocol, but she does not use any register in the other. The information bit proportion of the SQKD protocol in which Alice sends only one quantum state but uses a register is the double as that in the BKM2007 protocol. Furthermore, the information bit rate of the SQKD protocol in which Alice sends only one quantum state and does not use any register is not lower than that of the BKM2007 protocol.

  17. Generation of Exotic Quantum States of a Cold Atomic Ensemble

    DEFF Research Database (Denmark)

    Christensen, Stefan Lund

    Over the last decades quantum effects have become more and more controllable, leading to the implementations of various quantum information protocols. These protocols are all based on utilizing quantum correlation. In this thesis we consider how states of an atomic ensemble with such correlations...... can be created and characterized. First we consider a spin-squeezed state. This state is generated by performing quantum non-demolition measurements of the atomic population difference. We show a spectroscopically relevant noise reduction of -1.7dB, the ensemble is in a many-body entangled state...... — a nanofiber based light-atom interface. Using a dual-frequency probing method we measure and prepare an ensemble with a sub-Poissonian atom number distribution. This is a first step towards the implementation of more exotic quantum states....

  18. Quantum state transfer and network engineering

    International Nuclear Information System (INIS)

    Nikolopoulos, Georgios M.; Jex, Igor

    2014-01-01

    Presents the basics of large-scale quantum information processing and networking. Covers most aspects of the problems of state transfer and quantum network engineering. Reflects the interdisciplinary nature of the field. Presents various theoretical approaches as well as possible implementations and related experiments. Faithful communication is a necessary precondition for large-scale quantum information processing and networking, irrespective of the physical platform. Thus, the problems of quantum-state transfer and quantum-network engineering have attracted enormous interest over the last years, and constitute one of the most active areas of research in quantum information processing. The present volume introduces the reader to fundamental concepts and various aspects of this exciting research area, including links to other related areas and problems. The implementation of state-transfer schemes and the engineering of quantum networks are discussed in the framework of various quantum optical and condensed matter systems, emphasizing the interdisciplinary character of the research area. Each chapter is a review of theoretical or experimental achievements on a particular topic, written by leading scientists in the field. The volume aims at both newcomers as well as experienced researchers.

  19. Secret Sharing of a Quantum State.

    Science.gov (United States)

    Lu, He; Zhang, Zhen; Chen, Luo-Kan; Li, Zheng-Da; Liu, Chang; Li, Li; Liu, Nai-Le; Ma, Xiongfeng; Chen, Yu-Ao; Pan, Jian-Wei

    2016-07-15

    Secret sharing of a quantum state, or quantum secret sharing, in which a dealer wants to share a certain amount of quantum information with a few players, has wide applications in quantum information. The critical criterion in a threshold secret sharing scheme is confidentiality: with less than the designated number of players, no information can be recovered. Furthermore, in a quantum scenario, one additional critical criterion exists: the capability of sharing entangled and unknown quantum information. Here, by employing a six-photon entangled state, we demonstrate a quantum threshold scheme, where the shared quantum secrecy can be efficiently reconstructed with a state fidelity as high as 93%. By observing that any one or two parties cannot recover the secrecy, we show that our scheme meets the confidentiality criterion. Meanwhile, we also demonstrate that entangled quantum information can be shared and recovered via our setting, which shows that our implemented scheme is fully quantum. Moreover, our experimental setup can be treated as a decoding circuit of the five-qubit quantum error-correcting code with two erasure errors.

  20. Duality constructions from quantum state manifolds

    Science.gov (United States)

    Kriel, J. N.; van Zyl, H. J. R.; Scholtz, F. G.

    2015-11-01

    The formalism of quantum state space geometry on manifolds of generalised coherent states is proposed as a natural setting for the construction of geometric dual descriptions of non-relativistic quantum systems. These state manifolds are equipped with natural Riemannian and symplectic structures derived from the Hilbert space inner product. This approach allows for the systematic construction of geometries which reflect the dynamical symmetries of the quantum system under consideration. We analyse here in detail the two dimensional case and demonstrate how existing results in the AdS 2 /CF T 1 context can be understood within this framework. We show how the radial/bulk coordinate emerges as an energy scale associated with a regularisation procedure and find that, under quite general conditions, these state manifolds are asymptotically anti-de Sitter solutions of a class of classical dilaton gravity models. For the model of conformal quantum mechanics proposed by de Alfaro et al. [1] the corresponding state manifold is seen to be exactly AdS 2 with a scalar curvature determined by the representation of the symmetry algebra. It is also shown that the dilaton field itself is given by the quantum mechanical expectation values of the dynamical symmetry generators and as a result exhibits dynamics equivalent to that of a conformal mechanical system.

  1. Local copying of orthogonal entangled quantum states

    International Nuclear Information System (INIS)

    Anselmi, Fabio; Chefles, Anthony; Plenio, Martin B

    2004-01-01

    In classical information theory one can, in principle, produce a perfect copy of any input state. In quantum information theory, the no cloning theorem prohibits exact copying of non-orthogonal states. Moreover, if we wish to copy multiparticle entangled states and can perform only local operations and classical communication (LOCC), then further restrictions apply. We investigate the problem of copying orthogonal, entangled quantum states with an entangled blank state under the restriction to LOCC. Throughout, the subsystems have finite dimension D. We show that if all of the states to be copied are non-maximally entangled, then novel LOCC copying procedures based on entanglement catalysis are possible. We then study in detail the LOCC copying problem where both the blank state and at least one of the states to be copied are maximally entangled. For this to be possible, we find that all the states to be copied must be maximally entangled. We obtain a necessary and sufficient condition for LOCC copying under these conditions. For two orthogonal, maximally entangled states, we provide the general solution to this condition. We use it to show that for D = 2, 3, any pair of orthogonal, maximally entangled states can be locally copied using a maximally entangled blank state. However, we also show that for any D which is not prime, one can construct pairs of such states for which this is impossible

  2. Asymmetry and coherence weight of quantum states

    Science.gov (United States)

    Bu, Kaifeng; Anand, Namit; Singh, Uttam

    2018-03-01

    The asymmetry of quantum states is an important resource in quantum information processing tasks such as quantum metrology and quantum communication. In this paper, we introduce the notion of asymmetry weight—an operationally motivated asymmetry quantifier in the resource theory of asymmetry. We study the convexity and monotonicity properties of asymmetry weight and focus on its interplay with the corresponding semidefinite programming (SDP) forms along with its connection to other asymmetry measures. Since the SDP form of asymmetry weight is closely related to asymmetry witnesses, we find that the asymmetry weight can be regarded as a (state-dependent) asymmetry witness. Moreover, some specific entanglement witnesses can be viewed as a special case of an asymmetry witness—which indicates a potential connection between asymmetry and entanglement. We also provide an operationally meaningful coherence measure, which we term coherence weight, and investigate its relationship to other coherence measures like the robustness of coherence and the l1 norm of coherence. In particular, we show that for Werner states in any dimension d all three coherence quantifiers, namely, the coherence weight, the robustness of coherence, and the l1 norm of coherence, are equal and are given by a single letter formula.

  3. Random unitary maps for quantum state reconstruction

    International Nuclear Information System (INIS)

    Merkel, Seth T.; Riofrio, Carlos A.; Deutsch, Ivan H.; Flammia, Steven T.

    2010-01-01

    We study the possibility of performing quantum state reconstruction from a measurement record that is obtained as a sequence of expectation values of a Hermitian operator evolving under repeated application of a single random unitary map, U 0 . We show that while this single-parameter orbit in operator space is not informationally complete, it can be used to yield surprisingly high-fidelity reconstruction. For a d-dimensional Hilbert space with the initial observable in su(d), the measurement record lacks information about a matrix subspace of dimension ≥d-2 out of the total dimension d 2 -1. We determine the conditions on U 0 such that the bound is saturated, and show they are achieved by almost all pseudorandom unitary matrices. When we further impose the constraint that the physical density matrix must be positive, we obtain even higher fidelity than that predicted from the missing subspace. With prior knowledge that the state is pure, the reconstruction will be perfect (in the limit of vanishing noise) and for arbitrary mixed states, the fidelity is over 0.96, even for small d, and reaching F>0.99 for d>9. We also study the implementation of this protocol based on the relationship between random matrices and quantum chaos. We show that the Floquet operator of the quantum kicked top provides a means of generating the required type of measurement record, with implications on the relationship between quantum chaos and information gain.

  4. Experimentally measuring a quantum state by the Heisenberg exchange interaction in a single apparatus

    International Nuclear Information System (INIS)

    Peng Xinhua; Du Jiangfeng; Suter, D.

    2005-01-01

    Full text: Quantum information processing requires the effective measurement of quantum states. An important method, called quantum state tomography, needs measuring a complete set of observables on the measured system to determine its unknown quantum state ρ. The measurement involves certain noncommuting observables as a result of Bohr's complementarity. Very recently, Allahverdyan et al. proposed a new method in which the unknown quantum state r is determined by measuring a set of commuting observables in the price of a controlled interaction with an auxiliary system. If both systems S and A are spins, their z components (σ z ) can be chosen to measure after some specific Heisenberg exchange interaction. We study in detail a general Heisenberg XYZ model for a two-qubit system and present two classes of special Heisenberg interactions which can serve as the controlled interaction in Allahverdyan's scheme when the state of the auxiliary system A is initially completely disordered. Using the nuclear magnetic resonance techniques, the measurement scheme in a single apparatus has been experimentally demonstrated by designing the quantum circuit to simulate the Heisenberg exchange interaction. (author)

  5. Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

    Science.gov (United States)

    Priebe, Katharina E.; Rathje, Christopher; Yalunin, Sergey V.; Hohage, Thorsten; Feist, Armin; Schäfer, Sascha; Ropers, Claus

    2017-12-01

    Ultrafast electron and X-ray imaging and spectroscopy are the basis for an ongoing revolution in the understanding of dynamical atomic-scale processes in matter. The underlying technology relies heavily on laser science for the generation and characterization of ever shorter pulses. Recent findings suggest that ultrafast electron microscopy with attosecond-structured wavefunctions may be feasible. However, such future technologies call for means to both prepare and fully analyse the corresponding free-electron quantum states. Here, we introduce a framework for the preparation, coherent manipulation and characterization of free-electron quantum states, experimentally demonstrating attosecond electron pulse trains. Phase-locked optical fields coherently control the electron wavefunction along the beam direction. We establish a new variant of quantum state tomography—`SQUIRRELS'—for free-electron ensembles. The ability to tailor and quantitatively map electron quantum states will promote the nanoscale study of electron-matter entanglement and new forms of ultrafast electron microscopy down to the attosecond regime.

  6. How to control chemical hazards

    CERN Multimedia

    2012-01-01

    Improving protection against chemical hazards is one of the 2012 CERN safety objectives identified by the Director General. Identifying and drawing up a complete inventory of chemicals, and assessing the associated risks are important steps in this direction.   The HSE Unit has drawn up safety rules, guidelines and forms to help you to meet this objective. We would like to draw your attention to: • safety guidelines C-0-0-1 and C-1-0-2 (now also available in French), which deal with the identification of hazardous chemicals and the assessment of chemical risk; • safety guideline C-1-0-1, which deals with the storage of hazardous chemicals. All safety documents can be consulted at: cern.ch/regles-securite The HSE Unit will be happy to answer any questions you may have. Write to us at: safety-general@cern.ch The HSE Unit

  7. Femtosecond laser control of chemical reactions

    CSIR Research Space (South Africa)

    Du Plessis, A

    2010-08-31

    Full Text Available Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This can result in controllable...

  8. Non-adiabatic quantum state preparation and quantum state transport in chains of Rydberg atoms

    Science.gov (United States)

    Ostmann, Maike; Minář, Jiří; Marcuzzi, Matteo; Levi, Emanuele; Lesanovsky, Igor

    2017-12-01

    Motivated by recent progress in the experimental manipulation of cold atoms in optical lattices, we study three different protocols for non-adiabatic quantum state preparation and state transport in chains of Rydberg atoms. The protocols we discuss are based on the blockade mechanism between atoms which, when excited to a Rydberg state, interact through a van der Waals potential, and rely on single-site addressing. Specifically, we discuss protocols for efficient creation of an antiferromagnetic GHZ state, a class of matrix product states including a so-called Rydberg crystal and for the state transport of a single-qubit quantum state between two ends of a chain of atoms. We identify system parameters allowing for the operation of the protocols on timescales shorter than the lifetime of the Rydberg states while yielding high fidelity output states. We discuss the effect of positional disorder on the resulting states and comment on limitations due to other sources of noise such as radiative decay of the Rydberg states. The proposed protocols provide a testbed for benchmarking the performance of quantum information processing platforms based on Rydberg atoms.

  9. Symmetric-bounce quantum state of the universe

    Energy Technology Data Exchange (ETDEWEB)

    Page, Don N., E-mail: don@phys.ualberta.ca [Theoretical Physics Institute, Department of Physics, University of Alberta, Room 238 CEB, 11322 – 89 Avenue, Edmonton, Alberta T6G 2G7 (Canada)

    2009-09-01

    A proposal is made for the quantum state of the universe that has an initial state that is macroscopically time symmetric about a homogeneous, isotropic bounce of extremal volume and that at that bounce is microscopically in the ground state for inhomogeneous and/or anisotropic perturbation modes. The coarse-grained entropy is minimum at the bounce and then grows during inflation as the modes become excited away from the bounce and interact (assuming the presence of an inflaton, and in the part of the quantum state in which the inflaton is initially large enough to drive inflation). The part of this pure quantum state that dominates for observations is well approximated by quantum processes occurring within a Lorentzian expanding macroscopic universe. Because this part of the quantum state has no negative Euclidean action, one can avoid the early-time Boltzmann brains and Boltzmann solar systems that appear to dominate observations in the Hartle-Hawking no-boundary wavefunction.

  10. Symmetric-bounce quantum state of the universe

    International Nuclear Information System (INIS)

    Page, Don N.

    2009-01-01

    A proposal is made for the quantum state of the universe that has an initial state that is macroscopically time symmetric about a homogeneous, isotropic bounce of extremal volume and that at that bounce is microscopically in the ground state for inhomogeneous and/or anisotropic perturbation modes. The coarse-grained entropy is minimum at the bounce and then grows during inflation as the modes become excited away from the bounce and interact (assuming the presence of an inflaton, and in the part of the quantum state in which the inflaton is initially large enough to drive inflation). The part of this pure quantum state that dominates for observations is well approximated by quantum processes occurring within a Lorentzian expanding macroscopic universe. Because this part of the quantum state has no negative Euclidean action, one can avoid the early-time Boltzmann brains and Boltzmann solar systems that appear to dominate observations in the Hartle-Hawking no-boundary wavefunction

  11. Partial separability and entanglement criteria for multiqubit quantum states

    NARCIS (Netherlands)

    Seevinck, M.P.; Uffink, J.B.M.

    2008-01-01

    We explore the subtle relationships between partial separability and entanglement of subsystems in multiqubit quantum states and give experimentally accessible conditions that distinguish between various classes and levels of partial separability in a hierarchical order. These conditions take the

  12. Entropic Lower Bound for Distinguishability of Quantum States

    Directory of Open Access Journals (Sweden)

    Seungho Yang

    2015-01-01

    Full Text Available For a system randomly prepared in a number of quantum states, we present a lower bound for the distinguishability of the quantum states, that is, the success probability of determining the states in the form of entropy. When the states are all pure, acquiring the entropic lower bound requires only the density operator and the number of the possible states. This entropic bound shows a relation between the von Neumann entropy and the distinguishability.

  13. Quantum State Engineering Via Coherent-State Superpositions

    Science.gov (United States)

    Janszky, Jozsef; Adam, P.; Szabo, S.; Domokos, P.

    1996-01-01

    The quantum interference between the two parts of the optical Schrodinger-cat state makes possible to construct a wide class of quantum states via discrete superpositions of coherent states. Even a small number of coherent states can approximate the given quantum states at a high accuracy when the distance between the coherent states is optimized, e. g. nearly perfect Fock state can be constructed by discrete superpositions of n + 1 coherent states lying in the vicinity of the vacuum state.

  14. Quantum state propagation in linear photonic bandgap structures

    International Nuclear Information System (INIS)

    Severini, S; Tricca, D; Sibilia, C; Bertolotti, M; Perina, Jan

    2004-01-01

    In this paper we investigate the propagation of a generic quantum state in a corrugated waveguide, which reproduces a photonic bandgap structure. We find the conditions that assure the outcoming state to preserve the quantum properties of the incoming state. Then, focusing on a particular quantum state (realized by two counter-propagating coherent states), we study the possibility of preserving the quantum properties of this particular double coherent state even in the presence of absorption phenomena during propagation in the structure

  15. Chemical process control using Mat lab

    International Nuclear Information System (INIS)

    Kang, Sin Chun; Kim, Raeh Yeon; Kim, Yang Su; Oh, Min; Yeo, Yeong Gu; Jung, Yeon Su

    2001-07-01

    This book is about chemical process control, which includes the basis of process control with conception, function, composition of system and summary, change of laplace and linearization, modeling of chemical process, transfer function and block diagram, the first dynamic property of process, the second dynamic property of process, the dynamic property of combined process, control structure of feedback on component of control system, the dynamic property of feedback control loop, stability of closed loop control structure, expression of process, modification and composition of controller, analysis of vibration response and adjustment controller using vibration response.

  16. Method for preparation and readout of polyatomic molecules in single quantum states

    Science.gov (United States)

    Patterson, David

    2018-03-01

    Polyatomic molecular ions contain many desirable attributes of a useful quantum system, including rich internal degrees of freedom and highly controllable coupling to the environment. To date, the vast majority of state-specific experimental work on molecular ions has concentrated on diatomic species. The ability to prepare and read out polyatomic molecules in single quantum states would enable diverse experimental avenues not available with diatomics, including new applications in precision measurement, sensitive chemical and chiral analysis at the single-molecule level, and precise studies of Hz-level molecular tunneling dynamics. While cooling the motional state of a polyatomic ion via sympathetic cooling with a laser-cooled atomic ion is straightforward, coupling this motional state to the internal state of the molecule has proven challenging. Here we propose a method for readout and projective measurement of the internal state of a trapped polyatomic ion. The method exploits the rich manifold of technically accessible rotational states in the molecule to realize robust state preparation and readout with far less stringent engineering than quantum logic methods recently demonstrated on diatomic molecules. The method can be applied to any reasonably small (≲10 atoms) polyatomic ion with an anisotropic polarizability.

  17. Quantum state engineering in hybrid open quantum systems

    Science.gov (United States)

    Joshi, Chaitanya; Larson, Jonas; Spiller, Timothy P.

    2016-04-01

    We investigate a possibility to generate nonclassical states in light-matter coupled noisy quantum systems, namely, the anisotropic Rabi and Dicke models. In these hybrid quantum systems, a competing influence of coherent internal dynamics and environment-induced dissipation drives the system into nonequilibrium steady states (NESSs). Explicitly, for the anisotropic Rabi model, the steady state is given by an incoherent mixture of two states of opposite parities, but as each parity state displays light-matter entanglement, we also find that the full state is entangled. Furthermore, as a natural extension of the anisotropic Rabi model to an infinite spin subsystem, we next explored the NESS of the anisotropic Dicke model. The NESS of this linearized Dicke model is also an inseparable state of light and matter. With an aim to enrich the dynamics beyond the sustainable entanglement found for the NESS of these hybrid quantum systems, we also propose to combine an all-optical feedback strategy for quantum state protection and for establishing quantum control in these systems. Our present work further elucidates the relevance of such hybrid open quantum systems for potential applications in quantum architectures.

  18. Quantum state population transfer of lithium atoms induced by frequency-chirped laser pulses

    International Nuclear Information System (INIS)

    Ma Huanqiang; Zhang Xianzhou; Jia Guangrui; Zhang Yonghui; Jiang Lijuan

    2011-01-01

    Using the time-dependent multilevel approach (TDMA) and B-splines function, we have calculated the five quantum state population transfer of rydberg lithium atoms. We also analyse the influence of the four major parameters of the frequency-chirped laser pulses field on transition. The result shows that the population can be completely transferred to the target state by changing the parameters of the laser pulse and achieve manual controls to a certain degree. (authors)

  19. Design and experimental realization of an optimal scheme for teleportation of an n-qubit quantum state

    Science.gov (United States)

    Sisodia, Mitali; Shukla, Abhishek; Thapliyal, Kishore; Pathak, Anirban

    2017-12-01

    An explicit scheme (quantum circuit) is designed for the teleportation of an n-qubit quantum state. It is established that the proposed scheme requires an optimal amount of quantum resources, whereas larger amount of quantum resources have been used in a large number of recently reported teleportation schemes for the quantum states which can be viewed as special cases of the general n-qubit state considered here. A trade-off between our knowledge about the quantum state to be teleported and the amount of quantum resources required for the same is observed. A proof-of-principle experimental realization of the proposed scheme (for a 2-qubit state) is also performed using 5-qubit superconductivity-based IBM quantum computer. The experimental results show that the state has been teleported with high fidelity. Relevance of the proposed teleportation scheme has also been discussed in the context of controlled, bidirectional, and bidirectional controlled state teleportation.

  20. Teleportations of Mixed States and Multipartite Quantum States

    Institute of Scientific and Technical Information of China (English)

    YU Chang-Shui; WANG Ya-Hong; SONG He-Shan

    2007-01-01

    In this paper, we propose a protocol to deterministically teleport an unknown mixed state of qubit by utilizing a maximally bipartite entangled state of qubits as quantum channel. Ifa non-maximally entangled bipartite pure state is employed as quantum channel, the unknown mixed quantum state of qubit can be teleported with 1 - √1 - C2 probability, where C is the concurrence of the quantum channel. The protocol can also be generalized to teleport a mixed state of qudit or a multipartite mixed state. More important purpose is that, on the basis of the protocol, the teleportation of an arbitrary multipartite (pure or mixed) quantum state can be decomposed into the teleportation of each subsystem by employing separate entangled states as quantum channels. In the case of deterministic teleportation,Bob only needs to perform unitary transformations on his single particles in order to recover the initial teleported multipartite quantum state.

  1. Transfer of non-Gaussian quantum states of mechanical oscillator to light

    Science.gov (United States)

    Filip, Radim; Rakhubovsky, Andrey A.

    2015-11-01

    Non-Gaussian quantum states are key resources for quantum optics with continuous-variable oscillators. The non-Gaussian states can be deterministically prepared by a continuous evolution of the mechanical oscillator isolated in a nonlinear potential. We propose feasible and deterministic transfer of non-Gaussian quantum states of mechanical oscillators to a traveling light beam, using purely all-optical methods. The method relies on only basic feasible and high-quality elements of quantum optics: squeezed states of light, linear optics, homodyne detection, and electro-optical feedforward control of light. By this method, a wide range of novel non-Gaussian states of light can be produced in the future from the mechanical states of levitating particles in optical tweezers, including states necessary for the implementation of an important cubic phase gate.

  2. Channel capacities versus entanglement measures in multiparty quantum states

    International Nuclear Information System (INIS)

    Sen, Aditi; Sen, Ujjwal

    2010-01-01

    For quantum states of two subsystems, highly entangled states have a higher capacity of transmitting classical as well as quantum information, and vice versa. We show that this is no more the case in general: Quantum capacities of multiaccess channels, motivated by communication in quantum networks, do not have any relation with genuine multiparty entanglement measures. Importantly, the statement is demonstrated for arbitrary multipartite entanglement measures. Along with revealing the structural richness of multiaccess channels, this gives us a tool to classify multiparty quantum states from the perspective of its usefulness in quantum networks, which cannot be visualized by any genuine multiparty entanglement measure.

  3. Observation of moving wave packets reveals their quantum state

    International Nuclear Information System (INIS)

    Leonhardt, U.; Raymer, M.G.

    1996-01-01

    We show how to infer the quantum state of a wave packet from position probability distributions measured during the packet close-quote s motion in an arbitrary potential. We assume a nonrelativistic one-dimensional or radial wave packet. Temporal Fourier transformation and spatial sampling with respect to a newly found set of functions project the density-matrix elements out of the probability distributions. The sampling functions are derivatives of products of regular and irregular wave functions. We note that the ability to infer quantum states in this way depends on the structure of the Schroedinger equation. copyright 1996 The American Physical Society

  4. Quantum state transfer between light and matter via teleportation

    DEFF Research Database (Denmark)

    Krauter, Hanna; Sherson, Jacob Friis; Polzik, Eugene Simon

    2010-01-01

    that teleportation is also an important element of future quantum networks and it can be an ingredient for quantum computation. This article reports for the first time the teleportation from light to atoms. In the experiment discussed, the quantum state of a light beam is transferred to an atomic ensemble. The key......Quantum teleportation is an interesting feature of quantum mechanics. Entanglement is used as a link between two remote locations to transfer a quantum state without physically sending it – a process that cannot be realized utilizing merely classical tools. Furthermore it has become evident...

  5. Study on multipartite quantum states: preparation, simulation, and characterization

    International Nuclear Information System (INIS)

    Kruszynska, C.

    2009-01-01

    also study the efficiency of intermediate strategies, including sequences of purification and connection. We show that a multipartite strategy is to be used if one wishes to achieve high fidelity, whereas a bipartite strategy gives a better yield for low target fidelity. The third part focuses on the entanglement properties of pure quantum states describing n qubits. We introduce a generalization of the stabilizer formalism in which the condition that the stabilizer elements are products of local operators is relaxed. We characterize a class of generalized stabilizer states of three qubits and show that some of the entanglement properties of those states can be deduced from the particular form of a set of operators stabilizing them. We characterize all multipartite states which can be maximally entangled to local auxiliary systems using controlled operations. A state has this property if one can construct out of it an orthonormal basis by applying independent local unitary operations. This implies that those states can be used to encode locally the maximum amount of $n$ bits. Examples of these states are the so--called stabilizer states, which are used for quantum error correction and one--way quantum computing. We give a simple characterization of these states and construct a complete set of commuting unitary observables which characterize the state uniquely. Furthermore we show how these states can be prepared and discuss their applications. Finally, in the last part we introduce a class of variational states to describe quantum many-body systems. This class generalizes matrix product states which underly the density-matrix renormalization group approach by combining them with weighted graph states. This new variational class of states can be thought of as being prepared from matrix product states, followed by commuting unitary operations on arbitrary constituents, hence truly generalizing both matrix product and weighted graph states. We use this class of states to

  6. Can a quantum state over time resemble a quantum state at a single time?

    Science.gov (United States)

    Horsman, Dominic; Heunen, Chris; Pusey, Matthew F; Barrett, Jonathan; Spekkens, Robert W

    2017-09-01

    The standard formalism of quantum theory treats space and time in fundamentally different ways. In particular, a composite system at a given time is represented by a joint state, but the formalism does not prescribe a joint state for a composite of systems at different times. If there were a way of defining such a joint state, this would potentially permit a more even-handed treatment of space and time, and would strengthen the existing analogy between quantum states and classical probability distributions. Under the assumption that the joint state over time is an operator on the tensor product of single-time Hilbert spaces, we analyse various proposals for such a joint state, including one due to Leifer and Spekkens, one due to Fitzsimons, Jones and Vedral, and another based on discrete Wigner functions. Finding various problems with each, we identify five criteria for a quantum joint state over time to satisfy if it is to play a role similar to the standard joint state for a composite system: that it is a Hermitian operator on the tensor product of the single-time Hilbert spaces; that it represents probabilistic mixing appropriately; that it has the appropriate classical limit; that it has the appropriate single-time marginals; that composing over multiple time steps is associative. We show that no construction satisfies all these requirements. If Hermiticity is dropped, then there is an essentially unique construction that satisfies the remaining four criteria.

  7. Quantum State Transfer from a Single Photon to a Distant Quantum-Dot Electron Spin

    Science.gov (United States)

    He, Yu; He, Yu-Ming; Wei, Yu-Jia; Jiang, Xiao; Chen, Kai; Lu, Chao-Yang; Pan, Jian-Wei; Schneider, Christian; Kamp, Martin; Höfling, Sven

    2017-08-01

    Quantum state transfer from flying photons to stationary matter qubits is an important element in the realization of quantum networks. Self-assembled semiconductor quantum dots provide a promising solid-state platform hosting both single photon and spin, with an inherent light-matter interface. Here, we develop a method to coherently and actively control the single-photon frequency bins in superposition using electro-optic modulators, and measure the spin-photon entanglement with a fidelity of 0.796 ±0.020 . Further, by Greenberger-Horne-Zeilinger-type state projection on the frequency, path, and polarization degrees of freedom of a single photon, we demonstrate quantum state transfer from a single photon to a single electron spin confined in an InGaAs quantum dot, separated by 5 m. The quantum state mapping from the photon's polarization to the electron's spin is demonstrated along three different axes on the Bloch sphere, with an average fidelity of 78.5%.

  8. Quantum state propagation in linear photonic bandgap structures

    Czech Academy of Sciences Publication Activity Database

    Severini, S.; Tricca, S.; Sibilia, C.; Peřina, Jan

    2004-01-01

    Roč. 6, - (2004), s. 110-114 ISSN 1464-4266 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010921 Keywords : photonic crystals * coupled mode theory * decoherence * quantum states propagation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.746, year: 2004

  9. Teleportation of Quantum States through Mixed Entangled Pairs

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2006-01-01

    @@ We describe a protocol for quantum state teleportation via mixed entangled pairs. With the help of an ancilla,near-perfect teleportation might be achieved. For pure entangled pairs, perfect teleportation might be achieved with a certain probability without using an ancilla. The protocol is generalized to teleportation of multiparticle states and quantum secret sharing.

  10. Topology in quantum states. PEPS formalism and beyond

    Energy Technology Data Exchange (ETDEWEB)

    Aguado, M [Max-Planck-Institut fuer Quantenoptik. Hans-Kopfermann-Str. 1. D-85748 Garching (Germany); Cirac, J I [Max-Planck-Institut fuer Quantenoptik. Hans-Kopfermann-Str. 1. D-85748 Garching (Germany); Vidal, G [School of Physical Sciences. University of Queensland, Brisbane, QLD, 4072 (Australia)

    2007-11-15

    Topology has been proposed as a tool to protect quantum information encoding and processes. Work concerning the meaning of topology in quantum states as well as its characterisation in the projected entangled pair state (PEPS) formalism and related schemes is reviewed.

  11. Distinguishability of quantum states and shannon complexity in quantum cryptography

    Science.gov (United States)

    Arbekov, I. M.; Molotkov, S. N.

    2017-07-01

    The proof of the security of quantum key distribution is a rather complex problem. Security is defined in terms different from the requirements imposed on keys in classical cryptography. In quantum cryptography, the security of keys is expressed in terms of the closeness of the quantum state of an eavesdropper after key distribution to an ideal quantum state that is uncorrelated to the key of legitimate users. A metric of closeness between two quantum states is given by the trace metric. In classical cryptography, the security of keys is understood in terms of, say, the complexity of key search in the presence of side information. In quantum cryptography, side information for the eavesdropper is given by the whole volume of information on keys obtained from both quantum and classical channels. The fact that the mathematical apparatuses used in the proof of key security in classical and quantum cryptography are essentially different leads to misunderstanding and emotional discussions [1]. Therefore, one should be able to answer the question of how different cryptographic robustness criteria are related to each other. In the present study, it is shown that there is a direct relationship between the security criterion in quantum cryptography, which is based on the trace distance determining the distinguishability of quantum states, and the criterion in classical cryptography, which uses guesswork on the determination of a key in the presence of side information.

  12. ANALYTICAL SYNTHESIS OF CHEMICAL REACTOR CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    Alexander Labutin

    2017-02-01

    Full Text Available The problem of the analytical synthesis of the synergetic control system of chemical reactor for the realization of a complex series-parallel exothermal reaction has been solved. The synthesis of control principles is performed using the analytical design method of aggregated regulators. Synthesized nonlinear control system solves the problem of stabilization of the concentration of target component at the exit of reactor and also enables one to automatically transfer to new production using the equipment.

  13. No survival of Nonlocalilty of fermionic quantum states with alpha vacuum in the infinite acceleration limit

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Younghun, E-mail: yyhkwon@hanyang.ac.kr

    2015-09-02

    In this article, we investigate the nonlocal behavior of the quantum state of fermionic system having the alpha vacuum. We evaluate the maximum violation of CHSH inequality in the quantum state. Even when the maximally entangled quantum state is initially shared it cannot violate the CHSH inequality, regardless of any alpha vacuum, when the infinite acceleration is applied. It means that the nonlocality of the quantum state in fermionic system with the alpha vacuum cannot survive in the infinite acceleration limit.

  14. Generating continuous variable optical quantum states and entanglement

    International Nuclear Information System (INIS)

    Lam, P.K.; Bowen, W.P.; Schnabel, R.; Treps, N.; Buchler, B.C.; Bachor, H.-A.; Ralph, T.C.

    2002-01-01

    Full text: Quantum information research has recently been shown to have many applications in the field of communication and information processing. Quantum states and entanglement play a central role to almost all quantum information protocols, and form the basic building blocks for larger quantum information networks. We present an overview of the research activities at the quantum optics group at the ANU relating to this area. In particular, we demonstrate technology to suppress the noise on a coherent laser beam to below that of even vacuum. This quantum state of light is called 'squeezed light'. We show experimentally that by mixing two squeezed beams on a beam splitter, a pair of Einstein-Podolsky-Rosen (EPR) entangled beams can be created. This kind of entanglement exhibits below shot noise correlations between both the phase and amplitude quandratures of two beams. Our experimental results show conclusively that our entangled beams demonstrate the famous EPR paradox

  15. Direct measurement of nonlinear properties of bipartite quantum states.

    Science.gov (United States)

    Bovino, Fabio Antonio; Castagnoli, Giuseppe; Ekert, Artur; Horodecki, Paweł; Alves, Carolina Moura; Sergienko, Alexander Vladimir

    2005-12-09

    Nonlinear properties of quantum states, such as entropy or entanglement, quantify important physical resources and are frequently used in quantum-information science. They are usually calculated from a full description of a quantum state, even though they depend only on a small number of parameters that specify the state. Here we extract a nonlocal and a nonlinear quantity, namely, the Renyi entropy, from local measurements on two pairs of polarization-entangled photons. We also introduce a "phase marking" technique which allows the selection of uncorrupted outcomes even with nondeterministic sources of entangled photons. We use our experimental data to demonstrate the violation of entropic inequalities. They are examples of nonlinear entanglement witnesses and their power exceeds all linear tests for quantum entanglement based on all possible Bell-Clauser-Horne-Shimony-Holt inequalities.

  16. Exotic quantum states for charmed baryons at finite temperature

    Directory of Open Access Journals (Sweden)

    Jiaxing Zhao

    2017-12-01

    Full Text Available The significantly screened heavy-quark potential in hot medium provides the possibility to study exotic quantum states of three-heavy-quark systems. By solving the Schrödinger equation for a three-charm-quark system at finite temperature, we found that, there exist Borromean states which might be realized in high energy nuclear collisions, and the binding energies of the system satisfy precisely the scaling law for Efimov states in the resonance limit.

  17. A general framework for unambiguous detection of quantum states

    International Nuclear Information System (INIS)

    Eldar, Y.

    2004-01-01

    Full Text:The problem of detecting information stored in the state of a quantum system is a fundamental problem in quantum information theory. Several approaches have emerged to distinguishing between a collection of non-orthogonal quantum states. We consider the problem of unambiguous detection where we seek a measurement that with a certain probability returns an inconclusive result, but such that if the measurement returns an answer, then the answer is correct with probability 1. We begin by considering unambiguous discrimination between a set of linearly independent pure quantum states. We show that the design of the optimal measurement that minimizes the probability of an inconclusive result can be formulated as a semidefinite programming problem. Based on this formulation, we develop a set of necessary and sufficient conditions for an optimal quantum measurement. We show that the optimal measurement can be computed very efficiently in polynomial time by exploiting the many well-known algorithms for solving semidefinite programs, which are guaranteed to converge to the global optimum. Using the general conditions for optimality, we derive necessary and sufficient conditions so that the measurement that results in an equal probability of an inconclusive result for each one of the quantum states is optimal. We refer to this measurement as the equal-probability measurement (EPM). We then show that for any state set, the prior probabilities of the states can be chosen such that the EPM is optimal. Finally, we consider state sets with strong symmetry properties and equal prior probabilities for which the EPM is optimal. We next develop a general framework for unambiguous state discrimination between a collection of mixed quantum states, which can be applied to any number of states with arbitrary prior probabilities. In particular, we derive a set of necessary and sufficient conditions for an optimal measurement that minimizes the probability of an inconclusive

  18. Entanglement purification of multi-mode quantum states

    International Nuclear Information System (INIS)

    Clausen, J; Knoell, L; Welsch, D-G

    2003-01-01

    An iterative random procedure is considered allowing entanglement purification of a class of multi-mode quantum states. In certain cases, complete purification may be achieved using only a single signal state preparation. A physical implementation based on beam splitter arrays and non-linear elements is suggested. The influence of loss is analysed in the example of purification of entangled N-mode coherent states

  19. Understanding squeezing of quantum states with the Wigner function

    Science.gov (United States)

    Royer, Antoine

    1994-01-01

    The Wigner function is argued to be the only natural phase space function evolving classically under quadratic Hamiltonians with time-dependent bilinear part. This is used to understand graphically how certain quadratic time-dependent Hamiltonians induce squeezing of quantum states. The Wigner representation is also used to generalize Ehrenfest's theorem to the quantum uncertainties. This makes it possible to deduce features of the quantum evolution, such as squeezing, from the classical evolution, whatever the Hamiltonian.

  20. Discrete Wigner function and quantum-state tomography

    Science.gov (United States)

    Leonhardt, Ulf

    1996-05-01

    The theory of discrete Wigner functions and of discrete quantum-state tomography [U. Leonhardt, Phys. Rev. Lett. 74, 4101 (1995)] is studied in more detail guided by the picture of precession tomography. Odd- and even-dimensional systems (angular momenta and spins, bosons, and fermions) are considered separately. Relations between simple number theory and the quantum mechanics of finite-dimensional systems are pointed out. In particular, the multicomplementarity of the precession states distinguishes prime dimensions from composite ones.

  1. Weaving and neural complexity in symmetric quantum states

    Science.gov (United States)

    Susa, Cristian E.; Girolami, Davide

    2018-04-01

    We study the behaviour of two different measures of the complexity of multipartite correlation patterns, weaving and neural complexity, for symmetric quantum states. Weaving is the weighted sum of genuine multipartite correlations of any order, where the weights are proportional to the correlation order. The neural complexity, originally introduced to characterize correlation patterns in classical neural networks, is here extended to the quantum scenario. We derive closed formulas of the two quantities for GHZ states mixed with white noise.

  2. Transfer of an unknown quantum state, quantum networks, and memory

    International Nuclear Information System (INIS)

    Biswas, Asoka; Agarwal, G.S.

    2004-01-01

    We present a protocol for transfer of an unknown quantum state. The protocol is based on a two-mode cavity interacting dispersively in a sequential manner with three-level atoms in the Λ configuration. We propose a scheme for quantum networking using an atomic channel. We investigate the effect of cavity decoherence in the entire process. Further, we demonstrate the possibility of an efficient quantum memory for arbitrary superposition of two modes of a cavity containing one photon

  3. Unknown quantum states: The quantum de Finetti representation

    International Nuclear Information System (INIS)

    Caves, Carlton M.; Fuchs, Christopher A.; Schack, Ruediger

    2002-01-01

    We present an elementary proof of the quantum de Finetti representation theorem, a quantum analog of de Finetti's classical theorem on exchangeable probability assignments. This contrasts with the original proof of Hudson and Moody [Z. Wahrschein. verw. Geb. 33, 343 (1976)], which relies on advanced mathematics and does not share the same potential for generalization. The classical de Finetti theorem provides an operational definition of the concept of an unknown probability in Bayesian probability theory, where probabilities are taken to be degrees of belief instead of objective states of nature. The quantum de Finetti theorem, in a closely analogous fashion, deals with exchangeable density-operator assignments and provides an operational definition of the concept of an ''unknown quantum state'' in quantum-state tomography. This result is especially important for information-based interpretations of quantum mechanics, where quantum states, like probabilities, are taken to be states of knowledge rather than states of nature. We further demonstrate that the theorem fails for real Hilbert spaces and discuss the significance of this point

  4. Behavior of the maximum likelihood in quantum state tomography

    Science.gov (United States)

    Scholten, Travis L.; Blume-Kohout, Robin

    2018-02-01

    Quantum state tomography on a d-dimensional system demands resources that grow rapidly with d. They may be reduced by using model selection to tailor the number of parameters in the model (i.e., the size of the density matrix). Most model selection methods typically rely on a test statistic and a null theory that describes its behavior when two models are equally good. Here, we consider the loglikelihood ratio. Because of the positivity constraint ρ ≥ 0, quantum state space does not generally satisfy local asymptotic normality (LAN), meaning the classical null theory for the loglikelihood ratio (the Wilks theorem) should not be used. Thus, understanding and quantifying how positivity affects the null behavior of this test statistic is necessary for its use in model selection for state tomography. We define a new generalization of LAN, metric-projected LAN, show that quantum state space satisfies it, and derive a replacement for the Wilks theorem. In addition to enabling reliable model selection, our results shed more light on the qualitative effects of the positivity constraint on state tomography.

  5. Behavior of the maximum likelihood in quantum state tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blume-Kohout, Robin J [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States); Scholten, Travis L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States)

    2018-02-22

    Quantum state tomography on a d-dimensional system demands resources that grow rapidly with d. They may be reduced by using model selection to tailor the number of parameters in the model (i.e., the size of the density matrix). Most model selection methods typically rely on a test statistic and a null theory that describes its behavior when two models are equally good. Here, we consider the loglikelihood ratio. Because of the positivity constraint ρ ≥ 0, quantum state space does not generally satisfy local asymptotic normality (LAN), meaning the classical null theory for the loglikelihood ratio (the Wilks theorem) should not be used. Thus, understanding and quantifying how positivity affects the null behavior of this test statistic is necessary for its use in model selection for state tomography. We define a new generalization of LAN, metric-projected LAN, show that quantum state space satisfies it, and derive a replacement for the Wilks theorem. In addition to enabling reliable model selection, our results shed more light on the qualitative effects of the positivity constraint on state tomography.

  6. Intelligent Controller Design for a Chemical Process

    OpenAIRE

    Mr. Glan Devadhas G; Dr.Pushpakumar S.

    2010-01-01

    Chemical process control is a challenging problem due to the strong on*line non*linearity and extreme sensitivity to disturbances of the process. Ziegler – Nichols tuned PI and PID controllers are found to provide poor performances for higher*order and non–linear systems. This paper presents an application of one*step*ahead fuzzy as well as ANFIS (adaptive*network*based fuzzy inference system) tuning scheme for an Continuous Stirred Tank Reactor CSTR process. The controller is designed based ...

  7. WEED CONTROL EFFECTS ON SOIL CHEMICAL CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Lima e Silva

    2008-01-01

    Full Text Available The weed control procedures are known to affect the soil physical attributes and the nutrient amount taken up by weed roots. This work hypothesis is that weed control methods might also affect soil chemical attributes. Four experiments were carried out, three with maize (E-1, E-2 and E-3 and one with cotton (E-4, in randomized complete blocks design arranged in split-plots, with five replications. In E-1 experiment, the plots consisted of two weed control treatments: no-weed control and weed shovel-digging at 20 and 40 days after sowing; and the subplots consisted of six maize cultivars. In the three other experiments, the plots consisted of plant cultivars: four maize cultivars (E-2 and E-3 and four cotton cultivars (E-4. And, the subplots consisted of three weed control treatments: (1 no-weed control; (2 weed shovel-digging at 20 and 40 days after sowing; and (3 intercropping with cowpea (E-2 or Gliricidia sepium (Jacq. Walp. (E-3 and E-4. In all experiments, after harvest, eight soil samples were collected from each subplot (0-20 cm depth and composed in one sample. Soil chemical analysis results indicated that the weed control by shovel-digging or intercropping may increase or decrease some soil element concentrations and the alterations depend on the element and experiment considered. In E-2, the weed shovel-dug plots showed intermediate soil pH, lower S (sum of bases values and higher soil P concentrations than the other plots. In E-4, soil K and Na concentrations in plots without weed control did not differ from plots with intercropping, and in both, K and Na values were higher than in weed shovel-dug plots. Maize and cotton cultivars did not affect soil chemical characteristics.

  8. Programmable chemical controllers made from DNA

    Science.gov (United States)

    Chen, Yuan-Jyue; Dalchau, Neil; Srinivas, Niranjan; Phillips, Andrew; Cardelli, Luca; Soloveichik, David; Seelig, Georg

    2013-10-01

    Biological organisms use complex molecular networks to navigate their environment and regulate their internal state. The development of synthetic systems with similar capabilities could lead to applications such as smart therapeutics or fabrication methods based on self-organization. To achieve this, molecular control circuits need to be engineered to perform integrated sensing, computation and actuation. Here we report a DNA-based technology for implementing the computational core of such controllers. We use the formalism of chemical reaction networks as a 'programming language' and our DNA architecture can, in principle, implement any behaviour that can be mathematically expressed as such. Unlike logic circuits, our formulation naturally allows complex signal processing of intrinsically analogue biological and chemical inputs. Controller components can be derived from biologically synthesized (plasmid) DNA, which reduces errors associated with chemically synthesized DNA. We implement several building-block reaction types and then combine them into a network that realizes, at the molecular level, an algorithm used in distributed control systems for achieving consensus between multiple agents.

  9. Coherence properties and quantum state transportation in an optical conveyor belt.

    Science.gov (United States)

    Kuhr, S; Alt, W; Schrader, D; Dotsenko, I; Miroshnychenko, Y; Rosenfeld, W; Khudaverdyan, M; Gomer, V; Rauschenbeutel, A; Meschede, D

    2003-11-21

    We have prepared and detected quantum coherences of trapped cesium atoms with long dephasing times. Controlled transport by an "optical conveyor belt" over macroscopic distances preserves the atomic coherence with slight reduction of coherence time. The limiting dephasing effects are experimentally identified, and we present an analytical model of the reversible and irreversible dephasing mechanisms. Our experimental methods are applicable at the single-atom level. Coherent quantum bit operations along with quantum state transport open the route towards a "quantum shift register" of individual neutral atoms.

  10. Geometric manipulation of the quantum states of two-level atoms

    International Nuclear Information System (INIS)

    Tian, Mingzhen; Barber, Zeb W.; Fischer, Joe A.; Babbitt, Wm. Randall

    2004-01-01

    Manipulation of the quantum states of two-level atoms has been investigated using laser-controlled geometric phase change, which has the potential to build robust quantum logic gates for quantum computing. For a qubit based on two electronic transition levels of an atom, two basic quantum operations that can make any universal single qubit gate have been designed employing resonant laser pulses. An operation equivalent to a phase gate has been demonstrated using Tm 3+ doped in a yttrium aluminum garnet crystal

  11. Chemical barriers for controlling groundwater contamination

    International Nuclear Information System (INIS)

    Morrison, S.J.; Spangler, R.R.

    1993-01-01

    Chemical barriers are being explored as a low-cost means of controlling groundwater contamination. The barrier can intercept a contaminant plume and prevent migration by transferring contaminants from the groundwater to immobile solids. A chemical barrier can be emplaced in a landfill liner or in an aquifer cutoff wall or can be injected into a contaminant plume. Chemical barriers can be classified as either precipitation barriers or sorption barriers depending upon the dominant mode of contaminant extraction. In a precipitation barrier, contaminants are bound in the structures of newly formed phases; whereas, in a sorption barrier, contaminants attach to the surfaces of preexisting solids by adsorption or some other surface mechanism. Sorption of contaminants is pH dependent. A precipitation barrier can control the pH of the system, but alkaline groundwater may dominate the pH in a sorption barrier. A comparison is made of the characteristics of precipitation and sorption barriers. Experimental data on the extraction of uranium and molybdenum from simulated groundwater are used to demonstrate these concepts. 10 refs., 9 figs., 1 tab

  12. Chemical optimization algorithm for fuzzy controller design

    CERN Document Server

    Astudillo, Leslie; Castillo, Oscar

    2014-01-01

    In this book, a novel optimization method inspired by a paradigm from nature is introduced. The chemical reactions are used as a paradigm to propose an optimization method that simulates these natural processes. The proposed algorithm is described in detail and then a set of typical complex benchmark functions is used to evaluate the performance of the algorithm. Simulation results show that the proposed optimization algorithm can outperform other methods in a set of benchmark functions. This chemical reaction optimization paradigm is also applied to solve the tracking problem for the dynamic model of a unicycle mobile robot by integrating a kinematic and a torque controller based on fuzzy logic theory. Computer simulations are presented confirming that this optimization paradigm is able to outperform other optimization techniques applied to this particular robot application

  13. Computer Controlled Chemical Micro-Reactor

    International Nuclear Information System (INIS)

    Mechtilde, Schaefer; Eduard, Stach; Adreas, Foitzik

    2006-01-01

    Chemical reactions or chemical equilibria can be influenced and controlled by several parameters. The ratio of two liquid ingredients, the so called reactants or educts, plays an important role in determining the end product and its yield. The reactants must be weighed and accordingly mixed with the conventional batch mode. If the reaction is done in a microreactor or in several parallel working micro-reactors, units for allotting the educts in appropriate quantities are required. In this report we present a novel micro-reactor that allows the constant monitoring of the chemical reaction via Raman spectroscopy. Such monitoring enables an appropriate feedback on the steering parameters for the PC controlled micro-pumps for the appropriate educt flow rate of both liquids to get optimised ratios of ingredients at an optimised total flow rate. The micro-reactors are the core pieces of the design and are easily removable and can therefore be changed at any time to adapt the requirements of the chemical reaction. One type of reactor consists of a stainless steel base containing small scale milled channels covered with anodically bonded Pyrex glass. Another type of reactor has a base of anisotropically etched silicon, and is also covered with anodically bonded Pyrex glass. The glass window allows visual observation of the initial phase interface of the two educts in the reaction channels by optical microscopy and does not affect, in contrast to infrared spectroscopy, the Raman spectroscopic signal for detection of the reaction kinetics. On the basis of a test reaction, we present non-invasive and spatially highly resolved in-situ reaction analysis using Raman spectroscopy measured along the reaction channel at different locations

  14. Entanglement measure for general pure multipartite quantum states

    International Nuclear Information System (INIS)

    Heydari, Hoshang; Bjoerk, Gunnar

    2004-01-01

    We propose an explicit formula for a measure of entanglement of pure multipartite quantum states. We discuss the mathematical structure of the measure and give a brief explanation of its physical motivation. We apply the measure on some pure, tripartite, qubit states and demonstrate that, in general, the entanglement can depend on what actions are performed on the various subsystems, and specifically if the parties in possession of the subsystems cooperate or not. We also give some simple but illustrative examples of the entanglement of four-qubit and m-qubit states

  15. Generalized Choi states and 2-distillability of quantum states

    Science.gov (United States)

    Chen, Lin; Tang, Wai-Shing; Yang, Yu

    2018-05-01

    We investigate the distillability of bipartite quantum states in terms of positive and completely positive maps. We construct the so-called generalized Choi states and show that it is distillable when it has negative partial transpose. We convert the distillability problem of 2-copy n× n Werner states into the determination of the positivity of an Hermitian matrix. We obtain several sufficient conditions by which the positivity holds. Further, we investigate the case n=3 by the classification of 2× 3× 3 pure states.

  16. Minimum-error discrimination of entangled quantum states

    International Nuclear Information System (INIS)

    Lu, Y.; Coish, N.; Kaltenbaek, R.; Hamel, D. R.; Resch, K. J.; Croke, S.

    2010-01-01

    Strategies to optimally discriminate between quantum states are critical in quantum technologies. We present an experimental demonstration of minimum-error discrimination between entangled states, encoded in the polarization of pairs of photons. Although the optimal measurement involves projection onto entangled states, we use a result of J. Walgate et al. [Phys. Rev. Lett. 85, 4972 (2000)] to design an optical implementation employing only local polarization measurements and feed-forward, which performs at the Helstrom bound. Our scheme can achieve perfect discrimination of orthogonal states and minimum-error discrimination of nonorthogonal states. Our experimental results show a definite advantage over schemes not using feed-forward.

  17. Physics student ideas on quantum state and its formal representations

    International Nuclear Information System (INIS)

    Zuccarini, G.

    2014-01-01

    Developing a quantum way of thinking is a core and challenging task for physics students. The concept of quantum state, whose physical meaning is connected to the formal structure of the theory, plays an important role in the construction of a quantum perspective and in student difficulties elicited by research. A questionnaire and interview protocol were devised to explore student understanding of the state concept in connection to the properties of its formal representations and to quantum behavior. Results of a calibration of research instruments performed on 6 physics students from different universities are here presented.

  18. Experimental determination of the degree of polarization of quantum states

    DEFF Research Database (Denmark)

    Kothe-Termén, Christian; Madsen, Lars Skovgaard; Andersen, Ulrik Lund

    2013-01-01

    We demonstrate experimental excitation-manifold-resolved polarization characterization of quantum states of light ranging from the few-photon to the many-photon level. In contrast to the traditional characterization of polarization that is based on the Stokes parameters, we experimentally determine...... the Stokes vector of each excitation manifold separately. Only for states with a given photon number do the methods coincide. For states with an indeterminate photon number, for example Gaussian states, the employed method gives a richer and more accurate description. We apply the method both in theory...

  19. Quantum Bit Commitment and the Reality of the Quantum State

    Science.gov (United States)

    Srikanth, R.

    2018-01-01

    Quantum bit commitment is insecure in the standard non-relativistic quantum cryptographic framework, essentially because Alice can exploit quantum steering to defer making her commitment. Two assumptions in this framework are that: (a) Alice knows the ensembles of evidence E corresponding to either commitment; and (b) system E is quantum rather than classical. Here, we show how relaxing assumption (a) or (b) can render her malicious steering operation indeterminable or inexistent, respectively. Finally, we present a secure protocol that relaxes both assumptions in a quantum teleportation setting. Without appeal to an ontological framework, we argue that the protocol's security entails the reality of the quantum state, provided retrocausality is excluded.

  20. Extended superposed quantum-state initialization using disjoint prime implicants

    International Nuclear Information System (INIS)

    Rosenbaum, David; Perkowski, Marek

    2009-01-01

    Extended superposed quantum-state initialization using disjoint prime implicants is an algorithm for generating quantum arrays for the purpose of initializing a desired quantum superposition. The quantum arrays generated by this algorithm almost always use fewer gates than other algorithms and in the worst case use the same number of gates. These improvements are achieved by allowing certain parts of the quantum superposition that cannot be initialized directly by the algorithm to be initialized using special circuits. This allows more terms in the quantum superposition to be initialized at the same time which decreases the number of gates required by the generated quantum array.

  1. Remote unambiguous discrimination of linearly independent symmetric d-level quantum states

    International Nuclear Information System (INIS)

    Chen Libing; Liu Yuhua; Tan Peng; Lu Hong

    2009-01-01

    A set of linearly independent nonorthogonal symmetric d-level quantum states can be discriminated remotely and unambiguously with the aid of two-level Einstein-Podolsky-Rosen (EPR) states. We present a scheme for such a kind of remote unambiguous quantum state discrimination (UD). The probability of discrimination is in agreement with the optimal probability for local unambiguous discrimination among d symmetric states (Chefles and Barnettt 1998 Phys. Lett. A 250 223). This scheme consists of a remote generalized measurement described by a positive operator valued measurement (POVM). This remote POVM can be realized by performing a nonlocal 2d x 2d unitary operation on two spatially separated systems, one is the qudit which is encoded by one of the d symmetric nonorthogonal states to be distinguished and the other is an ancillary qubit, and a conventional local von Neumann orthogonal measurement on the ancilla. By decomposing the evolution process from the initial state to the final state, we construct a quantum network for realizing the remote POVM with a set of two-level nonlocal controlled-rotation gates, and thus provide a feasible physical means to realize the remote UD. A two-level nonlocal controlled-rotation gate can be implemented by using a two-level EPR pair in addition to local operations and classical communications (LOCCs)

  2. Average subentropy, coherence and entanglement of random mixed quantum states

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lin, E-mail: godyalin@163.com [Institute of Mathematics, Hangzhou Dianzi University, Hangzhou 310018 (China); Singh, Uttam, E-mail: uttamsingh@hri.res.in [Harish-Chandra Research Institute, Allahabad, 211019 (India); Pati, Arun K., E-mail: akpati@hri.res.in [Harish-Chandra Research Institute, Allahabad, 211019 (India)

    2017-02-15

    Compact expressions for the average subentropy and coherence are obtained for random mixed states that are generated via various probability measures. Surprisingly, our results show that the average subentropy of random mixed states approaches the maximum value of the subentropy which is attained for the maximally mixed state as we increase the dimension. In the special case of the random mixed states sampled from the induced measure via partial tracing of random bipartite pure states, we establish the typicality of the relative entropy of coherence for random mixed states invoking the concentration of measure phenomenon. Our results also indicate that mixed quantum states are less useful compared to pure quantum states in higher dimension when we extract quantum coherence as a resource. This is because of the fact that average coherence of random mixed states is bounded uniformly, however, the average coherence of random pure states increases with the increasing dimension. As an important application, we establish the typicality of relative entropy of entanglement and distillable entanglement for a specific class of random bipartite mixed states. In particular, most of the random states in this specific class have relative entropy of entanglement and distillable entanglement equal to some fixed number (to within an arbitrary small error), thereby hugely reducing the complexity of computation of these entanglement measures for this specific class of mixed states.

  3. Roughness as classicality indicator of a quantum state

    Science.gov (United States)

    Lemos, Humberto C. F.; Almeida, Alexandre C. L.; Amaral, Barbara; Oliveira, Adélcio C.

    2018-03-01

    We define a new quantifier of classicality for a quantum state, the Roughness, which is given by the L2 (R2) distance between Wigner and Husimi functions. We show that the Roughness is bounded and therefore it is a useful tool for comparison between different quantum states for single bosonic systems. The state classification via the Roughness is not binary, but rather it is continuous in the interval [ 0 , 1 ], being the state more classic as the Roughness approaches to zero, and more quantum when it is closer to the unity. The Roughness is maximum for Fock states when its number of photons is arbitrarily large, and also for squeezed states at the maximum compression limit. On the other hand, the Roughness approaches its minimum value for thermal states at infinite temperature and, more generally, for infinite entropy states. The Roughness of a coherent state is slightly below one half, so we may say that it is more a classical state than a quantum one. Another important result is that the Roughness performs well for discriminating both pure and mixed states. Since the Roughness measures the inherent quantumness of a state, we propose another function, the Dynamic Distance Measure (DDM), which is suitable for measure how much quantum is a dynamics. Using DDM, we studied the quartic oscillator, and we observed that there is a certain complementarity between dynamics and state, i.e. when dynamics becomes more quantum, the Roughness of the state decreases, while the Roughness grows as the dynamics becomes less quantum.

  4. Local decoherence-resistant quantum states of large systems

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Utkarsh; Sen, Aditi; Sen, Ujjwal, E-mail: ujjwal@hri.res.in

    2015-02-06

    We identify an effectively decoherence-free class of quantum states, each of which consists of a “minuscule” and a “large” sector, against local noise. In particular, the content of entanglement and other quantum correlations in the minuscule to large partition is independent of the number of particles in their large sectors, when all the particles suffer passage through local amplitude and phase damping channels. The states of the large sectors are distinct in terms of markedly different amounts of violation of Bell inequality. In case the large sector is macroscopic, such states are akin to the Schrödinger cat. - Highlights: • We identify an effectively decoherence-free class of quantum states of large systems. • We work with local noise models. • Decay of entanglement as well as information-theoretic quantum correlations considered. • The states are of the form of the Schrödinger cats, with minuscule and large sectors. • The states of the large sector are distinguishable by their violation of Bell inequality.

  5. Quantum state detection and state preparation based on cavity-enhanced nonlinear interaction of atoms with single photon

    Science.gov (United States)

    Hosseini, Mahdi

    Our ability to engineer quantum states of light and matter has significantly advanced over the past two decades, resulting in the production of both Gaussian and non-Gaussian optical states. The resulting tailored quantum states enable quantum technologies such as quantum optical communication, quantum sensing as well as quantum photonic computation. The strong nonlinear light-atom interaction is the key to deterministic quantum state preparation and quantum photonic processing. One route to enhancing the usually weak nonlinear light-atom interactions is to approach the regime of cavity quantum electrodynamics (cQED) interaction by means of high finesse optical resonators. I present results from the MIT experiment of large conditional cross-phase modulation between a signal photon, stored inside an atomic quantum memory, and a control photon that traverses a high-finesse optical cavity containing the atomic memory. I also present a scheme to probabilistically change the amplitude and phase of a signal photon qubit to, in principle, arbitrary values by postselection on a control photon that has interacted with that state. Notably, small changes of the control photon polarization measurement basis by few degrees can substantially change the amplitude and phase of the signal state. Finally, I present our ongoing effort at Purdue to realize similar peculiar quantum phenomena at the single photon level on chip scale photonic systems.

  6. Measurement and Quantum State Transfer in Superconducting Qubits

    Science.gov (United States)

    Mlinar, Eric

    The potential of superconducting qubits as the medium for a scalable quantum computer has motivated the pursuit of improved interactions within this system. Two challenges for the field of superconducting qubits are measurement fidelity, to accurately determine the state of the qubit, and the efficient transfer of quantum states. In measurement, the current state-of-the-art method employs dispersive readout, by coupling the qubit to a cavity and reading the resulting shift in cavity frequency to infer the qubit's state; however, this is vulnerable to Purcell relaxation, as well as being modeled off a simplified two-level abstraction of the qubit. In state transfer, the existing proposal for moving quantum states is mostly untested against non-idealities that will likely be present in an experiment. In this dissertation, we examine three problems within these two areas. We first describe a new scheme for fast and high-fidelity dispersive measurement specifically designed to circumvent the Purcell Effect. To do this, the qubit-resonator interaction is turned on only when the resonator is decoupled from the environment; then, after the resonator state has shifted enough to infer the qubit state, the qubit-resonator interaction is turned off before the resonator and environment are recoupled. We also show that the effectiveness of this "Catch-Disperse-Release'' procedure partly originates from quadrature squeezing of the resonator state induced by the Jaynes-Cummings nonlinearity. The Catch-Disperse-Release measurement scheme treats the qubit as a two-level system, which is a common simplification used in theoretical works. However, the most promising physical candidate for a superconducting qubit, the transmon, is a multi-level system. In the second work, we examine the effects of including the higher energy levels of the transmon. Specifically, we expand the eigenstate picture developed in the first work to encompass multiple qubit levels, and examine the resulting

  7. Influence of scattering processes on electron quantum states in nanowires

    Directory of Open Access Journals (Sweden)

    Pozdnyakov Dmitry

    2007-01-01

    Full Text Available AbstractIn the framework of quantum perturbation theory the self-consistent method of calculation of electron scattering rates in nanowires with the one-dimensional electron gas in the quantum limit is worked out. The developed method allows both the collisional broadening and the quantum correlations between scattering events to be taken into account. It is an alternativeper seto the Fock approximation for the self-energy approach based on Green’s function formalism. However this approach is free of mathematical difficulties typical to the Fock approximation. Moreover, the developed method is simpler than the Fock approximation from the computational point of view. Using the approximation of stable one-particle quantum states it is proved that the electron scattering processes determine the dependence of electron energy versus its wave vector.

  8. Programmable quantum-state discriminator by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Gopinath, T.; Das, Ranabir; Kumar, Anil

    2005-01-01

    A programmable quantum-state discriminator is implemented by using nuclear magnetic resonance. We use a two-qubit spin-1/2 system, one for the data qubit and one for the ancilla (program) qubit. This device does the unambiguous (error-free) discrimination of a pair of states of the data qubit that are symmetrically located about a fixed state. The device is used to discriminate both linearly polarized states and elliptically polarized states. The maximum probability of successful discrimination is achieved by suitably preparing the ancilla qubit. It is also shown that the probability of discrimination depends on the angle of the unitary operator of the protocol and ellipticity of the data qubit state

  9. Optimum unambiguous discrimination between subsets of nonorthogonal quantum states

    International Nuclear Information System (INIS)

    Sun Yuqing; Hillery, Mark; Bergou, Janos A.

    2002-01-01

    It is known that unambiguous discrimination among nonorthogonal but linearly independent quantum states is possible with a certain probability of success. Here, we consider a variant of that problem. Instead of discriminating among all of the different states, we shall only discriminate between two subsets of them. In particular, for the case of three nonorthogonal states, { vertical bar ψ 1 >, vertical bar ψ 2 >, vertical bar ψ 3 >}, we show that the optimal strategy to distinguish vertical bar ψ 1 > from the set { vertical bar ψ 2 >, vertical bar ψ 3 >} has a higher success rate than if we wish to discriminate among all three states. Somewhat surprisingly, for unambiguous discrimination the subsets need not be linearly independent. A fully analytical solution is presented, and we also show how to construct generalized interferometers (multiport) which provide an optical implementation of the optimal strategy

  10. Superposing pure quantum states with partial prior information

    Science.gov (United States)

    Dogra, Shruti; Thomas, George; Ghosh, Sibasish; Suter, Dieter

    2018-05-01

    The principle of superposition is an intriguing feature of quantum mechanics, which is regularly exploited in many different circumstances. A recent work [M. Oszmaniec et al., Phys. Rev. Lett. 116, 110403 (2016), 10.1103/PhysRevLett.116.110403] shows that the fundamentals of quantum mechanics restrict the process of superimposing two unknown pure states, even though it is possible to superimpose two quantum states with partial prior knowledge. The prior knowledge imposes geometrical constraints on the choice of input states. We discuss an experimentally feasible protocol to superimpose multiple pure states of a d -dimensional quantum system and carry out an explicit experimental realization for two single-qubit pure states with partial prior information on a two-qubit NMR quantum information processor.

  11. Bernstein's paradox of entangled quantum states

    International Nuclear Information System (INIS)

    Belinsky, A V; Chirkin, A S

    2013-01-01

    Bernstein's classical paradox of a regular colored-faced tetrahedron, while designed to illustrate the subtleties of probability theory, is strongly flawed in being asymmetric. Faces of tetrahedron are nonequivalent: three of them are single-colored, and one is many-colored. Therefore, even prior to formal calculations, a strong suspicion as to the independence of the color resulting statistics arises. Not so with entangled quantum states. In the schematic solutions proposed, while photon detection channels are completely symmetric and equivalent, the events that occur in them turn out to be statistically dependent, making the Bernstein paradox even more impressive due to the unusual behavior of quantum particles not obeying classical laws. As an illustrative example of the probability paradox, Greenberger–Horne–Zeilinger multiqubit states are considered. (methodological notes)

  12. Highly Nonclassical Quantum States and Environment Induced Decoherence

    Science.gov (United States)

    Foldi, Peter

    2004-06-01

    In this thesis concrete quantum systems are investigated in the framework of the environment induced decoherence. The focus is on the dynamics of highly nonclassical quantum states, the Wigner function of which are negative over some regions of their domains. One of the chosen physical systems is a diatomic molecule, where the potential energy of the nuclei is an anharmonic function of their distance. A system of two-level atoms, which can be important from the viewpoint of quantum information technology, is also investigated. A method is described that is valid in both systems and can determine the characteristic time of the decoherence in a dynamical way. The direction of the decoherence and its relation to energy dissipation is also studied. Finally, a scheme is proposed that can prepare decoherence-free states using the experimental techniques presently available.

  13. Reexamination of optimal quantum state estimation of pure states

    International Nuclear Information System (INIS)

    Hayashi, A.; Hashimoto, T.; Horibe, M.

    2005-01-01

    A direct derivation is given for the optimal mean fidelity of quantum state estimation of a d-dimensional unknown pure state with its N copies given as input, which was first obtained by Hayashi in terms of an infinite set of covariant positive operator valued measures (POVM's) and by Bruss and Macchiavello establishing a connection to optimal quantum cloning. An explicit condition for POVM measurement operators for optimal estimators is obtained, by which we construct optimal estimators with finite POVMs using exact quadratures on a hypersphere. These finite optimal estimators are not generally universal, where universality means the fidelity is independent of input states. However, any optimal estimator with finite POVM for M(>N) copies is universal if it is used for N copies as input

  14. New methods for the measurement and alteration of quantum states

    International Nuclear Information System (INIS)

    Steuernagel, O.

    1996-01-01

    Themes of this thesis are the mathematical representation, measurement-technical reconstruction, and preparation of quantum states as well as their alteration by measurement. The main topics of the considerations are quantum-mechanical system states, the complet description of which pursues by means of density operators. The first chapter presents a general mathematical scheme for the representaion of density operators by means of projection operators. The second chapter explains a scheme for the syntehsis of Fock states by means of a linear mixer. The third chapter answers the question, whether spontaneous emitted light, which is emitted by an atom with large spatial extension, can show self-interferences and lets conclude on thee coherent structure of the c.m. wave function of the emitting atom. The last chapter reconstructs measurement results on the coherence loss of atoms in an atomic-beam experiment by spontaneous emission in the language of the density-operator formalism

  15. Discrimination of mixed quantum states. Reversible maps and unambiguous strategies

    Energy Technology Data Exchange (ETDEWEB)

    Kleinmann, Matthias

    2008-06-30

    The discrimination of two mixed quantum states is a fundamental task in quantum state estimation and quantum information theory. In quantum state discrimination a quantum system is assumed to be in one of two possible - in general mixed - non-orthogonal quantum states. The discrimination then consists of a measurement strategy that allows to decide in which state the system was before the measurement. In unambiguous state discrimination the aim is to make this decision without errors, but it is allowed to give an inconclusive answer. Especially interesting are measurement strategies that minimize the probability of an inconclusive answer. A starting point for the analysis of this optimization problem was a result by Eldar et al. [Phys. Rev. A 69, 062318 (2004)], which provides non-operational necessary and sufficient conditions for a given measurement strategy to be optimal. These conditions are reconsidered and simplified in such a way that they become operational. The simplified conditions are the basis for further central results: It is shown that the optimal measurement strategy is unique, a statement that is e.g. of importance for the complexity analysis of optimal measurement devices. The optimal measurement strategy is derived for the case, where one of the possible input states has at most rank two, which was an open problem for many years. Furthermore, using the optimality criterion it is shown that there always exists a threshold probability for each state, such that below this probability it is optimal to exclude this state from the discrimination strategy. If the two states subject to discrimination can be brought to a diagonal structure with (2 x 2)-dimensional blocks, then the unambiguous discrimination of these states can be reduced to the unambiguous discrimination of pure states. A criterion is presented that allows to identify the presence of such a structure for two self-adjoint operators. This criterion consists of the evaluation of three

  16. On asymptotic continuity of functions of quantum states

    International Nuclear Information System (INIS)

    Synak-Radtke, Barbara; Horodecki, Michal

    2006-01-01

    A useful kind of continuity of quantum states functions in asymptotic regime is so-called asymptotic continuity. In this letter, we provide general tools for checking if a function possesses this property. First we prove equivalence of asymptotic continuity with so-called robustness under admixture. This allows us to show that relative entropy distance from a convex set including a maximally mixed state is asymptotically continuous. Subsequently, we consider arrowing-a way of building a new function out of a given one. The procedure originates from constructions of intrinsic information and entanglement of formation. We show that arrowing preserves asymptotic continuity for a class of functions (so-called subextensive ones). The result is illustrated by means of several examples. (letter to the editor)

  17. Partial transpose of random quantum states: Exact formulas and meanders

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Motohisa [Zentrum Mathematik, M5, Technische Universitaet Muenchen, Boltzmannstrasse 3, 85748 Garching (Germany); Sniady, Piotr [Zentrum Mathematik, M5, Technische Universitaet Muenchen, Boltzmannstrasse 3, 85748 Garching (Germany); Institute of Mathematics, Polish Academy of Sciences, ul. Sniadeckich 8, 00-956 Warszawa (Poland); Institute of Mathematics, University of Wroclaw, pl. Grunwaldzki 2/4, 50-384 Wroclaw (Poland)

    2013-04-15

    We investigate the asymptotic behavior of the empirical eigenvalues distribution of the partial transpose of a random quantum state. The limiting distribution was previously investigated via Wishart random matrices indirectly (by approximating the matrix of trace 1 by the Wishart matrix of random trace) and shown to be the semicircular distribution or the free difference of two free Poisson distributions, depending on how dimensions of the concerned spaces grow. Our use of Wishart matrices gives exact combinatorial formulas for the moments of the partial transpose of the random state. We find three natural asymptotic regimes in terms of geodesics on the permutation groups. Two of them correspond to the above two cases; the third one turns out to be a new matrix model for the meander polynomials. Moreover, we prove the convergence to the semicircular distribution together with its extreme eigenvalues under weaker assumptions, and show large deviation bound for the latter.

  18. Partial transpose of random quantum states: Exact formulas and meanders

    Science.gov (United States)

    Fukuda, Motohisa; Śniady, Piotr

    2013-04-01

    We investigate the asymptotic behavior of the empirical eigenvalues distribution of the partial transpose of a random quantum state. The limiting distribution was previously investigated via Wishart random matrices indirectly (by approximating the matrix of trace 1 by the Wishart matrix of random trace) and shown to be the semicircular distribution or the free difference of two free Poisson distributions, depending on how dimensions of the concerned spaces grow. Our use of Wishart matrices gives exact combinatorial formulas for the moments of the partial transpose of the random state. We find three natural asymptotic regimes in terms of geodesics on the permutation groups. Two of them correspond to the above two cases; the third one turns out to be a new matrix model for the meander polynomials. Moreover, we prove the convergence to the semicircular distribution together with its extreme eigenvalues under weaker assumptions, and show large deviation bound for the latter.

  19. Wigner function and the probability representation of quantum states

    Directory of Open Access Journals (Sweden)

    Man’ko Margarita A.

    2014-01-01

    Full Text Available The relation of theWigner function with the fair probability distribution called tomographic distribution or quantum tomogram associated with the quantum state is reviewed. The connection of the tomographic picture of quantum mechanics with the integral Radon transform of the Wigner quasidistribution is discussed. The Wigner–Moyal equation for the Wigner function is presented in the form of kinetic equation for the tomographic probability distribution both in quantum mechanics and in the classical limit of the Liouville equation. The calculation of moments of physical observables in terms of integrals with the state tomographic probability distributions is constructed having a standard form of averaging in the probability theory. New uncertainty relations for the position and momentum are written in terms of optical tomograms suitable for directexperimental check. Some recent experiments on checking the uncertainty relations including the entropic uncertainty relations are discussed.

  20. Can We Observe the Gravitational Quantum States of Positronium?

    Directory of Open Access Journals (Sweden)

    P. Crivelli

    2015-01-01

    Full Text Available We consider the feasibility of observing the gravitational quantum states of positronium. The proposed scheme employs the flow-throw technique used for the first observation of this effect with neutrons. Collimation and Stark deceleration of Rydberg positronium atoms allow selecting the required velocity class. If this experiment could be realized with positronium, it would lead to a determination of g for this matter-antimatter system at the few % level. As discussed in this contribution, most of the required techniques are currently available but important milestones have to be demonstrated experimentally before such an experiment could become reality. Those are the efficient focusing of a bunched positron beam, Stark deceleration of Rydberg positronium, and its subsequent excitation into states with large angular momentum. We provide an estimate of the efficiencies we expect for these steps and assuming those could be confirmed we calculate the signal rate.

  1. Generating and using truly random quantum states in Mathematica

    Science.gov (United States)

    Miszczak, Jarosław Adam

    2012-01-01

    The problem of generating random quantum states is of a great interest from the quantum information theory point of view. In this paper we present a package for Mathematica computing system harnessing a specific piece of hardware, namely Quantis quantum random number generator (QRNG), for investigating statistical properties of quantum states. The described package implements a number of functions for generating random states, which use Quantis QRNG as a source of randomness. It also provides procedures which can be used in simulations not related directly to quantum information processing. Program summaryProgram title: TRQS Catalogue identifier: AEKA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKA_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 7924 No. of bytes in distributed program, including test data, etc.: 88 651 Distribution format: tar.gz Programming language: Mathematica, C Computer: Requires a Quantis quantum random number generator (QRNG, http://www.idquantique.com/true-random-number-generator/products-overview.html) and supporting a recent version of Mathematica Operating system: Any platform supporting Mathematica; tested with GNU/Linux (32 and 64 bit) RAM: Case dependent Classification: 4.15 Nature of problem: Generation of random density matrices. Solution method: Use of a physical quantum random number generator. Running time: Generating 100 random numbers takes about 1 second, generating 1000 random density matrices takes more than a minute.

  2. Deterministic quantum state transfer between remote qubits in cavities

    Science.gov (United States)

    Vogell, B.; Vermersch, B.; Northup, T. E.; Lanyon, B. P.; Muschik, C. A.

    2017-12-01

    Performing a faithful transfer of an unknown quantum state is a key challenge for enabling quantum networks. The realization of networks with a small number of quantum links is now actively pursued, which calls for an assessment of different state transfer methods to guide future design decisions. Here, we theoretically investigate quantum state transfer between two distant qubits, each in a cavity, connected by a waveguide, e.g., an optical fiber. We evaluate the achievable success probabilities of state transfer for two different protocols: standard wave packet shaping and adiabatic passage. The main loss sources are transmission losses in the waveguide and absorption losses in the cavities. While special cases studied in the literature indicate that adiabatic passages may be beneficial in this context, it remained an open question under which conditions this is the case and whether their use will be advantageous in practice. We answer these questions by providing a full analysis, showing that state transfer by adiabatic passage—in contrast to wave packet shaping—can mitigate the effects of undesired cavity losses, far beyond the regime of coupling to a single waveguide mode and the regime of lossless waveguides, as was proposed so far. Furthermore, we show that the photon arrival probability is in fact bounded in a trade-off between losses due to non-adiabaticity and due to coupling to off-resonant waveguide modes. We clarify that neither protocol can avoid transmission losses and discuss how the cavity parameters should be chosen to achieve an optimal state transfer.

  3. Probing quantum entanglement, quantum discord, classical correlation, and the quantum state without disturbing them

    International Nuclear Information System (INIS)

    Li Zhenni; Jin Jiasen; Yu Changshui

    2011-01-01

    We present schemes for a type of one-parameter bipartite quantum state to probe quantum entanglement, quantum discord, the classical correlation, and the quantum state based on cavity QED. It is shown that our detection does not influence all these measured quantities. We also discuss how the spontaneous emission introduced by our probe atom influences our detection.

  4. SALE, Quality Control of Analytical Chemical Measurements

    International Nuclear Information System (INIS)

    Bush, W.J.; Gentillon, C.D.

    1985-01-01

    1 - Description of problem or function: The Safeguards Analytical Laboratory Evaluation (SALE) program is a statistical analysis program written to analyze the data received from laboratories participating in the SALE quality control and evaluation program. The system is aimed at identifying and reducing analytical chemical measurement errors. Samples of well-characterized materials are distributed to laboratory participants at periodic intervals for determination of uranium or plutonium concentration and isotopic distributions. The results of these determinations are statistically evaluated and participants are informed of the accuracy and precision of their results. 2 - Method of solution: Various statistical techniques produce the SALE output. Assuming an unbalanced nested design, an analysis of variance is performed, resulting in a test of significance for time and analyst effects. A trend test is performed. Both within- laboratory and between-laboratory standard deviations are calculated. 3 - Restrictions on the complexity of the problem: Up to 1500 pieces of data for each nuclear material sampled by a maximum of 75 laboratories may be analyzed

  5. Block-free optical quantum Banyan network based on quantum state fusion and fission

    International Nuclear Information System (INIS)

    Zhu Chang-Hua; Meng Yan-Hong; Quan Dong-Xiao; Zhao Nan; Pei Chang-Xing

    2014-01-01

    Optical switch fabric plays an important role in building multiple-user optical quantum communication networks. Owing to its self-routing property and low complexity, a banyan network is widely used for building switch fabric. While, there is no efficient way to remove internal blocking in a banyan network in a classical way, quantum state fusion, by which the two-dimensional internal quantum states of two photons could be combined into a four-dimensional internal state of a single photon, makes it possible to solve this problem. In this paper, we convert the output mode of quantum state fusion from spatial-polarization mode into time-polarization mode. By combining modified quantum state fusion and quantum state fission with quantum Fredkin gate, we propose a practical scheme to build an optical quantum switch unit which is block free. The scheme can be extended to building more complex units, four of which are shown in this paper. (general)

  6. Chemicals for crop protection and pest control

    National Research Council Canada - National Science Library

    Green, Maurice B; Hartley, Gilbert Spencer; West, Trustham Frederick

    1977-01-01

    .... For the most part, the conventional classification into insecticides, herbicides and fungicides has been followed and some more specialized chemicals are also classified according to their biological...

  7. Chemical weed control in Spinach (Spiniacia oleracea

    Directory of Open Access Journals (Sweden)

    A. Modhej

    2016-03-01

    Full Text Available Introduction Spinach (Spinacia oleracea is an annual plant of family Chenopodiaceae. It is cultivated in temperate and cold regions in Khouzestan in autumn and winter. Weeds are the main problems that limit the production of vegetables. Competition ability of spinach against weeds is very low and weeds cause the loss of quality and quantity in this plant. Weeds reduce germination and establishment and growth of spinach. Weed management in spinach should be done at the beginning of the season. Hand weeding is the best way to control weeds spinach, although due to the high cost it is not cost effective, but is steel common in large areas. Weed control spinach, using chemical methods, the number of weeds are kept below the threshold of economic damage. Materials and Methods The experiment was conducted in a randomized complete block design with 15 treatments and three replications. Treatments included pre-plant application of EPTC at 5 and 6 lit ha-1, pre-plant application of Trifluralin at 2 lit ha-1, pre-plant and pre-emergence application of Pendimethalin at 3 lit ha-1, pre-emergence and post-emergence application of Meteribouzin at 300 g ha-1, pre-emergence and post-emergence application of Meteribouzin at 400 g ha-1, pre-emergence and post-emergence application of Imazethapyr at 0.7 lit ha-1, pre-emergence and post-emergence application of Imazethapyr at 1 lit ha-1, weedy and weed free checks. Each plot the size of 2.5 × 2 meters and 10 row cultivation with distances between rows of 15 cm and the distance between the plants 25 cm and the sowing depth was 3 cm. The herbicide treatments were applied to the back sprayer with Flat fan nozzle with volume of consumption of 240 lit ha-1 solution. The final harvest was about 50 days after emergence. Sampling of weeds 10 days before harvest was performed with using quadrate 0.5 ×0.5. Results Discussion Important broad-leaf and narrow leaf weeds observed in the field, included field bindweed

  8. Reordering of Nuclear Quantum States in Rare Isotopes

    Science.gov (United States)

    Flanagan, Kieran

    2010-02-01

    A key question in modern nuclear physics relates to the ordering of quantum states, and whether the predictions made by the shell model hold true far from stability. Recent innovations in technology and techniques at radioactive beam facilities have allowed access to rare isotopes previously inaccessible to experimentalists. Measurements that have been performed in several regions of the nuclear chart have yielded surprising and dramatic changes in nuclear structure, where level ordering is quite different than expected from previous theoretical descriptions. In order to reconcile the difference between experiment and theory, new shell-model interactions have been proposed, which include the role of the tensor force as part of the monopole term from the expansion of the residual proton-neutron interaction. This has motivated a series of laser spectroscopy experiments that have studied the neutron-rich copper and gallium isotopes at the ISOLDE facility. This work has deduced without nuclear-model dependence the spin, moments and charge radii. The results of this work and their implications for nuclear structure near ^78Ni will be discussed. )

  9. No-bang quantum state of the cosmos

    International Nuclear Information System (INIS)

    Page, Don N

    2008-01-01

    A quantum state of the entire cosmos (universe or multiverse) is proposed which is the equal mixture of the Giddings-Marolf states that are asymptotically single de Sitter spacetimes in both past and future and are regular on the throat or neck of minimal 3-volume. That is, states are excluded that have a big bang or big crunch or which split into multiple asymptotic de Sitter spacetimes. (For simplicity, transitions between different values of the cosmological constant are assumed not to occur, though different positive values are allowed.) The entropy of this mixed state appears to be of the order of the three-fourth power of the Bekenstein-Hawking A/4 entropy of de Sitter spacetime. Most of the component pure states do not have rapid inflation, but when an inflaton is present and the states are weighted by the volume at the end of inflation, a much smaller number of states may dominate and give a large amount of inflation and hence may agree with observations

  10. No-bang quantum state of the cosmos

    Energy Technology Data Exchange (ETDEWEB)

    Page, Don N [Institute for Theoretical Physics, Department of Physics, University of Alberta, Room 238 CEB, 11322-89 Avenue Edmonton, Alberta, T6G 2G7 (Canada)], E-mail: don@phys.ualberta.ca

    2008-08-07

    A quantum state of the entire cosmos (universe or multiverse) is proposed which is the equal mixture of the Giddings-Marolf states that are asymptotically single de Sitter spacetimes in both past and future and are regular on the throat or neck of minimal 3-volume. That is, states are excluded that have a big bang or big crunch or which split into multiple asymptotic de Sitter spacetimes. (For simplicity, transitions between different values of the cosmological constant are assumed not to occur, though different positive values are allowed.) The entropy of this mixed state appears to be of the order of the three-fourth power of the Bekenstein-Hawking A/4 entropy of de Sitter spacetime. Most of the component pure states do not have rapid inflation, but when an inflaton is present and the states are weighted by the volume at the end of inflation, a much smaller number of states may dominate and give a large amount of inflation and hence may agree with observations.

  11. Creation, Storage, and On-Demand Release of Optical Quantum States with a Negative Wigner Function

    Directory of Open Access Journals (Sweden)

    Jun-ichi Yoshikawa

    2013-12-01

    Full Text Available Highly nonclassical quantum states of light, characterized by Wigner functions with negative values, have been all-optically created so far only in a heralded fashion. In this case, the desired output emerges rarely and randomly from a quantum-state generator. An important example is the heralded production of high-purity single-photon states, typically based on some nonlinear optical interaction. In contrast, on-demand single-photon sources are also reported, exploiting the quantized level structure of matter systems. These sources, however, lead to highly impure output states, composed mostly of vacuum. While such impure states may still exhibit certain single-photon-like features such as antibunching, they are not nonclassical enough for advanced quantum-information processing. On the other hand, the intrinsic randomness of pure, heralded states can be circumvented by first storing and then releasing them on demand. Here, we propose such a controlled release, and we experimentally demonstrate it for heralded single photons. We employ two optical cavities, where the photons are both created and stored inside one cavity and finally released through a dynamical tuning of the other cavity. We demonstrate storage times of up to 300 ns while keeping the single-photon purity around 50% after storage. Our experiment is the first demonstration of a negative Wigner function at the output of an on-demand photon source or a quantum memory. In principle, our storage system is compatible with all kinds of nonclassical states, including those known to be essential for many advanced quantum-information protocols.

  12. Chemical Spill Prevention, Control, and Countermeasures Plan: 100 Areas

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Y.M.

    1989-06-01

    The purpose of this Chemical Spill Prevention, Control, and Countermeasures (SPCC) Plan is to identify the chemical spill control practices, procedures, and containment devices Westinghouse Hanford Company (Westinghouse Hanford) employs to prevent a reportable quantity (RQ) of a hazardous substance (as defined in 40 CFR Part 302) from being released to the environment. The chemical systems and chemical storage facilities in the 100 Areas are described. This document traces the ultimate fate of accidental chemical spills at the 100 Areas. Also included in the document destinations, spill containment devices, and systems surveillance frequencies. 2 tabs.

  13. Chemical Spill Prevention, Control, and Countermeasures Plan: 100 Areas

    International Nuclear Information System (INIS)

    Chien, Y.M.

    1989-06-01

    The purpose of this Chemical Spill Prevention, Control, and Countermeasures (SPCC) Plan is to identify the chemical spill control practices, procedures, and containment devices Westinghouse Hanford Company (Westinghouse Hanford) employs to prevent a reportable quantity (RQ) of a hazardous substance (as defined in 40 CFR Part 302) from being released to the environment. The chemical systems and chemical storage facilities in the 100 Areas are described. This document traces the ultimate fate of accidental chemical spills at the 100 Areas. Also included in the document destinations, spill containment devices, and systems surveillance frequencies. 2 tabs

  14. Synthetic biology expands chemical control of microorganisms.

    Science.gov (United States)

    Ford, Tyler J; Silver, Pamela A

    2015-10-01

    The tools of synthetic biology allow researchers to change the ways engineered organisms respond to chemical stimuli. Decades of basic biology research and new efforts in computational protein and RNA design have led to the development of small molecule sensors that can be used to alter organism function. These new functions leap beyond the natural propensities of the engineered organisms. They can range from simple fluorescence or growth reporting to pathogen killing, and can involve metabolic coordination among multiple cells or organisms. Herein, we discuss how synthetic biology alters microorganisms' responses to chemical stimuli resulting in the development of microbes as toxicity sensors, disease treatments, and chemical factories. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. A scheme of quantum state discrimination over specified states via weak-value measurement

    Science.gov (United States)

    Chen, Xi; Dai, Hong-Yi; Liu, Bo-Yang; Zhang, Ming

    2018-04-01

    The commonly adopted projective measurements are invalid in the specified task of quantum state discrimination when the discriminated states are superposition of planar-position basis states whose complex-number probability amplitudes have the same magnitude but different phases. Therefore we propose a corresponding scheme via weak-value measurement and examine the feasibility of this scheme. Furthermore, the role of the weak-value measurement in quantum state discrimination is analyzed and compared with one in quantum state tomography in this Letter.

  16. Preservation of quantum states via a super-Zeno effect on ensemble quantum computers

    International Nuclear Information System (INIS)

    Ting-Ting, Ren; Jun, Luo; Xian-Ping, Sun; Ming-Sheng, Zhan

    2009-01-01

    Following a recent proposal by Dhar et al (2006 Phys. Rev. Lett. 96 100405), we demonstrate experimentally the preservation of quantum states in a two-qubit system based on a super-Zeno effect using liquid-state nuclear magnetic resonance techniques. Using inverting radiofrequency pulses and delicately selecting time intervals between two pulses, we suppress the effect of decoherence of quantum states. We observe that preservation of the quantum state |11) with the super-Zeno effect is three times more efficient than the ordinary one with the standard Zeno effect. (general)

  17. Realization of quantum state privacy amplification in a nuclear magnetic resonance quantum system

    International Nuclear Information System (INIS)

    Hao, Liang; Wang, Chuan; Long, Gui Lu

    2010-01-01

    Quantum state privacy amplification (QSPA) is the quantum analogue of classical privacy amplification. If the state information of a series of single-particle states has some leakage, QSPA reduces this leakage by condensing the state information of two particles into the state of one particle. Recursive applications of the operations will eliminate the quantum state information leakage to a required minimum level. In this paper, we report the experimental implementation of a quantum state privacy amplification protocol in a nuclear magnetic resonance system. The density matrices of the states are constructed in the experiment, and the experimental results agree well with theory.

  18. The Control of Chemical and Biological Weapons.

    Science.gov (United States)

    Alexander, Archibald S.; And Others

    This book is composed of four papers prepared to illuminate the problem areas which might arise if the policies of the 1925 Geneva Protocol and other measures to limit chemical and biological weapons are ratified by the United States Senate. The papers included are: Legal Aspects of the Geneva Protocol of 1925; The Use of Herbicides in War: A…

  19. Tensor fields on orbits of quantum states and applications

    Energy Technology Data Exchange (ETDEWEB)

    Volkert, Georg Friedrich

    2010-07-19

    On classical Lie groups, which act by means of a unitary representation on finite dimensional Hilbert spaces H, we identify two classes of tensor field constructions. First, as pull-back tensor fields of order two from modified Hermitian tensor fields, constructed on Hilbert spaces by means of the property of having the vertical distributions of the C{sub 0}-principal bundle H{sub 0} {yields} P(H) over the projective Hilbert space P(H) in the kernel. And second, directly constructed on the Lie group, as left-invariant representation-dependent operator-valued tensor fields (LIROVTs) of arbitrary order being evaluated on a quantum state. Within the NP-hard problem of deciding whether a given state in a n-level bi-partite quantum system is entangled or separable (Gurvits, 2003), we show that both tensor field constructions admit a geometric approach to this problem, which evades the traditional ambiguity on defining metrical structures on the convex set of mixed states. In particular by considering manifolds associated to orbits passing through a selected state when acted upon by the local unitary group U(n) x U(n) of Schmidt coefficient decomposition inducing transformations, we find the following results: In the case of pure states we show that Schmidt-equivalence classes which are Lagrangian submanifolds define maximal entangled states. This implies a stronger statement as the one proposed by Bengtsson (2007). Moreover, Riemannian pull-back tensor fields split on orbits of separable states and provide a quantitative characterization of entanglement which recover the entanglement measure proposed by Schlienz and Mahler (1995). In the case of mixed states we highlight a relation between LIROVTs of order two and a class of computable separability criteria based on the Bloch-representation (de Vicente, 2007). (orig.)

  20. Tensor fields on orbits of quantum states and applications

    International Nuclear Information System (INIS)

    Volkert, Georg Friedrich

    2010-01-01

    On classical Lie groups, which act by means of a unitary representation on finite dimensional Hilbert spaces H, we identify two classes of tensor field constructions. First, as pull-back tensor fields of order two from modified Hermitian tensor fields, constructed on Hilbert spaces by means of the property of having the vertical distributions of the C 0 -principal bundle H 0 → P(H) over the projective Hilbert space P(H) in the kernel. And second, directly constructed on the Lie group, as left-invariant representation-dependent operator-valued tensor fields (LIROVTs) of arbitrary order being evaluated on a quantum state. Within the NP-hard problem of deciding whether a given state in a n-level bi-partite quantum system is entangled or separable (Gurvits, 2003), we show that both tensor field constructions admit a geometric approach to this problem, which evades the traditional ambiguity on defining metrical structures on the convex set of mixed states. In particular by considering manifolds associated to orbits passing through a selected state when acted upon by the local unitary group U(n) x U(n) of Schmidt coefficient decomposition inducing transformations, we find the following results: In the case of pure states we show that Schmidt-equivalence classes which are Lagrangian submanifolds define maximal entangled states. This implies a stronger statement as the one proposed by Bengtsson (2007). Moreover, Riemannian pull-back tensor fields split on orbits of separable states and provide a quantitative characterization of entanglement which recover the entanglement measure proposed by Schlienz and Mahler (1995). In the case of mixed states we highlight a relation between LIROVTs of order two and a class of computable separability criteria based on the Bloch-representation (de Vicente, 2007). (orig.)

  1. Separability of quantum states and the violation of Bell-type inequalities

    International Nuclear Information System (INIS)

    Loubenets, Elena R.

    2004-01-01

    In contrast to the widespread opinion that any separable quantum state satisfies every classical probabilistic constraint, we present a simple example where separable quantum state does not satisfy the original Bell inequality although the latter inequality, in its perfect correlation form, is valid for all joint classical measurements. In a very general setting, we discuss inequalities for joint experiments upon a bipartite quantum system. For any separable quantum state, we derive quantum analogs of the original Bell inequality and specify the conditions sufficient for a separable state to satisfy the original Bell inequality. We introduce the extended Clauser-Horne-Shimony-Holt inequality and prove that, for any separable quantum state, this inequality holds for a variety of linear combinations

  2. Construction of spaces of kinematic quantum states for field theories via projective techniques

    International Nuclear Information System (INIS)

    Okołów, Andrzej

    2013-01-01

    We present a method of constructing a space of quantum states for a field theory: given phase space of a theory, we define a family of physical systems each possessing a finite number of degrees of freedom, next we define a space of quantum states for each finite system, finally using projective techniques we organize all these spaces into a space of quantum states which corresponds to the original phase space. This construction is kinematic in this sense that it bases merely on the structure of the phase space of a theory and does not take into account possible constraints on the space. The construction is a generalization of a construction by Kijowski—the latter one is limited to theories of linear phase spaces, while the former one is free of this limitation. The method presented in this paper enables to construct a space of quantum states for the teleparallel equivalent of general relativity. (paper)

  3. General linear-optical quantum state generation scheme: Applications to maximally path-entangled states

    International Nuclear Information System (INIS)

    VanMeter, N. M.; Lougovski, P.; Dowling, Jonathan P.; Uskov, D. B.; Kieling, K.; Eisert, J.

    2007-01-01

    We introduce schemes for linear-optical quantum state generation. A quantum state generator is a device that prepares a desired quantum state using product inputs from photon sources, linear-optical networks, and postselection using photon counters. We show that this device can be concisely described in terms of polynomial equations and unitary constraints. We illustrate the power of this language by applying the Groebner-basis technique along with the notion of vacuum extensions to solve the problem of how to construct a quantum state generator analytically for any desired state, and use methods of convex optimization to identify bounds to success probabilities. In particular, we disprove a conjecture concerning the preparation of the maximally path-entangled |n,0>+|0,n> (NOON) state by providing a counterexample using these methods, and we derive a new upper bound on the resources required for NOON-state generation

  4. Direct estimation of elements of quantum states algebra and entanglement detection via linear contractions

    International Nuclear Information System (INIS)

    Horodecki, Pawel

    2003-01-01

    Possibility of some nonlinear-like operations in quantum mechanics are studied. Some general formula for real linear maps are derived. With the results we show how to perform physically separability tests based on any linear contraction (on product states) that either is real or Hermitian. We also show how to estimate either product or linear combinations of quantum states without knowledge about the states themselves. This can be viewed as a sort of quantum computing on quantum states algebra

  5. Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chen Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen (Germany); Ueta, Hirokazu; Beck, Rainer D. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne (Switzerland); Bisson, Regis [Aix-Marseille Universite, PIIM, CNRS, UMR 7345, 13397 Marseille (France)

    2013-05-15

    We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS). RAIRS is a non-invasive infrared spectroscopic detection technique that enables online monitoring of the buildup of reaction products on the target surface during reactant deposition by a molecular beam. The product uptake rate obtained by calibrated RAIRS detection yields the coverage dependent state-resolved reaction probability S({theta}). Furthermore, the infrared absorption spectra of the adsorbed products obtained by the RAIRS technique provide structural information, which help to identify nascent reaction products, investigate reaction pathways, and determine branching ratios for different pathways of a chemisorption reaction. Measurements of the dissociative chemisorption of methane on Pt(111) with this new apparatus are presented to illustrate the utility of RAIRS detection for highly detailed studies of chemical reactions at the gas/surface interface.

  6. Photodissociation of quantum state-selected diatomic molecules yields new insight into ultracold chemistry

    Science.gov (United States)

    McDonald, Mickey; McGuyer, Bart H.; Lee, Chih-Hsi; Apfelbeck, Florian; Zelevinsky, Tanya

    2016-05-01

    When a molecule is subjected to a sufficiently energetic photon it can break apart into fragments through a process called ``photodissociation''. For over 70 years this simple chemical reaction has served as a vital experimental tool for acquiring information about molecular structure, since the character of the photodissociative transition can be inferred by measuring the 3D photofragment angular distribution (PAD). While theoretical understanding of this process has gradually evolved from classical considerations to a fully quantum approach, experiments to date have not yet revealed the full quantum nature of this process. In my talk I will describe recent experiments involving the photodissociation of ultracold, optical lattice-trapped, and fully quantum state-resolved 88Sr2 molecules. Optical absorption images of the PADs produced in these experiments reveal features which are inherently quantum mechanical in nature, such as matter-wave interference between output channels, and are sensitive to the quantum statistics of the molecular wavefunctions. The results of these experiments cannot be predicted using quasiclassical methods. Instead, we describe our results with a fully quantum mechanical model yielding new intuition about ultracold chemistry.

  7. Chemical controls on subsurface radionuclide transport

    International Nuclear Information System (INIS)

    King, K.J.; Killey, R.W.D.

    1990-01-01

    Chemical and biochemical processes can affect the movement of contaminants in groundwater. Materials can be almost completely removed from circulation by processes such as precipitation and coprecipitation. Organic compounds or contaminants that are hazardous may be degraded or formed during groundwater transport. Studies at the Chalk River Laboratories of AECL have focused on radionuclide transport, although other contaminants have been and are being investigated. This paper summarizes findings from research that extends back more than 30 years. Much of the work on reactive contaminant transport has centered on 90 Sr; other contaminants have also been considered, however, and features of their behaviour are also reviewed. (25 refs., 5 figs., 4 tabs.)

  8. Quality Control Guidelines for SAM Chemical Methods

    Science.gov (United States)

    Learn more about quality control guidelines and recommendations for the analysis of samples using the chemistry methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  9. Active disturbance rejection controller for chemical reactor

    International Nuclear Information System (INIS)

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I.

    2015-01-01

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method

  10. Active disturbance rejection controller for chemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I., E-mail: roxana.both@aut.utcluj.ro [Technical University of Cluj-Napoca, 400114 Cluj-Napoca (Romania)

    2015-03-10

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method.

  11. Physical chemical quality control of the molybdenum technetium generator

    International Nuclear Information System (INIS)

    Olive, E.; Cruz, J.; Isaac, M.; Gamboa, R.; D'Alessandro, K.; Desdin, L.F.

    1995-01-01

    Comparative operational procedure imported molybdenum technetium generators have been made. Procedures for determination of chemical, radiochemical and radionuclidic purities that may be applied in Hospital's laboratories and in the quality control of generators production are developed

  12. NONLINEAR MODEL PREDICTIVE CONTROL OF CHEMICAL PROCESSES

    Directory of Open Access Journals (Sweden)

    SILVA R. G.

    1999-01-01

    Full Text Available A new algorithm for model predictive control is presented. The algorithm utilizes a simultaneous solution and optimization strategy to solve the model's differential equations. The equations are discretized by equidistant collocation, and along with the algebraic model equations are included as constraints in a nonlinear programming (NLP problem. This algorithm is compared with the algorithm that uses orthogonal collocation on finite elements. The equidistant collocation algorithm results in simpler equations, providing a decrease in computation time for the control moves. Simulation results are presented and show a satisfactory performance of this algorithm.

  13. Controlling the accuracy of chemical analysis

    International Nuclear Information System (INIS)

    Suschny, O.; Danesi, P.R.

    1991-01-01

    The involvement of the IAEA in quantitative analysis began in the early 1960's with radiochemical work connected with the environment. It than expanded to cover analysis (mostly by nuclear techniques) of samples for projects associated with human health, agriculture, hydrology and international safeguards. This article highlights the IAEA activities in the field of quality control in quantitative analysis

  14. Chemical sensors and gas sensors for process control in biotechnology

    International Nuclear Information System (INIS)

    Williams, D.E.

    1988-04-01

    This paper is concerned with the possibilities for chemical measurement of the progress of biotechnological processes which are offered by devices already developed for other demanding applications. It considers the potential use of ultrasonic instrumentation originally developed for the nuclear industry, gas measurement methods from the fields of environmental monitoring and combustion control, nuclear instruments developed for the oil, mining and chemical industries, robotic systems and advanced control techniques. (author)

  15. Chemical factors that control lignin polymerization.

    Science.gov (United States)

    Sangha, Amandeep K; Davison, Brian H; Standaert, Robert F; Davis, Mark F; Smith, Jeremy C; Parks, Jerry M

    2014-01-09

    Lignin is a complex, branched polymer that reinforces plant tissue. Understanding the factors that govern lignin structure is of central importance to the development of technologies for converting lignocellulosic biomass into fuels because lignin imparts resistance to chemical, enzymatic, and mechanical deconstruction. Lignin is formed by enzymatic oxidation of phenolic monomers (monolignols) of three main types, guaiacyl (G), syringyl (S), and p-hydroxyphenyl (H) subunits. It is known that increasing the relative abundance of H subunits results in lower molecular weight lignin polymers and hence more easily deconstructed biomass, but it is not known why. Here, we report an analysis of frontier molecular orbitals in mono-, di-, and trilignols, calculated using density functional theory, which points to a requirement of strong p-electron density on the reacting phenolic oxygen atom of the neutral precursor for enzymatic oxidation to occur. This model is consistent with a proton-coupled electron transfer (PCET) mechanism and for the first time explains why H subunits in certain linkages (β-β or β-5) react poorly and tend to "cap" the polymer. In general, β-5 linkages with either a G or H terminus are predicted to inhibit elongation. More broadly, the model correctly accounts for the reactivity of the phenolic groups in a diverse set of dilignols comprising H and G subunits. Thus, we provide a coherent framework for understanding the propensity toward growth or termination of different terminal subunits in lignin.

  16. Bulk and interface quantum states of electrons in multi-layer heterostructures with topological materials

    Science.gov (United States)

    Nikolic, Aleksandar; Zhang, Kexin; Barnes, C. H. W.

    2018-06-01

    In this article we describe the bulk and interface quantum states of electrons in multi-layer heterostructures in one dimension, consisting of topological insulators (TIs) and topologically trivial materials. We use and extend an effective four-band continuum Hamiltonian by introducing position dependence to the eight material parameters of the Hamiltonian. We are able to demonstrate complete conduction-valence band mixing in the interface states. We find evidence for topological features of bulk states of multi-layer TI heterostructures, as well as demonstrating both complete and incomplete conduction-valence band inversion at different bulk state energies. We show that the linear k z terms in the low-energy Hamiltonian, arising from overlap of p z orbitals between different atomic layers in the case of chalcogenides, control the amount of tunneling from TIs to trivial insulators. Finally, we show that the same linear k z terms in the low-energy Hamiltonian affect the material’s ability to form the localised interface state, and we demonstrate that due to this effect the spin and probability density localisation in a thin film of Sb2Te3 is incomplete. We show that changing the parameter that controls the magnitude of the overlap of p z orbitals affects the transport characteristics of the topologically conducting states, with incomplete topological state localisation resulting in increased backscattering.

  17. High precision optical spectroscopy and quantum state selected photodissociation of ultracold 88Sr2 molecules in an optical lattice

    Science.gov (United States)

    McDonald, Mickey

    2017-04-01

    Over the past several decades, rapid progress has been made toward the accurate characterization and control of atoms, epitomized by the ever-increasing accuracy and precision of optical atomic lattice clocks. Extending this progress to molecules will have exciting implications for chemistry, condensed matter physics, and precision tests of physics beyond the Standard Model. My thesis describes work performed over the past six years to establish the state of the art in manipulation and quantum control of ultracold molecules. We describe a thorough set of measurements characterizing the rovibrational structure of weakly bound 88Sr2 molecules from several different perspectives, including determinations of binding energies; linear, quadratic, and higher order Zeeman shifts; transition strengths between bound states; and lifetimes of narrow subradiant states. Finally, we discuss measurements of photofragment angular distributions produced by photodissociation of molecules in single quantum states, leading to an exploration of quantum-state-resolved ultracold chemistry. The images of exploding photofragments produced in these studies exhibit dramatic interference effects and strongly violate semiclassical predictions, instead requiring a fully quantum mechanical description.

  18. Neural-Network Quantum States, String-Bond States, and Chiral Topological States

    Science.gov (United States)

    Glasser, Ivan; Pancotti, Nicola; August, Moritz; Rodriguez, Ivan D.; Cirac, J. Ignacio

    2018-01-01

    Neural-network quantum states have recently been introduced as an Ansatz for describing the wave function of quantum many-body systems. We show that there are strong connections between neural-network quantum states in the form of restricted Boltzmann machines and some classes of tensor-network states in arbitrary dimensions. In particular, we demonstrate that short-range restricted Boltzmann machines are entangled plaquette states, while fully connected restricted Boltzmann machines are string-bond states with a nonlocal geometry and low bond dimension. These results shed light on the underlying architecture of restricted Boltzmann machines and their efficiency at representing many-body quantum states. String-bond states also provide a generic way of enhancing the power of neural-network quantum states and a natural generalization to systems with larger local Hilbert space. We compare the advantages and drawbacks of these different classes of states and present a method to combine them together. This allows us to benefit from both the entanglement structure of tensor networks and the efficiency of neural-network quantum states into a single Ansatz capable of targeting the wave function of strongly correlated systems. While it remains a challenge to describe states with chiral topological order using traditional tensor networks, we show that, because of their nonlocal geometry, neural-network quantum states and their string-bond-state extension can describe a lattice fractional quantum Hall state exactly. In addition, we provide numerical evidence that neural-network quantum states can approximate a chiral spin liquid with better accuracy than entangled plaquette states and local string-bond states. Our results demonstrate the efficiency of neural networks to describe complex quantum wave functions and pave the way towards the use of string-bond states as a tool in more traditional machine-learning applications.

  19. Ecologically sustainable chemical recommendations for agricultural pest control?

    Science.gov (United States)

    Thomson, Linda J; Hoffmann, Ary A

    2007-12-01

    Effective pest control remains an essential part of food production, and it is provided both by chemicals and by natural enemies within agricultural ecosystems. These methods of control are often in conflict because of the negative impact of chemicals on natural enemies. There are already well-established approaches such as those provided by the International Organization for Biological and Integrated Control-Pesticides and Beneficial Organisms for testing, collecting, and publishing information on responses of natural enemies to chemicals based on laboratory responses of specific organisms; however, these tests do not assess the cumulative impact of chemical inputs across an entire season or consider impacts on the complex communities of natural enemies that can provide effective pest control on a farm. Here, we explore the potential of different approaches for assessing the impact of chemicals on agricultural ecosystems and we propose a simple metric for sustainable chemical use on farms that minimizes overall impact on beneficial groups. We suggest ways in which the effectiveness of metrics can be extended to include persistence and habitat features. Such metrics can assist farmers in developing targets for sustainable chemical use as demonstrated in the viticultural industry.

  20. Chemical mechanisms in mercury emission control technologies

    Energy Technology Data Exchange (ETDEWEB)

    Olson, E.S.; Laumb, J.D.; Benson, S.A.; Dunham, G.E.; Sharma, R.K.; Mibeck, B.A.; Miller, S.J.; Holmes, M.J.; Pavlish, J.H. [University of North Dakota, Energy and Environmental Research Center, Grand Forks, ND (United States)

    2003-05-01

    The emission of elemental mercury in the flue gas from coal-burning power plants is a major environmental concern. Control technologies utilizing activated carbon show promise and are currently under intense review. Oxidation and capture of elemental mercury on activated carbon was extensively investigated in a variety of flue gas atmospheres. Extensive parametric testing with individual and a variety of combinations and concentrations of reactive flue gas components and spectroscopic examination of the sulfur and chlorine forms present before and after breakthrough have led to an improved model to explain the kinetic and capacity results. The improved model delineates the independent Lewis acid oxidation site as well as a zig-zag carbene site on the carbon edge that performs as a Lewis base in reacting with both the oxidized mercury formed at the oxidation site and with the acidic flue gas components in competing reactions to form organochlorine, sulfinate, and sulfate ester moieties on the carbon edge.

  1. Remote interactions on two distributed quantum systems: nonlocal unambiguous quantum-state discrimination

    International Nuclear Information System (INIS)

    Chen Libing; Jin Ruibo; Lu Hong

    2008-01-01

    Remote quantum-state discrimination is a critical step for the implementation of quantum communication network and distributed quantum computation. We present a protocol for remotely implementing the unambiguous discrimination between nonorthogonal states using quantum entanglements, local operations, and classical communications. This protocol consists of a remote generalized measurement described by a positive operator valued measurement (POVM). We explicitly construct the required remote POVM. The remote POVM can be realized by performing a nonlocal controlled-rotation operation on two spatially separated qubits, one is an ancillary qubit and the other is the qubit which is encoded by two nonorthogonal states to be distinguished, and a conventional local Von Neumann orthogonal measurement on the ancilla. The particular pair of states that can be remotely and unambiguously distinguished is specified by the state of the ancilla. The probability of successful discrimination is not optimal for all admissible pairs. However, for some subset it can be very close to an optimal value in an ordinary local POVM

  2. Regression relation for pure quantum states and its implications for efficient computing.

    Science.gov (United States)

    Elsayed, Tarek A; Fine, Boris V

    2013-02-15

    We obtain a modified version of the Onsager regression relation for the expectation values of quantum-mechanical operators in pure quantum states of isolated many-body quantum systems. We use the insights gained from this relation to show that high-temperature time correlation functions in many-body quantum systems can be controllably computed without complete diagonalization of the Hamiltonians, using instead the direct integration of the Schrödinger equation for randomly sampled pure states. This method is also applicable to quantum quenches and other situations describable by time-dependent many-body Hamiltonians. The method implies exponential reduction of the computer memory requirement in comparison with the complete diagonalization. We illustrate the method by numerically computing infinite-temperature correlation functions for translationally invariant Heisenberg chains of up to 29 spins 1/2. Thereby, we also test the spin diffusion hypothesis and find it in a satisfactory agreement with the numerical results. Both the derivation of the modified regression relation and the justification of the computational method are based on the notion of quantum typicality.

  3. Geometric measure of quantum discord and total quantum correlations in an N-partite quantum state

    International Nuclear Information System (INIS)

    Hassan, Ali Saif M; Joag, Pramod S

    2012-01-01

    Quantum discord, as introduced by Ollivier and Zurek (2001 Phys. Rev. Lett. 88 017901), is a measure of the discrepancy between quantum versions of two classically equivalent expressions for mutual information and is found to be useful in quantification and application of quantum correlations in mixed states. It is viewed as a key resource present in certain quantum communication tasks and quantum computational models without containing much entanglement. An early step toward the quantification of quantum discord in a quantum state was by Dakic et al (2010 Phys. Rev. Lett. 105 190502) who introduced a geometric measure of quantum discord and derived an explicit formula for any two-qubit state. Recently, Luo and Fu (2010 Phys. Rev. A 82 034302) introduced a generic form of the geometric measure of quantum discord for a bipartite quantum state. We extend these results and find generic forms of the geometric measure of quantum discord and total quantum correlations in a general N-partite quantum state. Further, we obtain computable exact formulas for the geometric measure of quantum discord and total quantum correlations in an N-qubit quantum state. The exact formulas for the N-qubit quantum state can be used to get experimental estimates of the quantum discord and the total quantum correlation. (paper)

  4. Chemical weed control in barley (hordeum vulgare)

    International Nuclear Information System (INIS)

    Sarwar, M.; Hassan, S.W.; Abid, A.A.

    2008-01-01

    Effect of two different pre-emergence herbicides i.e. Terbutryn (lgron-500FW) A, 1.01.25 kg a.t. ha/sup -1/ and Flurochloridone (Racer-25 CS) a 0.31, 0.37, 0.44, 0.50 and 0.56 Kg a.i. ha/sup -1/ on weeds and yield of barley wad studied under field conditions hb/sup -1/. All the herbicides significantly reduce the dry weight of weed Maximum reduction (70%) was observed in terbutryn a 1.0 Kg a.i. ha/sup -1/ Growth and yield parameters like number of spike lets per spike. Number of grams per spike. 1000-grain weight. Biological yield. Grain yield straw yield and harvest index showed significant response to various herbicides doses under study. Application of Flurochloridone (Racer-25 (CS) a 0.44 kg a.i. ha/sup -1/ and Terbutryn (lgran-500 FW) a 1.0 kg a.i). The data further revealed that in general all herbicide application treatments exhibited superior performance in respect of growth and yield over control. (author)

  5. Towards room temperature solid state quantum devices at the edge of quantum chaos for long-living quantum states

    International Nuclear Information System (INIS)

    Prati, Enrico

    2015-01-01

    Long living coherent quantum states have been observed in biological systems up to room temperature. Light harvesting in chromophoresis realized by excitonic systems living at the edge of quantum chaos, where energy level distribution becomes semi-Poissonian. On the other hand, artificial materials suffer the loss of coherence of quantum states in quantum information processing, but semiconductor materials are known to exhibit quantum chaotic conditions, so the exploitation of similar conditions are to be considered. The advancements of nanofabrication, together with the control of implantation of individual atoms at nanometric precision, may open the experimental study of such special regime at the edge of the phase transitions for the electronic systems obtained by implanting impurity atoms in a silicon transistor. Here I review the recent advancements made in the field of theoretical description of the light harvesting in biological system in its connection with phase transitions at the few atoms scale and how it would be possible to achieve transition point to quantum chaotic regime. Such mechanism may thus preserve quantum coherent states at room temperature in solid state devices, to be exploited for quantum information processing as well as dissipation-free quantum electronics. (paper)

  6. Chemical and physical quality control of the HIPPURAN-131I

    International Nuclear Information System (INIS)

    Morin Zorilla, J.; Olive, E.; Isaac, M.; Cruz, J.

    1989-01-01

    Some physico-chemical methods for analytical control of Hippuran- 131 I are compared. The most convenient to applicate in hospitals and in more specialized quality control laboratories are recommended. The quality of Hippuran- 131 I produced by ISOTOP (USSR) is also evaluated. The product met the requirement of the International Pharmacopeia

  7. Temporal Control over Transient Chemical Systems using Structurally Diverse Chemical Fuels.

    Science.gov (United States)

    Chen, Jack L-Y; Maiti, Subhabrata; Fortunati, Ilaria; Ferrante, Camilla; Prins, Leonard J

    2017-08-25

    The next generation of adaptive, intelligent chemical systems will rely on a continuous supply of energy to maintain the functional state. Such systems will require chemical methodology that provides precise control over the energy dissipation process, and thus, the lifetime of the transiently activated function. This manuscript reports on the use of structurally diverse chemical fuels to control the lifetime of two different systems under dissipative conditions: transient signal generation and the transient formation of self-assembled aggregates. The energy stored in the fuels is dissipated at different rates by an enzyme, which installs a dependence of the lifetime of the active system on the chemical structure of the fuel. In the case of transient signal generation, it is shown that different chemical fuels can be used to generate a vast range of signal profiles, allowing temporal control over two orders of magnitude. Regarding self-assembly under dissipative conditions, the ability to control the lifetime using different fuels turns out to be particularly important as stable aggregates are formed only at well-defined surfactant/fuel ratios, meaning that temporal control cannot be achieved by simply changing the fuel concentration. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The statutory approach: the control of chemical products

    International Nuclear Information System (INIS)

    Briens, F.

    1997-01-01

    The evaluation and management of risks linked with chemical products and in particular with petroleum products is now performed using all the available tools developed by the OECD or the European Union in order to harmonize the procedures between member states. This paper describes the statutory liabilities linked to the trade of chemical products of industrial use in the case of new and of existing chemical substances (classification, labelling, risk evaluation and reduction, physico-chemical properties, toxicological and eco-toxicological studies, neutralization, limitation of trade and use, import/export, protection of the ozone layer, etc..). It refers to the legal framework (orders, by-laws, decrees, guidelines..) defined by the OECD and the European Community and recalls the organization and administration of the competent authorities for the control of chemical products. (J.S.)

  9. Versatile Dual Photoresponsive System for Precise Control of Chemical Reactions.

    Science.gov (United States)

    Xu, Can; Bing, Wei; Wang, Faming; Ren, Jinsong; Qu, Xiaogang

    2017-08-22

    A versatile method for photoregulation of chemical reactions was developed through a combination of near-infrared (NIR) and ultraviolet (UV) light sensitive materials. This regulatory effect was achieved through photoresponsive modulation of reaction temperature and pH values, two prominent factors influencing reaction kinetics. Photothermal nanomaterial graphene oxide (GO) and photobase reagent malachite green carbinol base (MGCB) were selected for temperature and pH regulation, respectively. Using nanocatalyst- and enzyme-mediated chemical reactions as model systems, we demonstrated the feasibility and high efficiency of this method. In addition, a photoresponsive, multifunctional "Band-aid"-like hydrogel platform was presented for programmable wound healing. Overall, this simple, efficient, and reversible system was found to be effective for controlling a wide variety of chemical reactions. Our work may provide a method for remote and sustainable control over chemical reactions for industrial and biomedical applications.

  10. An impurity-induced gap system as a quantum data bus for quantum state transfer

    International Nuclear Information System (INIS)

    Chen, Bing; Li, Yong; Song, Z.; Sun, C.-P.

    2014-01-01

    We introduce a tight-binding chain with a single impurity to act as a quantum data bus for perfect quantum state transfer. Our proposal is based on the weak coupling limit of the two outermost quantum dots to the data bus, which is a gapped system induced by the impurity. By connecting two quantum dots to two sites of the data bus, the system can accomplish a high-fidelity and long-distance quantum state transfer. Numerical simulations for finite system show that the numerical and analytical results of the effective coupling strength agree well with each other. Moreover, we study the robustness of this quantum communication protocol in the presence of disorder in the couplings between the nearest-neighbor quantum dots. We find that the gap of the system plays an important role in robust quantum state transfer

  11. Optimal dynamics for quantum-state and entanglement transfer through homogeneous quantum systems

    International Nuclear Information System (INIS)

    Banchi, L.; Apollaro, T. J. G.; Cuccoli, A.; Vaia, R.; Verrucchi, P.

    2010-01-01

    The capability of faithfully transmit quantum states and entanglement through quantum channels is one of the key requirements for the development of quantum devices. Different solutions have been proposed to accomplish such a challenging task, which, however, require either an ad hoc engineering of the internal interactions of the physical system acting as the channel or specific initialization procedures. Here we show that optimal dynamics for efficient quantum-state and entanglement transfer can be attained in generic quantum systems with homogeneous interactions by tuning the coupling between the system and the two attached qubits. We devise a general procedure to determine the optimal coupling, and we explicitly implement it in the case of a channel consisting of a spin-(1/2)XY chain. The quality of quantum-state and entanglement transfer is found to be very good and, remarkably, almost independent of the channel length.

  12. The hydrogen atom-deuterium molecule reaction: Experimental determination of product quantum state distributions

    International Nuclear Information System (INIS)

    Rinnen, K.

    1989-01-01

    The H + H 2 atom exchange reaction (and its isotopic analogs) is the simplest neutral bimolecular chemical reaction because of the small number of electrons in the system and the lightness of the nuclei. The H 3 potential energy surface (PES) is the most accurately known reactive surface (LSTH surface); there have been both quasiclassical trajectory (QCT) and quantal calculations performed on it. This is one of the few systems for which theory is ahead of experiment, and many theoretical predictions await experimental comparison. The H + D 2 → HD + D reaction is studied using thermal D 2 (∼298 K) and translationally hot hydrogen atoms. Photolysis of HI at 266 nm generates H atoms with center-of-mass collision energies of 1.3 and 0.55 eV, both of which are above the classical reaction barrier of 0.42 eV. The rovibrational population distribution of the molecular product is measured by (2+1) resonance-enhanced multiphoton ionization (REMPI). A major effort has been directed toward calibrating the (2+1) REMPI detection procedure, to determine quantitatively the relationship between ion signals and relative quantum state populations for HD. An effusive, high-temperature nozzle has been constructed to populate thermally the high rovibrational levels observed in the reaction. The results are compared to theoretical calculations of the E,F 1 Σ g + - X 1 Σ g + two-photon transition moments. For the H + D 2 reaction, the populations of all energetically accessible HD product levels are measured. Specifically, the following levels are observed: HD(v = 0, J = 0-15), HD(v = 1, J = 0-12), and HD(v = 2, J = 0-8). Of the available energy, 73% is partitioned into product translation, 18% into HD rotation, and 9% into HD vibration

  13. Is the Quantum State Real? An Extended Review of ψ-ontology Theorems

    Directory of Open Access Journals (Sweden)

    Matthew Saul Leifer

    2014-11-01

    Full Text Available Towards the end of 2011, Pusey, Barrett and Rudolph derived a theorem that aimed to show that the quantum state must be ontic (a state of reality in a broad class of realist approaches to quantum theory. This result attracted a lot of attention and controversy. The aim of this review article is to review the background to the Pusey–Barrett–Rudolph Theorem, to provide a clear presentation of the theorem itself, and to review related work that has appeared since the publication of the Pusey–Barrett–Rudolph paper. In particular, this review: Explains what it means for the quantum state to be ontic or epistemic (a state of knowledge; Reviews arguments for and against an ontic interpretation of the quantum state as they existed prior to the Pusey–Barrett–Rudolph Theorem; Explains why proving the reality of the quantum state is a very strong constraint on realist theories in that it would imply many of the known no-go theorems, such as Bell's Theorem and the need for an exponentially large ontic state space; Provides a comprehensive presentation of the Pusey–Barrett–Rudolph Theorem itself, along with subsequent improvements and criticisms of its assumptions; Reviews two other arguments for the reality of the quantum state: the first due to Hardy and the second due to Colbeck and Renner, and explains why their assumptions are less compelling than those of the Pusey–Barrett–Rudolph Theorem; Reviews subsequent work aimed at ruling out stronger notions of what it means for the quantum state to be epistemic and points out open questions in this area. The overall aim is not only to provide the background needed for the novice in this area to understand the current status, but also to discuss often overlooked subtleties that should be of interest to the experts. Quanta 2014; 3: 67–155.

  14. Determining treatment frequency for controlling weeds on traffic islands using chemical and non-chemical weed control

    DEFF Research Database (Denmark)

    Rask, Anne Merete; Larsen, S.U.; Andreasen, Christian

    2013-01-01

    Many public authorities rely on the use of non-chemical weed control methods, due to stringent restrictions on herbicide use in urban areas. However, these methods usually require more repeated treatments than chemical weed management, resulting in increased costs of weed management. In order...... of treatments per year were required: glyphosate 2.5, hot water 3, flames 5, hot air/flames 5.5 and steam 5.5 treatments. The results demonstrate that the weed control should be adjusted to the prescribed quality for the traffic islands by regularly assessing the need for weed control. They also show...... to investigate the efficacy of four non-chemical weed control methods and glyphosate treatment, experiments were carried out on traffic islands in the growing seasons 2005 and 2006. Three trial sites were each divided into six treatment areas, which were either treated with glyphosate, flame, steam, hot air...

  15. Hierarchical optimal control of large-scale nonlinear chemical processes.

    Science.gov (United States)

    Ramezani, Mohammad Hossein; Sadati, Nasser

    2009-01-01

    In this paper, a new approach is presented for optimal control of large-scale chemical processes. In this approach, the chemical process is decomposed into smaller sub-systems at the first level, and a coordinator at the second level, for which a two-level hierarchical control strategy is designed. For this purpose, each sub-system in the first level can be solved separately, by using any conventional optimization algorithm. In the second level, the solutions obtained from the first level are coordinated using a new gradient-type strategy, which is updated by the error of the coordination vector. The proposed algorithm is used to solve the optimal control problem of a complex nonlinear chemical stirred tank reactor (CSTR), where its solution is also compared with the ones obtained using the centralized approach. The simulation results show the efficiency and the capability of the proposed hierarchical approach, in finding the optimal solution, over the centralized method.

  16. Control of chemical dynamics by lasers: theoretical considerations.

    Science.gov (United States)

    Kondorskiy, Alexey; Nanbu, Shinkoh; Teranishi, Yoshiaki; Nakamura, Hiroki

    2010-06-03

    Theoretical ideas are proposed for laser control of chemical dynamics. There are the following three elementary processes in chemical dynamics: (i) motion of the wave packet on a single adiabatic potential energy surface, (ii) excitation/de-excitation or pump/dump of wave packet, and (iii) nonadiabatic transitions at conical intersections of potential energy surfaces. A variety of chemical dynamics can be controlled, if we can control these three elementary processes as we desire. For (i) we have formulated the semiclassical guided optimal control theory, which can be applied to multidimensional real systems. The quadratic or periodic frequency chirping method can achieve process (ii) with high efficiency close to 100%. Concerning process (iii) mentioned above, the directed momentum method, in which a predetermined momentum vector is given to the initial wave packet, makes it possible to enhance the desired transitions at conical intersections. In addition to these three processes, the intriguing phenomenon of complete reflection in the nonadiabatic-tunneling-type of potential curve crossing can also be used to control a certain class of chemical dynamics. The basic ideas and theoretical formulations are provided for the above-mentioned processes. To demonstrate the effectiveness of these controlling methods, numerical examples are shown by taking the following processes: (a) vibrational photoisomerization of HCN, (b) selective and complete excitation of the fine structure levels of K and Cs atoms, (c) photoconversion of cyclohexadiene to hexatriene, and (d) photodissociation of OHCl to O + HCl.

  17. Cryptanalysis of Multiparty Quantum Secret Sharing of Quantum State Using Entangled States

    International Nuclear Information System (INIS)

    Su-Juan, Qin; Qiao-Yan, Wen; Fu-Chen, Zhu

    2008-01-01

    Security of a quantum secret sharing of quantum state protocol proposed by Guo et al. [Chin. Phys. Lett. 25 (2008) 16] is reexamined. It is shown that an eavesdropper can obtain some of the transmitted secret information by monitoring the classical channel or the entire secret by intercepting the quantum states, and moreover, the eavesdropper can even maliciously replace the secret message with an arbitrary message without being detected. Finally, the deep reasons why an eavesdropper can attack this protocol are discussed and the modified protocol is presented to amend the security loopholes

  18. Correlations in local measurements on a quantum state, and complementarity as an explanation of nonclassicality

    DEFF Research Database (Denmark)

    Wu, Shengjun; Poulsen, Uffe Vestergaard; Mølmer, Klaus

    2009-01-01

    and the classical correlations and we relate our quantitative finding to the so-called classical correlation locked in a quantum state. We derive upper bounds for the sum of classical correlation obtained by measurements in different mutually unbiased bases and we show that the complementarity gap is also present......We consider the classical correlations that two observers can extract by measurements on a bipartite quantum state and we discuss how they are related to the quantum mutual information of the state. We show with several examples how complementarity gives rise to a gap between the quantum...... in the deterministic quantum computation with one quantum bit....

  19. Nonexistence of a universal quantum machine to examine the precision of unknown quantum states

    International Nuclear Information System (INIS)

    Pang, Shengshi; Wu, Shengjun; Chen, Zeng-Bing

    2011-01-01

    In this work, we reveal a type of impossibility discovered in our recent research which forbids comparing the closeness of multiple unknown quantum states with any nontrivial threshold in a perfect or unambiguous way. This impossibility is distinct from the existing impossibilities in that it is a ''collective'' impossibility on multiple quantum states; most other ''no-go'' theorems are concerned with only one single state each time, i.e., it is an impossibility on a nonlocal quantum operation. This impossibility may provide new insight into the nature of quantum mechanics, and it implies more limitations on quantum information tasks than the existing no-go theorems.

  20. Efficient quantum state transfer in an engineered chain of quantum bits

    Science.gov (United States)

    Sandberg, Martin; Knill, Emanuel; Kapit, Eliot; Vissers, Michael R.; Pappas, David P.

    2016-03-01

    We present a method of performing quantum state transfer in a chain of superconducting quantum bits. Our protocol is based on engineering the energy levels of the qubits in the chain and tuning them all simultaneously with an external flux bias. The system is designed to allow sequential adiabatic state transfers, resulting in on-demand quantum state transfer from one end of the chain to the other. Numerical simulations of the master equation using realistic parameters for capacitive nearest-neighbor coupling, energy relaxation, and dephasing show that fast, high-fidelity state transfer should be feasible using this method.

  1. QED Effects in Molecules: Test on Rotational Quantum States of H2

    Science.gov (United States)

    Salumbides, E. J.; Dickenson, G. D.; Ivanov, T. I.; Ubachs, W.

    2011-07-01

    Quantum electrodynamic effects have been systematically tested in the progression of rotational quantum states in the XΣg+1, v=0 vibronic ground state of molecular hydrogen. High-precision Doppler-free spectroscopy of the EFΣg+1-XΣg+1 (0,0) band was performed with 0.005cm-1 accuracy on rotationally hot H2 (with rotational quantum states J up to 16). QED and relativistic contributions to rotational level energies as high as 0.13cm-1 are extracted, and are in perfect agreement with recent calculations of QED and high-order relativistic effects for the H2 ground state.

  2. Teleportation is necessary for faithful quantum state transfer through noisy channels of maximal rank

    International Nuclear Information System (INIS)

    Romano, Raffaele; Loock, Peter van

    2010-01-01

    Quantum teleportation enables deterministic and faithful transmission of quantum states, provided a maximally entangled state is preshared between sender and receiver, and a one-way classical channel is available. Here, we prove that these resources are not only sufficient, but also necessary, for deterministically and faithfully sending quantum states through any fixed noisy channel of maximal rank, when a single use of the cannel is admitted. In other words, for this family of channels, there are no other protocols, based on different (and possibly cheaper) sets of resources, capable of replacing quantum teleportation.

  3. Dynamics and Control of Chemical Reactors-Selectively Surveyed

    DEFF Research Database (Denmark)

    Jørgensen, S. B.; Jensen, N.

    1989-01-01

    The chemical reactor or bioreactor is physically at a central position in a process, and often with a decisive role on the overall technical and economical performance. Even though application of feedback control on reactors is gaining momentum and on-line optimization has been implemented....... For bioreactors the theory and practice of reactor design, dynamics and control have to be adapted to the peculiarities of the biological catalysts. Enzymes, the protein catalysts, are the simplest ones, which have many common features with chemical catalysts. The living cells are much more complex, these growing...... in industry, many reactor control problems are still left unsolved or only partly solved using open loop strategies where disturbance rejection and model inaccuracies have to be handled through manual reactor control and feedback control of raw material preprocessing and product purification operations...

  4. Process Control Systems in the Chemical Industry: Safety vs. Security

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Hahn; Thomas Anderson

    2005-04-01

    Traditionally, the primary focus of the chemical industry has been safety and productivity. However, recent threats to our nation’s critical infrastructure have prompted a tightening of security measures across many different industry sectors. Reducing vulnerabilities of control systems against physical and cyber attack is necessary to ensure the safety, security and effective functioning of these systems. The U.S. Department of Homeland Security has developed a strategy to secure these vulnerabilities. Crucial to this strategy is the Control Systems Security and Test Center (CSSTC) established to test and analyze control systems equipment. In addition, the CSSTC promotes a proactive, collaborative approach to increase industry's awareness of standards, products and processes that can enhance the security of control systems. This paper outlines measures that can be taken to enhance the cybersecurity of process control systems in the chemical sector.

  5. [Prospects in getting accordance between chemical analytic control means and medical technical requirements to safety system concerning chemical weapons destruction].

    Science.gov (United States)

    Rembovskiĭ, V R; Mogilenkova, L A; Savel'eva, E I

    2005-01-01

    The major unit monitoring chemical weapons destruction objects is a system of chemical analyticcontrol over the technologic process procedures and possibility of environment and workplace pollution withtoxicchemicals and their destruction products. At the same time, physical and chemical control means meet sanitary and hygienic requirements incompletely. To provide efficient control, internationally recognized approaches should be adapted to features of Russian system monitoring pollution of chemical weapons destruction objects with toxic chemicals.

  6. Does runoff or temperature control chemical weathering rates?

    International Nuclear Information System (INIS)

    Eiriksdottir, Eydis Salome; Gislason, Sigurdur Reynir; Oelkers, Eric H.

    2011-01-01

    Highlights: → The rate chemical weathering is affected by both temperature and runoff. Separating out these two factors is challenging because runoff tends to increase with increasing temperature. → In this study, natural river water samples collected on basaltic catchments over a five year period are used together with experimentally derived dissolution rate model for basaltic glass to pull apart the effects of runoff and temperature. → This study shows that the rate of chemical denudation is controlled by both temperature and runoff, but is dominated by runoff. - Abstract: The rate of chemical denudation is controlled by both temperature and runoff. The relative role of these two factors in the rivers of NE Iceland is determined through the rigorous analysis of their water chemistry over a 5-a period. River catchments are taken to be analogous to laboratory flow reactors; like the fluid in flow reactors, the loss of each dissolved element in river water is the sum of that of the original rainwater plus that added from kinetically controlled dissolution and precipitation reactions. Consideration of the laboratory determined dissolution rate behaviour of basalts and measured water chemistry indicates that the maximum effect of changing temperature on chemical denudation in the NE Icelandic rivers was 5-25% of the total change, whereas that of runoff was 75-95%. The bulk of the increased denudation rates with runoff appear to stem from an increase in reactive surface area for chemical weathering of catchment solids.

  7. The Potential Of Cultural And Chemical Control Practices For ...

    African Journals Online (AJOL)

    The Potential Of Cultural And Chemical Control Practices For Enhancing ... and a significant (P < 0.05) increase in yield components of hands per bunch and finger ... Une étude de l\\'effet de la population de plantes, l\\'application des engrais, ...

  8. Methylene Diphosphonate Chemical and Biological control of MDP complex

    International Nuclear Information System (INIS)

    Aungurarat, Angkanan; Ngamprayad, Tippanan

    2000-01-01

    Technetium-9 9m MDP easy prepared from MDP kits which different sources such as OAP (In house), SIGMA. The resulting Tc 9 9m -MDP preparations were controlled in chemical and biological tests to compare the different results in these cases: radiochemical purity, the quantity of starting material and biodistribution result

  9. MIMO Self-Tuning Control of Chemical Process Operation

    DEFF Research Database (Denmark)

    Hallager, L.; Jørgensen, S. B.; Goldschmidt, L.

    1984-01-01

    The problem of selecting a feasible model structure for a MIMO self-tuning controller (MIMOSC) is addressed. The dependency of the necessary structure complexity in relation to the specific process operating point is investigated. Experimental results from a fixed-bed chemical reactor are used...

  10. Chemical control of blossom blight disease of sarpagandha caused ...

    African Journals Online (AJOL)

    ONOS

    2010-09-20

    Sep 20, 2010 ... Chemical control of blossom blight disease of sarpagandha caused by Colletotrichum capsici. R. S. Shukla, Abdul-Khaliq and M. Alam*. Department of Plant Pathology, Central Institute of Medicinal and Aromatic Plants, Council of Scientific and Industrial. Research, P. O. CIMAP, Lucknow–226 015, India.

  11. Effective chemical control of fruit flies (Diptera: Tephritidae) pests in ...

    African Journals Online (AJOL)

    Effective chemical control of fruit flies (Diptera: Tephritidae) pests in mango orchards in northern Côte-d'Ivoire. OR N'depo, N Hala, A N'da Adopo, F Coulibaly, PK Kouassi, JF Vayssieres, M de Meyer ...

  12. Chemical Weed Control Increases Survival and Growth in Hardwood Plantings

    Science.gov (United States)

    Gayne G. Erdmann

    1967-01-01

    In a plantation of four hardwood species on a silt loam soil planted to 1-0 stock, 4 pounds of active atrazine or simazine controlled weeds effectively without injuring the trees. Chemical weed control was better on plowed and disked ground than on unprepared ground. Yellow-poplar and white ash grew faster on prepared ground. Black walnut and red oak did not respond...

  13. Enhancing multi-step quantum state tomography by PhaseLift

    Science.gov (United States)

    Lu, Yiping; Zhao, Qing

    2017-09-01

    Multi-photon system has been studied by many groups, however the biggest challenge faced is the number of copies of an unknown state are limited and far from detecting quantum entanglement. The difficulty to prepare copies of the state is even more serious for the quantum state tomography. One possible way to solve this problem is to use adaptive quantum state tomography, which means to get a preliminary density matrix in the first step and revise it in the second step. In order to improve the performance of adaptive quantum state tomography, we develop a new distribution scheme of samples and extend it to three steps, that is to correct it once again based on the density matrix obtained in the traditional adaptive quantum state tomography. Our numerical results show that the mean square error of the reconstructed density matrix by our new method is improved to the level from 10-4 to 10-9 for several tested states. In addition, PhaseLift is also applied to reduce the required storage space of measurement operator.

  14. Simulating quantum state engineering in spontaneous parametric down-conversion using classical light

    CSIR Research Space (South Africa)

    Zhang, Y

    2014-07-01

    Full Text Available range of pump beams for quantum state engineering and confirm that the results are in agreement with theory. Our approach offers high photon count rates, is quick to yield results and can easily be converted back to a SPDC setup. It is likely to be a...

  15. Device-independent characterizations of a shared quantum state independent of any Bell inequalities

    Science.gov (United States)

    Wei, Zhaohui; Sikora, Jamie

    2017-03-01

    In a Bell experiment two parties share a quantum state and perform local measurements on their subsystems separately, and the statistics of the measurement outcomes are recorded as a Bell correlation. For any Bell correlation, it turns out that a quantum state with minimal size that is able to produce this correlation can always be pure. In this work, we first exhibit two device-independent characterizations for the pure state that Alice and Bob share using only the correlation data. Specifically, we give two conditions that the Schmidt coefficients must satisfy, which can be tight, and have various applications in quantum tasks. First, one of the characterizations allows us to bound the entanglement between Alice and Bob using Renyi entropies and also to bound the underlying Hilbert space dimension. Second, when the Hilbert space dimension bound is tight, the shared pure quantum state has to be maximally entangled. Third, the second characterization gives a sufficient condition that a Bell correlation cannot be generated by particular quantum states. We also show that our results can be generalized to the case of shared mixed states.

  16. Randomizing quantum states to Shatten p -norm for all p ≥ 1

    International Nuclear Information System (INIS)

    Jeong, Kabgyun

    2014-01-01

    We formularize a method for randomizing quantum states with respect to the Shatten p-norms (p ≥ 1) in trace class. In particular, this work includes the operator norm, p = ∞, and the trace norm, p = 1, simultaneously in a single statement via McDiarmid's inequality and a net construction

  17. Probabilistic Teleportation of Multi-particle d-Level Quantum State

    Institute of Scientific and Technical Information of China (English)

    CAO Min; ZHU Shi-Qun

    2005-01-01

    The general scheme for teleportation of a multi-particle d-level quantum state is presented when m pairs of partially entangled particles are utilized as quantum channels. The probabilistic teleportation can be achieved with a successful probability of d-1∏N=0(CN0)2/dM,which is determined by the smallest coefficients of each entangled channels.

  18. Central-moment description of polarization for quantum states of light

    DEFF Research Database (Denmark)

    Björk, G.; Söderholm, J.; Kim, Y.-S.

    2012-01-01

    We present a moment expansion for the systematic characterization of the polarization properties of quantum states of light. Specifically,we link the method to themeasurements of the Stokes operator in different directions on the Poincar´e sphere and provide a scheme for polarization tomography w...

  19. Chemical potential and reaction electronic flux in symmetry controlled reactions.

    Science.gov (United States)

    Vogt-Geisse, Stefan; Toro-Labbé, Alejandro

    2016-07-15

    In symmetry controlled reactions, orbital degeneracies among orbitals of different symmetries can occur along a reaction coordinate. In such case Koopmans' theorem and the finite difference approximation provide a chemical potential profile with nondifferentiable points. This results in an ill-defined reaction electronic flux (REF) profile, since it is defined as the derivative of the chemical potential with respect to the reaction coordinate. To overcome this deficiency, we propose a new way for the calculation of the chemical potential based on a many orbital approach, suitable for reactions in which symmetry is preserved. This new approach gives rise to a new descriptor: symmetry adapted chemical potential (SA-CP), which is the chemical potential corresponding to a given irreducible representation of a symmetry group. A corresponding symmetry adapted reaction electronic flux (SA-REF) is also obtained. Using this approach smooth chemical potential profiles and well defined REFs are achieved. An application of SA-CP and SA-REF is presented by studying the Cs enol-keto tautomerization of thioformic acid. Two SA-REFs are obtained, JA'(ξ) and JA'' (ξ). It is found that the tautomerization proceeds via an in-plane delocalized 3-center 4-electron O-H-S hypervalent bond which is predicted to exist only in the transition state (TS) region. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Pollution control in oil, gas and chemical plants

    CERN Document Server

    Bahadori, Alireza

    2014-01-01

    This unique book covers the fundamental requirements for air, soil, noise and water pollution control in oil and gas refineries, chemical plants, oil terminals, petrochemical plants, and related facilities. Coverage includes design and operational considerations relevant to critical systems such as monitoring of water pollution control, equipment, and engineering techniques as well as engineering/technological methods related to soil, noise and air pollution control. This book also: ·         Covers a diverse list of pollution control strategies important to practitioners, ranging from waste water gathering systems and oil/suspended solids removal to chemical flocculation units, biological treatment, and sludge handling and treatment ·         Provides numerous step-by-step tutorials that orient both entry level and veteran engineers to the essentials of pollution control methods in petroleum and chemical industries ·         Includes a comprehensive glossary providing readers with...

  1. Incorporation of chemical kinetic models into process control

    International Nuclear Information System (INIS)

    Herget, C.J.; Frazer, J.W.

    1981-01-01

    An important consideration in chemical process control is to determine the precise rationing of reactant streams, particularly when a large time delay exists between the mixing of the reactants and the measurement of the product. In this paper, a method is described for incorporating chemical kinetic models into the control strategy in order to achieve optimum operating conditions. The system is first characterized by determining a reaction rate surface as a function of all input reactant concentrations over a feasible range. A nonlinear constrained optimization program is then used to determine the combination of reactants which produces the specified yield at minimum cost. This operating condition is then used to establish the nominal concentrations of the reactants. The actual operation is determined through a feedback control system employing a Smith predictor. The method is demonstrated on a laboratory bench scale enzyme reactor

  2. Economic model predictive control theory, formulations and chemical process applications

    CERN Document Server

    Ellis, Matthew; Christofides, Panagiotis D

    2017-01-01

    This book presents general methods for the design of economic model predictive control (EMPC) systems for broad classes of nonlinear systems that address key theoretical and practical considerations including recursive feasibility, closed-loop stability, closed-loop performance, and computational efficiency. Specifically, the book proposes: Lyapunov-based EMPC methods for nonlinear systems; two-tier EMPC architectures that are highly computationally efficient; and EMPC schemes handling explicitly uncertainty, time-varying cost functions, time-delays and multiple-time-scale dynamics. The proposed methods employ a variety of tools ranging from nonlinear systems analysis, through Lyapunov-based control techniques to nonlinear dynamic optimization. The applicability and performance of the proposed methods are demonstrated through a number of chemical process examples. The book presents state-of-the-art methods for the design of economic model predictive control systems for chemical processes. In addition to being...

  3. Towards benchmarking of multivariable controllers in chemical/biochemical industries: Plantwide control for ethylene glycol production

    DEFF Research Database (Denmark)

    Huusom, Jakob Kjøbsted; Bialas, Dawid Jan; Jørgensen, John Bagterp

    2011-01-01

    In this paper we discuss a simple yet realistic benchmark plant for evaluation and comparison of advanced multivariable control for chemical and biochemical processes. The benchmark plant is based on recycle-separator-recycle systems for ethylene glycol production and implemented in Matlab...... for education purposes (operator training, student education, etc) as well as scientific research into chemical process control where it enables rapid evaluation and comparison of advanced multivariable controllers as demonstrated in this study....

  4. Controlling organic chemical hazards in food manufacturing: a hazard analysis critical control points (HACCP) approach.

    Science.gov (United States)

    Ropkins, K; Beck, A J

    2002-08-01

    Hazard analysis by critical control points (HACCP) is a systematic approach to the identification, assessment and control of hazards. Effective HACCP requires the consideration of all hazards, i.e., chemical, microbiological and physical. However, to-date most 'in-place' HACCP procedures have tended to focus on the control of microbiological and physical food hazards. In general, the chemical component of HACCP procedures is either ignored or limited to applied chemicals, e.g., food additives and pesticides. In this paper we discuss the application of HACCP to a broader range of chemical hazards, using organic chemical contaminants as examples, and the problems that are likely to arise in the food manufacturing sector. Chemical HACCP procedures are likely to result in many of the advantages previously identified for microbiological HACCP procedures: more effective, efficient and economical than conventional end-point-testing methods. However, the high costs of analytical monitoring of chemical contaminants and a limited understanding of formulation and process optimisation as means of controlling chemical contamination of foods are likely to prevent chemical HACCP becoming as effective as microbiological HACCP.

  5. Chemical and ecological control methods for Epitrix spp.

    Directory of Open Access Journals (Sweden)

    A. G. S. Cuthbertson

    2015-01-01

    Full Text Available Very little information exists in regards to the control options available for potato flea beetles, Epitrix spp. This short review covers both chemical and ecological options currently available for control of Epitrix spp. Synthetic pyrethroids are the weapon of choice for the beetles. However, the impetus in integrated pest management is to do timely (early-season applications with something harsh which will give long-term protection at a time when there are not a lot of beneficials in the field. Finding the balance for control of Epitrix spp. is proving difficult.

  6. Scheme for quantum state manipulation in coupled cavities

    Science.gov (United States)

    Lin, Jin-Zhong

    By controlling the parameters of the system, the effective interaction between different atoms is achieved in different cavities. Based on the interaction, scheme to generate three-atom Greenberger-Horne-Zeilinger (GHZ) is proposed in coupled cavities. Spontaneous emission of excited states and decay of cavity modes can be suppressed efficiently. In addition, the scheme is robust against the variation of hopping rate between cavities.

  7. Manipulating collective quantum states of ultracold atoms by probing

    DEFF Research Database (Denmark)

    Wade, Andrew Christopher James

    2015-01-01

    The field of cold gases has grown dramatically over the past few decades. The exquisite experimental control of their environment and properties has lead to landmark achievements, and has motivated the pursuit of quantum technologies with ultracold atoms. At the same time, the theory of measureme......The field of cold gases has grown dramatically over the past few decades. The exquisite experimental control of their environment and properties has lead to landmark achievements, and has motivated the pursuit of quantum technologies with ultracold atoms. At the same time, the theory...... of measurements on quantum systems has grown into a well established field. Experimental demonstrations of nondestructive continuous measurements on individual quantum systems now occur in many laboratories. Such experiments with ultracold atoms have shown great progress, but the exploitation of the quantum...... nature of the measurement interaction and backaction is yet to be realised. This dissertation is concerned with ultracold atoms and their control via fully quantum mechanical probes. Nonclassical, squeezed and entangled states of matter and single photon sources are important for fundamental studies...

  8. Nonlinear model predictive control for chemical looping process

    Science.gov (United States)

    Joshi, Abhinaya; Lei, Hao; Lou, Xinsheng

    2017-08-22

    A control system for optimizing a chemical looping ("CL") plant includes a reduced order mathematical model ("ROM") that is designed by eliminating mathematical terms that have minimal effect on the outcome. A non-linear optimizer provides various inputs to the ROM and monitors the outputs to determine the optimum inputs that are then provided to the CL plant. An estimator estimates the values of various internal state variables of the CL plant. The system has one structure adapted to control a CL plant that only provides pressure measurements in the CL loops A and B, a second structure adapted to a CL plant that provides pressure measurements and solid levels in both loops A, and B, and a third structure adapted to control a CL plant that provides full information on internal state variables. A final structure provides a neural network NMPC controller to control operation of loops A and B.

  9. Communication: Control of chemical reactions using electric field gradients

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, Shivaraj D.; Tsori, Yoav, E-mail: tsori@bgu.ac.il [Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

    2016-05-21

    We examine theoretically a new idea for spatial and temporal control of chemical reactions. When chemical reactions take place in a mixture of solvents, an external electric field can alter the local mixture composition, thereby accelerating or decelerating the rate of reaction. The spatial distribution of electric field strength can be non-trivial and depends on the arrangement of the electrodes producing it. In the absence of electric field, the mixture is homogeneous and the reaction takes place uniformly in the reactor volume. When an electric field is applied, the solvents separate and the reactants are concentrated in the same phase or separate to different phases, depending on their relative miscibility in the solvents, and this can have a large effect on the kinetics of the reaction. This method could provide an alternative way to control runaway reactions and to increase the reaction rate without using catalysts.

  10. Communication: Control of chemical reactions using electric field gradients.

    Science.gov (United States)

    Deshmukh, Shivaraj D; Tsori, Yoav

    2016-05-21

    We examine theoretically a new idea for spatial and temporal control of chemical reactions. When chemical reactions take place in a mixture of solvents, an external electric field can alter the local mixture composition, thereby accelerating or decelerating the rate of reaction. The spatial distribution of electric field strength can be non-trivial and depends on the arrangement of the electrodes producing it. In the absence of electric field, the mixture is homogeneous and the reaction takes place uniformly in the reactor volume. When an electric field is applied, the solvents separate and the reactants are concentrated in the same phase or separate to different phases, depending on their relative miscibility in the solvents, and this can have a large effect on the kinetics of the reaction. This method could provide an alternative way to control runaway reactions and to increase the reaction rate without using catalysts.

  11. Method and apparatus for controlling gas evolution from chemical reactions

    Science.gov (United States)

    Skorpik, James R.; Dodson, Michael G.

    1999-01-01

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846.

  12. Rough Mirror as a Quantum State Selector: Analysis and Design

    International Nuclear Information System (INIS)

    Nesvizhevsky, V. V.; Lamy, F.; Meyerovich, A. E.; Escobar, M.

    2014-01-01

    We report analysis of rough mirrors used as the gravitational state selectors in neutron beam and similar experiments. The key to mirror properties is its roughness correlation function (CF) which is extracted from the precision optical scanning measurements of the surface profile. To identify CF in the presence of fluctuation-driven fat tails, we perform numerical experiments with computer-generated random surfaces with the known CF. These numerical experiments provide a reliable identification procedure which we apply to the actual rough mirror. The extracted CF allows us to make predictions for ongoing GRANIT experiments. We also propose a radically new design for rough mirrors based on Monte Carlo simulations for the 1D Ising model. The implementation of this design provides a controlled environment with predictable scattering properties

  13. Integrated Process Design, Control and Analysis of Intensified Chemical Processes

    DEFF Research Database (Denmark)

    Mansouri, Seyed Soheil

    chemical processes; for example, intensified processes such as reactive distillation. Most importantly, it identifies and eliminates potentially promising design alternatives that may have controllability problems later. To date, a number of methodologies have been proposed and applied on various problems......, that the same principles that apply to a binary non-reactive compound system are valid also for a binary-element or a multi-element system. Therefore, it is advantageous to employ the element based method for multicomponent reaction-separation systems. It is shown that the same design-control principles...

  14. Gravitationally self-bound quantum states in unstable potentials

    Science.gov (United States)

    Jääskeläinen, Markku

    2018-04-01

    Quantum mechanics at present cannot be unified with the theory of gravity at the deepest level, and to guide research towards the solution of this fundamental problem, we need to look for ways to observe or refute predictions originating from attempts to combine quantum theory with gravity. The influence of the gravitational field created by the material density given by the wave function itself gives rise to nontrivial phenomena. In this study I consider the wave function for the center-of-mass coordinate of a spherical mass distribution under the influence of the self-interaction of Newtonian gravity. I solve numerically for the ground state in the presence of an unstable potential and find that the energy of the free-space bound state can be lowered despite the nontrapping character of the potential. The center-of-mass ground state becomes increasingly localized for the used unstable potentials, although only in a limited parameter regime. The feebleness of the energy shift makes the observation of these effects demanding and requires further developments in the cooling of material particles. In addition, the influence of gravitational perturbations that are present in typical laboratory settings necessitates the use of extremely quiet and controlled environments such as those provided by recently proposed space-borne experiments.

  15. Quantum Discord Determines the Interferometric Power of Quantum States

    Science.gov (United States)

    Girolami, Davide; Souza, Alexandre M.; Giovannetti, Vittorio; Tufarelli, Tommaso; Filgueiras, Jefferson G.; Sarthour, Roberto S.; Soares-Pinto, Diogo O.; Oliveira, Ivan S.; Adesso, Gerardo

    2014-05-01

    Quantum metrology exploits quantum mechanical laws to improve the precision in estimating technologically relevant parameters such as phase, frequency, or magnetic fields. Probe states are usually tailored to the particular dynamics whose parameters are being estimated. Here we consider a novel framework where quantum estimation is performed in an interferometric configuration, using bipartite probe states prepared when only the spectrum of the generating Hamiltonian is known. We introduce a figure of merit for the scheme, given by the worst-case precision over all suitable Hamiltonians, and prove that it amounts exactly to a computable measure of discord-type quantum correlations for the input probe. We complement our theoretical results with a metrology experiment, realized in a highly controllable room-temperature nuclear magnetic resonance setup, which provides a proof-of-concept demonstration for the usefulness of discord in sensing applications. Discordant probes are shown to guarantee a nonzero phase sensitivity for all the chosen generating Hamiltonians, while classically correlated probes are unable to accomplish the estimation in a worst-case setting. This work establishes a rigorous and direct operational interpretation for general quantum correlations, shedding light on their potential for quantum technology.

  16. Subfemtosecond directional control of chemical processes in molecules

    Science.gov (United States)

    Alnaser, Ali S.; Litvinyuk, Igor V.

    2017-02-01

    Laser pulses with a waveform-controlled electric field and broken inversion symmetry establish the opportunity to achieve directional control of molecular processes on a subfemtosecond timescale. Several techniques could be used to break the inversion symmetry of an electric field. The most common ones include combining a fundamental laser frequency with its second harmonic or with higher -frequency pulses (or pulse trains) as well as using few-cycle pulses with known carrier-envelope phase (CEP). In the case of CEP, control over chemical transformations, typically occurring on a timescale of many femtoseconds, is driven by much faster sub-cycle processes of subfemtosecond to few-femtosecond duration. This is possible because electrons are much lighter than nuclei and fast electron motion is coupled to the much slower nuclear motion. The control originates from populating coherent superpositions of different electronic or vibrational states with relative phases that are dependent on the CEP or phase offset between components of a two-color pulse. In this paper, we review the recent progress made in the directional control over chemical processes, driven by intense few-cycle laser pulses a of waveform-tailored electric field, in different molecules.

  17. Classes of n-copy undistillable quantum states with negative partial transposition

    International Nuclear Information System (INIS)

    Bandyopadhyay, Somshubhro; Roychowdhury, Vwani

    2003-01-01

    The discovery of entangled quantum states from which one cannot distill pure entanglement constitutes a fundamental recent advance in the field of quantum information. Such bipartite bound-entangled (BE) quantum states could fall into two distinct categories: (1) Inseparable states with positive partial transposition (PPT), and (2) states with negative partial transposition (NPT). While the existence of PPT BE states has been confirmed, only one class of conjectured NPT BE states has been discovered so far. We provide explicit constructions of a variety of multicopy undistillable NPT states, and conjecture that they constitute families of NPT BE states. For example, we show that for every pure state of Schmidt rank greater than or equal to 3, one can construct n-copy undistillable NPT states, for any n≥1. The abundance of such conjectured NPT BE states, we believe, considerably strengthens the notion that being NPT is only a necessary condition for a state to be distillable

  18. Conditions for the classicality of the center of mass of many-particle quantum states

    International Nuclear Information System (INIS)

    Oriols, Xavier; Benseny, Albert

    2017-01-01

    We discuss the conditions for the classicality of quantum states with a very large number of identical particles. By defining the center of mass from a large set of Bohmian particles, we show that it follows a classical trajectory when the distribution of the Bohmian particle positions in a single experiment is always equal to the marginal distribution of the quantum state in physical space. This result can also be interpreted as a single experiment generalization of the well-known Ehrenfest theorem. We also demonstrate that the classical trajectory of the center of mass is fully compatible with a quantum (conditional) wave function solution of a classical non-linear Schrödinger equation. Our work shows clear evidence for a quantum–classical inter-theory unification, and opens new possibilities for practical quantum computations with decoherence. (paper)

  19. Quantum state engineering with flux-biased Josephson phase qubits by rapid adiabatic passages

    Science.gov (United States)

    Nie, W.; Huang, J. S.; Shi, X.; Wei, L. F.

    2010-09-01

    In this article, the scheme of quantum computing based on the Stark-chirped rapid adiabatic passage (SCRAP) technique [L. F. Wei, J. R. Johansson, L. X. Cen, S. Ashhab, and F. Nori, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.100.113601 100, 113601 (2008)] is extensively applied to implement quantum state manipulations in flux-biased Josephson phase qubits. The broken-parity symmetries of bound states in flux-biased Josephson junctions are utilized to conveniently generate the desirable Stark shifts. Then, assisted by various transition pulses, universal quantum logic gates as well as arbitrary quantum state preparations can be implemented. Compared with the usual π-pulse operations widely used in experiments, the adiabatic population passages proposed here are insensitive to the details of the applied pulses and thus the desirable population transfers can be satisfyingly implemented. The experimental feasibility of the proposal is also discussed.

  20. Quantum state engineering with flux-biased Josephson phase qubits by rapid adiabatic passages

    International Nuclear Information System (INIS)

    Nie, W.; Huang, J. S.; Shi, X.; Wei, L. F.

    2010-01-01

    In this article, the scheme of quantum computing based on the Stark-chirped rapid adiabatic passage (SCRAP) technique [L. F. Wei, J. R. Johansson, L. X. Cen, S. Ashhab, and F. Nori, Phys. Rev. Lett. 100, 113601 (2008)] is extensively applied to implement quantum state manipulations in flux-biased Josephson phase qubits. The broken-parity symmetries of bound states in flux-biased Josephson junctions are utilized to conveniently generate the desirable Stark shifts. Then, assisted by various transition pulses, universal quantum logic gates as well as arbitrary quantum state preparations can be implemented. Compared with the usual π-pulse operations widely used in experiments, the adiabatic population passages proposed here are insensitive to the details of the applied pulses and thus the desirable population transfers can be satisfyingly implemented. The experimental feasibility of the proposal is also discussed.

  1. Robustness of spin-coupling distributions for perfect quantum state transfer

    International Nuclear Information System (INIS)

    Zwick, Analia; Alvarez, Gonzalo A.; Stolze, Joachim; Osenda, Omar

    2011-01-01

    The transmission of quantum information between different parts of a quantum computer is of fundamental importance. Spin chains have been proposed as quantum channels for transferring information. Different configurations for the spin couplings were proposed in order to optimize the transfer. As imperfections in the creation of these specific spin-coupling distributions can never be completely avoided, it is important to find out which systems are optimally suited for information transfer by assessing their robustness against imperfections or disturbances. We analyze different spin coupling distributions of spin chain channels designed for perfect quantum state transfer. In particular, we study the transfer of an initial state from one end of the chain to the other end. We quantify the robustness of different coupling distributions against perturbations and we relate it to the properties of the energy eigenstates and eigenvalues. We find that the localization properties of the systems play an important role for robust quantum state transfer.

  2. Efficient method for computing the maximum-likelihood quantum state from measurements with additive Gaussian noise.

    Science.gov (United States)

    Smolin, John A; Gambetta, Jay M; Smith, Graeme

    2012-02-17

    We provide an efficient method for computing the maximum-likelihood mixed quantum state (with density matrix ρ) given a set of measurement outcomes in a complete orthonormal operator basis subject to Gaussian noise. Our method works by first changing basis yielding a candidate density matrix μ which may have nonphysical (negative) eigenvalues, and then finding the nearest physical state under the 2-norm. Our algorithm takes at worst O(d(4)) for the basis change plus O(d(3)) for finding ρ where d is the dimension of the quantum state. In the special case where the measurement basis is strings of Pauli operators, the basis change takes only O(d(3)) as well. The workhorse of the algorithm is a new linear-time method for finding the closest probability distribution (in Euclidean distance) to a set of real numbers summing to one.

  3. Quantum-state transfer through long-range correlated disordered channels

    Science.gov (United States)

    Almeida, Guilherme M. A.; de Moura, Francisco A. B. F.; Lyra, Marcelo L.

    2018-05-01

    We study quantum-state transfer in XX spin-1/2 chains where both communicating spins are weakly coupled to a channel featuring disordered on-site magnetic fields. Fluctuations are modeled by long-range correlated sequences with self-similar profile obeying a power-law spectrum. We show that the channel is able to perform almost perfect quantum-state transmissions even in the presence of significant amounts of disorder provided the degree of those correlations is strong enough, with the cost of having long transfer times and unavoidable timing errors. Still, we show that the lack of mirror symmetry in the channel does not affect much the likelihood of having high-quality outcomes. Our results suggest that coexistence between localized and delocalized states can diminish effects of static perturbations in solid-state devices for quantum communication.

  4. Pechukas-Yukawa approach to the evolution of the quantum state of a parametrically perturbed system

    Science.gov (United States)

    Qureshi, Mumnuna A.; Zhong, Johnny; Qureshi, Zihad; Mason, Peter; Betouras, Joseph J.; Zagoskin, Alexandre M.

    2018-03-01

    We consider the evolution of the quantum states of a Hamiltonian that is parametrically perturbed via a term proportional to the adiabatic parameter λ (t ) . Starting with the Pechukas-Yukawa mapping of the energy eigenvalue evolution in a generalized Calogero-Sutherland model of a one-dimensional classical gas, we consider the adiabatic approximation with two different expansions of the quantum state in powers of d λ /d t and compare them with a direct numerical simulation. We show that one of these expansions (Magnus series) is especially convenient for the description of nonadiabatic evolution of the system. Applying the expansion to the exact cover 3-satisfiability problem, we obtain the occupation dynamics, which provides insight into the population of states and sources of decoherence in a quantum system.

  5. Probabilistic Teleportation of Arbitrary Two-Qubit Quantum State via Non-Symmetric Quantum Channel

    Directory of Open Access Journals (Sweden)

    Kan Wang

    2018-03-01

    Full Text Available Quantum teleportation has significant meaning in quantum information. In particular, entangled states can also be used for perfectly teleporting the quantum state with some probability. This is more practical and efficient in practice. In this paper, we propose schemes to use non-symmetric quantum channel combinations for probabilistic teleportation of an arbitrary two-qubit quantum state from sender to receiver. The non-symmetric quantum channel is composed of a two-qubit partially entangled state and a three-qubit partially entangled state, where partially entangled Greenberger–Horne–Zeilinger (GHZ state and W state are considered, respectively. All schemes are presented in detail and the unitary operations required are given in concise formulas. Methods are provided for reducing classical communication cost and combining operations to simplify the manipulation. Moreover, our schemes are flexible and applicable in different situations.

  6. AMAZON RAINFOREST COSMETICS: CHEMICAL APPROACH FOR QUALITY CONTROL

    Directory of Open Access Journals (Sweden)

    Mariko Funasaki

    2016-02-01

    Full Text Available The market for natural cosmetics featuring ingredients derived from Amazon natural resources is growing worldwide. However, there is neither enough scientific basis nor quality control of these ingredients. This paper is an account of the chemical constituents and their biological activities of fourteen Amazonian species used in cosmetic industry, including açaí (Euterpe oleracea, andiroba (Carapa guianensis, bacuri (Platonia insignis, Brazil nut (Bertholletia excelsa, buriti (Mauritia vinifera or M. flexuosa, cumaru (Dipteryx odorata, cupuaçu (Theobroma grandiflorum, guarana (Paullinia cupana, mulateiro (Calycophyllum spruceanum, murumuru (Astrocaryum murumuru, patawa (Oenocarpus bataua or Jessenia bataua, pracaxi (Pentaclethra macroloba, rosewood (Aniba rosaeodora, and ucuuba (Virola sebifera. Based on the reviewed articles, we selected chemical markers for the quality control purpose and evaluated analytical methods. Even though chromatographic and spectroscopic methods are major analytical techniques in the studies of these species, molecular approaches will also be important as used in food and medicine traceability. Only a little phytochemical study is available about most of the Amazonian species and some species such as açaí and andiroba have many reports on chemical constituents, but studies on biological activities of isolated compounds and sampling with geographical variation are limited.

  7. Full characterization of a three-photon Greenberger-Horne-Zeilinger state using quantum state tomography.

    Science.gov (United States)

    Resch, K J; Walther, P; Zeilinger, A

    2005-02-25

    We have performed the first experimental tomographic reconstruction of a three-photon polarization state. Quantum state tomography is a powerful tool for fully describing the density matrix of a quantum system. We measured 64 three-photon polarization correlations and used a "maximum-likelihood" reconstruction method to reconstruct the Greenberger-Horne-Zeilinger state. The entanglement class has been characterized using an entanglement witness operator and the maximum predicted values for the Mermin inequality were extracted.

  8. ψ-Epistemic Models are Exponentially Bad at Explaining the Distinguishability of Quantum States

    Science.gov (United States)

    Leifer, M. S.

    2014-04-01

    The status of the quantum state is perhaps the most controversial issue in the foundations of quantum theory. Is it an epistemic state (state of knowledge) or an ontic state (state of reality)? In realist models of quantum theory, the epistemic view asserts that nonorthogonal quantum states correspond to overlapping probability measures over the true ontic states. This naturally accounts for a large number of otherwise puzzling quantum phenomena. For example, the indistinguishability of nonorthogonal states is explained by the fact that the ontic state sometimes lies in the overlap region, in which case there is nothing in reality that could distinguish the two states. For this to work, the amount of overlap of the probability measures should be comparable to the indistinguishability of the quantum states. In this Letter, I exhibit a family of states for which the ratio of these two quantities must be ≤2de-cd in Hilbert spaces of dimension d that are divisible by 4. This implies that, for large Hilbert space dimension, the epistemic explanation of indistinguishability becomes implausible at an exponential rate as the Hilbert space dimension increases.

  9. Random sampling of quantum states: a survey of methods and some issues regarding the Overparametrized Method

    International Nuclear Information System (INIS)

    Maziero, Jonas

    2015-01-01

    The numerical generation of random quantum states (RQS) is an important procedure for investigations in quantum information science. Here, we review some methods that may be used for performing that task. We start by presenting a simple procedure for generating random state vectors, for which the main tool is the random sampling of unbiased discrete probability distributions (DPD). Afterwards, the creation of random density matrices is addressed. In this context, we first present the standard method, which consists in using the spectral decomposition of a quantum state for getting RQS from random DPDs and random unitary matrices. In the sequence, the Bloch vector parametrization method is described. This approach, despite being useful in several instances, is not in general convenient for RQS generation. In the last part of the article, we regard the overparametrized method (OPM) and the related Ginibre and Bures techniques. The OPM can be used to create random positive semidefinite matrices with unit trace from randomly produced general complex matrices in a simple way that is friendly for numerical implementations. We consider a physically relevant issue related to the possible domains that may be used for the real and imaginary parts of the elements of such general complex matrices. Subsequently, a too fast concentration of measure in the quantum state space that appears in this parametrization is noticed. (author)

  10. Fast reconstruction of high-qubit-number quantum states via low-rate measurements

    Science.gov (United States)

    Li, K.; Zhang, J.; Cong, S.

    2017-07-01

    Due to the exponential complexity of the resources required by quantum state tomography (QST), people are interested in approaches towards identifying quantum states which require less effort and time. In this paper, we provide a tailored and efficient method for reconstructing mixed quantum states up to 12 (or even more) qubits from an incomplete set of observables subject to noises. Our method is applicable to any pure or nearly pure state ρ and can be extended to many states of interest in quantum information processing, such as a multiparticle entangled W state, Greenberger-Horne-Zeilinger states, and cluster states that are matrix product operators of low dimensions. The method applies the quantum density matrix constraints to a quantum compressive sensing optimization problem and exploits a modified quantum alternating direction multiplier method (quantum-ADMM) to accelerate the convergence. Our algorithm takes 8 ,35 , and 226 seconds, respectively, to reconstruct superposition state density matrices of 10 ,11 ,and12 qubits with acceptable fidelity using less than 1 % of measurements of expectation. To our knowledge it is the fastest realization that people can achieve using a normal desktop. We further discuss applications of this method using experimental data of mixed states obtained in an ion trap experiment of up to 8 qubits.

  11. Prospects for Studies of the Free Fall and Gravitational Quantum States of Antimatter

    Directory of Open Access Journals (Sweden)

    G. Dufour

    2015-01-01

    Full Text Available Different experiments are ongoing to measure the effect of gravity on cold neutral antimatter atoms such as positronium, muonium, and antihydrogen. Among those, the project GBAR at CERN aims to measure precisely the gravitational fall of ultracold antihydrogen atoms. In the ultracold regime, the interaction of antihydrogen atoms with a surface is governed by the phenomenon of quantum reflection which results in bouncing of antihydrogen atoms on matter surfaces. This allows the application of a filtering scheme to increase the precision of the free fall measurement. In the ultimate limit of smallest vertical velocities, antihydrogen atoms are settled in gravitational quantum states in close analogy to ultracold neutrons (UCNs. Positronium is another neutral system involving antimatter for which free fall under gravity is currently being investigated at UCL. Building on the experimental techniques under development for the free fall measurement, gravitational quantum states could also be observed in positronium. In this contribution, we report on the status of the ongoing experiments and discuss the prospects of observing gravitational quantum states of antimatter and their implications.

  12. COLLABORATIVE TRIAL AND QUALITY CONTROL IN CHEMICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Narsito Narsito

    2010-06-01

    Full Text Available Abstract                                                             This paper deals with some practical problems related to the quality of analytical chemical data usually met in practice. Special attention is given to the topic of quality control in analytical chemistry, since analytical data is one of the primary information from which some important scientifically based decision are to be made. The present paper starts with brief description on some fundamental aspects associated with quality of analytical data, such as sources of variation of analytical data, criteria for quality of analytical method, quality assurance in chemical analysis. The assessment of quality parameter for analytical method like the use of standard materials as well as standard methods is given. Concerning with the quality control of analytical data, the use of several techniques, such as control samples and control charts, in monitoring analytical data in quality control program are described qualitatively.  In the final part of this paper, some important remarks for the preparation of collaborative trials, including the evaluation of accuracy and reproducibility of analytical method are also given Keywords: collaborative trials, quality control, analytical data Abstract                                                             This paper deals with some practical problems related to the quality of analytical chemical data usually met in practice. Special attention is given to the topic of quality control in analytical chemistry, since analytical data is one of the primary information from which some important scientifically based decision are to be made. The present paper starts with brief description on some fundamental aspects associated with quality of analytical data, such as sources of variation of analytical data, criteria for quality of

  13. An electrochemical study of natural and chemically controlled eumelanin

    Directory of Open Access Journals (Sweden)

    Ri Xu

    2017-12-01

    Full Text Available Eumelanin is the most common form of the pigment melanin in the human body, with functions including antioxidant behavior, metal chelation, and free radical scavenging. This biopigment is of interest for biologically derived batteries and supercapacitors. In this work, we characterized the voltammetric properties of chemically controlled eumelanins produced from 5,6-dihydroxyindole (DHI and 5,6-dihydroxyindole-2-carboxylic acid (DHICA building blocks, namely, DHI-melanin, DHICA-melanin, and natural eumelanin, extracted from the ink sac of cuttlefish, Sepia melanin. Eumelanin electrodes were studied for their cyclic voltammetric properties in acidic buffers including Na+, K+, NH4+, and Cu2+ ions.

  14. An electrochemical study of natural and chemically controlled eumelanin

    Science.gov (United States)

    Xu, Ri; Prontera, Carmela Tania; Di Mauro, Eduardo; Pezzella, Alessandro; Soavi, Francesca; Santato, Clara

    2017-12-01

    Eumelanin is the most common form of the pigment melanin in the human body, with functions including antioxidant behavior, metal chelation, and free radical scavenging. This biopigment is of interest for biologically derived batteries and supercapacitors. In this work, we characterized the voltammetric properties of chemically controlled eumelanins produced from 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) building blocks, namely, DHI-melanin, DHICA-melanin, and natural eumelanin, extracted from the ink sac of cuttlefish, Sepia melanin. Eumelanin electrodes were studied for their cyclic voltammetric properties in acidic buffers including Na+, K+, NH4+, and Cu2+ ions.

  15. Using Chemicals to Optimize Conformance Control in Fractured Reservoirs; TOPICAL

    International Nuclear Information System (INIS)

    Seright, Randall S.; Liang, Jenn-Tai; Schrader, Richard; Hagstrom II, John; Wang, Ying; Kumar, Ananad; Wavrik, Kathryn

    2001-01-01

    This report describes work performed during the third and final year of the project, Using Chemicals to Optimize Conformance Control in Fractured Reservoirs. This research project had three objectives. The first objective was to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas. The second objective was to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems. The third objective was to develop procedures to optimize blocking agent placement in naturally fractured reservoirs

  16. Study on chemical reactivity control of liquid sodium. Research program

    International Nuclear Information System (INIS)

    Saito, Jun-ichi; Ara, Kuniaki; Sugiyama, Ken-ichiro; Kitagawa, Hiroshi; Oka, Nobuki; Yoshioka, Naoki

    2007-01-01

    Liquid sodium has the excellent properties as coolant of the fast breeder reactor (FBR). On the other hand, it reacts high with water and oxygen. So an innovative technology to suppress the reactivity is desired. The purpose of this study is to control the chemical reactivity of liquid sodium by dispersing the nanometer-size metallic particles (we call them Nano-particles) into liquid sodium. We focus on the atomic interaction between Nano-particles and sodium atoms. And we try to apply it to suppress the chemical reactivity of liquid sodium. Liquid sodium dispersing Nano-particles is named 'Nano-fluid'. Research programs of this study are the Nano-particles production, the evaluation of reactivity suppression of liquid sodium and the feasibility study to FBR plant. In this paper, the research programs and status are described. The important factors for particle production were understood. In order to evaluate the chemical reactivity of Nano-fluid the research programs were planned. The feasibility of the application of Nano-fluid to the coolant of FBR plant was evaluated preliminarily from the viewpoint of design and operation. (author)

  17. Constraints on Non-Newtonian Gravity From the Experiment on Neutron Quantum States in the Earth's Gravitational Field.

    Science.gov (United States)

    Nesvizhevsky, V V; Protasov, K V

    2005-01-01

    An upper limit to non-Newtonian attractive forces is obtained from the measurement of quantum states of neutrons in the Earth's gravitational field. This limit improves the existing constraints in the nanometer range.

  18. Combined Noncyclic Scheduling and Advanced Control for Continuous Chemical Processes

    Directory of Open Access Journals (Sweden)

    Damon Petersen

    2017-12-01

    Full Text Available A novel formulation for combined scheduling and control of multi-product, continuous chemical processes is introduced in which nonlinear model predictive control (NMPC and noncyclic continuous-time scheduling are efficiently combined. A decomposition into nonlinear programming (NLP dynamic optimization problems and mixed-integer linear programming (MILP problems, without iterative alternation, allows for computationally light solution. An iterative method is introduced to determine the number of production slots for a noncyclic schedule during a prediction horizon. A filter method is introduced to reduce the number of MILP problems required. The formulation’s closed-loop performance with both process disturbances and updated market conditions is demonstrated through multiple scenarios on a benchmark continuously stirred tank reactor (CSTR application with fluctuations in market demand and price for multiple products. Economic performance surpasses cyclic scheduling in all scenarios presented. Computational performance is sufficiently light to enable online operation in a dual-loop feedback structure.

  19. Intelligent process control of fiber chemical vapor deposition

    Science.gov (United States)

    Jones, John Gregory

    Chemical Vapor Deposition (CVD) is a widely used process for the application of thin films. In this case, CVD is being used to apply a thin film interface coating to single crystal monofilament sapphire (Alsb2Osb3) fibers for use in Ceramic Matrix Composites (CMC's). The hot-wall reactor operates at near atmospheric pressure which is maintained using a venturi pump system. Inert gas seals obviate the need for a sealed system. A liquid precursor delivery system has been implemented to provide precise stoichiometry control. Neural networks have been implemented to create real-time process description models trained using data generated based on a Navier-Stokes finite difference model of the process. Automation of the process to include full computer control and data logging capability is also presented. In situ sensors including a quadrupole mass spectrometer, thermocouples, laser scanner, and Raman spectrometer have been implemented to determine the gas phase reactants and coating quality. A fuzzy logic controller has been developed to regulate either the gas phase or the in situ temperature of the reactor using oxygen flow rate as an actuator. Scanning electron microscope (SEM) images of various samples are shown. A hierarchical control structure upon which the control structure is based is also presented.

  20. A non-chemical system for online weed control.

    Science.gov (United States)

    Rueda-Ayala, Victor; Peteinatos, Gerassimos; Gerhards, Roland; Andújar, Dionisio

    2015-03-30

    Non-chemical weed control methods need to be directed towards a site-specific weeding approach, in order to be able to compete the conventional herbicide equivalents. A system for online weed control was developed. It automatically adjusts the tine angle of a harrow and creates different levels of intensity: from gentle to aggressive. Two experimental plots in a maize field were harrowed with two consecutive passes. The plots presented from low to high weed infestation levels. Discriminant capabilities of an ultrasonic sensor were used to determine the crop and weed variability of the field. A controlling unit used ultrasonic readings to adjust the tine angle, producing an appropriate harrowing intensity. Thus, areas with high crop and weed densities were more aggressively harrowed, while areas with lower densities were cultivated with a gentler treatment; areas with very low densities or without weeds were not treated. Although the weed development was relatively advanced and the soil surface was hard, the weed control achieved by the system reached an average of 51% (20%-91%), without causing significant crop damage as a result of harrowing. This system is proposed as a relatively low cost, online, and real-time automatic harrow that improves the weed control efficacy, reduces energy consumption, and avoids the usage of herbicide.

  1. Zero-contingent entropy of quantum states of a Hydrogen atom

    International Nuclear Information System (INIS)

    Charvot, R.; Majernik, V.

    1996-01-01

    We calculated the zero-contingent entropy for the position of electron in H-atom as a function of its quantum numbers and compared it with the corresponding value of the Shannon entropy. The values of zero-contingent entropy of quantum states of H-atom correlate well with the corresponding values of Shannon's entropy. This points out that, besides the Shannon entropy, the zero-contingent entropy represents an appropriate, and mathematically rather simple, measure of the spreading out of the wave functions in H-atom. (authors)

  2. Transfer of d-level quantum states through spin chains by random swapping

    International Nuclear Information System (INIS)

    Bayat, A.; Karimipour, V.

    2007-01-01

    We generalize an already proposed protocol for quantum state transfer to spin chains of arbitrary spin. An arbitrary unknown d-level state is transferred through a chain with rather good fidelity by the natural dynamics of the chain. We compare the performance of this protocol for various values of d. A by-product of our study is a much simpler method for picking up the state at the destination as compared with the one proposed previously. We also discuss entanglement distribution through such chains and show that the quality of entanglement transition increases with the number of levels d

  3. Decoherence and thermalization of a pure quantum state in quantum field theory.

    Science.gov (United States)

    Giraud, Alexandre; Serreau, Julien

    2010-06-11

    We study the real-time evolution of a self-interacting O(N) scalar field initially prepared in a pure, coherent quantum state. We present a complete solution of the nonequilibrium quantum dynamics from a 1/N expansion of the two-particle-irreducible effective action at next-to-leading order, which includes scattering and memory effects. We demonstrate that, restricting one's attention (or ability to measure) to a subset of the infinite hierarchy of correlation functions, one observes an effective loss of purity or coherence and, on longer time scales, thermalization. We point out that the physics of decoherence is well described by classical statistical field theory.

  4. Quantum locking of classical correlations and quantum discord of classical-quantum states

    OpenAIRE

    BOIXO, S.; AOLITA, L.; CAVALCANTI, D.; MODI, K.; WINTER, A.

    2011-01-01

    A locking protocol between two parties is as follows: Alice gives an encrypted classical message to Bob which she does not want Bob to be able to read until she gives him the key. If Alice is using classical resources, and she wants to approach unconditional security, then the key and the message must have comparable sizes. But if Alice prepares a quantum state, the size of the key can be comparatively negligible. This effect is called quantum locking. Entanglement does not play a role in thi...

  5. Helical quantum states in HgTe quantum dots with inverted band structures.

    Science.gov (United States)

    Chang, Kai; Lou, Wen-Kai

    2011-05-20

    We investigate theoretically the electron states in HgTe quantum dots (QDs) with inverted band structures. In sharp contrast to conventional semiconductor quantum dots, the quantum states in the gap of the HgTe QD are fully spin-polarized and show ringlike density distributions near the boundary of the QD and spin-angular momentum locking. The persistent charge currents and magnetic moments, i.e., the Aharonov-Bohm effect, can be observed in such a QD structure. This feature offers us a practical way to detect these exotic ringlike edge states by using the SQUID technique.

  6. Gaussian Error Correction of Quantum States in a Correlated Noisy Channel

    DEFF Research Database (Denmark)

    Lassen, Mikael Østergaard; Berni, Adriano; Madsen, Lars Skovgaard

    2013-01-01

    Noise is the main obstacle for the realization of fault-tolerant quantum information processing and secure communication over long distances. In this work, we propose a communication protocol relying on simple linear optics that optimally protects quantum states from non-Markovian or correlated...... noise. We implement the protocol experimentally and demonstrate the near-ideal protection of coherent and entangled states in an extremely noisy channel. Since all real-life channels are exhibiting pronounced non-Markovian behavior, the proposed protocol will have immediate implications in improving...... the performance of various quantum information protocols....

  7. Tomography of the quantum state of photons entangled in high dimensions

    CSIR Research Space (South Africa)

    Agnew, M

    2011-12-01

    Full Text Available with unit trace [5]. By choosing the appropriate coefficients of the Gell-Mann matrices, we can minimize ?2, thus producing the closest physical density ma- trix that represents the high-dimensionally entangled quantum state. IV. RESULTS AND DISCUSSION.... Zeilinger, Phys. Rev. Lett. 94, 070402 (2005). [10] D. N. Matsukevich, P. Maunz, D. L. Moehring, S. Olmschenk, and C. Monroe, Phys. Rev. Lett. 100, 150404 (2008). [11] B. Jack, J. Leach, H. Ritsch, S. M. Barnett, M. J. Padgett, and S. Franke-Arnold, New...

  8. Population Transfer between Two Quantum States by Piecewise Chirping of Femtosecond Pulses: Theory and Experiment

    International Nuclear Information System (INIS)

    Zhdanovich, S.; Shapiro, E. A.; Shapiro, M.; Hepburn, J. W.; Milner, V.

    2008-01-01

    We propose and experimentally demonstrate the method of population transfer by piecewise adiabatic passage between two quantum states. Coherent excitation of a two-level system with a train of ultrashort laser pulses is shown to reproduce the effect of an adiabatic passage, conventionally achieved with a single frequency-chirped pulse. By properly adjusting the amplitudes and phases of the pulses in the excitation pulse train, we achieve complete and robust population transfer to the target state. The piecewise nature of the process suggests a possibility for the selective population transfer in complex quantum systems

  9. Cheat sensitive quantum bit commitment via pre- and post-selected quantum states

    Science.gov (United States)

    Li, Yan-Bing; Wen, Qiao-Yan; Li, Zi-Chen; Qin, Su-Juan; Yang, Ya-Tao

    2014-01-01

    Cheat sensitive quantum bit commitment is a most important and realizable quantum bit commitment (QBC) protocol. By taking advantage of quantum mechanism, it can achieve higher security than classical bit commitment. In this paper, we propose a QBC schemes based on pre- and post-selected quantum states. The analysis indicates that both of the two participants' cheat strategies will be detected with non-zero probability. And the protocol can be implemented with today's technology as a long-term quantum memory is not needed.

  10. Optimal conclusive teleportation of a d-dimensional two-particle unknown quantum state

    Institute of Scientific and Technical Information of China (English)

    Yang Yu-Guang; Wen Qiao-Yan; Zhu Fu-Chen

    2006-01-01

    A conclusive teleportation protocol of a d-dimensional two-particle unknown quantum state using three ddimensional particles in an arbitrary pure state is proposed. A sender teleports the unknown state conclusively to a receiver by using the positive operator valued measure(POVM) and introducing an ancillary qudit to perform the generalized Bell basis measurement. We calculate the optimal teleportation fidelity. We also discuss and analyse the reason why the information on the teleported state is lost in the course of the protocol.

  11. Entanglement and quantum state transfer between two atoms trapped in two indirectly coupled cavities

    Science.gov (United States)

    Zheng, Bin; Shen, Li-Tuo; Chen, Ming-Feng

    2016-05-01

    We propose a one-step scheme for implementing entanglement generation and the quantum state transfer between two atomic qubits trapped in two different cavities that are not directly coupled to each other. The process is realized through engineering an effective asymmetric X-Y interaction for the two atoms involved in the gate operation and an auxiliary atom trapped in an intermediate cavity, induced by virtually manipulating the atomic excited states and photons. We study the validity of the scheme as well as the influences of the dissipation by numerical simulation and demonstrate that it is robust against decoherence.

  12. Fortran code for generating random probability vectors, unitaries, and quantum states

    Directory of Open Access Journals (Sweden)

    Jonas eMaziero

    2016-03-01

    Full Text Available The usefulness of generating random configurations is recognized in many areas of knowledge. Fortran was born for scientific computing and has been one of the main programming languages in this area since then. And several ongoing projects targeting towards its betterment indicate that it will keep this status in the decades to come. In this article, we describe Fortran codes produced, or organized, for the generation of the following random objects: numbers, probability vectors, unitary matrices, and quantum state vectors and density matrices. Some matrix functions are also included and may be of independent interest.

  13. Chemical control of electrical contact to sp2 carbon atoms

    Science.gov (United States)

    Frederiksen, Thomas; Foti, Giuseppe; Scheurer, Fabrice; Speisser, Virginie; Schull, Guillaume

    2014-04-01

    Carbon-based nanostructures are attracting tremendous interest as components in ultrafast electronics and optoelectronics. The electrical interfaces to these structures play a crucial role for the electron transport, but the lack of control at the atomic scale can hamper device functionality and integration into operating circuitry. Here we study a prototype carbon-based molecular junction consisting of a single C60 molecule and probe how the electric current through the junction depends on the chemical nature of the foremost electrode atom in contact with the molecule. We find that the efficiency of charge injection to a C60 molecule varies substantially for the considered metallic species, and demonstrate that the relative strength of the metal-C bond can be extracted from our transport measurements. Our study further suggests that a single-C60 junction is a basic model to explore the properties of electrical contacts to meso- and macroscopic sp2 carbon structures.

  14. Can Chemical Mouthwash Agents Achieve Plaque/Gingivitis Control?

    Science.gov (United States)

    Van der Weijden, Fridus A; Van der Sluijs, Eveline; Ciancio, Sebastian G; Slot, Dagmar E

    2015-10-01

    Also note that structured abstracts are not allowed per journal style: What is the effect of a mouthwash containing various active chemical ingredients on plaque control and managing gingivitis in adults based on evidence gathered from existing systematic reviews? The summarized evidence suggests that mouthwashes containing chlorhexidine(CHX) and essential oils (EO) had a large effect supported by a strong body of evidence. Also there was strong evidence for a moderate effect of cetylpyridinium chloride(CPC). Evidence suggests that a CHX mouthwash is the first choice, the most reliable alternative is EO. No difference between CHX and EO with respect to gingivitis was observed. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Evaluation of chemical, botanical and cultural managements of termites control.

    Science.gov (United States)

    Dufera, Jiregna Tasisa; Fufa, Tena Gobena

    2014-01-15

    The study was conducted at Bojdi Dirmaji District, Wollega Zone (Western Ethiopia) using Randomized Complete Block Design with three replications. Eight different treatments of chemical, botanical and cultural control methods independently and in combinations were evaluated to identify the most effective method which is environmentally sustainable and economically feasible in controlling the termite problems. The data were collected over 12 weeks and analysis of variance showed significant difference among the treatments for all parameters. Maesa lanceolata 100 g alone showed lower percent damage between 2-8 weeks (33.3%), later on after 9-12 weeks it become non significant and the destructed mound was recovered. Mound treated with Diazinon 60% EC at the rate of 25 and 20 mL alone and Diazinon 60% EC combination with queen removal at rate of 15 and 10 mL showed significant control overall the treatment. From the results of the study the lower rate of Diazinon 60% EC (10 mL per mound) and queen removal could be better option to manage the termite problem and could be more sustainable and integrated manner in the study area.

  16. Size-controlled synthesis of transition metal nanoparticles through chemical and photo-chemical routes

    Science.gov (United States)

    Tangeysh, Behzad

    The central objective of this work is developing convenient general procedures for controlling the formation and stabilization of nanoscale transition metal particles. Contemporary interest in developing alternative synthetic approaches for producing nanoparticles arises in large part from expanding applications of the nanomaterials in areas such as catalysis, electronics and medicine. This research focuses on advancing the existing nanoparticle synthetic routes by using a new class of polymer colloid materials as a chemical approach, and the laser irradiation of metal salt solution as a photo-chemical method to attain size and shape selectivity. Controlled synthesis of small metal nanoparticles with sizes ranging from 1 to 5nm is still a continuing challenge in nanomaterial synthesis. This research utilizes a new class of polymer colloid materials as nano-reactors and protective agents for controlling the formation of small transition metal nanoparticles. The polymer colloid particles were formed from cross-linking of dinegatively charged metal precursors with partially protonated poly dimethylaminoethylmethacrylate (PDMAEMA). Incorporation of [PtCl6]2- species into the colloidal particles prior to the chemical reduction was effectively employed as a new strategy for synthesis of unusually small platinum nanoparticles with narrow size distributions (1.12 +/-0.25nm). To explore the generality of this approach, in a series of proof-of-concept studies, this method was successfully employed for the synthesis of small palladium (1.4 +/-0.2nm) and copper nanoparticles (1.5 +/-0.6nm). The polymer colloid materials developed in this research are pH responsive, and are designed to self-assemble and/or disassemble by varying the levels of protonation of the polymer chains. This unique feature was used to tune the size of palladium nanoparticles in a small range from 1nm to 5nm. The procedure presented in this work is a new convenient room temperature route for synthesis of

  17. Design and Control of Chemical Grouting : Volume 3 - Engineering Practice

    Science.gov (United States)

    1983-04-01

    Recent improvements in the engineering practice of chemical grouting have provided increased confidence in this method of ground modification. Designers can significantly improve the success of chemical grouting by defining their grouting program obj...

  18. A Self-Calibrating Remote Control Chemical Monitoring System

    Energy Technology Data Exchange (ETDEWEB)

    Jessica Croft

    2007-06-01

    The Susie Mine, part of the Upper Tenmile Mining Area, is located in Rimini, MT about 15 miles southwest of Helena, MT. The Upper Tenmile Creek Mining Area is an EPA Superfund site with 70 abandoned hard rock mines and several residential yards prioritized for clean up. Water from the Susie mine flows into Tenmile Creek from which the city of Helena draws part of its water supply. MSE Technology Applications in Butte, Montana was contracted by the EPA to build a treatment system for the Susie mine effluent and demonstrate a system capable of treating mine waste water in remote locations. The Idaho National Lab was contracted to design, build and demonstrate a low maintenance self-calibrating monitoring system that would monitor multiple sample points, allow remote two-way communications with the control software and allow access to the collected data through a web site. The Automated Chemical Analysis Monitoring (ACAM) system was installed in December 2006. This thesis documents the overall design of the hardware, control software and website, the data collected while MSE-TA’s system was operational, the data collected after MSE-TA’s system was shut down and suggested improvements to the existing system.

  19. Distinguishing mixed quantum states: Minimum-error discrimination versus optimum unambiguous discrimination

    International Nuclear Information System (INIS)

    Herzog, Ulrike; Bergou, Janos A.

    2004-01-01

    We consider two different optimized measurement strategies for the discrimination of nonorthogonal quantum states. The first is ambiguous discrimination with a minimum probability of inferring an erroneous result, and the second is unambiguous, i.e., error-free, discrimination with a minimum probability of getting an inconclusive outcome, where the measurement fails to give a definite answer. For distinguishing between two mixed quantum states, we investigate the relation between the minimum-error probability achievable in ambiguous discrimination, and the minimum failure probability that can be reached in unambiguous discrimination of the same two states. The latter turns out to be at least twice as large as the former for any two given states. As an example, we treat the case where the state of the quantum system is known to be, with arbitrary prior probability, either a given pure state, or a uniform statistical mixture of any number of mutually orthogonal states. For this case we derive an analytical result for the minimum probability of error and perform a quantitative comparison with the minimum failure probability

  20. An Improved Quantum Information Hiding Protocol Based on Entanglement Swapping of χ-type Quantum States

    International Nuclear Information System (INIS)

    Xu Shu-Jiang; Wang Lian-Hai; Ding Qing-Yan; Zhang Shu-Hui; Chen Xiu-Bo

    2016-01-01

    In 2011, Qu et al. proposed a quantum information hiding protocol based on the entanglement swapping of χ-type quantum states. Because a χ-type state can be described by the 4-particle cat states which have good symmetry, the possible output results of the entanglement swapping between a given χ-type state and all of the 16 χ-type states are divided into 8 groups instead of 16 groups of different results when the global phase is not considered. So it is difficult to read out the secret messages since each result occurs twice in each line (column) of the secret messages encoding rule for the original protocol. In fact, a 3-bit instead of a 4-bit secret message can be encoded by performing two unitary transformations on 2 particles of a χ-type quantum state in the original protocol. To overcome this defect, we propose an improved quantum information hiding protocol based on the general term formulas of the entanglement swapping among χ-type states. (paper)

  1. Quantum states and their marginals. From multipartite entanglement to quantum error-correcting codes

    International Nuclear Information System (INIS)

    Huber, Felix Michael

    2017-01-01

    At the heart of the curious phenomenon of quantum entanglement lies the relation between the whole and its parts. In my thesis, I explore different aspects of this theme in the multipartite setting by drawing connections to concepts from statistics, graph theory, and quantum error-correcting codes: first, I address the case when joint quantum states are determined by their few-body parts and by Jaynes' maximum entropy principle. This can be seen as an extension of the notion of entanglement, with less complex states already being determined by their few-body marginals. Second, I address the conditions for certain highly entangled multipartite states to exist. In particular, I present the solution of a long-standing open problem concerning the existence of an absolutely maximally entangled state on seven qubits. This sheds light on the algebraic properties of pure quantum states, and on the conditions that constrain the sharing of entanglement amongst multiple particles. Third, I investigate Ulam's graph reconstruction problems in the quantum setting, and obtain legitimacy conditions of a set of states to be the reductions of a joint graph state. Lastly, I apply and extend the weight enumerator machinery from quantum error correction to investigate the existence of codes and highly entangled states in higher dimensions. This clarifies the physical interpretation of the weight enumerators and of the quantum MacWilliams identity, leading to novel applications in multipartite entanglement.

  2. The quantum state vector in phase space and Gabor's windowed Fourier transform

    International Nuclear Information System (INIS)

    Bracken, A J; Watson, P

    2010-01-01

    Representations of quantum state vectors by complex phase space amplitudes, complementing the description of the density operator by the Wigner function, have been defined by applying the Weyl-Wigner transform to dyadic operators, linear in the state vector and anti-linear in a fixed 'window state vector'. Here aspects of this construction are explored, and a connection is established with Gabor's 'windowed Fourier transform'. The amplitudes that arise for simple quantum states from various choices of windows are presented as illustrations. Generalized Bargmann representations of the state vector appear as special cases, associated with Gaussian windows. For every choice of window, amplitudes lie in a corresponding linear subspace of square-integrable functions on phase space. A generalized Born interpretation of amplitudes is described, with both the Wigner function and a generalized Husimi function appearing as quantities linear in an amplitude and anti-linear in its complex conjugate. Schroedinger's time-dependent and time-independent equations are represented on phase space amplitudes, and their solutions described in simple cases.

  3. 31 CFR 598.309 - Narcotic drug; controlled substance; listed chemical.

    Science.gov (United States)

    2010-07-01

    ...; listed chemical. 598.309 Section 598.309 Money and Finance: Treasury Regulations Relating to Money and... SANCTIONS REGULATIONS General Definitions § 598.309 Narcotic drug; controlled substance; listed chemical. The terms narcotic drug, controlled substance, and listed chemical have the meanings given those terms...

  4. A quick and easy test for deciding entanglement status of an N-qubit pure quantum state

    International Nuclear Information System (INIS)

    Mehendale, D.P.; Joag, P.S.

    2018-01-01

    We develop a simple criterion in terms of a necessary-sufficient condition (NS condition) for deciding separability of an arbitrary n-qubit pure quantum state. This NS condition provides a quick and easy test procedure to determine the entanglement status of a pure quantum state. We normalize the given quantum state and using this normalized state we can easily build a simplest system of equations containing trigonometric functions by making use of the well known Bloch Sphere representation for single qubit states and check whether or not this system of equations is consistent. According to proposed NS condition the given pure quantum state is separable (entangled) if and only if the above mentioned system of equations is consistent (inconsistent). We build this system of equations by equating the coefficients of computational basis states in the superposition representing the given pure quantum state with certain products of trigonometric functions obtained using standard Bloch Sphere representation for single qubit states. To establish separability of given state one requires to find a valid solution of the above mentioned system of equations but entanglement on the other hand follows when any two equations in this system of equations are mutually inconsistent. Thus, entanglement of the state can follow easily if one succeeds in finding any two mutually inconsistent equations in the above mentioned system of equations.

  5. Time-resolved measurement of the quantum states of photons using two-photon interference with short-time reference pulses

    International Nuclear Information System (INIS)

    Ren Changliang; Hofmann, Holger F.

    2011-01-01

    To fully utilize the energy-time degree of freedom of photons for optical quantum-information processes, it is necessary to control and characterize the temporal quantum states of the photons at extremely short time scales. For measurements of the temporal coherence of the quantum states beyond the time resolution of available detectors, two-photon interference with a photon in a short-time reference pulse may be a viable alternative. In this paper, we derive the temporal measurement operators for the bunching statistics of a single-photon input state with a photon from a weak coherent reference pulse. It is shown that the effects of the pulse shape of the reference pulse can be expressed in terms of a spectral filter selecting the bandwidth within which the measurement can be treated as an ideal projection on eigenstates of time. For full quantum tomography, temporal coherence can be determined by using superpositions of reference pulses at two different times. Moreover, energy-time entanglement can be evaluated based on the two-by-two entanglement observed in the coherences between pairs of detection times.

  6. Physical controls on directed virus assembly at nanoscale chemical templates

    International Nuclear Information System (INIS)

    Cheung, C L; Chung, S; Chatterji, A; Lin, T; Johnson, J E; Hok, S; Perkins, J; De Yoreo, J

    2006-01-01

    Viruses are attractive building blocks for nanoscale heterostructures, but little is understood about the physical principles governing their directed assembly. In-situ force microscopy was used to investigate organization of Cowpea Mosaic Virus engineered to bind specifically and reversibly at nanoscale chemical templates with sub-30nm features. Morphological evolution and assembly kinetics were measured as virus flux and inter-viral potential were varied. The resulting morphologies were similar to those of atomic-scale epitaxial systems, but the underlying thermodynamics was analogous to that of colloidal systems in confined geometries. The 1D templates biased the location of initial cluster formation, introduced asymmetric sticking probabilities, and drove 1D and 2D condensation at subcritical volume fractions. The growth kinetics followed a t 1/2 law controlled by the slow diffusion of viruses. The lateral expansion of virus clusters that initially form on the 1D templates following introduction of polyethylene glycol (PEG) into the solution suggests a significant role for weak interaction

  7. Synthesis, chemical and biological quality control of radioiodinated peptides

    International Nuclear Information System (INIS)

    Rafii, H.; Khalaj, A.; Beiki, D.; Motameidi, F.; Maloobi, M.; Karimian-dehghan, M.; Keshavarrzi, F.

    2002-01-01

    Iodinated compounds with I-131, 125 and 123 have been widely used for biochemical function studies. In conjunction with SPECT, [I-123] labelled proteins have various diagnostic and therapeutic applications in nuclear medicine. Preparation of some radioiodinated peptides with tyrosine and/or lysine groups on their main chain molecules can be carried out with both direct and indirect methods, but lack of these groups in molecule cause the molecule dose not lend itself for direct radioiodination. In this study, human IgG and Formyl-Methyl-Leucyl-Phenylalanine, FMLF, have been chosen as a model compounds for direct and indirect radioiodination respectively. Here, we will describe the labelling procedure of [I-125] IgG using chloramine-T as a suitable oxidant agent and [I-125 and I-131] FMLF by indirect method using ATE/SIB as a prosthetic group in multi-step reactions. The obtained results for chemical quality control of intermediate radioiodinated SIB by HPLC and two labelled IgG and FMLF will be also discussed. Biological results, biodistribution studies and SPECT scans on mice per-injected labelled FMLF show a low uptake of thyroid but a high at urine and bladder, perhaps because of low molecular weight of FMLF. In this case, it seems to be better to separate the reaction mixture of labelled FMLF by BPLC than Sephadex-G50 gel filtration. (Author)

  8. Detecting a set of entanglement measures in an unknown tripartite quantum state by local operations and classical communication

    International Nuclear Information System (INIS)

    Bai Yankui; Li Shushen; Zheng Houzhi; Wang, Z. D.

    2006-01-01

    We propose a more general method for detecting a set of entanglement measures, i.e., negativities, in an arbitrary tripartite quantum state by local operations and classical communication. To accomplish the detection task using this method, three observers do not need to perform partial transposition maps by the structural physical approximation; instead, they only need to collectively measure some functions via three local networks supplemented by a classical communication. With these functions, they are able to determine the set of negativities related to the tripartite quantum state

  9. Universal and Deterministic Manipulation of the Quantum State of Harmonic Oscillators: A Route to Unitary Gates for Fock State Qubits

    International Nuclear Information System (INIS)

    Santos, Marcelo Franca

    2005-01-01

    We present a simple quantum circuit that allows for the universal and deterministic manipulation of the quantum state of confined harmonic oscillators. The scheme is based on the selective interactions of the referred oscillator with an auxiliary three-level system and a classical external driving source, and enables any unitary operations on Fock states, two by two. One circuit is equivalent to a single qubit unitary logical gate on Fock states qubits. Sequences of similar protocols allow for complete, deterministic, and state-independent manipulation of the harmonic oscillator quantum state

  10. The significance of feedback control for chemical sensors

    NARCIS (Netherlands)

    Bergveld, Piet

    1992-01-01

    The conventional way of applying chemical sensors is in an open-loop configuration. A parameter of the chemical domain, such as a gas or ion concentration, is converted into a parameter of the mechanical or electrical domain, often with non-linear transfer characteristics. The paramagnetic oxygen

  11. Inventory Control: A Small Electronic Device for Studying Chemical Kinetics.

    Science.gov (United States)

    Perez-Rodriguez, A. L.; Calvo-Aguilar, J. L.

    1984-01-01

    Shows how the rate of reaction can be studied using a simple electronic device that overcomes the difficulty students encounter in solving the differential equations describing chemical equilibrium. The device, used in conjunction with an oscilloscope, supplies the voltages that represent the chemical variables that take part in the equilibrium.…

  12. Femtosecond laser control of chemical reaction of carbon monoxide and hydrogen

    CSIR Research Space (South Africa)

    Du Plessis, A

    2010-09-01

    Full Text Available Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This can result in controllable...

  13. Deterministic Generation of Quantum State Transfer Between Spatially Separated Single Molecule Magnets

    International Nuclear Information System (INIS)

    Song Peijun; Lue Xinyou; Huang Pei; Hao Xiangying; Yang Xiaoxue

    2010-01-01

    We propose a new scheme for realizing deterministic quantum state transfer (QST) between two spatially separated single molecule magnets (SMMs) with the framework of cavity quantum electrodynamics (QED). In the present scheme, two SMMs are trapped in two spatially separated optical cavities coupled by an optical fiber. Through strictly numerically simulating, we demonstrate that our scheme is robust with respect to the SMMs' spontaneous decay and fiber loss under the conditions of dispersive SMMs-field interaction and strong coupling of cavity fiber. In addition, we also discuss the influence of photon leakage out of cavities and show that our proposal is good enough to demonstrate the generation of QST with high fidelity utilizing the current experimental technology. The present investigation provides research opportunities for realizing QST between solid-state qubits and may result in a substantial impact on the progress of solid-state-based quantum communications network. (general)

  14. Quantum paradox of choice: More freedom makes summoning a quantum state harder

    Science.gov (United States)

    Adlam, Emily; Kent, Adrian

    2016-06-01

    The properties of quantum information in space-time can be investigated by studying operational tasks, such as "summoning," in which an unknown quantum state is supplied at one point and a call is made at another for it to be returned at a third. Hayden and May [arXiv:1210.0913] recently proved necessary and sufficient conditions for guaranteeing successful return of a summoned state for finite sets of call and return points when there is a guarantee of at most one summons. We prove necessary and sufficient conditions when there may be several possible summonses and complying with any one constitutes success, and we demonstrate the existence of an apparent paradox: The extra freedom makes it strictly harder to complete the summoning task. This result has practical applications for distributed quantum computing and cryptography and implications for our understanding of relativistic quantum information and its localization in space-time.

  15. Quantum state transfer via a two-qubit Heisenberg XXZ spin model

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jia; Zhang Guofeng [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Chen Ziyu [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)], E-mail: chenzy@buaa.edu.cn

    2008-04-14

    Transfer of quantum states through a two-qubit Heisenberg XXZ spin model with a nonuniform magnetic field b is investigated by means of quantum theory. The influences of b, the spin exchange coupling J and the effective transfer time T=Jt on the fidelity have been studied for some different initial states. Results show that fidelity of the transferred state is determined not only by J, T and b but also by the initial state of this quantum system. Ideal information transfer can be realized for some kinds of initial states. We also found that the interactions of the z-component J{sub z} and uniform magnetic field B do not have any contribution to the fidelity. These results may be useful for quantum information processing.

  16. Quantum state transfer via a two-qubit Heisenberg XXZ spin model

    International Nuclear Information System (INIS)

    Liu Jia; Zhang Guofeng; Chen Ziyu

    2008-01-01

    Transfer of quantum states through a two-qubit Heisenberg XXZ spin model with a nonuniform magnetic field b is investigated by means of quantum theory. The influences of b, the spin exchange coupling J and the effective transfer time T=Jt on the fidelity have been studied for some different initial states. Results show that fidelity of the transferred state is determined not only by J, T and b but also by the initial state of this quantum system. Ideal information transfer can be realized for some kinds of initial states. We also found that the interactions of the z-component J z and uniform magnetic field B do not have any contribution to the fidelity. These results may be useful for quantum information processing

  17. Influence of the atomic structure on the quantum state of sputtered Ir atoms

    International Nuclear Information System (INIS)

    Bastiaansen, J.; Philipsen, V.; Lievens, P.; Silverans, R.E.; Vandeweert, E.

    2004-01-01

    The probability of the ejection of a neutral atom in a specific quantum state after keV-ion beam sputtering is often interpreted in terms of the interaction between the atomic states of the escaping atom and the electronic states of the solid. In this work, we examined this interplay in the sputtering of iridium as this element has--unlike the elements employed in previous investigations--a complex atomic structure due to strong configuration interactions. Double-resonant two-photon laser ionization is used to probe the sputtered Ir atoms yielding information about the probability for an ejected atom to populate a specific atomic state and its escape velocity. The qualitative features of the corresponding population partition and state-selective velocity distributions show the influence of the excitation energy and the electronic structure of the different atomic states. A comparison is made between the experimental data and predictions from the resonant electron transfer description

  18. Optimal experiment design for quantum state tomography: Fair, precise, and minimal tomography

    International Nuclear Information System (INIS)

    Nunn, J.; Smith, B. J.; Puentes, G.; Walmsley, I. A.; Lundeen, J. S.

    2010-01-01

    Given an experimental setup and a fixed number of measurements, how should one take data to optimally reconstruct the state of a quantum system? The problem of optimal experiment design (OED) for quantum state tomography was first broached by Kosut et al.[R. Kosut, I. Walmsley, and H. Rabitz, e-print arXiv:quant-ph/0411093 (2004)]. Here we provide efficient numerical algorithms for finding the optimal design, and analytic results for the case of 'minimal tomography'. We also introduce the average OED, which is independent of the state to be reconstructed, and the optimal design for tomography (ODT), which minimizes tomographic bias. Monte Carlo simulations confirm the utility of our results for qubits. Finally, we adapt our approach to deal with constrained techniques such as maximum-likelihood estimation. We find that these are less amenable to optimization than cruder reconstruction methods, such as linear inversion.

  19. Symmetric Informationally-Complete Quantum States as Analogues to Orthonormal Bases and Minimum-Uncertainty States

    Directory of Open Access Journals (Sweden)

    D. Marcus Appleby

    2014-03-01

    Full Text Available Recently there has been much effort in the quantum information community to prove (or disprove the existence of symmetric informationally complete (SIC sets of quantum states in arbitrary finite dimension. This paper strengthens the urgency of this question by showing that if SIC-sets exist: (1 by a natural measure of orthonormality, they are as close to being an orthonormal basis for the space of density operators as possible; and (2 in prime dimensions, the standard construction for complete sets of mutually unbiased bases and Weyl-Heisenberg covariant SIC-sets are intimately related: The latter represent minimum uncertainty states for the former in the sense of Wootters and Sussman. Finally, we contribute to the question of existence by conjecturing a quadratic redundancy in the equations for Weyl-Heisenberg SIC-sets.

  20. Entanglement Potential Versus Negativity of Wigner Function for SUP-Operated Quantum States

    Science.gov (United States)

    Chatterjee, Arpita

    2018-02-01

    We construct a distinct category of nonclassical quantum states by applying a superposition of products (SUP) of field annihilation (\\hat {a}) and creation (\\hat {a}^{\\dagger }) operators of the type (s\\hat {a}\\hat {a}^{\\dagger }+t\\hat {a}^{\\dagger }\\hat {a}), with s2+t2=1, upon thermal and even coherent states. We allow these SUP operated states to undergo a decoherence process and then describe the nonclassical features of the resulted field by using the entanglement potential (EP) and the negativity of the Wigner distribution function. Our analysis reveals that both the measures are reduced in the linear loss process. The partial negativity of the Wigner function disappears when losses exceed 50% but EP exists always.

  1. Self-guided method to search maximal Bell violations for unknown quantum states

    Science.gov (United States)

    Yang, Li-Kai; Chen, Geng; Zhang, Wen-Hao; Peng, Xing-Xiang; Yu, Shang; Ye, Xiang-Jun; Li, Chuan-Feng; Guo, Guang-Can

    2017-11-01

    In recent decades, a great variety of research and applications concerning Bell nonlocality have been developed with the advent of quantum information science. Providing that Bell nonlocality can be revealed by the violation of a family of Bell inequalities, finding maximal Bell violation (MBV) for unknown quantum states becomes an important and inevitable task during Bell experiments. In this paper we introduce a self-guided method to find MBVs for unknown states using a stochastic gradient ascent algorithm (SGA), by parametrizing the corresponding Bell operators. For three investigated systems (two qubit, three qubit, and two qutrit), this method can ascertain the MBV of general two-setting inequalities within 100 iterations. Furthermore, we prove SGA is also feasible when facing more complex Bell scenarios, e.g., d -setting d -outcome Bell inequality. Moreover, compared to other possible methods, SGA exhibits significant superiority in efficiency, robustness, and versatility.

  2. Macroscopic Quantum States and Quantum Phase Transition in the Dicke Model

    International Nuclear Information System (INIS)

    Lian Jin-Ling; Zhang Yuan-Wei; Liang Jiu-Qing

    2012-01-01

    The energy spectrum of Dicke Hamiltonians with and without the rotating wave approximation for an arbitrary atom number is obtained analytically by means of the variational method, in which the effective pseudo-spin Hamiltonian resulting from the expectation value in the boson-field coherent state is diagonalized by the spin-coherent-state transformation. In addition to the ground-state energy, an excited macroscopic quantum-state is found corresponding to the south- and north-pole gauges of the spin-coherent states, respectively. Our results of ground-state energies in exact agreement with various approaches show that these models exhibit a zero-temperature quantum phase transition of the second order for any number of atoms, which was commonly considered as a phenomenon of the thermodynamic limit with the atom number tending to infinity. The critical behavior of the geometric phase is analyzed. (general)

  3. Moments of generalized Husimi distributions and complexity of many-body quantum states

    International Nuclear Information System (INIS)

    Sugita, Ayumu

    2003-01-01

    We consider generalized Husimi distributions for many-body systems, and show that their moments are good measures of complexity of many-body quantum states. Our construction of the Husimi distribution is based on the coherent state of the single-particle transformation group. Then the coherent states are independent-particle states, and, at the same time, the most localized states in the Husimi representation. Therefore delocalization of the Husimi distribution, which can be measured by the moments, is a sign of many-body correlation (entanglement). Since the delocalization of the Husimi distribution is also related to chaoticity of the dynamics, it suggests a relation between entanglement and chaos. Our definition of the Husimi distribution can be applied not only to systems of distinguishable particles, but also to those of identical particles, i.e., fermions and bosons. We derive an algebraic formula to evaluate the moments of the Husimi distribution

  4. Implementing nonprojective measurements via linear optics: An approach based on optimal quantum-state discrimination

    International Nuclear Information System (INIS)

    Loock, Peter van; Nemoto, Kae; Munro, William J.; Raynal, Philippe; Luetkenhaus, Norbert

    2006-01-01

    We discuss the problem of implementing generalized measurements [positive operator-valued measures (POVMs)] with linear optics, either based upon a static linear array or including conditional dynamics. In our approach, a given POVM shall be identified as a solution to an optimization problem for a chosen cost function. We formulate a general principle: the implementation is only possible if a linear-optics circuit exists for which the quantum mechanical optimum (minimum) is still attainable after dephasing the corresponding quantum states. The general principle enables us, for instance, to derive a set of necessary conditions for the linear-optics implementation of the POVM that realizes the quantum mechanically optimal unambiguous discrimination of two pure nonorthogonal states. This extends our previous results on projection measurements and the exact discrimination of orthogonal states

  5. Collapsing a perfect superposition to a chosen quantum state without measurement.

    Directory of Open Access Journals (Sweden)

    Ahmed Younes

    Full Text Available Given a perfect superposition of [Formula: see text] states on a quantum system of [Formula: see text] qubits. We propose a fast quantum algorithm for collapsing the perfect superposition to a chosen quantum state [Formula: see text] without applying any measurements. The basic idea is to use a phase destruction mechanism. Two operators are used, the first operator applies a phase shift and a temporary entanglement to mark [Formula: see text] in the superposition, and the second operator applies selective phase shifts on the states in the superposition according to their Hamming distance with [Formula: see text]. The generated state can be used as an excellent input state for testing quantum memories and linear optics quantum computers. We make no assumptions about the used operators and applied quantum gates, but our result implies that for this purpose the number of qubits in the quantum register offers no advantage, in principle, over the obvious measurement-based feedback protocol.

  6. Quantum State Transmission in a Superconducting Charge Qubit-Atom Hybrid

    Science.gov (United States)

    Yu, Deshui; Valado, María Martínez; Hufnagel, Christoph; Kwek, Leong Chuan; Amico, Luigi; Dumke, Rainer

    2016-01-01

    Hybrids consisting of macroscopic superconducting circuits and microscopic components, such as atoms and spins, have the potential of transmitting an arbitrary state between different quantum species, leading to the prospective of high-speed operation and long-time storage of quantum information. Here we propose a novel hybrid structure, where a neutral-atom qubit directly interfaces with a superconducting charge qubit, to implement the qubit-state transmission. The highly-excited Rydberg atom located inside the gate capacitor strongly affects the behavior of Cooper pairs in the box while the atom in the ground state hardly interferes with the superconducting device. In addition, the DC Stark shift of the atomic states significantly depends on the charge-qubit states. By means of the standard spectroscopic techniques and sweeping the gate voltage bias, we show how to transfer an arbitrary quantum state from the superconducting device to the atom and vice versa. PMID:27922087

  7. A homodyne detector integrated onto a photonic chip for measuring quantum states and generating random numbers

    Science.gov (United States)

    Raffaelli, Francesco; Ferranti, Giacomo; Mahler, Dylan H.; Sibson, Philip; Kennard, Jake E.; Santamato, Alberto; Sinclair, Gary; Bonneau, Damien; Thompson, Mark G.; Matthews, Jonathan C. F.

    2018-04-01

    Optical homodyne detection has found use as a characterisation tool in a range of quantum technologies. So far implementations have been limited to bulk optics. Here we present the optical integration of a homodyne detector onto a silicon photonics chip. The resulting device operates at high speed, up 150 MHz, it is compact and it operates with low noise, quantified with 11 dB clearance between shot noise and electronic noise. We perform on-chip quantum tomography of coherent states with the detector and show that it meets the requirements for characterising more general quantum states of light. We also show that the detector is able to produce quantum random numbers at a rate of 1.2 Gbps, by measuring the vacuum state of the electromagnetic field and applying off-line post processing. The produced random numbers pass all the statistical tests provided by the NIST test suite.

  8. Comment on ''Semiquantum-key distribution using less than four quantum states''

    International Nuclear Information System (INIS)

    Boyer, Michel; Mor, Tal

    2011-01-01

    For several decades it was believed that information-secure key distribution requires both the sender and receiver to have the ability to generate and/or manipulate quantum states. Earlier, we showed that quantum key distribution in which one party is classical is possible [Boyer, Kenigsberg, and Mor, Phys. Rev. Lett. 99, 140501 (2007)]. A surprising and very nice extension of that result was suggested by Zou, Qiu, Li, Wu, and Li [Phys. Rev. A 79, 052312 (2009)]. Their paper suggests that it is sufficient for the originator of the states (the person holding the quantum technology) to generate just one state. The resulting semiquantum key distribution, which we call here 'quantum key distribution with classical Alice' is indeed completely robust against eavesdropping. However, their proof (that no eavesdropper can get information without being possibly detected) is faulty. We provide here a fully detailed and direct proof of their very important result.

  9. Quantum teleportation via noisy bipartite and tripartite accelerating quantum states: beyond the single mode approximation

    Science.gov (United States)

    Zounia, M.; Shamirzaie, M.; Ashouri, A.

    2017-09-01

    In this paper quantum teleportation of an unknown quantum state via noisy maximally bipartite (Bell) and maximally tripartite (Greenberger-Horne-Zeilinger (GHZ)) entangled states are investigated. We suppose that one of the observers who would receive the sent state accelerates uniformly with respect to the sender. The interactions of the quantum system with its environment during the teleportation process impose noises. These (unital and nonunital) noises are: phase damping, phase flip, amplitude damping and bit flip. In expressing the modes of the Dirac field used as qubits, in the accelerating frame, the so-called single mode approximation is not imposed. We calculate the fidelities of teleportation, and discuss their behaviors using suitable plots. The effects of noise, acceleration and going beyond the single mode approximation are discussed. Although the Bell states bring higher fidelities than GHZ states, the global behaviors of the two quantum systems with respect to some noise types, and therefore their fidelities, are different.

  10. Towards optimal experimental tests on the reality of the quantum state

    International Nuclear Information System (INIS)

    Knee, George C

    2017-01-01

    The Barrett–Cavalcanti–Lal–Maroney (BCLM) argument stands as the most effective means of demonstrating the reality of the quantum state. Its advantages include being derived from very few assumptions, and a robustness to experimental error. Finding the best way to implement the argument experimentally is an open problem, however, and involves cleverly choosing sets of states and measurements. I show that techniques from convex optimisation theory can be leveraged to numerically search for these sets, which then form a recipe for experiments that allow for the strongest statements about the ontology of the wavefunction to be made. The optimisation approach presented is versatile, efficient and can take account of the finite errors present in any real experiment. I find significantly improved low-cardinality sets which are guaranteed partially optimal for a BCLM test in low Hilbert space dimension. I further show that mixed states can be more optimal than pure states. (paper)

  11. Conditions for uniqueness of product representations for separable quantum channels and separable quantum states

    International Nuclear Information System (INIS)

    Cohen, Scott M.

    2014-01-01

    We give a sufficient condition that an operator sum representation of a separable quantum channel in terms of product operators is the unique product representation for that channel, and then provide examples of such channels for any number of parties. This result has implications for efforts to determine whether or not a given separable channel can be exactly implemented by local operations and classical communication. By the Choi-Jamiolkowski isomorphism, it also translates to a condition for the uniqueness of product state ensembles representing a given quantum state. These ideas follow from considerations concerning whether or not a subspace spanned by a given set of product operators contains at least one additional product operator

  12. Chemical Weed Control in Saffron (Crocus sativus Fields

    Directory of Open Access Journals (Sweden)

    majid abbaspoor

    2018-01-01

    Full Text Available Introduction Saffron is derived from the stigmas of the saffron (Crocus sativus L. It is the world’s most expensive spice and has been widely used in many countries. It is also increasingly used for medicinal purposes. Weed control in this perennial, small and low growing crop, needs a lot of labor work. Chemical approach is one of the most effective methods for weed control in saffron. Currently, some herbicide options are available for applications in saffron. For example, satisfactory broadleaved weed control would be achieved by post-emergence application of metribuzin and ioxynil after harvesting saffron flowers. Application of glyphosate and/or 2, 4-D / 2, 4-DB are used to clean up the beds prior to the new season’s flowering and growth of saffron in New Zealand. The selective weed control of weeds in saffron has not been widely reported elsewhere but some in Iran. The choice of herbicide(s depends on the kind of weeds present. In some literatures metribuzin showed promising results for weed control in saffron fields. It is selectively used for control of annual grasses and numerous broad-leaved weeds. The objective of this study was the evaluation of the efficacy of 15 herbicides with different mode of actions, selected on the basis of dominant weed flora and previous studies, on weeds grown in saffron fields. Materials and Methods A field study was conducted to evaluate the efficacy of herbicides for weed control in saffron (Crocus sativus in Agricultural and Natural Resources Research and Education Center of Khorasan Razavi Province, Mashhad, in 2014-2015 growing season. The experiment was conducted in a completely randomized block design with three replications. Treatments were consisted of metsulfuron-methyl + sulfosulfuron (Total® at dose of 40 g ha-1, sulfosulfuron (Apirus® at dose of 26.6 g ha-1, oxadiazon (Ronestar® at dose of 2 l ha-1, oxyflurofen (Goal® at dose of 2 l ha-1, mesosulfuron + idosulfuron + diflufenican

  13. Metabolic Engineering of Chemical Defence Pathways in Plant Disease Control

    DEFF Research Database (Denmark)

    Rook, Frederik

    2016-01-01

    on each topic. The chapter reviews the some of the scientific and technical challenges in metabolic engineering and the new possibilities emerging from recent technological developments. It concludes by discussing the outlook for bioengineered chemical defences as part of crop protection strategies, also...... with antimicrobial properties for use in crop protection. It presents an overview of the metabolic engineering efforts made in the area of plant chemical defence. For in-depth information on the characteristics of a specific class of chemical defence compounds, the reader is referred to the specialized reviews...

  14. One-state vector formalism for the evolution of a quantum state through nested Mach-Zehnder interferometers

    Czech Academy of Sciences Publication Activity Database

    Bartkiewicz, K.; Černoch, A.; Javůrek, D.; Lemr, K.; Soubusta, Jan; Svozilík, J.

    2015-01-01

    Roč. 91, č. 1 (2015), "012103-1"-"012103-4" ISSN 1050-2947 Institutional support: RVO:68378271 Keywords : one-state vector * quantum state * Mach-Zehnder interferometer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.808, year: 2014

  15. Physico-chemical quality control 131I-sodium 2-iodohippurate

    International Nuclear Information System (INIS)

    Morin, J.; Olive, E.; Issac, M.; Cruz, J.

    1992-01-01

    Some physico-chemical methods for analytical control 131 I-sodium 2-iodohippurate are compared. The most convenient to applicate in hospital and in more especialized quality control laboratories are recommended

  16. CHEMICAL CONTROL OF BEAN WEEVIL, ACANTHOSCELIDES OBTECTUS SAY IN STORAGE CONDITION

    Directory of Open Access Journals (Sweden)

    M PORCA

    2003-12-01

    Full Text Available The paper presents the positive results obtained by some pesticides applied against the bean weevil - Acanthoscelides obtectus Say, after a synthetic rewiew of the potential chemical methods which may be used in the chemical control of the insectes harmful to the stored bean seeds. The chemical control is realised treatments wits syntetic pyrethroid (permetrin, deltametrin and organophosphoric insecticides (malation, pirimifos metil, fenitrotion and chlrorpirifos-metil.

  17. Chemically triggered ejection of membrane tubules controlled by intermonolayer friction.

    Science.gov (United States)

    Fournier, J-B; Khalifat, N; Puff, N; Angelova, M I

    2009-01-09

    We report a chemically driven membrane shape instability that triggers the ejection of a tubule growing exponentially toward a chemical source. The instability is initiated by a dilation of the exposed monolayer, which is coupled to the membrane spontaneous curvature and slowed down by intermonolayer friction. Our experiments are performed by local delivery of a basic pH solution to a giant vesicle. Quantitative fits of the data give an intermonolayer friction coefficient b approximately 2x10;{9} J s/m;{4}. The exponential growth of the tubule may be explained by a Marangoni stress yielding a pulling force proportional to its length.

  18. 78 FR 64210 - Extension of Review Periods Under the Toxic Substances Control Act; Certain Chemicals and...

    Science.gov (United States)

    2013-10-28

    ... Under the Toxic Substances Control Act; Certain Chemicals and Microorganisms; Premanufacture... 325 and 324110), e.g., chemical manufacturing and petroleum refineries. The North American Industrial... Agency under section 5 of the Toxic Substances Control Act (TSCA), received by EPA on or before October 1...

  19. Compatible biological and chemical control systems for Rhizoctonia solani in potato

    NARCIS (Netherlands)

    Boogert, van den P.H.J.F.; Luttikholt, A.J.G.

    2004-01-01

    A series of chemical and biological control agents were tested for compatibility with the Rhizoctonia-specific biocontrol fungus Verticillium biguttatum aimed at designing novel control strategies for black scurf (Rhizoctonia solani) and other tuber diseases in potato. The efficacy of chemicals,

  20. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  1. Chemical factors controlling actinide sorption in the environment

    International Nuclear Information System (INIS)

    Beall, G.W.; Allard, B.

    1979-01-01

    The solid geologic media and the aqueous phase are of equal importance for the retention of actinides in the environment. The composition of the water is largely determined by the mineralogical composition of the rock that it is in equilibrium with. The chemical form of the actinides and their sorption, are highly dependent on the composition of the water with respect to pH, redox potential, and concentration of anions like carbonate, phosphate, fluoride, and organic acids

  2. Improvement of chemical control in the water-steam cycle of thermal power plants

    International Nuclear Information System (INIS)

    Rajakovic-Ognjanovic, Vladana N.; Zivojinovic, Dragana Z.; Grgur, Branimir N.; Rajakovic, Ljubinka V.

    2011-01-01

    A more effective chemical control in the water-steam cycle (WSC) of thermal power plants (TPP) is proposed in this paper. Minimization of corrosion effects by the production of ultra pure water and its strict control is the basis of all the investigated processes. The research involved the analysis of water samples in the WSC through key water quality parameters and by the most convenient analytical tools. The necessity for the stricter chemical control is demonstrated through a concrete example of the TPP Nikola Tesla, Serbia. After a thorough analysis of the chemical control system of the WSC, diagnostic and control parameters were chosen for continuous systematic measurements. Sodium and chloride ions were recognized as the ions which indicate the corrosion potential of the water and give insight into the proper production and maintenance of water within the WSC. Chemical transformations of crucial corrosion elements, iron and silica, were considered and related to their quantitative values. - Research highlights: → The more effective chemical control in the water-steam cycle of thermal power plant Nikola Tesla, Serbia. → In chemical control the diagnostic and control parameters were optimized and introduced for the systematic measurements in the water-steam cycle. → Sodium and chloride ions were recognized as ions which indicate corrosion potential of water and give insight to proper function of production and maintenance of water within water-team cycle. → Chemical transformations of crucial corrosion elements, iron and silica are considered and related with their quantitative values.

  3. The chemical monitoring and control during temporary turbine trip or reactor scram of nuclear power plant

    International Nuclear Information System (INIS)

    Liu Heng

    2012-01-01

    During normal operation, a malfunction of equipment or improper operation sometimes results in a turbine trip or reactor scram or even cold shutdown. Because present chemical control strategy and programs aimed at the situation of normal operation and planed refueling outage, no integrate emergency program of radiochemical and chemical control had been developed to focus on this urgent and unexpected situation. After many years of practice and experience feedback, chemists have created an emergency collaborative program of radiochemical and chemical control which aims at these unexpected situations such as unplanned unit down power, turbine trip, or reactor scram. The program defines different radiochemical and chemical control measures and steps during different status to monitor primary loop dose rate variation, fuel assembly integrity and water chemical excursion to prevent components from corrosion. (author)

  4. Connections of geometric measure of entanglement of pure symmetric states to quantum state estimation

    International Nuclear Information System (INIS)

    Chen Lin; Zhu Huangjun; Wei, Tzu-Chieh

    2011-01-01

    We study the geometric measure of entanglement (GM) of pure symmetric states related to rank 1 positive-operator-valued measures (POVMs) and establish a general connection with quantum state estimation theory, especially the maximum likelihood principle. Based on this connection, we provide a method for computing the GM of these states and demonstrate its additivity property under certain conditions. In particular, we prove the additivity of the GM of pure symmetric multiqubit states whose Majorana points under Majorana representation are distributed within a half sphere, including all pure symmetric three-qubit states. We then introduce a family of symmetric states that are generated from mutually unbiased bases and derive an analytical formula for their GM. These states include Dicke states as special cases, which have already been realized in experiments. We also derive the GM of symmetric states generated from symmetric informationally complete POVMs (SIC POVMs) and use it to characterize all inequivalent SIC POVMs in three-dimensional Hilbert space that are covariant with respect to the Heisenberg-Weyl group. Finally, we describe an experimental scheme for creating the symmetric multiqubit states studied in this article and a possible scheme for measuring the permanence of the related Gram matrix.

  5. Λ < 0 quantum gravity in 2 + 1 dimensions: I. Quantum states and stringy S-matrix

    International Nuclear Information System (INIS)

    Krasnov, Kirill

    2002-01-01

    We consider the theory of pure gravity in 2 + 1 dimensions, with negative cosmological constant. The theory contains simple matter in the form of point particles; the latter are classically described as lines of conical singularities. We propose a formalism in which quantum amplitudes for the process involving black holes and point particles are obtained as conformal field theory (CFT) correlation functions on Riemann surfaces X. Point particles are described by the CFT vertex operators; black holes (asymptotic regions) are in correspondence with boundaries of X. We consider two examples: the amplitude for emission of a particle by the BTZ black hole and the amplitude of black-hole creation by two point particles. We then define an inner product between quantum states. The value of this inner product can be interpreted as the amplitude for one set of point particles to go into another set producing black holes. The full particle S-matrix is then given by the sum of all such amplitudes. This S-matrix is that of a non-critical string theory, with the worldsheet CFT being essentially the Liouville theory. Λ < 0 quantum gravity in 2 + 1 dimensions is thus a string theory

  6. Quantum state engineering and reconstruction in cavity QED. An analytical approach

    International Nuclear Information System (INIS)

    Lougovski, P.

    2004-01-01

    The models of a strongly-driven micromaser and a one-atom laser are developed. Their analytical solutions are obtained by means of phase space techniques. It is shown how to exploit the model of a one-atom laser for simultaneous generation and monitoring of the decoherence of the atom-field ''Schroedinger cat'' states. The similar machinery applied to the problem of the generation of the maximally-entangled states of two atoms placed inside an optical cavity permits its analytical solution. The steady-state solution of the problem exhibits a structure in which the two-atom maximally-entangled state correlates with the vacuum state of the cavity. As a consequence, it is demonstrated that the atomic maximally-entangled state, depending on a coupling regime, can be produced via a single or a sequence of no-photon measurements. The question of the implementation of a quantum memory device using a dispersive interaction between the collective internal ground state of an atomic ensemble and two orthogonal modes of a cavity is addressed. The problem of quantum state reconstruction in the context of cavity quantum electrodynamics is considered. The optimal operational definition of the Wigner function of a cavity field is worked out. It is based on the Fresnel transform of the atomic inversion of a probe atom. The general integral transformation for the Wigner function reconstruction of a particle in an arbitrary symmetric potential is derived

  7. Sufficient condition for a quantum state to be genuinely quantum non-Gaussian

    Science.gov (United States)

    Happ, L.; Efremov, M. A.; Nha, H.; Schleich, W. P.

    2018-02-01

    We show that the expectation value of the operator \\hat{{ \\mathcal O }}\\equiv \\exp (-c{\\hat{x}}2)+\\exp (-c{\\hat{p}}2) defined by the position and momentum operators \\hat{x} and \\hat{p} with a positive parameter c can serve as a tool to identify quantum non-Gaussian states, that is states that cannot be represented as a mixture of Gaussian states. Our condition can be readily tested employing a highly efficient homodyne detection which unlike quantum-state tomography requires the measurements of only two orthogonal quadratures. We demonstrate that our method is even able to detect quantum non-Gaussian states with positive–definite Wigner functions. This situation cannot be addressed in terms of the negativity of the phase-space distribution. Moreover, we demonstrate that our condition can characterize quantum non-Gaussianity for the class of superposition states consisting of a vacuum and integer multiples of four photons under more than 50 % signal attenuation.

  8. Unifying neural-network quantum states and correlator product states via tensor networks

    Science.gov (United States)

    Clark, Stephen R.

    2018-04-01

    Correlator product states (CPS) are a powerful and very broad class of states for quantum lattice systems whose (unnormalised) amplitudes in a fixed basis can be sampled exactly and efficiently. They work by gluing together states of overlapping clusters of sites on the lattice, called correlators. Recently Carleo and Troyer (2017 Science 355 602) introduced a new type sampleable ansatz called neural-network quantum states (NQS) that are inspired by the restricted Boltzmann model used in machine learning. By employing the formalism of tensor networks we show that NQS are a special form of CPS with novel properties. Diagramatically a number of simple observations become transparent. Namely, that NQS are CPS built from extensively sized GHZ-form correlators making them uniquely unbiased geometrically. The appearance of GHZ correlators also relates NQS to canonical polyadic decompositions of tensors. Another immediate implication of the NQS equivalence to CPS is that we are able to formulate exact NQS representations for a wide range of paradigmatic states, including superpositions of weighed-graph states, the Laughlin state, toric code states, and the resonating valence bond state. These examples reveal the potential of using higher dimensional hidden units and a second hidden layer in NQS. The major outlook of this study is the elevation of NQS to correlator operators allowing them to enhance conventional well-established variational Monte Carlo approaches for strongly correlated fermions.

  9. Gauging Quantum States: From Global to Local Symmetries in Many-Body Systems

    Directory of Open Access Journals (Sweden)

    Jutho Haegeman

    2015-02-01

    Full Text Available We present an operational procedure to transform global symmetries into local symmetries at the level of individual quantum states, as opposed to typical gauging prescriptions for Hamiltonians or Lagrangians. We then construct a compatible gauging map for operators, which preserves locality and reproduces the minimal coupling scheme for simple operators. By combining this construction with the formalism of projected entangled-pair states (PEPS, we can show that an injective PEPS for the matter fields is gauged into a G-injective PEPS for the combined gauge-matter system, which potentially has topological order. We derive the corresponding parent Hamiltonian, which is a frustration-free gauge-theory Hamiltonian closely related to the Kogut-Susskind Hamiltonian at zero coupling constant. We can then introduce gauge dynamics at finite values of the coupling constant by applying a local filtering operation. This scheme results in a low-parameter family of gauge-invariant states of which we can accurately probe the phase diagram, as we illustrate by studying a Z_{2} gauge theory with Higgs matter.

  10. Evidence for the epistemic view of quantum states: A toy theory

    International Nuclear Information System (INIS)

    Spekkens, Robert W.

    2007-01-01

    We present a toy theory that is based on a simple principle: the number of questions about the physical state of a system that are answered must always be equal to the number that are unanswered in a state of maximal knowledge. Many quantum phenomena are found to have analogues within this toy theory. These include the noncommutativity of measurements, interference, the multiplicity of convex decompositions of a mixed state, the impossibility of discriminating nonorthogonal states, the impossibility of a universal state inverter, the distinction between bipartite and tripartite entanglement, the monogamy of pure entanglement, no cloning, no broadcasting, remote steering, teleportation, entanglement swapping, dense coding, mutually unbiased bases, and many others. The diversity and quality of these analogies is taken as evidence for the view that quantum states are states of incomplete knowledge rather than states of reality. A consideration of the phenomena that the toy theory fails to reproduce, notably, violations of Bell inequalities and the existence of a Kochen-Specker theorem, provides clues for how to proceed with this research program

  11. Wave packet interferometry and quantum state reconstruction by acousto-optic phase modulation

    International Nuclear Information System (INIS)

    Tekavec, Patrick F.; Dyke, Thomas R.; Marcus, Andrew H.

    2006-01-01

    Studies of wave packet dynamics often involve phase-selective measurements of coherent optical signals generated from sequences of ultrashort laser pulses. In wave packet interferometry (WPI), the separation between the temporal envelopes of the pulses must be precisely monitored or maintained. Here we introduce a new (and easy to implement) experimental scheme for phase-selective measurements that combines acousto-optic phase modulation with ultrashort laser excitation to produce an intensity-modulated fluorescence signal. Synchronous detection, with respect to an appropriately constructed reference, allows the signal to be simultaneously measured at two phases differing by 90 deg. Our method effectively decouples the relative temporal phase from the pulse envelopes of a collinear train of optical pulse pairs. We thus achieve a robust and high signal-to-noise scheme for WPI applications, such as quantum state reconstruction and electronic spectroscopy. The validity of the method is demonstrated, and state reconstruction is performed, on a model quantum system - atomic Rb vapor. Moreover, we show that our measurements recover the correct separation between the absorptive and dispersive contributions to the system susceptibility

  12. Bipartite discrimination of independently prepared quantum states as a counterexample to a parallel repetition conjecture

    Science.gov (United States)

    Akibue, Seiseki; Kato, Go

    2018-04-01

    For distinguishing quantum states sampled from a fixed ensemble, the gap in bipartite and single-party distinguishability can be interpreted as a nonlocality of the ensemble. In this paper, we consider bipartite state discrimination in a composite system consisting of N subsystems, where each subsystem is shared between two parties and the state of each subsystem is randomly sampled from a particular ensemble comprising the Bell states. We show that the success probability of perfectly identifying the state converges to 1 as N →∞ if the entropy of the probability distribution associated with the ensemble is less than 1, even if the success probability is less than 1 for any finite N . In other words, the nonlocality of the N -fold ensemble asymptotically disappears if the probability distribution associated with each ensemble is concentrated. Furthermore, we show that the disappearance of the nonlocality can be regarded as a remarkable counterexample of a fundamental open question in theoretical computer science, called a parallel repetition conjecture of interactive games with two classically communicating players. Measurements for the discrimination task include a projective measurement of one party represented by stabilizer states, which enable the other party to perfectly distinguish states that are sampled with high probability.

  13. Quantum state-resolved, bulk gas energetics: Comparison of theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    McCaffery, Anthony J., E-mail: A.J.McCaffery@sussex.ac.uk [Department of Chemistry, University of Sussex, Brighton, Sussex BN1 6SJ (United Kingdom)

    2016-05-21

    Until very recently, the computational model of state-to-state energy transfer in large gas mixtures, introduced by the author and co-workers, has had little experimental data with which to assess the accuracy of its predictions. In a novel experiment, Alghazi et al. [Chem. Phys. 448, 76 (2015)] followed the equilibration of highly vibrationally excited CsH(D) in baths of H{sub 2}(D{sub 2}) with simultaneous time- and quantum state-resolution. Modal temperatures of vibration, rotation, and translation for CsH(D) were obtained and presented as a function of pump-probe delay time. Here the data from this study are used as a test of the accuracy of the computational method, and in addition, the consequent changes in bath gas modal temperatures, not obtainable in the experiment, are predicted. Despite large discrepancies between initial CsH(D) vibrational states in the experiment and those available using the computational model, the quality of agreement is sufficient to conclude that the model’s predictions constitute at least a very good representation of the overall equilibration that, for some measurements, is very accurate.

  14. Transfer behavior of quantum states between atoms in photonic crystal coupled cavities

    International Nuclear Information System (INIS)

    Zhang Ke; Li Zhiyuan

    2010-01-01

    In this article, we discuss the one-excitation dynamics of a quantum system consisting of two two-level atoms each interacting with one of two coupled single-mode cavities via spontaneous emission. When the atoms and cavities are tuned into resonance, a wide variety of time-evolution behaviors can be realized by modulating the atom-cavity coupling strength g and the cavity-cavity hopping strength λ. The dynamics is solved rigorously via the eigenproblem of an ordinary coupled linear system and simple analytical solutions are derived at several extreme situations of g and λ. In the large hopping limit where g >λ, the time-evolution behavior of the system is characterized by the usual slowly varying carrier envelope superimposed upon a fast and violent oscillation. At a certain instant, the energy is fully transferred from the one quantum subsystem to the other. When the two interaction strengths are comparable in magnitude, the dynamics acts as a continuous pulse having irregular frequency and line shape of peaks and valleys, and the complicated time-evolution behaviors are ascribed to the violent competition between all the one-excitation quantum states. The coupled quantum system of atoms and cavities makes a good model to study cavity quantum electrodynamics with great freedoms of many-body interaction.

  15. LAMBDA < 0 quantum gravity in 2 + 1 dimensions: I. Quantum states and stringy S-matrix

    CERN Document Server

    Krasnov, K V

    2002-01-01

    We consider the theory of pure gravity in 2 + 1 dimensions, with negative cosmological constant. The theory contains simple matter in the form of point particles; the latter are classically described as lines of conical singularities. We propose a formalism in which quantum amplitudes for the process involving black holes and point particles are obtained as conformal field theory (CFT) correlation functions on Riemann surfaces X. Point particles are described by the CFT vertex operators; black holes (asymptotic regions) are in correspondence with boundaries of X. We consider two examples: the amplitude for emission of a particle by the BTZ black hole and the amplitude of black-hole creation by two point particles. We then define an inner product between quantum states. The value of this inner product can be interpreted as the amplitude for one set of point particles to go into another set producing black holes. The full particle S-matrix is then given by the sum of all such amplitudes. This S-matrix is that o...

  16. Comment on ``Semiquantum-key distribution using less than four quantum states''

    Science.gov (United States)

    Boyer, Michel; Mor, Tal

    2011-04-01

    For several decades it was believed that information-secure key distribution requires both the sender and receiver to have the ability to generate and/or manipulate quantum states. Earlier, we showed that quantum key distribution in which one party is classical is possible [Boyer, Kenigsberg, and Mor, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.99.140501 99, 140501 (2007)]. A surprising and very nice extension of that result was suggested by Zou, Qiu, Li, Wu, and Li [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.79.052312 79, 052312 (2009)]. Their paper suggests that it is sufficient for the originator of the states (the person holding the quantum technology) to generate just one state. The resulting semiquantum key distribution, which we call here “quantum key distribution with classical Alice” is indeed completely robust against eavesdropping. However, their proof (that no eavesdropper can get information without being possibly detected) is faulty. We provide here a fully detailed and direct proof of their very important result.

  17. Simulation of n-qubit quantum systems. IV. Parametrizations of quantum states, matrices and probability distributions

    Science.gov (United States)

    Radtke, T.; Fritzsche, S.

    2008-11-01

    Entanglement is known today as a key resource in many protocols from quantum computation and quantum information theory. However, despite the successful demonstration of several protocols, such as teleportation or quantum key distribution, there are still many open questions of how entanglement affects the efficiency of quantum algorithms or how it can be protected against noisy environments. The investigation of these and related questions often requires a search or optimization over the set of quantum states and, hence, a parametrization of them and various other objects. To facilitate this kind of studies in quantum information theory, here we present an extension of the FEYNMAN program that was developed during recent years as a toolbox for the simulation and analysis of quantum registers. In particular, we implement parameterizations of hermitian and unitary matrices (of arbitrary order), pure and mixed quantum states as well as separable states. In addition to being a prerequisite for the study of many optimization problems, these parameterizations also provide the necessary basis for heuristic studies which make use of random states, unitary matrices and other objects. Program summaryProgram title: FEYNMAN Catalogue identifier: ADWE_v4_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWE_v4_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 24 231 No. of bytes in distributed program, including test data, etc.: 1 416 085 Distribution format: tar.gz Programming language: Maple 11 Computer: Any computer with Maple software installed Operating system: Any system that supports Maple; program has been tested under Microsoft Windows XP, Linux Classification: 4.15 Does the new version supersede the previous version?: Yes Nature of problem: During the last decades

  18. Joint quantum state tomography of an entangled qubit–resonator hybrid

    International Nuclear Information System (INIS)

    LinPeng, X Y; Zhang, H Z; Xu, K; Li, C Y; Zhong, Y P; Wang, Z L; Wang, H; Xie, Q W

    2013-01-01

    The integration of superconducting qubits and resonators in one circuit offers a promising solution for quantum information processing (QIP), which also realizes the on-chip analogue of cavity quantum electrodynamics (QED), known as circuit QED. In most prototype circuit designs, qubits are active processing elements and resonators are peripherals. As resonators typically have better coherence performance and more accessible energy levels, it is proposed that the entangled qubit–resonator hybrid can be used as a processing element. To achieve such a goal, an accurate measurement of the hybrid is first necessary. Here we demonstrate a joint quantum state tomography (QST) technique to fully characterize an entangled qubit–resonator hybrid. We benchmarked our QST technique by generating and accurately characterizing multiple states, e.g. |gN〉 + |e(N − 1)〉 where (|g〉 and |e〉) are the ground and excited states of the qubit and (|0〉,…,|N〉) are Fock states of the resonator. We further provided a numerical method to improve the QST efficiency and measured the decoherence dynamics of the bipartite hybrid, witnessing dissipation coming from both the qubit and the N-photon Fock state. As such, the joint QST presents an important step toward actively using the qubit–resonator element for QIP in hybrid quantum devices and for studying circuit QED. (paper)

  19. An integrated processor for photonic quantum states using a broadband light–matter interface

    International Nuclear Information System (INIS)

    Saglamyurek, E; Sinclair, N; Slater, J A; Heshami, K; Oblak, D; Tittel, W

    2014-01-01

    Faithful storage and coherent manipulation of quantum optical pulses are key for long distance quantum communications and quantum computing. Combining these functions in a light–matter interface that can be integrated on-chip with other photonic quantum technologies, e.g. sources of entangled photons, is an important step towards these applications. To date there have only been a few demonstrations of coherent pulse manipulation utilizing optical storage devices compatible with quantum states, and that only in atomic gas media (making integration difficult) and with limited capabilities. Here we describe how a broadband waveguide quantum memory based on the atomic frequency comb (AFC) protocol can be used as a programmable processor for essentially arbitrary spectral and temporal manipulations of individual quantum optical pulses. Using weak coherent optical pulses at the few photon level, we experimentally demonstrate sequencing, time-to-frequency multiplexing and demultiplexing, splitting, interfering, temporal and spectral filtering, compressing and stretching as well as selective delaying. Our integrated light–matter interface offers high-rate, robust and easily configurable manipulation of quantum optical pulses and brings fully practical optical quantum devices one step closer to reality. Furthermore, as the AFC protocol is suitable for storage of intense light pulses, our processor may also find applications in classical communications. (paper)

  20. Does an Emphasis on the Concept of Quantum States Enhance Students' Understanding of Quantum Mechanics?

    Science.gov (United States)

    Greca, Ileana Maria; Freire, Olival

    Teaching physics implies making choices. In the case of teaching quantum physics, besides an educational choice - the didactic strategy - another choice must be made, an epistemological one, concerning the interpretation of quantum theory itself. These two choices are closely connected. We have chosen a didactic strategy that privileges the phenomenological-conceptual approach, with emphasis upon quantum features of the systems, instead of searching for classical analogies. This choice has led us to present quantum theory associated with an orthodox, yet realistic, interpretation of the concept of quantum state, considered as the key concept of quantum theory, representing the physical reality of a system, independent of measurement processes. The results of the mplementation of this strategy, with three groups of engineering students, showed that more than a half of them attained a reasonable understanding of the basics of quantum mechanics (QM) for this level. In addition, a high degree of satisfaction was attained with the classes as 80% of the students of the experimental groups claimed to have liked it and to be interested in learning more about QM.

  1. Cell cycle controls: potential targets for chemical carcinogens?

    OpenAIRE

    Afshari, C A; Barrett, J C

    1993-01-01

    The progression of the cell cycle is controlled by the action of both positive and negative growth regulators. The key players in this activity include a family of cyclins and cyclin-dependent kinases, which are themselves regulated by other kinases and phosphatases. Maintenance of balanced cell cycle controls may be directly linked to genomic stability. Loss of the check-points involved in cell cycle control may result in unrepaired DNA damage during DNA synthesis or mitosis leading to genet...

  2. Preparation and coherent manipulation of pure quantum states of a single molecular ion

    Science.gov (United States)

    Chou, Chin-Wen; Kurz, Christoph; Hume, David B.; Plessow, Philipp N.; Leibrandt, David R.; Leibfried, Dietrich

    2017-05-01

    Laser cooling and trapping of atoms and atomic ions has led to advances including the observation of exotic phases of matter, the development of precision sensors and state-of-the-art atomic clocks. The same level of control in molecules could also lead to important developments such as controlled chemical reactions and sensitive probes of fundamental theories, but the vibrational and rotational degrees of freedom in molecules pose a challenge for controlling their quantum mechanical states. Here we use quantum-logic spectroscopy, which maps quantum information between two ion species, to prepare and non-destructively detect quantum mechanical states in molecular ions. We develop a general technique for optical pumping and preparation of the molecule into a pure initial state. This enables us to observe high-resolution spectra in a single ion (CaH+) and coherent phenomena such as Rabi flopping and Ramsey fringes. The protocol requires a single, far-off-resonant laser that is not specific to the molecule, so many other molecular ions, including polyatomic species, could be treated using the same methods in the same apparatus by changing the molecular source. Combined with the long interrogation times afforded by ion traps, a broad range of molecular ions could be studied with unprecedented control and precision. Our technique thus represents a critical step towards applications such as precision molecular spectroscopy, stringent tests of fundamental physics, quantum computing and precision control of molecular dynamics.

  3. Microfabricated Chemical Sensors for Safety and Emission Control Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Chen, L.-Y.; Knight, D.; Liu, C. C.; Wu, Q. H.

    1998-01-01

    Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication (MicroElectroMechanical Systems (MEMS)-based) technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  4. Development of Chemical Process Design and Control for Sustainability

    Science.gov (United States)

    This contribution describes a novel process systems engineering framework that couples advanced control with sustainability evaluation and decision making for the optimization of process operations to minimize environmental impacts associated with products, materials, and energy....

  5. 78 FR 39337 - Importer of Controlled Substances, Notice of Application, Boehringer Ingelheim Chemicals

    Science.gov (United States)

    2013-07-01

    ... DEPARTMENT OF JUSTICE Drug Enforcement Administration Importer of Controlled Substances, Notice of Application, Boehringer Ingelheim Chemicals Pursuant to Title 21 Code of Federal Regulations 1301.34(a), this is notice that on May 31, 2013, Boehringer Ingelheim Chemicals, 2820 N. Normandy Drive, Petersburg...

  6. 77 FR 43863 - Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals Inc.

    Science.gov (United States)

    2012-07-26

    ... DEPARTMENT OF JUSTICE Drug Enforcement Administration Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals Inc. Pursuant to Sec. 1301.33(a), Title 21 of the Code of Federal Regulations (CFR), this is notice that on June 8, 2012, Boehringer Ingelheim Chemicals...

  7. 77 FR 43861 - Importer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals

    Science.gov (United States)

    2012-07-26

    ... DEPARTMENT OF JUSTICE Drug Enforcement Administration Importer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals Pursuant to Title 21 Code of Federal Regulations 1301.34(a), this is notice that on June 8, 2012, Boehringer Ingelheim Chemicals, Inc., 2820 N. Normandy Drive...

  8. 78 FR 39340 - Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals, Inc.

    Science.gov (United States)

    2013-07-01

    ... DEPARTMENT OF JUSTICE Drug Enforcement Administration Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals, Inc. Pursuant to Sec. 1301.33(a), Title 21 of the Code of Federal Regulations (CFR), this is notice that on May 31, 2013, Boehringer Ingelheim Chemicals...

  9. Manipulating molecular quantum states with classical metal atom inputs: demonstration of a single molecule NOR logic gate.

    Science.gov (United States)

    Soe, We-Hyo; Manzano, Carlos; Renaud, Nicolas; de Mendoza, Paula; De Sarkar, Abir; Ample, Francisco; Hliwa, Mohamed; Echavarren, Antonio M; Chandrasekhar, Natarajan; Joachim, Christian

    2011-02-22

    Quantum states of a trinaphthylene molecule were manipulated by putting its naphthyl branches in contact with single Au atoms. One Au atom carries 1-bit of classical information input that is converted into quantum information throughout the molecule. The Au-trinaphthylene electronic interactions give rise to measurable energy shifts of the molecular electronic states demonstrating a NOR logic gate functionality. The NOR truth table of the single molecule logic gate was characterized by means of scanning tunnelling spectroscopy.

  10. Tunable self-assembled spin chains of strongly interacting cold atoms for demonstration of reliable quantum state transfer

    DEFF Research Database (Denmark)

    Loft, N. J. S.; Marchukov, O. V.; Petrosyan, D.

    2016-01-01

    We have developed an efficient computational method to treat long, one-dimensional systems of strongly-interacting atoms forming self-assembled spin chains. Such systems can be used to realize many spin chain model Hamiltonians tunable by the external confining potential. As a concrete...... demonstration, we consider quantum state transfer in a Heisenberg spin chain and we show how to determine the confining potential in order to obtain nearly-perfect state transfer....

  11. Bell nonlocality and fully entangled fraction measured in an entanglement-swapping device without quantum state tomography

    Czech Academy of Sciences Publication Activity Database

    Bartkiewicz, K.; Lemr, K.; Černoch, Antonín; Miranowicz, A.

    2017-01-01

    Roč. 95, č. 3 (2017), s. 1-7, č. článku 030102. ISSN 2469-9926 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : Bell nonlocality * fully entangled fraction * entanglement-swapping device * quantum state tomography Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.925, year: 2016

  12. Theory of Correlated Pairs of Electrons Oscillating in Resonant Quantum States to Reach the Critical Temperature in a Metal

    OpenAIRE

    Aroche, Raúl Riera; Rosas-Cabrera, Rodrigo Arturo; Burgos, Rodrigo Arturo Rosas; Betancourt-Riera, René; Betancourt-Riera, Ricardo

    2017-01-01

    The formation of Correlated Electron Pairs Oscillating around the Fermi level in Resonant Quantum States (CEPO-RQS), when a metal is cooled to its critical temperature T=Tc, is studied. The necessary conditions for the existence of CEPO-RQS are analyzed. The participation of electron-electron interaction screened by an electron dielectric constant of the form proposed by Thomas Fermi is considered and a physical meaning for the electron-phonon-electron interaction in the formation of the CEPO...

  13. Development of Chemical Process Design and Control for Sustainability

    Directory of Open Access Journals (Sweden)

    Shuyun Li

    2016-07-01

    Full Text Available This contribution describes a novel process systems engineering framework that couples advanced control with sustainability evaluation for the optimization of process operations to minimize environmental impacts associated with products, materials and energy. The implemented control strategy combines a biologically-inspired method with optimal control concepts for finding more sustainable operating trajectories. The sustainability assessment of process operating points is carried out by using the U.S. EPA’s Gauging Reaction Effectiveness for the ENvironmental Sustainability of Chemistries with a multi-Objective Process Evaluator (GREENSCOPE tool that provides scores for the selected indicators in the economic, material efficiency, environmental and energy areas. The indicator scores describe process performance on a sustainability measurement scale, effectively determining which operating point is more sustainable if there are more than several steady states for one specific product manufacturing. Through comparisons between a representative benchmark and the optimal steady states obtained through the implementation of the proposed controller, a systematic decision can be made in terms of whether the implementation of the controller is moving the process towards a more sustainable operation. The effectiveness of the proposed framework is illustrated through a case study of a continuous fermentation process for fuel production, whose material and energy time variation models are characterized by multiple steady states and oscillatory conditions.

  14. Development of Chemical Process Design and Control for ...

    Science.gov (United States)

    This contribution describes a novel process systems engineering framework that couples advanced control with sustainability evaluation and decision making for the optimization of process operations to minimize environmental impacts associated with products, materials, and energy. The implemented control strategy combines a biologically inspired method with optimal control concepts for finding more sustainable operating trajectories. The sustainability assessment of process operating points is carried out by using the U.S. E.P.A.’s Gauging Reaction Effectiveness for the ENvironmental Sustainability of Chemistries with a multi-Objective Process Evaluator (GREENSCOPE) tool that provides scores for the selected indicators in the economic, material efficiency, environmental and energy areas. The indicator scores describe process performance on a sustainability measurement scale, effectively determining which operating point is more sustainable if there are more than several steady states for one specific product manufacturing. Through comparisons between a representative benchmark and the optimal steady-states obtained through implementation of the proposed controller, a systematic decision can be made in terms of whether the implementation of the controller is moving the process towards a more sustainable operation. The effectiveness of the proposed framework is illustrated through a case study of a continuous fermentation process for fuel production, whose materi

  15. Helium leak and chemical impurities control technology in HTTR

    International Nuclear Information System (INIS)

    Tochio, Daisuke; Shimizu, Atsushi; Hamamoto, Shimpei; Sakaba, Nariaki

    2014-01-01

    Japan Atomic Energy Agency (JAEA) has designed and developed high-temperature gas-cooled reactor (HTGR) hydrogen cogeneration system named gas turbine high-temperature reactor (GTHTR300C) as a commercial HTGR. Helium gas is used as the primary coolant in HTGR. Helium gas is easy to leak, and the primary helium leakage should be controlled tightly from the viewpoint of preventing the release of radioactive materials to the environment. Moreover from the viewpoint of preventing the oxidization of graphite and metallic material, the helium coolant chemistry should be controlled tightly. The primary helium leakage and the helium coolant chemistry during the operation is the major factor in the HTGR for commercialization of HTGR system. This paper shows the design concept and the obtained operational experience on the primary helium leakage control and primary helium impurity control in the high-temperature engineering test reactor (HTTR) of JAEA. Moreover, the future plan to obtain operational experience of these controls for commercialization of HTGR system is shown. (author)

  16. Control of Maillard Reactions in Foods: Strategies and Chemical Mechanisms.

    Science.gov (United States)

    Lund, Marianne N; Ray, Colin A

    2017-06-14

    Maillard reactions lead to changes in food color, organoleptic properties, protein functionality, and protein digestibility. Numerous different strategies for controlling Maillard reactions in foods have been attempted during the past decades. In this paper, recent advances in strategies for controlling the Maillard reaction and subsequent downstream reaction products in food systems are critically reviewed. The underlying mechanisms at play are presented, strengths and weaknesses of each strategy are discussed, and reasonable reaction mechanisms are proposed to reinforce the evaluations. The review includes strategies involving addition of functional ingredients, such as plant polyphenols and vitamins, as well as enzymes. The resulting trapping or modification of Maillard targets, reactive intermediates, and advanced glycation endproducts (AGEs) are presented with their potential unwanted side effects. Finally, recent advances in processing for control of Maillard reactions are discussed.

  17. Efficacy and mechanisms of non-antibacterial, chemical plaque control by dentifrices - An in vitro study

    NARCIS (Netherlands)

    Busscher, Henk J.; White, Don J.; Atema-Smit, Jelly; van der Mei, Henny C.

    Objectives: The provision of antiplaque benefits to dentifrices assists patients in improving hygiene and reducing susceptibility to gingivitis and caries. Chemical plaque control involves different mechanisms and is mostly associated with antibacterial effects, but also includes effects on pellicle

  18. Application of hazard analysis critical control points (HACCP) to organic chemical contaminants in food.

    Science.gov (United States)

    Ropkins, K; Beck, A J

    2002-03-01

    Hazard Analysis Critical Control Points (HACCP) is a systematic approach to the identification, assessment, and control of hazards that was developed as an effective alternative to conventional end-point analysis to control food safety. It has been described as the most effective means of controlling foodborne diseases, and its application to the control of microbiological hazards has been accepted internationally. By contrast, relatively little has been reported relating to the potential use of HACCP, or HACCP-like procedures, to control chemical contaminants of food. This article presents an overview of the implementation of HACCP and discusses its application to the control of organic chemical contaminants in the food chain. Although this is likely to result in many of the advantages previously identified for microbiological HACCP, that is, more effective, efficient, and economical hazard management, a number of areas are identified that require further research and development. These include: (1) a need to refine the methods of chemical contaminant identification and risk assessment employed, (2) develop more cost-effective monitoring and control methods for routine chemical contaminant surveillance of food, and (3) improve the effectiveness of process optimization for the control of chemical contaminants in food.

  19. Quantum State-Resolved Collision Dynamics of Nitric Oxide at Ionic Liquid and Molten Metal Surfaces

    Science.gov (United States)

    Zutz, Amelia Marie

    Detailed molecular scale interactions at the gas-liquid interface are explored with quantum state-to-state resolved scattering of a jet-cooled beam of NO(2pi1/2; N = 0) from ionic liquid and molten metal surfaces. The scattered distributions are probed via laser-induced fluorescence methods, which yield rotational and spin-orbit state populations that elucidate the dynamics of energy transfer at the gas-liquid interface. These collision dynamics are explored as a function of incident collision energy, surface temperature, scattering angle, and liquid identity, all of which are found to substantially affect the degree of rotational, electronic and vibrational excitation of NO via collisions at the liquid surface. Rotational distributions observed reveal two distinct scattering pathways, (i) molecules that trap, thermalize and eventually desorb from the surface (trapping-desorption, TD), and (ii) those that undergo prompt recoil (impulsive scattering, IS) prior to complete equilibration with the liquid surface. Thermally desorbing NO molecules are found to have rotational temperatures close to, but slightly cooler than the surface temperature, indicative of rotational dependent sticking probabilities on liquid surfaces. Nitric oxide is a radical with multiple low-lying electronic states that serves as an ideal candidate for exploring nonadiabatic state-changing collision dynamics at the gas-liquid interface, which induce significant excitation from ground (2pi1/2) to excited (2pi 3/2) spin-orbit states. Molecular beam scattering of supersonically cooled NO from hot molten metals (Ga and Au, Ts = 300 - 1400 K) is also explored, which provide preliminary evidence for vibrational excitation of NO mediated by thermally populated electron-hole pairs in the hot, conducting liquid metals. The results highlight the presence of electronically nonadiabatic effects and build toward a more complete characterization of energy transfer dynamics at gas-liquid interfaces.

  20. The conundrum of chemical boll weevil control in subtropical regions

    Science.gov (United States)

    The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a tropical Mesoamerican insect that invaded the United States in 1893, spreading across the Cotton Belt as the key pest of cotton and causing billions of dollars in yield losses and insecticide-based control efforts;...

  1. Comparison between chemical and biological control of Fusarium ...

    African Journals Online (AJOL)

    ... College of Education, Jeddah, Saudi Arabia. The results revealed that treatment with the fungicide carbomar or T. harzianum as well as with B. subtilis, in presence of F. solani increased the % of healthy seedlings as well as their length , fresh and dry weight than in presence of F. solani alone but still less than the control.

  2. Soft Sensors: Chemoinformatic Model for Efficient Control and Operation in Chemical Plants.

    Science.gov (United States)

    Funatsu, Kimito

    2016-12-01

    Soft sensor is statistical model as an essential tool for controlling pharmaceutical, chemical and industrial plants. I introduce soft sensor, the roles, the applications, the problems and the research examples such as adaptive soft sensor, database monitoring and efficient process control. The use of soft sensor enables chemical industrial plants to be operated more effectively and stably. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Chemical modelling as a management tool for water pollution control

    Energy Technology Data Exchange (ETDEWEB)

    Limpitlaw, D. [University of the Witwatersrand, Johannesburg (South Africa). Dept. of Mining Engineering

    1996-12-31

    In a colliery currently being re-mined by opencast methods, the coal seam was originally extracted using bord and pillar mining. Depressions in the seam floor have facilitated the formation of large underground water bodies. This water has become acidic and contaminated by heavy metals. Mine water is treated by a liming plant and then released into evaporation pans. Seepage from the pans enters a natural wetlands. The de-watering of old workings ahead of mining periodically subjects the liming plant to large quantities of low quality water, and a nett export of salts such as sulphate occurs. As the mine is situated in a sensitive river catchment, this pollution is unacceptable. A chemical speciation program developed by the US Environmental Protection Agency was used to analyse effluent from the liming plant and wetland. Liming plant effluent water was found to vary greatly due to the conditions prevalent in the different water bodies. The liming plant and wetland were periodically subjected to pollution loads beyond the wetland`s assimilative capacity, resulting failure of the system. Despite this, the software provided evidence of the wetland`s pollution-ameliorating potential. 8 refs., 12 figs.

  4. Weed clearance in Hudiara Nallah by chemical weed control

    International Nuclear Information System (INIS)

    Dhillon, G.S.

    1981-01-01

    Hudiara Nallah is a flood stream in West Punjab. It has a length of about 45km and breadth of nearly 25 metres. About 20 subsidiary drains join with the Nallah. These drains have a length of about 270km. The Nallah has a discharge capacity of 1248 cusecs. Most of the subsidiary drains start from ponds which are generally infected with Eichhornia plants. These plants enter into the subsidiary drains and finally into Hudiara Nallah. The plants float freely on the surface of water and multiply at a high rate. One plant of the weed propagates to 24 plants in a period of one month. The plants thus cover the whole drain in a few months. The weed also originates from seeds. Their heavy growth forms a mat-like surface. The weeds also choke bridges and sometimes cause damage to their structures. These obstruct the flow of water and decrease the carrying capacity of the drain. Their infestation thus causes floods and the very purpose of the drains gets lost. Thus the Nallah is heavily infested with Eichhornia crassipes (water hyacinth weed). Due to its fast propagation and heavy infestation it was not possible to clear the weed manually. The problem was, therefore, referred to the Chemistry Division of the Irrigation and Power Research Institute, Amritsar, by the Drainage Circle of the Irrigation Department in June 1978 when weed propagation was in full swing. A chemical treatment method of eradication was attempted

  5. Selection of chemical markers for the quality control of medicinal plants of the genus Cecropia.

    Science.gov (United States)

    Rivera-Mondragón, Andrés; Ortíz, Orlando O; Bijttebier, Sebastiaan; Vlietinck, Arnold; Apers, Sandra; Pieters, Luc; Caballero-George, Catherina

    2017-12-01

    Several Cecropia (Cecropiaceae) species are traditionally used in Latin America for the treatment of a variety of diseases including diabetes, arterial hypertension, asthma, bronchitis, anxiety, and inflammation. At present, a number of commercial products based on these plants have been introduced into the market with very little information on methods for guaranteeing their quality and safety. This work proposes potential chemical markers for the quality control of the raw materials of Cecropia obtusifolia Bertol., Cecropia peltata L., Cecropia glaziovii Snethl., Cecropia pachystachya Trécul, and Cecropia hololeuca Miq. The Herbal Chemical Marker Ranking System (Herb MaRS) developed by the National Institute of Complementary Medicine (NICM) at the University of Western Sydney was used for selecting chemical markers for the quality control of selected medicinal species of Cecropia. This review covers the period from 1982 to 2016. Chlorogenic acid, flavonoidal glycosides (orientin, isoorientin, vitexin, isovitexin, and rutin), catechin, epicatechin, procyanidins (B2, B5, and C1), steroids (β-sitosterol), and triterpenoids (α-amyrin, pomolic, tormentic and ursolic acids) were selected as chemical markers for the quality control of the leaves. It is necessary to establish comprehensive standards for guaranteeing quality, safety and efficacy of herbal drugs. The selection of adequate chemical markers for quality control purposes requires a good knowledge about the chemical composition of medicinal plants and their associated biological properties. To the best of our knowledge this review article is the first to address the identification and quantitative determination of the chemical markers for the genus Cecropia.

  6. Chemical inventory control program for mixed and hazardous waste facilities at SRS

    International Nuclear Information System (INIS)

    Ades, M.J.; Vincent, A.M. III.

    1997-01-01

    Mixed Waste (MW) and Hazardous Waste (HW) are being stored at the Savannah River Site (SRS) pending onsite and/or offsite treatment and disposal. The inventory control for these wastes has recently been brought under Technical Safety Requirements (TSR) in accordance with DOE Order 5480.22. With the TSRs was the question of the degree of rigor with which the inventory is to be tracked, considering that the variety of chemicals present, or that could be present, numbers in the hundreds. This paper describes the graded approach program to track Solid Waste (SW) inventories relative to TSRs. The approach uses a ratio of the maximum anticipated chemical inventory to the permissible inventory in accordance with Emergency Response Planning Guideline (ERPG) limits for on- and off-site receptors. A specific threshold ratio can then be determined. The chemicals above this threshold ratio are to be included in the chemical inventory control program. The chemicals that fall below the threshold ratio are managed in accordance with existing practice per State and RCRA hazardous materials requirements. Additionally, the facilities are managed in accordance with process safety management principles, specifically using process hazards analyses, which provides safety assurance for even the small quantities that may be excluded from the formal inventory control program. The method yields a practical approach to chemical inventory control, while maintaining appropriate chemical safety margins. The resulting number of specific chemicals that require inclusion in a rigorous inventory control program is greatly reduced by about 80%, thereby resulting in significant reduction in chemical data management while preserving appropriate safety margins

  7. Materials control and accountability at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Denning, G.E.; Britschgi, J.J.; Spraktes, F.W.

    1985-01-01

    The ICPP high enriched uranium recovery process has historically been operated as a single Material Balance Area (MBA), with input and output measurement capabilities. Safeguards initiated changes in the last five years have resulted in significant materials control and accountability improvements. Those changes include semi-automation of process accountability measurement, data collection and recording; definition of Sub-MBAs; standard plant cleanouts; and, bimonthly inventory estimates. Process monitoring capabilities are also being installed to provide independent operational procedural compliance verification, process anomaly detection, and enhanced materials traceability. Development of a sensitivity analysis approach to defining process measurement requirements is in progress

  8. Algorithmization of problems on the personnel information support in the automatic chemical control systems at NPP

    International Nuclear Information System (INIS)

    Vilkov, N.Ya.; Kryukov, Yu.V.; Cheshun, A.V.

    2001-01-01

    When elaborating software for the standard algorithms of the information support of the efficient control (keeping) of water chemistry operation (WCO) at the NPP power units one introduces an approach when the systems of chemical control are realized as the systems of quality control of in-loop physical and chemical processes gathering force in the course of time. Elaboration of algorithms to proceed data of the operational chemical control seeks for elaboration of the statistic procedures to detect anomalies of the processes at the early stages of their development more efficient in contrast to the standard procedures of control. The introduced procedure is used in the demonstration model of the system for diagnostics of some typical reasons of violation of the first circuit WCO of WWER-1000 power units [ru

  9. PROCESS CONTROL IN THE EDUCATION OF ORGANIC CHEMICAL TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    lstván Csontos

    2001-06-01

    Full Text Available Las prácticas de laboratorio demuestran la importancia de los modernos procesos de control en las tecnologías de química orgánica. Se necesitaba desarrollar un sistema que une las ventajas de los calorímetros de reacción con las de modelo de los reactores controladas de la industria. El diseño de hardware y de software se permite trasladar el programa desarrollado en el laboratorio para el nivel industrial. El algoritmo general para las reacciones de diazotación y clormetilación es aplicado para el sintésis del cloruro de benzo-diazonio y cloruro de dietoxi-benzil en las prácticas de laboratorio.

  10. Implications and control of fuel-cladding chemical interaction for LMFBR fuel pin design

    International Nuclear Information System (INIS)

    Roake, W.E.

    1977-01-01

    Fuel-cladding-chemical-interaction (FCCI) is typically incorporated into the design of an LMFBR fuel pin as a wastage allowance. Several interrelated factors are considered during the evolution of an LMFBR fuel pin design. Those which are indirectly affected by FCCI include: allowable pin power, fuel restructuring, fission gas migration and release from the fuel, fuel cracking, fuel swelling, in-reactor cladding creep, cladding swelling, and the cladding mechanical strain. Chemical activity of oxygen is the most readily controlled factor in FCCI. Two methods are being investigated: control of total oxygen inventory by limiting fuel O/M, and control of oxygen activity with buffer metals

  11. Implications and control of fuel-cladding chemical interaction for LMFBR fuel pin design

    Energy Technology Data Exchange (ETDEWEB)

    Roake, W E [Westinghouse-Hanford Co., Richland, WA (United States)

    1977-04-01

    Fuel-cladding-chemical-interaction (FCCI) is typically incorporated into the design of an LMFBR fuel pin as a wastage allowance. Several interrelated factors are considered during the evolution of an LMFBR fuel pin design. Those which are indirectly affected by FCCI include: allowable pin power, fuel restructuring, fission gas migration and release from the fuel, fuel cracking, fuel swelling, in-reactor cladding creep, cladding swelling, and the cladding mechanical strain. Chemical activity of oxygen is the most readily controlled factor in FCCI. Two methods are being investigated: control of total oxygen inventory by limiting fuel O/M, and control of oxygen activity with buffer metals.

  12. Plant management in natural areas: balancing chemical, mechanical, and cultural control methods

    Science.gov (United States)

    Steven Manning; James. Miller

    2011-01-01

    After determining the best course of action for control of an invasive plant population, it is important to understand the variety of methods available to the integrated pest management professional. A variety of methods are now widely used in managing invasive plants in natural areas, including chemical, mechanical, and cultural control methods. Once the preferred...

  13. Development of Computational Approaches for Simulation and Advanced Controls for Hybrid Combustion-Gasification Chemical Looping

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Abhinaya; Lou, Xinsheng; Neuschaefer, Carl; Chaudry, Majid; Quinn, Joseph

    2012-07-31

    This document provides the results of the project through September 2009. The Phase I project has recently been extended from September 2009 to March 2011. The project extension will begin work on Chemical Looping (CL) Prototype modeling and advanced control design exploration in preparation for a scale-up phase. The results to date include: successful development of dual loop chemical looping process models and dynamic simulation software tools, development and test of several advanced control concepts and applications for Chemical Looping transport control and investigation of several sensor concepts and establishment of two feasible sensor candidates recommended for further prototype development and controls integration. There are three sections in this summary and conclusions. Section 1 presents the project scope and objectives. Section 2 highlights the detailed accomplishments by project task area. Section 3 provides conclusions to date and recommendations for future work.

  14. Nanoscale control of reversible chemical reaction between fullerene C60 molecules using scanning tunneling microscope.

    Science.gov (United States)

    Nakaya, Masato; Kuwahara, Yuji; Aono, Masakazu; Nakayama, Tomonobu

    2011-04-01

    The nanoscale control of reversible chemical reactions, the polymerization and depolymerization between C60 molecules, has been investigated. Using a scanning tunneling microscope (STM), the polymerization and depolymerization can be controlled at designated positions in ultrathin films of C60 molecules. One of the two chemical reactions can be selectively induced by controlling the sample bias voltage (V(s)); the application of negative and positive values of V(s) results in polymerization and depolymerization, respectively. The selectivity between the two chemical reactions becomes extremely high when the thickness of the C60 film increases to more than three molecular layers. We conclude that STM-induced negative and positive electrostatic ionization are responsible for the control of the polymerization and depolymerization, respectively.

  15. An approach to quantitate and control the mutagenic hazards of environmental chemical and radioactive pollutants

    International Nuclear Information System (INIS)

    Murthy, M.S.S.

    1977-01-01

    Human population, both at the occupational and non-occupational levels, is exposed to the environment polluted by man-made chemicals and radiation sources. The parameters required for quantitating mutagenic hazards of any agent are listed and it has been pointed out that though sufficient information of this nature is available in the case of radiations, it is almost impossible to collect similar information for chemical substances due to their number running into astronomical figures. A short-cut approach, therefore, is suggested to quantitate and control the mutagenic hazards of these pollutants. It is to express the mutagenic hazards of a chemical substance in terms of equivalent radiation units. The unit proposed for this purpose is called as Rem-Equivalent Chemical (REC). Total mutagenic burden to the society should take account of exposure from both chemicals and radiations. Advantages and limitation of this approach are discussed. (M.G.B.)

  16. Material compatibility and corrosion control of the KWU chemical cleaning process

    International Nuclear Information System (INIS)

    Odar, S.

    1994-01-01

    The concentrations of salt impurities within the deposits on the tube sheet and in the tube to tube-support-plate crevices can induce a variety of corrosion mechanisms on steam generator tubes. One of the most effective ways of counteracting corrosion mechanisms and thus of improving steam generator performance is to clean the steam generators and keep them in a clean condition. As shown by field results chemical cleaning is a way of removing hazardous deposits from steam generators. All available chemical cleaning processes use inhibitors to control the corrosion except the KWU chemical cleaning process. In this article the corrosion control technique of KWU Chemical Cleaning Process without using conventional inhibitors will be explained and the state of the field experience with respect to material compatibility will be presented. (author). 4 figs., 1 tab., 8 refs

  17. Chemical markers for the quality control of herbal medicines: an overview

    Directory of Open Access Journals (Sweden)

    Lung Cheng Chuen

    2008-06-01

    Full Text Available Abstract Selection of chemical markers is crucial for the quality control of herbal medicines, including authentication of genuine species, harvesting the best quality raw materials, evaluation of post-harvesting handling, assessment of intermediates and finished products, and detection of harmful or toxic ingredients. Ideal chemical markers should be the therapeutic components of herbal medicines. However, for most herbal medicines, the therapeutic components have not been fully elucidated or easily monitored. Bioactive, characteristic, main, synergistic, correlative, toxic and general components may be selected. This article reviews the effective use of chemical markers in the quality control of herbal medicines including the selection criteria considering the roles and physicochemical factors which may affect the effective use of chemical markers.

  18. Chemical signal activation of an organocatalyst enables control over soft material formation.

    Science.gov (United States)

    Trausel, Fanny; Maity, Chandan; Poolman, Jos M; Kouwenberg, D S J; Versluis, Frank; van Esch, Jan H; Eelkema, Rienk

    2017-10-12

    Cells can react to their environment by changing the activity of enzymes in response to specific chemical signals. Artificial catalysts capable of being activated by chemical signals are rare, but of interest for creating autonomously responsive materials. We present an organocatalyst that is activated by a chemical signal, enabling temporal control over reaction rates and the formation of materials. Using self-immolative chemistry, we design a deactivated aniline organocatalyst that is activated by the chemical signal hydrogen peroxide and catalyses hydrazone formation. Upon activation of the catalyst, the rate of hydrazone formation increases 10-fold almost instantly. The responsive organocatalyst enables temporal control over the formation of gels featuring hydrazone bonds. The generic design should enable the use of a large range of triggers and organocatalysts, and appears a promising method for the introduction of signal response in materials, constituting a first step towards achieving communication between artificial chemical systems.Enzymes regulated by chemical signals are common in biology, but few such artificial catalysts exist. Here, the authors design an aniline catalyst that, when activated by a chemical trigger, catalyses formation of hydrazone-based gels, demonstrating signal response in a soft material.

  19. Materials Safety Data Sheets: the basis for control of toxic chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Ketchen, E.E.; Porter, W.E.

    1979-09-01

    The Material Safety Data Sheets contained in this volume are the basis for the Toxic Chemical Control Program developed by the Industrial Hygiene Department, Health Division, ORNL. The three volumes are the update and expansion of ORNL/TM-5721 and ORNL/TM-5722 Material Safety Data Sheets: The Basis for Control of Toxic Chemicals, Volume I and Volume II. As such, they are a valuable adjunct to the data cards issued with specific chemicals. The chemicals are identified by name, stores catalog number where appropriate, and sequence numbers from the NIOSH Registry of Toxic Effects of Chemical Substances, 1977 Edition, if available. The data sheets were developed and compiled to aid in apprising the employees of hazards peculiar to the handling and/or use of specific toxic chemicals. Space limitation necessitate the use of descriptive medical terms and toxicological abbreviations. A glossary and an abbreviation list were developed to define some of those sometimes unfamiliar terms and abbreviations. The page numbers are keyed to the catalog number in the chemical stores at ORNL.

  20. Control of neuronal network organization by chemical surface functionalization of multi-walled carbon nanotube arrays

    International Nuclear Information System (INIS)

    Liu Jie; Bibari, Olivier; Marchand, Gilles; Benabid, Alim-Louis; Sauter-Starace, Fabien; Appaix, Florence; De Waard, Michel

    2011-01-01

    Carbon nanotube substrates are promising candidates for biological applications and devices. Interfacing of these carbon nanotubes with neurons can be controlled by chemical modifications. In this study, we investigated how chemical surface functionalization of multi-walled carbon nanotube arrays (MWNT-A) influences neuronal adhesion and network organization. Functionalization of MWNT-A dramatically modifies the length of neurite fascicles, cluster inter-connection success rate, and the percentage of neurites that escape from the clusters. We propose that chemical functionalization represents a method of choice for developing applications in which neuronal patterning on MWNT-A substrates is required.

  1. Control of neuronal network organization by chemical surface functionalization of multi-walled carbon nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jie; Bibari, Olivier; Marchand, Gilles; Benabid, Alim-Louis; Sauter-Starace, Fabien [CEA, LETI-Minatec, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France); Appaix, Florence; De Waard, Michel, E-mail: fabien.sauter@cea.fr, E-mail: michel.dewaard@ujf-grenoble.fr [Inserm U836, Grenoble Institute of Neuroscience, Site Sante la Tronche, Batiment Edmond J Safra, Chemin Fortune Ferrini, BP170, 38042 Grenoble Cedex 09 (France)

    2011-05-13

    Carbon nanotube substrates are promising candidates for biological applications and devices. Interfacing of these carbon nanotubes with neurons can be controlled by chemical modifications. In this study, we investigated how chemical surface functionalization of multi-walled carbon nanotube arrays (MWNT-A) influences neuronal adhesion and network organization. Functionalization of MWNT-A dramatically modifies the length of neurite fascicles, cluster inter-connection success rate, and the percentage of neurites that escape from the clusters. We propose that chemical functionalization represents a method of choice for developing applications in which neuronal patterning on MWNT-A substrates is required.

  2. Automatic control of the effluent turbidity from a chemically enhanced primary treatment with microsieving.

    Science.gov (United States)

    Väänänen, J; Memet, S; Günther, T; Lilja, M; Cimbritz, M; la Cour Jansen, J

    2017-10-01

    For chemically enhanced primary treatment (CEPT) with microsieving, a feedback proportional integral controller combined with a feedforward compensator was used in large pilot scale to control effluent water turbidity to desired set points. The effluent water turbidity from the microsieve was maintained at various set points in the range 12-80 NTU basically independent for a number of studied variations in influent flow rate and influent wastewater compositions. Effluent turbidity was highly correlated with effluent chemical oxygen demand (COD). Thus, for CEPT based on microsieving, controlling the removal of COD was possible. Thereby incoming carbon can be optimally distributed between biological nitrogen removal and anaerobic digestion for biogas production. The presented method is based on common automation and control strategies; therefore fine tuning and optimization for specific requirements are simplified compared to model-based dosing control.

  3. Report: EPA Should Assess Needs and Implement Management Controls to Ensure Effective Incorporation of Chemical Safety Research Products

    Science.gov (United States)

    Report #17-P-0294, June 23, 2017. With management controls that ensure the collaborative development of research products and prioritize chemical safety research needs, the EPA would be better able to conduct faster chemical risk assessments.

  4. Traceability and Quality Control in Traditional Chinese Medicine: From Chemical Fingerprint to Two-Dimensional Barcode

    Directory of Open Access Journals (Sweden)

    Yong Cai

    2015-01-01

    Full Text Available Chemical fingerprinting is currently a widely used tool that enables rapid and accurate quality evaluation of Traditional Chinese Medicine (TCM. However, chemical fingerprints are not amenable to information storage, recognition, and retrieval, which limit their use in Chinese medicine traceability. In this study, samples of three kinds of Chinese medicines were randomly selected and chemical fingerprints were then constructed by using high performance liquid chromatography. Based on chemical data, the process of converting the TCM chemical fingerprint into two-dimensional code is presented; preprocess and filtering algorithm are also proposed aiming at standardizing the large amount of original raw data. In order to know which type of two-dimensional code (2D is suitable for storing data of chemical fingerprints, current popular types of 2D codes are analyzed and compared. Results show that QR Code is suitable for recording the TCM chemical fingerprint. The fingerprint information of TCM can be converted into data format that can be stored as 2D code for traceability and quality control.

  5. Retrofitting existing chemical scrubbers to biotrickling filters for H2S emission control.

    Science.gov (United States)

    Gabriel, David; Deshusses, Marc A

    2003-05-27

    Biological treatment is a promising alternative to conventional air-pollution control methods, but thus far biotreatment processes for odor control have always required much larger reactor volumes than chemical scrubbers. We converted an existing full-scale chemical scrubber to a biological trickling filter and showed that effective treatment of hydrogen sulfide (H2S) in the converted scrubber was possible even at gas contact times as low as 1.6 s. That is 8-20 times shorter than previous biotrickling filtration reports and comparable to usual contact times in chemical scrubbers. Significant removal of reduced sulfur compounds, ammonia, and volatile organic compounds present in traces in the air was also observed. Continuous operation for >8 months showed stable performance and robust behavior for H2S treatment, with pollutant-removal performance comparable to that achieved by using a chemical scrubber. Our study demonstrates that biotrickling filters can replace chemical scrubbers and be a safer, more economical technique for odor control.

  6. Economic Benefit from Progressive Integration of Scheduling and Control for Continuous Chemical Processes

    Directory of Open Access Journals (Sweden)

    Logan D. R. Beal

    2017-12-01

    Full Text Available Performance of integrated production scheduling and advanced process control with disturbances is summarized and reviewed with four progressive stages of scheduling and control integration and responsiveness to disturbances: open-loop segregated scheduling and control, closed-loop segregated scheduling and control, open-loop scheduling with consideration of process dynamics, and closed-loop integrated scheduling and control responsive to process disturbances and market fluctuations. Progressive economic benefit from dynamic rescheduling and integrating scheduling and control is shown on a continuously stirred tank reactor (CSTR benchmark application in closed-loop simulations over 24 h. A fixed horizon integrated scheduling and control formulation for multi-product, continuous chemical processes is utilized, in which nonlinear model predictive control (NMPC and continuous-time scheduling are combined.

  7. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xiang Wang

    2013-01-01

    Full Text Available We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  8. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    KAUST Repository

    Wang, Xiang; Li, Shunbo; Wang, Limu; Yi, Xin; Hui, Yu Sanna; Qin, Jianhua; Wen, Weijia

    2013-01-01

    We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS) and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  9. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    KAUST Repository

    Wang, Xiang

    2013-01-01

    We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS) and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  10. Modeling and control of diffusion and low-pressure chemical vapor deposition furnaces

    Science.gov (United States)

    De Waard, H.; De Koning, W. L.

    1990-03-01

    In this paper a study is made of the heat transfer inside cylindrical resistance diffusion and low-pressure chemical vapor deposition furnaces, aimed at developing an improved temperature controller. A model of the thermal behavior is derived which also covers the important class of furnaces equipped with semitransparent quartz process tubes. The model takes into account the thermal behavior of the thermocouples. It is shown that currently used temperature controllers are highly inefficient for very large scale integration applications. Based on the model an alternative temperature controller of the linear-quadratic-Gaussian type is proposed which features direct wafer temperature control. Some simulation results are given.

  11. Volumetric and chemical control auxiliary circuit for a PWR primary circuit

    International Nuclear Information System (INIS)

    Costes, D.

    1990-01-01

    The volumetric and chemical control circuit has an expansion tank with at least one water-steam chamber connected to the primary circuit by a sampling pipe and a reinjection pipe. The sampling pipe feeds jet pumps controlled by valves. An action on these valves and pumps regulates the volume of the water in the primary circuit. A safety pipe controlled by a flap automatically injects water from the chamber into the primary circuit in case of ruptures. The auxiliary circuit has also systems for purifying the water and controlling the boric acid and hydrogen content [fr

  12. Controlling the resistivity gradient in chemical vapor deposition-deposited aluminum-doped zinc oxide

    NARCIS (Netherlands)

    Ponomarev, M. V.; Verheijen, M. A.; Keuning, W.; M. C. M. van de Sanden,; Creatore, M.

    2012-01-01

    Aluminum-doped ZnO (ZnO:Al) grown by chemical vapor deposition (CVD) generally exhibit a major drawback, i.e., a gradient in resistivity extending over a large range of film thickness. The present contribution addresses the plasma-enhanced CVD deposition of ZnO: Al layers by focusing on the control

  13. 76 FR 38169 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2011-06-29

    ... (7405M), Office of Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania... gold leaf, dyeing mixtures, antifreeze mixtures, extraction of resins and waxes, preservative for...: June 21, 2011. Maria J. Doa, Director, Chemical Control Division, Office of Pollution Prevention and...

  14. A cellular automata approach to chemical reactions : 1 reaction controlled systems

    NARCIS (Netherlands)

    Korte, de A.C.J.; Brouwers, H.J.H.

    2013-01-01

    A direct link between the chemical reaction controlled (shrinking core) model and cellular automata, to study the dissolution of particles, is derived in this paper. Previous research on first and second order reactions is based on the concentration of the reactant. The present paper describes the

  15. Natural control in cabbage root fly populations and influence of chemicals

    NARCIS (Netherlands)

    Abu Yaman, I.K.

    1960-01-01

    To facilitate studies on the natural and chemical control of Hylemya (Erioischia) brassicae (Bch.) in Holland, the bionomics and abundance of the Anthomyiid were investigated in 1959-9 in fields in which cauliflower was grown. The numbers of eggs and larvae were estimated by scrutiny of

  16. Non- chemical methods of seed treatment for control of seed- borne pathogens on vegetables

    NARCIS (Netherlands)

    Amein, T.; Wright, S.A.I.; Wickstrom, M.; Schmitt, A.; Koch, E.; Wolf, van der J.M.; Groot, S.P.C.; Werner, S.; Jahn, M.

    2006-01-01

    The aim of EU-project "Seed Treatments for Organic Vegetable Production" (STOVE) was to evaluate non-chemical methods for control of seed-borne pathogens in organic vegetable production. Physical (hot air, hot water and electron) and biologi-cal (microorganisms and different agents of natural

  17. Control of Chemical Equilibrium by Solvent: A Basis for Teaching Physical Chemistry of Solutions

    Science.gov (United States)

    Prezhdo, Oleg V.; Craig, Colleen F.; Fialkov, Yuriy; Prezhdo, Victor V.

    2007-01-01

    The study demonstrates that the solvent present in a system can highly alter and control the chemical equilibrium of a system. The results show that the dipole moment and polarizibility of a system can be highly altered by using different mixed solvents.

  18. Controllable chemical vapor deposition of large area uniform nanocrystalline graphene directly on silicon dioxide

    DEFF Research Database (Denmark)

    Sun, Jie; Lindvall, Niclas; Cole, Matthew T.

    2012-01-01

    Metal-catalyst-free chemical vapor deposition (CVD) of large area uniform nanocrystalline graphene on oxidized silicon substrates is demonstrated. The material grows slowly, allowing for thickness control down to monolayer graphene. The as-grown thin films are continuous with no observable pinholes...

  19. Chemical analysis and quality control of Ginkgo biloba leaves, extracts, and phytopharmaceuticals

    NARCIS (Netherlands)

    Beek, van T.A.; Montoro, P.

    2009-01-01

    The chemical analysis and quality control of Ginkgo leaves, extracts, phytopharmaceuticals and some herbal supplements is comprehensively reviewed. The review is an update of a similar, earlier review in this journal [T.A. van Beek, J. Chromatogr. A 967 (2002) 21¿55]. Since 2001 over 3000 papers on

  20. Experimental Investigation of Electro-chemical Processes Controlled by High Magnetic Fields.

    Czech Academy of Sciences Publication Activity Database

    Mathon, Ph.; Nouri, A.; Alemany, A.; Chopart, J.P.; Sobolík, Václav

    2006-01-01

    Roč. 42, 4 (2006) , s. 363-369 ISSN 0024-998X Institutional research plan: CEZ:AV0Z40720504 Keywords : lorentz and magnetic force * diffusion-controlled regime * electrical current Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  1. Femtosecond laser induced and controlled chemical reaction of carbon monoxide and hydrogen

    CSIR Research Space (South Africa)

    Du Plessis, A

    2011-07-01

    Full Text Available Results from experiments aimed at bimolecular chemical reaction control of CO and H2 at room temperature and pressure, without any catalyst, using shaped femtosecond laser pulses are presented. A stable reaction product (CO2) was measured after...

  2. 78 FR 40175 - Exempt Chemical Preparations Under the Controlled Substances Act

    Science.gov (United States)

    2013-07-03

    ...Standard, Inc M-8270-04-ASL, Method 8270B-- Amber ampule: 1 mL...... 1/28/2013 Base/Neutrals Mix. Accu... CSA and its implementing regulations are designed to prevent, detect, and eliminate the diversion of... controlled substances and listed chemicals for legitimate medical, scientific, research, and industrial...

  3. Data acquisition and control system with a programmable logic controller (PLC) for a pulsed chemical oxygen-iodine laser

    Science.gov (United States)

    Yu, Haijun; Li, Guofu; Duo, Liping; Jin, Yuqi; Wang, Jian; Sang, Fengting; Kang, Yuanfu; Li, Liucheng; Wang, Yuanhu; Tang, Shukai; Yu, Hongliang

    2015-02-01

    A user-friendly data acquisition and control system (DACS) for a pulsed chemical oxygen -iodine laser (PCOIL) has been developed. It is implemented by an industrial control computer,a PLC, and a distributed input/output (I/O) module, as well as the valve and transmitter. The system is capable of handling 200 analogue/digital channels for performing various operations such as on-line acquisition, display, safety measures and control of various valves. These operations are controlled either by control switches configured on a PC while not running or by a pre-determined sequence or timings during the run. The system is capable of real-time acquisition and on-line estimation of important diagnostic parameters for optimization of a PCOIL. The DACS system has been programmed using software programmable logic controller (PLC). Using this DACS, more than 200 runs were given performed successfully.

  4. Phase distribution of ecologically controlled chemical elements in production of extraction phosphoric acid

    International Nuclear Information System (INIS)

    Kazak, V.G.; Agnelov, A.I.; Zajtsev, P.M.

    1995-01-01

    Content of 16 ecologically controlled chemical element (among them Cd, Sr, Th, U, V, Y) in solid and liquid phases of extraction phosphorus acid (EPA) production is determined. These elements are recommended to control by Scientific research institute of human ecology and environment to establish their extraction coefficients to phosphogypsum and EPA and optimal variant of production of ecologically sate phosphorus fertilizers. X-ray fluorescent, atomic-absorption and polarographic methods are used for analysis these elements

  5. Chemical control of ticks on cattle and the resistance of these parasites to acaricides.

    Science.gov (United States)

    George, J E; Pound, J M; Davey, R B

    2004-01-01

    Toward the end of the nineteenth century a complex of problems related to ticks and tick-borne diseases of cattle created a demand for methods to control ticks and reduce losses of cattle. The discovery and use of arsenical solutions in dipping vats for treating cattle to protect them against ticks revolutionized tick and tick-borne disease control programmes. Arsenic dips for cattle were used for about 40 years before the evolution of resistance of ticks to the chemical, and the development and marketing of synthetic organic acaricides after World War II provided superior alternative products. Most of the major groups of organic pesticides are represented on the list of chemicals used to control ticks on cattle. Unfortunately, the successive evolution of resistance of ticks to acaricides in each chemical group with the concomitant reduction in the usefulness of a group of acaricides is a major reason for the diversity of acaricides. Whether a producer chooses a traditional method for treating cattle with an acaricide or uses a new method, he must recognize the benefits, limitations and potential problems with each application method and product. Simulation models and research were the basis of recommendations for tick control strategies advocating approaches that reduced reliance on acaricides. These recommendations for controlling ticks on cattle are in harmony with recommendations for reducing the rate of selection for acaricide resistance. There is a need to transfer knowledge about tick control and resistance mitigation strategies to cattle producers.

  6. Symmetrical Windowing for Quantum States in Quasi-Classical Trajectory Simulations

    Science.gov (United States)

    Cotton, Stephen Joshua

    An approach has been developed for extracting approximate quantum state-to-state information from classical trajectory simulations which "quantizes" symmetrically both the initial and final classical actions associated with the degrees of freedom of interest using quantum number bins (or "window functions") which are significantly narrower than unit-width. This approach thus imposes a more stringent quantization condition on classical trajectory simulations than has been traditionally employed, while doing so in a manner that is time-symmetric and microscopically reversible. To demonstrate this "symmetric quasi-classical" (SQC) approach for a simple real system, collinear H + H2 reactive scattering calculations were performed [S.J. Cotton and W.H. Miller, J. Phys. Chem. A 117, 7190 (2013)] with SQC-quantization applied to the H 2 vibrational degree of freedom (DOF). It was seen that the use of window functions of approximately 1/2-unit width led to calculated reaction probabilities in very good agreement with quantum mechanical results over the threshold energy region, representing a significant improvement over what is obtained using the traditional quasi-classical procedure. The SQC approach was then applied [S.J. Cotton and W.H. Miller, J. Chem. Phys. 139, 234112 (2013)] to the much more interesting and challenging problem of incorporating non-adiabatic effects into what would otherwise be standard classical trajectory simulations. To do this, the classical Meyer-Miller (MM) Hamiltonian was used to model the electronic DOFs, with SQC-quantization applied to the classical "electronic" actions of the MM model---representing the occupations of the electronic states---in order to extract the electronic state population dynamics. It was demonstrated that if one ties the zero-point energy (ZPE) of the electronic DOFs to the SQC windowing function's width parameter this very simple SQC/MM approach is capable of quantitatively reproducing quantum mechanical results for

  7. Employing online quantum random number generators for generating truly random quantum states in Mathematica

    Science.gov (United States)

    Miszczak, Jarosław Adam

    2013-01-01

    The presented package for the Mathematica computing system allows the harnessing of quantum random number generators (QRNG) for investigating the statistical properties of quantum states. The described package implements a number of functions for generating random states. The new version of the package adds the ability to use the on-line quantum random number generator service and implements new functions for retrieving lists of random numbers. Thanks to the introduced improvements, the new version provides faster access to high-quality sources of random numbers and can be used in simulations requiring large amount of random data. New version program summaryProgram title: TRQS Catalogue identifier: AEKA_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKA_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 18 134 No. of bytes in distributed program, including test data, etc.: 2 520 49 Distribution format: tar.gz Programming language: Mathematica, C. Computer: Any supporting Mathematica in version 7 or higher. Operating system: Any platform supporting Mathematica; tested with GNU/Linux (32 and 64 bit). RAM: Case-dependent Supplementary material: Fig. 1 mentioned below can be downloaded. Classification: 4.15. External routines: Quantis software library (http://www.idquantique.com/support/quantis-trng.html) Catalogue identifier of previous version: AEKA_v1_0 Journal reference of previous version: Comput. Phys. Comm. 183(2012)118 Does the new version supersede the previous version?: Yes Nature of problem: Generation of random density matrices and utilization of high-quality random numbers for the purpose of computer simulation. Solution method: Use of a physical quantum random number generator and an on-line service providing access to the source of true random

  8. Renninger's Gedankenexperiment, the collapse of the wave function in a rigid quantum metamaterial and the reality of the quantum state vector.

    Science.gov (United States)

    Savel'ev, Sergey E; Zagoskin, Alexandre M

    2018-06-25

    A popular interpretation of the "collapse" of the wave function is as being the result of a local interaction ("measurement") of the quantum system with a macroscopic system ("detector"), with the ensuing loss of phase coherence between macroscopically distinct components of its quantum state vector. Nevetheless as early as in 1953 Renninger suggested a Gedankenexperiment, in which the collapse is triggered by non-observation of one of two mutually exclusive outcomes of the measurement, i.e., in the absence of interaction of the quantum system with the detector. This provided a powerful argument in favour of "physical reality" of (nonlocal) quantum state vector. In this paper we consider a possible version of Renninger's experiment using the light propagation through a birefringent quantum metamaterial. Its realization would provide a clear visualization of a wave function collapse produced by a "non-measurement", and make the concept of a physically real quantum state vector more acceptable.

  9. Controlled assembly of organic whispering-gallery-mode microlasers as highly sensitive chemical vapor sensors.

    Science.gov (United States)

    Gao, Miaomiao; Wei, Cong; Lin, Xianqing; Liu, Yuan; Hu, Fengqin; Zhao, Yong Sheng

    2017-03-09

    We demonstrate the fabrication of organic high Q active whispering-gallery-mode (WGM) resonators from π-conjugated polymer by a controlled emulsion-solvent-evaporation method, which can simultaneously provide optical gain and act as an effective resonant cavity. By measuring the shift of their lasing modes on exposure to organic vapor, we successfully monitored the slight concentration variation in the chemical gas. These microlaser sensors demonstrated high detection sensitivity and good signal repeatability under continuous chemical gas treatments. The results offer an effective strategy to design miniaturized optical sensors.

  10. Localized temperature and chemical reaction control in nanoscale space by nanowire array.

    Science.gov (United States)

    Jin, C Yan; Li, Zhiyong; Williams, R Stanley; Lee, K-Cheol; Park, Inkyu

    2011-11-09

    We introduce a novel method for chemical reaction control with nanoscale spatial resolution based on localized heating by using a well-aligned nanowire array. Numerical and experimental analysis shows that each individual nanowire could be selectively and rapidly Joule heated for local and ultrafast temperature modulation in nanoscale space (e.g., maximum temperature gradient 2.2 K/nm at the nanowire edge; heating/cooling time chemical reactions such as polymer decomposition/cross-linking and direct and localized hydrothermal synthesis of metal oxide nanowires were demonstrated.

  11. Chemical-Reaction-Controlled Phase Separated Drops: Formation, Size Selection, and Coarsening

    Science.gov (United States)

    Wurtz, Jean David; Lee, Chiu Fan

    2018-02-01

    Phase separation under nonequilibrium conditions is exploited by biological cells to organize their cytoplasm but remains poorly understood as a physical phenomenon. Here, we study a ternary fluid model in which phase-separating molecules can be converted into soluble molecules, and vice versa, via chemical reactions. We elucidate using analytical and simulation methods how drop size, formation, and coarsening can be controlled by the chemical reaction rates, and categorize the qualitative behavior of the system into distinct regimes. Ostwald ripening arrest occurs above critical reaction rates, demonstrating that this transition belongs entirely to the nonequilibrium regime. Our model is a minimal representation of the cell cytoplasm.

  12. Chemical weathering as a mechanism for the climatic control of bedrock river incision

    Science.gov (United States)

    Murphy, Brendan P.; Johnson, Joel P. L.; Gasparini, Nicole M.; Sklar, Leonard S.

    2016-04-01

    Feedbacks between climate, erosion and tectonics influence the rates of chemical weathering reactions, which can consume atmospheric CO2 and modulate global climate. However, quantitative predictions for the coupling of these feedbacks are limited because the specific mechanisms by which climate controls erosion are poorly understood. Here we show that climate-dependent chemical weathering controls the erodibility of bedrock-floored rivers across a rainfall gradient on the Big Island of Hawai‘i. Field data demonstrate that the physical strength of bedrock in streambeds varies with the degree of chemical weathering, which increases systematically with local rainfall rate. We find that incorporating the quantified relationships between local rainfall and erodibility into a commonly used river incision model is necessary to predict the rates and patterns of downcutting of these rivers. In contrast to using only precipitation-dependent river discharge to explain the climatic control of bedrock river incision, the mechanism of chemical weathering can explain strong coupling between local climate and river incision.

  13. A multi target approach to control chemical reactions in their inhomogeneous solvent environment

    International Nuclear Information System (INIS)

    Keefer, Daniel; Thallmair, Sebastian; Zauleck, Julius P P; Vivie-Riedle, Regina de

    2015-01-01

    Shaped laser pulses offer a powerful tool to manipulate molecular quantum systems. Their application to chemical reactions in solution is a promising concept to redesign chemical synthesis. Along this road, theoretical developments to include the solvent surrounding are necessary. An appropriate theoretical treatment is helpful to understand the underlying mechanisms. In our approach we simulate the solvent by randomly selected snapshots from molecular dynamics trajectories. We use multi target optimal control theory to optimize pulses for the various arrangements of explicit solvent molecules simultaneously. This constitutes a major challenge for the control algorithm, as the solvent configurations introduce a large inhomogeneity to the potential surfaces. We investigate how the algorithm handles the new challenges and how well the controllability of the system is preserved with increasing complexity. Additionally, we introduce a way to statistically estimate the efficiency of the optimized laser pulses in the complete thermodynamical ensemble. (paper)

  14. Thermally activated reaction–diffusion-controlled chemical bulk reactions of gases and solids

    Directory of Open Access Journals (Sweden)

    S. Möller

    2015-01-01

    Full Text Available The chemical kinetics of the reaction of thin films with reactive gases is investigated. The removal of thin films using thermally activated solid–gas to gas reactions is a method to in-situ control deposition inventory in vacuum and plasma vessels. Significant scatter of experimental deposit removal rates at apparently similar conditions was observed in the past, highlighting the need for understanding the underlying processes. A model based on the presence of reactive gas in the films bulk and chemical kinetics is presented. The model describes the diffusion of reactive gas into the film and its chemical interaction with film constituents in the bulk using a stationary reaction–diffusion equation. This yields the reactive gas concentration and reaction rates. Diffusion and reaction rate limitations are depicted in parameter studies. Comparison with literature data on tokamak co-deposit removal results in good agreement of removal rates as a function of pressure, film thickness and temperature.

  15. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, T.R. [Univ. of Rochester, NY (United States)

    1993-12-01

    This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.

  16. Margins of safety provided by COSHH Essentials and the ILO Chemical Control Toolkit.

    Science.gov (United States)

    Jones, Rachael M; Nicas, Mark

    2006-03-01

    COSHH Essentials, developed by the UK Health and Safety Executive, and the Chemical Control Toolkit (Toolkit) proposed by the International Labor Organization, are 'control banding' approaches to workplace risk management intended for use by proprietors of small and medium-sized businesses. Both systems group chemical substances into hazard bands based on toxicological endpoint and potency. COSSH Essentials uses the European Union's Risk-phrases (R-phrases), whereas the Toolkit uses R-phrases and the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Each hazard band is associated with a range of airborne concentrations, termed exposure bands, which are to be attained by the implementation of recommended control technologies. Here we analyze the margin of safety afforded by the systems and, for each hazard band, define the minimal margin as the ratio of the minimum airborne concentration that produced the toxicological endpoint of interest in experimental animals to the maximum concentration in workplace air permitted by the exposure band. We found that the minimal margins were always occupational exposure limits, we argue that the minimal margins are better indicators of health protection. Further, given the small margins observed, we feel it is important that revisions of these systems provide the exposure bands to users, so as to permit evaluation of control technology capture efficiency.

  17. Testing the control of mineral supply rates on chemical erosion in the Klamath Mountains

    Science.gov (United States)

    West, N.; Ferrier, K.

    2017-12-01

    The relationship between rates of chemical erosion and mineral supply is central to many problems in Earth science, including the role of tectonics in the global carbon cycle, nutrient supply to soils and streams via soil production, and lithologic controls on landscape evolution. We aim to test the relationship between mineral supply rates and chemical erosion in the forested uplands of the Klamath mountains, along a latitudinal transect of granodioritic plutons that spans an expected gradient in mineral supply rates associated with the geodynamic response to the migration of the Mendocino Triple Junction. We present 10Be-derived erosion rates and Zr-derived chemical depletion factors, as well as bulk soil and rock geochemistry on 10 ridgetops along the transect to test hypotheses about supply-limited and kinetically-limited chemical erosion. Previous studies in this area, comparing basin-averaged erosion rates and modeled uplift rates, suggest this region may be adjusted to an approximate steady state. Our preliminary results suggest that chemical erosion at these sites is influenced by both mineral supply rates and dissolution kinetics.

  18. New methods for the measurement and alteration of quantum states; Neue Methoden zur Messung und Veraenderung von Quantenzustaenden

    Energy Technology Data Exchange (ETDEWEB)

    Steuernagel, O.

    1996-07-01

    Themes of this thesis are the mathematical representation, measurement-technical reconstruction, and preparation of quantum states as well as their alteration by measurement. The main topics of the considerations are quantum-mechanical system states, the complet description of which pursues by means of density operators. The first chapter presents a general mathematical scheme for the representaion of density operators by means of projection operators. The second chapter explains a scheme for the syntehsis of Fock states by means of a linear mixer. The third chapter answers the question, whether spontaneous emitted light, which is emitted by an atom with large spatial extension, can show self-interferences and lets conclude on thee coherent structure of the c.m. wave function of the emitting atom. The last chapter reconstructs measurement results on the coherence loss of atoms in an atomic-beam experiment by spontaneous emission in the language of the density-operator formalism.

  19. Dynamics of interacting qubits coupled to a common bath: Non-Markovian quantum-state-diffusion approach

    International Nuclear Information System (INIS)

    Zhao Xinyu; Jing Jun; Corn, Brittany; Yu Ting

    2011-01-01

    Non-Markovian dynamics is studied for two interacting qubits strongly coupled to a dissipative bosonic environment. We derive a non-Markovian quantum-state-diffusion (QSD) equation for the coupled two-qubit system without any approximations, and in particular, without the Markov approximation. As an application and illustration of our derived time-local QSD equation, we investigate the temporal behavior of quantum coherence dynamics. In particular, we find a strongly non-Markovian regime where entanglement generation is significantly modulated by the environmental memory. Additionally, we study residual entanglement in the steady state by analyzing the steady-state solution of the QSD equation. Finally, we discuss an approximate QSD equation.

  20. Integrated Microfluidic Membrane Transistor Utilizing Chemical Information for On-Chip Flow Control

    Science.gov (United States)

    Frank, Philipp; Schreiter, Joerg; Haefner, Sebastian; Paschew, Georgi; Voigt, Andreas; Richter, Andreas

    2016-01-01

    Microfluidics is a great enabling technology for biology, biotechnology, chemistry and general life sciences. Despite many promising predictions of its progress, microfluidics has not reached its full potential yet. To unleash this potential, we propose the use of intrinsically active hydrogels, which work as sensors and actuators at the same time, in microfluidic channel networks. These materials transfer a chemical input signal such as a substance concentration into a mechanical output. This way chemical information is processed and analyzed on the spot without the need for an external control unit. Inspired by the development electronics, our approach focuses on the development of single transistor-like components, which have the potential to be used in an integrated circuit technology. Here, we present membrane isolated chemical volume phase transition transistor (MIS-CVPT). The device is characterized in terms of the flow rate from source to drain, depending on the chemical concentration in the control channel, the source-drain pressure drop and the operating temperature. PMID:27571209

  1. Remote-controlling chemical reactions by light: towards chemistry with high spatio-temporal resolution.

    Science.gov (United States)

    Göstl, Robert; Senf, Antti; Hecht, Stefan

    2014-03-21

    The foundation of the chemical enterprise has always been the creation of new molecular entities, such as pharmaceuticals or polymeric materials. Over the past decades, this continuing effort of designing compounds with improved properties has been complemented by a strong effort to render their preparation (more) sustainable by implementing atom as well as energy economic strategies. Therefore, synthetic chemistry is typically concerned with making specific bonds and connections in a highly selective and efficient manner. However, to increase the degree of sophistication and expand the scope of our work, we argue that the modern aspiring chemist should in addition be concerned with attaining (better) control over when and where chemical bonds are being made or broken. For this purpose, photoswitchable molecular systems, which allow for external modulation of chemical reactions by light, are being developed and in this review we are covering the current state of the art of this exciting new field. These "remote-controlled synthetic tools" provide a remarkable opportunity to perform chemical transformations with high spatial and temporal resolution and should therefore allow regulating biological processes as well as material and device performance.

  2. Integrated Microfluidic Membrane Transistor Utilizing Chemical Information for On-Chip Flow Control.

    Science.gov (United States)

    Frank, Philipp; Schreiter, Joerg; Haefner, Sebastian; Paschew, Georgi; Voigt, Andreas; Richter, Andreas

    2016-01-01

    Microfluidics is a great enabling technology for biology, biotechnology, chemistry and general life sciences. Despite many promising predictions of its progress, microfluidics has not reached its full potential yet. To unleash this potential, we propose the use of intrinsically active hydrogels, which work as sensors and actuators at the same time, in microfluidic channel networks. These materials transfer a chemical input signal such as a substance concentration into a mechanical output. This way chemical information is processed and analyzed on the spot without the need for an external control unit. Inspired by the development electronics, our approach focuses on the development of single transistor-like components, which have the potential to be used in an integrated circuit technology. Here, we present membrane isolated chemical volume phase transition transistor (MIS-CVPT). The device is characterized in terms of the flow rate from source to drain, depending on the chemical concentration in the control channel, the source-drain pressure drop and the operating temperature.

  3. Controlled air incineration of hazardous chemical and mixed waste at Los Alamos

    International Nuclear Information System (INIS)

    Borduin, L.C.; Hutchins, D.A.; Vavruska, J.J.; Warner, C.L.

    1987-01-01

    The Los Alamos National Laboratory (LANL) Controlled Air Incineration (CAI) system, originally developed for transuranic (TRU) waste volume reduction studies, is currently being qualified for hazardous chemical and mixed waste treatment under provisions of the Resource Conservation and Recovery Act (RCRA). The objective is to obtain a permanent RCRA Part B permit for thermal disposal of hazardous and mixed wastes generated by LANL. Constructed in the mid-1970s as a demonstration project for incineration of TRU solid wastes, the CAI process was substantially modified and tested in 1980-1983 for acceptance of both liquid and solid hazardous chemicals. Successful demonstration of TRU solid waste processing objectives in 1979 and later chemical waste incineration studies have been documented in several publications. In 1984, the LANL CAI became the first US Dept. of Energy (DOE) incinerator to be permitted for polychlorinated biphenyl disposal under the Toxic Substances Control Act. Following establishment of Environmental Protection Agency (EPA) jurisdiction over DOE chemical waste management in 1984, LANL sought and was granted interim status for the CAI and applied for a trial burn permit in the overall laboratory RCRA Part B application. A trial burn and final report have been completed; results have been submitted to EPA and the New Mexico Environmental Improvement Division. This paper provides an overview of trial burn planning and results together with the operational status of LANL's CAI

  4. Pulse-density modulation control of chemical oscillation far from equilibrium in a droplet open-reactor system.

    Science.gov (United States)

    Sugiura, Haruka; Ito, Manami; Okuaki, Tomoya; Mori, Yoshihito; Kitahata, Hiroyuki; Takinoue, Masahiro

    2016-01-20

    The design, construction and control of artificial self-organized systems modelled on dynamical behaviours of living systems are important issues in biologically inspired engineering. Such systems are usually based on complex reaction dynamics far from equilibrium; therefore, the control of non-equilibrium conditions is required. Here we report a droplet open-reactor system, based on droplet fusion and fission, that achieves dynamical control over chemical fluxes into/out of the reactor for chemical reactions far from equilibrium. We mathematically reveal that the control mechanism is formulated as pulse-density modulation control of the fusion-fission timing. We produce the droplet open-reactor system using microfluidic technologies and then perform external control and autonomous feedback control over autocatalytic chemical oscillation reactions far from equilibrium. We believe that this system will be valuable for the dynamical control over self-organized phenomena far from equilibrium in chemical and biomedical studies.

  5. Los Alamos Controlled Air Incinerator for hazardous chemical and mixed radioactive wastes

    International Nuclear Information System (INIS)

    Vavruska, J.S.; Borduin, L.C.; Hutchins, D.A.; Koenig, R.A.; Warner, C.L.

    1986-01-01

    The Los Alamos Controlled Air Incinerator (CAI) is currently the only radioactive waste incineration facility in the US permitted to treat polychlorinated biphenyls (PCBs). The CAI was developed in the mid-1970's as a demonstration system for volume reduction of transuranic (TRU) contaminated combustible solid wastes. It has since undergone additions and modifications to accommodate hazardous chemical wastes in response to a need within the Department of Energy (DOE) to treat mixed radioactive/chemical wastes. An overview of these additions which include a liquid feed system, a high intensity liquid injection burner, and an activated carbon adsorption unit is presented here. Also included is a discussion of the procedures required for Toxic Substances Control Act (TSCA) and Resource Conservation and Recovery Act (RCRA) permitting of the CAI

  6. Chemical Control for Host-Parasitoid Model within the Parasitism Season and Its Complex Dynamics

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2016-01-01

    Full Text Available In the present paper, we develop a host-parasitoid model with Holling type II functional response function and chemical control, which can be applied at any time of each parasitism season or pest generation, and focus on addressing the importance of the timing of application pesticide during the parasitism season or pest generation in successful pest control. Firstly, the existence and stability of both the host and parasitoid populations extinction equilibrium and parasitoid-free equilibrium have been investigated. Secondly, the effects of key parameters on the threshold conditions have been discussed in more detail, which shows the importance of pesticide application times on the pest control. Thirdly, the complex dynamics including multiple attractors coexistence, chaotic behavior, and initial sensitivity have been studied by using numerical bifurcation analyses. Finally, the uncertainty and sensitivity of all the parameters on the solutions of both the host and parasitoid populations are investigated, which can help us to determine the key parameters in designing the pest control strategy. The present research can help us to further understand the importance of timings of pesticide application in the pest control and to improve the classical chemical control and to make management decisions.

  7. 76 FR 17778 - Control of Ergocristine, a Chemical Precursor Used in the Illicit Manufacture of Lysergic Acid...

    Science.gov (United States)

    2011-03-31

    ... 1117-AB24 Control of Ergocristine, a Chemical Precursor Used in the Illicit Manufacture of Lysergic... for the List I chemicals ergotamine and ergonovine to illicitly manufacture the schedule I controlled..., due to growing concerns regarding its use for the illicit manufacture of LSD. [[Page 17779...

  8. Control charts technique - a tool to data analysis for chemical experiments

    International Nuclear Information System (INIS)

    Yadav, M.B.; Venugopal, V.

    1999-01-01

    A procedure using control charts technique has been developed to analyse data of a chemical experiment which was conducted to assign a value to uranium content in Rb 2 U(SO 4 ) 3 . A value of (34.164 ± 0.031)% has been assigned against (34.167 ± 0.042)% already assigned by analysis of variance (ANOVA) technique. These values do not differ significantly. Merits and demerits of the two techniques have been discussed. (author)

  9. Neutronics and mass transport in a chemical reactor associated with controlled thermonuclear fusion reactor

    International Nuclear Information System (INIS)

    Dang, V.D.; Steinberg, M.; Lazareth, O.W.; Powell, J.R.

    1976-05-01

    The formation of ozone from oxygen and the dissociation carbon dioxide to carbon monoxide and oxygen is studied in a gamma-neutron chemical process blanket associated with a controlled thermonuclear reactor. Materials used for reactor tube wall will affect the efficiency of the energy absorption by the reactants and consequently the yield of reaction products. Three kinds of materials, aluminum, stainless steel and fiber (Al 2 O 3 )-aluminium are investigated for the tube wall material in the study

  10. Spatial patterns and controls of soil chemical weathering rates along a transient hillslope

    Science.gov (United States)

    Yoo, K.; Mudd, S.M.; Sanderman, J.; Amundson, Ronald; Blum, A.

    2009-01-01

    Hillslopes have been intensively studied by both geomorphologists and soil scientists. Whereas geomorphologists have focused on the physical soil production and transport on hillslopes, soil scientists have been concerned with the topographic variation of soil geochemical properties. We combined these differing approaches and quantified soil chemical weathering rates along a grass covered hillslope in Coastal California. The hillslope is comprised of both erosional and depositional sections. In the upper eroding section, soil production is balanced by physical erosion and chemical weathering. The hillslope then transitions to a depositional slope where soil accumulates due to a historical reduction of channel incision at the hillslope's base. Measurements of hillslope morphology and soil thickness were combined with the elemental composition of the soil and saprolite, and interpreted through a process-based model that accounts for both chemical weathering and sediment transport. Chemical weathering of the minerals as they moved downslope via sediment transport imparted spatial variation in the geochemical properties of the soil. Inverse modeling of the field and laboratory data revealed that the long-term soil chemical weathering rates peak at 5 g m- 2 yr- 1 at the downslope end of the eroding section and decrease to 1.5 g m- 2 yr- 1 within the depositional section. In the eroding section, soil chemical weathering rates appear to be primarily controlled by the rate of mineral supply via colluvial input from upslope. In the depositional slope, geochemical equilibrium between soil water and minerals appeared to limit the chemical weathering rate. Soil chemical weathering was responsible for removing 6% of the soil production in the eroding section and 5% of colluvial influx in the depositional slope. These were among the lowest weathering rates reported for actively eroding watersheds, which was attributed to the parent material with low amount of weatherable

  11. Chemical control of different Digitaria insularis populations and management of a glyphosate-resistant population

    OpenAIRE

    CORREIA,N.M.; ACRA,L.T.; BALIEIRO,G.

    2015-01-01

    This study aimed to control different populations of Digitaria insularisby glyphosate herbicide, isolated and mixed, besides the combination of methods (chemical and mechanical) to manage resistant adult plants. Three experiments were conducted, one in pots which were maintained under non-controlled conditions and two under field conditions. In the experiment in pots, twelve populations of D. insularis were sprayed with isolated glyphosate (1.44 and 2.16 kg a.e. ha-1) and mixed (1.44 and 2.16...

  12. X-ray fluorescence control of chemical composition of cast iron

    International Nuclear Information System (INIS)

    Prekina, I.M.; Rozova, O.F.; Loran, A.V.; Teplitskaya, G.A.; Smagunova, A.N.

    1995-01-01

    A method of x-ray fluorescence analysis developed for analytical set (KRF-18 diffractometer/DVK-3 computer) is used to control cast iron composition. A quantitative evaluation of errors attributed to the violation of conditions of cast iron sampling from the flow and to the quality of preparing samples for XFA is obtained. It is shown that the main component of the integral experimental error is attributed to nonuniformity of chemical composition of cast iron. Metrological studies show that reproductibility, convergence, accuracy, and sensitivity of the method match the requirements characteristic of the control process. 4 refs.; 2 tabs

  13. In-reactor performance of methods to control fuel-cladding chemical interaction

    International Nuclear Information System (INIS)

    Weber, E.T.; Gibby, R.L.; Wilson, C.N.; Lawrence, L.A.; Adamson, M.G.

    1979-01-01

    Inner surface corrosion of austenitic stainless steel cladding by oxygen and reactive fission product elements requires a 50 μm wastage allowance in current FBR reference oxide fuel pin design. Elimination or reduction of this wastage allowance could result in better reactor efficiency and economics through improvements in fuel pin performance and reliability. Reduction in cladding thickness and replacement of equivalent volume with fuel result in improved breeding capability. Of the factors affecting fuel-cladding chemical interaction (FCCI), oxygen activity within the fuel pin can be most readily controlled and/or manipulated without degrading fuel pin performance or significantly increasing fuel fabrication costs. There are two major approaches to control oxygen activity within an oxide fuel pin: (1) control of total oxygen inventory and chemical activity (Δ anti GO 2 ) by use of low oxygen-to-metal ratio (O/M) fuel; and (2) incorporation of a material within the fuel pin to provide in-situ control of oxygen activity (Δ anti GO 2 ) and fixation of excess oxygen prior to, or in preference to reaction with the cladding. The paper describes irradiation tests which were conducted in EBR-II and GETR incorporating oxygen buffer/getter materials and very low O/M fuel to control oxygen activity in sealed fuel pins

  14. Reply to "Comment on 'One-state vector formalism for the evolution of a quantum state through nested Mach-Zehnder interferometers'"

    Czech Academy of Sciences Publication Activity Database

    Bartkiewicz, K.; Černoch, A.; Javůrek, D.; Lemr, K.; Soubusta, Jan; Svozilík, J.

    2016-01-01

    Roč. 93, č. 3 (2016), 1-2, č. článku 036104. ISSN 2469-9926 Institutional support: RVO:68378271 Keywords : one-state vector * quantum state * Mach-Zehnder interferometer Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.925, year: 2016

  15. Uso de diferentes herbicidas no controle de Myriophyllum aquaticum Chemical Control of Myriophyllum aquaticum

    Directory of Open Access Journals (Sweden)

    E. Negrisoli

    2003-01-01

    Full Text Available Este estudo teve a finalidade de avaliar, em condições de caixa d'água, o controle químico de Myriophyllum aquaticum (pinheiro-d'água, através de herbicidas aplicados em pós-emergência. Os herbicidas e respectivas doses (g ha-1 foram: diquat (Reward a 204 g i.a. ha-1; diquat a 102 e 204 g i.a. ha-1 + Agral a 0,1%; 2,4-D (DMA 806 BR a 167, 335, 670 e 1.340 g e.a. ha-1; glyphosate (Rodeo a 3.360 g e.a. ha-1 + Aterbane a 0,5%; e imazapyr (Arsenal a 250 g e.a. ha-1. As parcelas foram constituídas por caixas d'água de 0,60 x 0,60 x 0,45 m, com 120 litros de água + 20 litros de solo e 20 ramos por caixa. Utilizou-se um pulverizador costal a pressão constante de CO2 a 2 bar, pontas 110.02 VS, com um consumo de calda de 180 l ha-1. O controle foi avaliado visualmente aos 2, 6, 9,11, 13, 17, 20, 23, 26, 30 e 36 dias após a aplicação dos herbicidas (DAAH. Inicialmente, o herbicida diquat foi o composto que apresentou os sintomas mais severos de intoxicação nos ramos de pinheiro-d'água aos 2 DAAH, com 65% de controle em média, e aos 20 DAAH ele atingiu o controle máximo (99%, porém ocorreram rebrotas a partir dos 23 DAAH, independentemente da adição ou não de Agral e das doses testadas. O herbicida 2,4-D proporcionou 100% de controle dos ramos a partir dos 23 DAAH para as doses de 1.340 e 670 g ha-1, não ocorrendo rebrotas; já para as demais doses testadas (335 e 167 g ha-1 o controle não foi eficiente, pois ocorreram rebrotas. Os herbicidas glyphosate e imazapyr não foram eficientes no controle desta espécie.This work was carried out at the Advanced Weed Research Nucleus - UNESP, Botucatu-SP, to evaluate the control of Myriophyllum aquaticum by applying different herbicides in post emergence. The herbicides and doses (g ha-1 tested were: diquat (Reward at 204 g a.i. ha-1, diquat at 102 and 204 g a.i. ha-1 + agral at 0.1% v/v; 2,4-D (DMA 806 BR at 1,340, 670, 335 and 167 g a.e. ha-1; glyphosate (Rodeo at 3.360 g a.e. ha-1

  16. Controllingchemical nose” biosensor characteristics by modulating gold nanoparticle shape and concentration

    Directory of Open Access Journals (Sweden)

    Mohit S. Verma

    2015-09-01

    Full Text Available Conventional lock-and-key biosensors often only detect a single pathogen because they incorporate biomolecules with high specificity. “Chemical nose” biosensors are overcoming this limitation and identifying multiple pathogens simultaneously by obtaining a unique set of responses for each pathogen of interest, but the number of pathogens that can be distinguished is limited by the number of responses obtained. Herein, we use a gold nanoparticle-based “chemical nose” to show that changing the shapes of nanoparticles can increase the number of responses available for analysis and expand the types of bacteria that can be identified. Using four shapes of nanoparticles (nanospheres, nanostars, nanocubes, and nanorods, we demonstrate that each shape provides a unique set of responses in the presence of different bacteria, which can be exploited for enhanced specificity of the biosensor. Additionally, the concentration of nanoparticles controls the detection limit of the biosensor, where a lower concentration provides better detection limit. Thus, here we lay a foundation for designing “chemical nose” biosensors and controlling their characteristics using gold nanoparticle morphology and concentration. Keywords: Morphology, Color change, Staphylococcus aureus, Point-of-care, Nanocubes, Nanorods

  17. Development of hazard analysis by critical control points (HACCP) procedures to control organic chemical hazards in the agricultural production of raw food commodities.

    Science.gov (United States)

    Ropkins, Karl; Ferguson, Andrew; Beck, Angus J

    2003-01-01

    Hazard Analysis by Critical Control Points (HACCP) is a systematic approach to the identification, assessment, and control of hazards in the food chain. Effective HACCP requires the consideration of all chemical microbiological, and physical hazards. However, current procedures focus primarily on microbiological and physical hazards, while chemical aspects of HACCP have received relatively little attention. In this article we discuss the application of HACCP to organic chemical contaminants and the problems that are likely to be encountered in agriculture. We also present generic templates for the development of organic chemical contaminant HACCP procedures for selected raw food commodities, that is, cereal crops,raw meats, and milk.

  18. Mass transfer rate through liquid membranes: interfacial chemical reactions and diffusion as simultaneous permeability controlling factors

    International Nuclear Information System (INIS)

    Danesi, P.R.; Horwitz, E.P.; Vandegrift, G.F.; Chiarizia, R.

    1981-01-01

    Equations describing the permeability of a liquid membrane to metal cations have been derived taking into account aqueous diffusion, membrane diffusion, and interfacial chemical reactions as simultaneous permeability controlling factors. Diffusion and chemical reactions have been coupled by a simple model analogous to the one previously described by us to represent liquid-liquid extraction kinetics. The derived equations, which make use of experimentally determined interfacial reaction mechanisms, qualitatively fit unexplained literature data regarding Cu 2+ transfer through liquid membranes. Their use to predict and optimize membrane permeability in practical separation processes by setting the appropriate concentration of the membrane carrier [LIX 64 (General Mills), a commercial β-hydroxy-oxime] and the pH of the aqueous copper feed solution is briefly discussed. 4 figures

  19. Attempts to identify a control system for chemical reactivity in the living state using virtual energy.

    Science.gov (United States)

    Reid, B L; Bourke, C

    2001-07-01

    This thesis explores the activation of chemicals in metabolic systems from the viewpoint that this activation is under the control of elements of the space-sea in which the chemicals are immersed. Themselves inert, the chemicals are theorised to exploit a force or action issuing from space (fluctuation) and characterized by the homogeneity (termed symmetry) of this medium. The fluctuation is heterogenized upon collision with matter from the intervention of well recognized fields of gravity and electromagnetism at the instant of its issue to form the near field of radiation. Fractions of original space waves and of their intrinsic spin are produced resulting in the activation of the orbitals (valency) in the chemical itself. The thesis continues: the disturbed fluctuation must return to space, obliging in turn, a prior return to the homogeneous state requiring special restorative wave rearrangements known as resonance. The success of the restorative resonance is signalled by a singularity of the fluctuation now propelled to infinity (space), and the contingent chemical reactions thereby terminated. Compromise to this return can occur from many causes and, in its presence, activation of the orbitals continues. They now effectively constitute autonomous reactions alienated from the system as a whole. The thesis is supported from evidence from diverse fields such as space theory, history of quantum field theory in attempts to derive its meaning, dielectrics and the near field of electromagnetic radiation, electron-space interactions at the Fermi surface during phase transitions and evolution of equilibrium conditions in resonance phenomena. The utility of the hypothesis rests on recognition of the resonance condition at various points in the system sufficiently macroscopic as to be available clinically as an abrupt interface between physiology and pathology. Copyright 2001 Harcourt Publishers Ltd.

  20. [Risk assessment and risk control for occupational exposure to chemical toxicants from an isophorone nitrile device].

    Science.gov (United States)

    Wang, Dejun; Fu, Xiaokuan; Kong, Fanling; Sui, Shaofeng; Jiang, Yuanyuan; Du, Yinglin; Zhou, Jingyang

    2014-06-01

    Risk assessment and risk control for occupational exposure to chemical toxicants were performed on an isophorone nitrile device with an annual production of 5,000 tons, based on improved Singaporean semi-quantitative risk assessment method, with consideration of actual situation in China and in the present project. With the use of engineering analysis and identification of occupational hazards in the improved Singaporean semi-quantitative risk assessment method, hazard rating (HR) and risk assessment were performed on chemical toxicants from an isophorone nitrile device with an annual production of 5,000 tons. The chemical toxicants in the isophorone nitrile device were mainly isophorone, hydrocyanic acid, methanol, phosphoric acid, sodium hydroxide, and sodium cyanide; the HR values were mild hazard (2), extreme hazard (5), mild hazard (2), mild hazard (2), moderate hazard (3), and extreme hazard (5), respectively, and the corresponding exposure rating (ER) values were 2.09, 2.72, 2.76, 1.68, 2.0, and 1.59, respectively. The risk of chemical toxicants in this project was assessed according to the formula Risk = [HR×ER](1/2). Hydrocyanic acid was determined as high risk, sodium hydroxide and sodium cyanide as medium risk, and isophorone, methanol, and phosphoric acid as low risk. Priority in handling of risks was determined by risk rating. The table of risk control measure was established for pre-assessment of occupational hazards. With risk assessment in this study, we concluded that the isophorone nitrile device with 5,000 ton annual production was a high-occupational hazard device. This device is a project of extreme occupational hazard. The improved Singaporean semi-quantitative risk assessment method is a scientific and applicable method, and is especially suitable for pre-evaluation of on-site project with no analogy.

  1. Controlled density of vertically aligned carbon nanotubes in a triode plasma chemical vapor deposition system

    International Nuclear Information System (INIS)

    Lim, Sung Hoon; Park, Kyu Chang; Moon, Jong Hyun; Yoon, Hyun Sik; Pribat, Didier; Bonnassieux, Yvan; Jang, Jin

    2006-01-01

    We report on the growth mechanism and density control of vertically aligned carbon nanotubes using a triode plasma enhanced chemical vapor deposition system. The deposition reactor was designed in order to allow the intermediate mesh electrode to be biased independently from the ground and power electrodes. The CNTs grown with a mesh bias of + 300 V show a density of ∼ 1.5 μm -2 and a height of ∼ 5 μm. However, CNTs do not grow when the mesh electrode is biased to - 300 V. The growth of CNTs can be controlled by the mesh electrode bias which in turn controls the plasma density and ion flux on the sample

  2. Efficacy of different chemicals for the control of aphid (acyrthosiphon pisum) on guar (cymopisis tetragonolobus) crop

    International Nuclear Information System (INIS)

    Din, Q.M.U.; Hussain, I.; Abbas, G.; Abbas, Z.

    2009-01-01

    An experiment was carried out to evaluate the efficacy of different chemicals far the control of aphid on guar crop at Adaptive Research Farm Karor during the three successive kharif seasons i.e. 2006-07 and 2008. The experiments were laid out in Randomized Complete Block Design with three replications and five treatments viz T1=control, T2 Bifenthrin at the rate 375 ml ha/sup -1/, T3=Primore 50PP at the rate 850 ml ha/sup -1/ T4=Furathiocrab at the rate 750 ml ha/sup -1/ and T5=Carbosulfan at the rate 1250 ml ha/sup -1/. All the treatments (T4) caused significant decrease in the Pest population as compared to the control. Treatment (T4) where Furathiocrab was applied at the rate. 750 ml ha/sup -1/ during the years 2006, 2007 and 2008 respectively. (author)

  3. Model-Based Integrated Process Design and Controller Design of Chemical Processes

    DEFF Research Database (Denmark)

    Abd Hamid, Mohd Kamaruddin Bin

    that is typically formulated as a mathematical programming (optimization with constraints) problem is solved by the so-called reverse approach by decomposing it into four sequential hierarchical sub-problems: (i) pre-analysis, (ii) design analysis, (iii) controller design analysis, and (iv) final selection......This thesis describes the development and application of a new systematic modelbased methodology for performing integrated process design and controller design (IPDC) of chemical processes. The new methodology is simple to apply, easy to visualize and efficient to solve. Here, the IPDC problem...... are ordered according to the defined performance criteria (objective function). The final selected design is then verified through rigorous simulation. In the pre-analysis sub-problem, the concepts of attainable region and driving force are used to locate the optimal process-controller design solution...

  4. Chemical control and design considerations for CANDU-PHW steam generators

    International Nuclear Information System (INIS)

    Frost, C.R.; Churchill, B.R.

    1978-01-01

    Ontario Hydro presently operates eight nuclear power units with a total capacitiy of about 4000 MW(e) net. Operating experience has been with Monel-400 and with Inconel-600 tubed steam generators using sodium phosphate or all volatile control of the boiler steam and water system. With a heavy water Heat Transport System, steam generator tube integrity is an essential ingredient of economical power production. Only three steam generator tube failures have occurred so far in about 40 unit-years operation. None was attributable to corrosion. Factors in the good reliability are, careful engineering design, good quality control at all stages of tubing and steam generator manufacture and close chemical control. The continuing evolution of our steam generator design means that future requirements will be more stringent. (author)

  5. Statistical process control support during Defense Waste Processing Facility chemical runs

    International Nuclear Information System (INIS)

    Brown, K.G.

    1994-01-01

    The Product Composition Control System (PCCS) has been developed to ensure that the wasteforms produced by the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) will satisfy the regulatory and processing criteria that will be imposed. The PCCS provides rigorous, statistically-defensible management of a noisy, multivariate system subject to multiple constraints. The system has been successfully tested and has been used to control the production of the first two melter feed batches during DWPF Chemical Runs. These operations will demonstrate the viability of the DWPF process. This paper provides a brief discussion of the technical foundation for the statistical process control algorithms incorporated into PCCS, and describes the results obtained and lessons learned from DWPF Cold Chemical Run operations. The DWPF will immobilize approximately 130 million liters of high-level nuclear waste currently stored at the Site in 51 carbon steel tanks. Waste handling operations separate this waste into highly radioactive sludge and precipitate streams and less radioactive water soluble salts. (In a separate facility, soluble salts are disposed of as low-level waste in a mixture of cement slag, and flyash.) In DWPF, the precipitate steam (Precipitate Hydrolysis Aqueous or PHA) is blended with the insoluble sludge and ground glass frit to produce melter feed slurry which is continuously fed to the DWPF melter. The melter produces a molten borosilicate glass which is poured into stainless steel canisters for cooling and, ultimately, shipment to and storage in a geologic repository

  6. Beverton-Holt discrete pest management models with pulsed chemical control and evolution of pesticide resistance

    Science.gov (United States)

    Liang, Juhua; Tang, Sanyi; Cheke, Robert A.

    2016-07-01

    Pest resistance to pesticides is usually managed by switching between different types of pesticides. The optimal switching time, which depends on the dynamics of the pest population and on the evolution of the pesticide resistance, is critical. Here we address how the dynamic complexity of the pest population, the development of resistance and the spraying frequency of pulsed chemical control affect optimal switching strategies given different control aims. To do this, we developed novel discrete pest population growth models with both impulsive chemical control and the evolution of pesticide resistance. Strong and weak threshold conditions which guarantee the extinction of the pest population, based on the threshold values of the analytical formula for the optimal switching time, were derived. Further, we addressed switching strategies in the light of chosen economic injury levels. Moreover, the effects of the complex dynamical behaviour of the pest population on the pesticide switching times were also studied. The pesticide application period, the evolution of pesticide resistance and the dynamic complexity of the pest population may result in complex outbreak patterns, with consequent effects on the pesticide switching strategies.

  7. In silico models for predicting vector control chemicals targeting Aedes aegypti

    Science.gov (United States)

    Devillers, J.; Lagneau, C.; Lattes, A.; Garrigues, J.C.; Clémenté, M.M.; Yébakima, A.

    2014-01-01

    Human arboviral diseases have emerged or re-emerged in numerous countries worldwide due to a number of factors including the lack of progress in vaccine development, lack of drugs, insecticide resistance in mosquitoes, climate changes, societal behaviours, and economical constraints. Thus, Aedes aegypti is the main vector of the yellow fever and dengue fever flaviviruses and is also responsible for several recent outbreaks of the chikungunya alphavirus. As for the other mosquito species, the A. aegypti control relies heavily on the use of insecticides. However, because of increasing resistance to the different families of insecticides, reduction of Aedes populations is becoming increasingly difficult. Despite the unquestionable utility of insecticides in fighting mosquito populations, there are very few new insecticides developed and commercialized for vector control. This is because the high cost of the discovery of an insecticide is not counterbalanced by the ‘low profitability’ of the vector control market. Fortunately, the use of quantitative structure–activity relationship (QSAR) modelling allows the reduction of time and cost in the discovery of new chemical structures potentially active against mosquitoes. In this context, the goal of the present study was to review all the existing QSAR models on A. aegypti. The homology and pharmacophore models were also reviewed. Specific attention was paid to show the variety of targets investigated in Aedes in relation to the physiology and ecology of the mosquito as well as the diversity of the chemical structures which have been proposed, encompassing man-made and natural substances. PMID:25275884

  8. NMR studies on the chemical alteration of soil organic matter precursors during controlled charring

    Science.gov (United States)

    Knicker, Heike

    2010-05-01

    Beside the production of volatiles, vegetation fire transforms various amounts of labile organic components into recalcitrant dark colored and highly aromatic structures. They are incorporated into soils and are assumed to represent an important sink within the global carbon cycle. In order to elucidate the real importance of PyOM as a C-sink, a good understanding of its chemistry is crucial. Although several 'Black Carbon' (BC) models are reported, a commonly accepted view of the chemistry involved in its formation is still missing. Its biogeochemical recalcitrance is commonly associated with a highly condensed aromatic structure. However, recent studies indicated that this view may be oversimplified for PyOM derived from vegetation fire. In order to bring some more light on the structural properties of PyOM produced during vegetation fire, charred plant residues and model chars derived from typical plant macromolecules (casein, cellulose, lignin and condensed tannins) were subjected to controlled charring under oxic conditions (350°C and 450°C) and then characterized by nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Subsequently, the chemical features of the PyOM were related to its chemical recalcitrance as determined by chemical oxidation with acid potassium dichromate. Charring cellulose (350°C, 8 min) yielded in a low C-recovery (11%). Treating casein in the same way resulted in a survival of 62% of its C and 46% of its N. Comparable high C-recoveries are reported for lignin. After charring Lolium perenne, 34% of its N and C were recovered. NMR-spectroscopic studies revealed that for this sample most of the charred N and C occurred in pyrrole-type structures. Our studies further indicate that the aromatic skeleton of char accumulating after a vegetation fire must contain remains of the lignin backbone and considerable contributions of furans and anhydrosugars from thermally altered cellulose. Enhancing the temperature during the

  9. Comparison of numerical and physico-chemical models for on-line spectrophotometric control of uranium

    International Nuclear Information System (INIS)

    Corriou, J.P.; Boisde, G.

    1986-04-01

    In view of on-line spectrophotometric control of fuel reprocessing streams, a physico-chemical model able to predict uranium and nitric acid concentrations in an uranyl nitrate-nitric acid system has been searched. Thus the influences of the following parameters: uranium, nitrate, hydrogen ion concentrations, ionic strength, on the equilibria of complexation of uranium (VI) nitrate have been evaluated. Extinction coefficients for the uranium mononitrate and uranium dinitrate complexes are given between 410 and 440 nm. The apparent equilibrium constants are determined as a function of the ionic strength. The limitations of this predictive model are emphasized and comparisons with numerical models are discussed. (16 refs)

  10. Time variant layer control in atmospheric pressure chemical vapor deposition based growth of graphene

    KAUST Repository

    Qaisi, Ramy M.; Smith, Casey; Hussain, Muhammad Mustafa

    2013-01-01

    Graphene is a semi-metallic, transparent, atomic crystal structure material which is promising for its high mobility, strength and transparency - potentially applicable for radio frequency (RF) circuitry and energy harvesting and storage applications. Uniform (same number of layers), continuous (not torn or discontinuous), large area (100 mm to 200 mm wafer scale), low-cost, reliable growth are the first hand challenges for its commercialization prospect. We show a time variant uniform (layer control) growth of bi- to multi-layer graphene using atmospheric chemical vapor deposition system. We use Raman spectroscopy for physical characterization supported by electrical property analysis. © 2013 IEEE.

  11. Chemical control of vegetation on urban sites: agronomic and ecotoxicological aspects

    International Nuclear Information System (INIS)

    Zanin, G.; Otto, S.

    1996-01-01

    The problem of the chemical control of spontaneous vegetation on urban sites is tackled. A method is presented to identify the best herbicides under both the agronomic and ecotoxicological aspects. Selection of the herbicides from the agronomic point of view is on the basis of the qualitative characteristics of the vegetation (life-form types periodicity types botanical composition), surveyed at 5 different times on the year while selection from the environmental viewpoint is based on an evaluation integrated with a series of ecotoxicological indices. The best solution was tested in a pilot area and the contamination of the water compartment evaluated both on entering and leaving the water treatment works

  12. Effect of genes controlling radiation sensitivity on chemical mutagenesis in yeast

    International Nuclear Information System (INIS)

    Prakash, L.

    1975-01-01

    Ultraviolet radiation, x radiation, nitrogen mustard, methyl methanesulfonate, and dimethyl sulfate were found to revert all the tester strains with the same efficiency or without any dependence on simple types of base-pair changes, and it was concluded that these mutagens were nonspecific in the types of base-pair changes produced. The cycl-131 tester was used in studies designed to determine the genetic control of mutation induction using a variety of mutagens. The rad 6 and rad g genes greatly reduce the frequency of chemically induced reversion of cycl-131

  13. Time variant layer control in atmospheric pressure chemical vapor deposition based growth of graphene

    KAUST Repository

    Qaisi, Ramy M.

    2013-04-01

    Graphene is a semi-metallic, transparent, atomic crystal structure material which is promising for its high mobility, strength and transparency - potentially applicable for radio frequency (RF) circuitry and energy harvesting and storage applications. Uniform (same number of layers), continuous (not torn or discontinuous), large area (100 mm to 200 mm wafer scale), low-cost, reliable growth are the first hand challenges for its commercialization prospect. We show a time variant uniform (layer control) growth of bi- to multi-layer graphene using atmospheric chemical vapor deposition system. We use Raman spectroscopy for physical characterization supported by electrical property analysis. © 2013 IEEE.

  14. Use of direct washing of chemical dispense nozzle for defect control

    Science.gov (United States)

    Linnane, Michael; Mack, George; Longstaff, Christopher; Winter, Thomas

    2006-03-01

    Demands for continued defect reduction in 300mm IC manufacturing are driving process engineers to examine all aspects of the chemical apply process for improvement. Historically, the defect contribution from photoresist apply nozzles has been minimized through a carefully controlled process of "dummy dispenses" to keep the photoresist in the tip "fresh" and remove any solidified material, a preventive maintenance regime involving periodic cleaning or replacing of the nozzles, and reliance on a pool of solvent within the nozzle storage block to keep the photoresist from solidifying at the nozzle tip. The industry standard has worked well for the most part but has limitations in terms of cost effectiveness and absolute defect elimination. In this study, we investigate the direct washing of the chemical apply nozzle to reduce defects seen on the coated wafer. Data is presented on how the direct washing of the chemical dispense nozzle can be used to reduce coating related defects, reduce material costs from the reduction of "dummy dispense", and can reduce equipment downtime related to nozzle cleaning or replacement.

  15. Compatibility of chemical insecticides and entomopathogenic fungi for control of soybean defoliating pest, Rachiplusia nu.

    Science.gov (United States)

    Pelizza, Sebastian A; Schalamuk, Santiago; Simón, María R; Stenglein, Sebastian A; Pacheco-Marino, Suani G; Scorsetti, Ana C

    Rachiplusia nu (Guenée) (Lepidoptera: Noctuidae) is one of the major lepidopteran pests defoliating soybeans (Glycine max Merrill) in Argentina. The combined use of chemical insecticides and entomopathogenic fungi is a promising pest-control option to minimize adverse chemical effects. In this work, we evaluated the interactions between five insecticides-two being considered biorational-and five fungal entomopathogenic strains under laboratory conditions in order to determine the possible usefulness of combinations of these agents against R. nu. The insecticides were tested for compatibility at four doses by in vitro bioassay and for the lethality of R. nu by inoculations at three doses. Fungal strains were applied at 1×10 8 , 1×10 6 , and 1×10 4 conidia/ml. The combinations of those insecticides with Beauveria bassiana (LPSc 1067, LPSc 1082, LPSc 1098), Metarhizium anisopliae (LPSc 907), and Metarhizium robertsii (LPSc 963) caused higher R. nu-larval mortalities than any of the individual agents alone. We observed significant differences in the in vitro conidial viability, vegetative growth, and conidia production of the five strains of entomopathogenic fungi exposed to different doses of the chemical insecticides. The combination gamma-cyhalothrin-LPSc-1067 caused the highest percent mortality of R. nu larvae, with synergism occurring between the two agents at 50% and 25% of the maximum field doses. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Host Resistance and Chemical Control for Management of Sclerotinia Stem Rot of Soybean in Ohio.

    Science.gov (United States)

    Huzar-Novakowiski, Jaqueline; Paul, Pierce A; Dorrance, Anne E

    2017-08-01

    Recent outbreaks of Sclerotinia stem rot (SSR) of soybean in Ohio, along with new fungicides and cultivars with resistance to this disease, have led to a renewed interest in studies to update disease management guidelines. The effect of host resistance (in moderately resistant [MR] and moderately susceptible [MS] cultivars) and chemical control on SSR and yield was evaluated in 12 environments from 2014 to 2016. The chemical treatments evaluated were an untreated check, four fungicides (boscalid, picoxystrobin, pyraclostrobin, and thiophanate-methyl), and one herbicide (lactofen) applied at soybean growth stage R1 (early flowering) alone or at R1 followed by a second application at R2 (full flowering). SSR developed in 6 of 12 environments, with mean disease incidence in the untreated check of 2.5 to 41%. The three environments with high levels of SSR (disease incidence in the untreated check >20%) were used for further statistical analysis. There were significant effects (P Pyraclostrobin increased SSR compared with the untreated check in the three environments with high levels of disease. In the six fields where SSR did not develop, chemical treatment did not increase yield, nor was the yield from the MR cultivar significantly different from the MS cultivar. For Ohio, MR cultivars alone were effective for management of SSR in soybean fields where this disease has historically occurred.

  17. Controlled growth of epitaxial CeO2 thin films with self-organized nanostructure by chemical solution method

    DEFF Research Database (Denmark)

    Yue, Zhao; Grivel, Jean-Claude

    2013-01-01

    Chemical solution deposition is a versatile technique to grow oxide thin films with self-organized nanostructures. Morphology and crystallographic orientation control of CeO2 thin films grown on technical NiW substrates by a chemical solution deposition method are achieved in this work. Based...

  18. Postharvest biological control of brown rot in peaches after cold storage preceded by preharvest chemical control 1

    Directory of Open Access Journals (Sweden)

    Elizandra Pivotto Pavanello

    2015-12-01

    Full Text Available ABSTRACT Pathogenic fungi cause skin darkening and peach quality depreciation in post harvest. Therefore, alternative techniques to chemical treatment are necessary in order to reduce risks to human health. The aim of this study was to evaluate the effect of the application of Trichoderma harzianum in association with different fungicides applied before harvest to 'Eldorado' peaches for brown rot control and other quality parameters during storage. The treatments consisted of five preharvest fungicide applications (control, captan, iprodione, iminoctadine and tebuconazole associated with postharvest application of T. harzianum, after cold storage (with and without application, in three evaluation times (zero, two and four days at 20 °C, resulting in a 5x2x3 factorial design. The application of T. harzianum only brought benefits to the control of brown rot when combined with the fungicide captan, at zero day shelf life. After two days, there was a greater skin darkening in peaches treated with T. harzianum compared with peaches without the treatment, except for peaches treated with the fungicide iprodione and T. harzianum The application of T. harzianum during postharvest showed no benefits for the control of brown rot, however, the association with fungicides reduced the incidence of Rhizopus stolonifer during the shelf life.

  19. Enhanced carrier collection efficiency and reduced quantum state absorption by electron doping in self-assembled quantum dot solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tian, E-mail: tianlee@umd.edu, E-mail: dage@ece.umd.edu; Dagenais, Mario, E-mail: tianlee@umd.edu, E-mail: dage@ece.umd.edu [Department of Electrical Engineering, University of Maryland, College Park, Maryland 20742 (United States); Lu, Haofeng; Fu, Lan; Tan, Hark Hoe; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)

    2015-02-02

    Reduced quantum dot (QD) absorption due to state filling effects and enhanced electron transport in doped QDs are demonstrated to play a key role in solar energy conversion. Reduced QD state absorption with increased n-doping is observed in the self-assembled In{sub 0.5}Ga{sub 0.5}As/GaAs QDs from high resolution below-bandgap external quantum efficiency (EQE) measurement, which is a direct consequence of the Pauli exclusion principle. We also show that besides partial filling of the quantum states, electron-doping produces negatively charged QDs that exert a repulsive Coulomb force on the mobile electrons, thus altering the electron trajectory and reducing the probability of electron capture, leading to an improved collection efficiency of photo-generated carriers, as indicated by an absolute above-bandgap EQE measurement. The resulting redistribution of the mobile electron in the planar direction is further validated by the observed photoluminescence intensity dependence on doping.

  20. Chemical quality of different argentine honey varieties, irradiated to control american foulbrood

    International Nuclear Information System (INIS)

    Zunich, C.D.; Markowski, I.; Narvaiz, Patricia

    2011-01-01

    'American foulbrood' is a disease that seriously affects bees. Honey may be contaminated with spores of the related bacteria, Paenibacillus larvae larvae, which is a great drawback for trade. The scientific literature reports that these spores, resistant to heat and chemicals, are inactivated in honey when it is irradiated al 10 kGy, being this treatment mandatory in the Republic of Southafrica. Irradiated food wholesomeness is endorsed by the World Health Organization. Considering that Argentina is an important honey producer and exporter, the aim of this work was to evaluate the effect of ionizing radiation on some of its commercial chemical parameters along storage time. Honeys with different characteristics, coming from five different regions of the country: Middle, Patagonia, North, Litoral, Humid Pampa, were provided by producers from a commission called 'Packaged honey' of the National Food, Fishery and Agriculture Ministry. Fifteen kg of each honey variety were packaged in 500 g polypropylene recipes with polyethylene lids, and irradiated at the semi industrial cobalt-60 facility of the Ezeiza Atomic Center, 500,000 Ci of activity, with doses of 0, 10 and 20 kilo Grays. Control and irradiated samples were stored at room temperature for 10 months. Some standardized chemical analysis required by the Argentine Food Code (AFC) were performed on the first, fourth and tenth storage months: water content, acidity, diastase content, reducing sugars, and hydroxymethylfurfural. Reducing sugars and diastase activity slightly diminished, and acidity slightly increased, along storage which is typical in this product; no significant differences were found between control and irradiated samples. Hydroxymethylfurfural values, related to aging or thermal abuse, diminished slightly though significantly due to irradiation, which would not affect the product quality as regulations require not to surpass a maximum value, 40 mg/kg in the AFC. So ionizing

  1. Post-control surveillance of Triatoma infestans and Triatoma sordida with chemically-baited sticky traps.

    Science.gov (United States)

    Rojas de Arias, Antonieta; Abad-Franch, Fernando; Acosta, Nidia; López, Elsa; González, Nilsa; Zerba, Eduardo; Tarelli, Guillermo; Masuh, Héctor

    2012-01-01

    Chagas disease prevention critically depends on keeping houses free of triatomine vectors. Insecticide spraying is very effective, but re-infestation of treated dwellings is commonplace. Early detection-elimination of re-infestation foci is key to long-term control; however, all available vector-detection methods have low sensitivity. Chemically-baited traps are widely used in vector and pest control-surveillance systems; here, we test this approach for Triatoma spp. detection under field conditions in the Gran Chaco. Using a repeated-sampling approach and logistic models that explicitly take detection failures into account, we simultaneously estimate vector occurrence and detection probabilities. We then model detection probabilities (conditioned on vector occurrence) as a function of trapping system to measure the effect of chemical baits. We find a positive effect of baits after three (odds ratio [OR] 5.10; 95% confidence interval [CI(95)] 2.59-10.04) and six months (OR 2.20, CI(95) 1.04-4.65). Detection probabilities are estimated at p ≈ 0.40-0.50 for baited and at just p ≈ 0.15 for control traps. Bait effect is very strong on T. infestans (three-month assessment: OR 12.30, CI(95) 4.44-34.10; p ≈ 0.64), whereas T. sordida is captured with similar frequency in baited and unbaited traps. Chemically-baited traps hold promise for T. infestans surveillance; the sensitivity of the system at detecting small re-infestation foci rises from 12.5% to 63.6% when traps are baited with semiochemicals. Accounting for imperfect detection, infestation is estimated at 26% (CI(95) 16-40) after three and 20% (CI(95) 11-34) after six months. In the same assessments, traps detected infestation in 14% and 8.5% of dwellings, whereas timed manual searches (the standard approach) did so in just 1.4% of dwellings only in the first survey. Since infestation rates are the main indicator used for decision-making in control programs, the approach we present may help improve T

  2. Control of bursting synchronization in networks of Hodgkin-Huxley-type neurons with chemical synapses.

    Science.gov (United States)

    Batista, C A S; Viana, R L; Ferrari, F A S; Lopes, S R; Batista, A M; Coninck, J C P

    2013-04-01

    Thermally sensitive neurons present bursting activity for certain temperature ranges, characterized by fast repetitive spiking of action potential followed by a short quiescent period. Synchronization of bursting activity is possible in networks of coupled neurons, and it is sometimes an undesirable feature. Control procedures can suppress totally or partially this collective behavior, with potential applications in deep-brain stimulation techniques. We investigate the control of bursting synchronization in small-world networks of Hodgkin-Huxley-type thermally sensitive neurons with chemical synapses through two different strategies. One is the application of an external time-periodic electrical signal and another consists of a time-delayed feedback signal. We consider the effectiveness of both strategies in terms of protocols of applications suitable to be applied by pacemakers.

  3. Can Coffee Chemical Compounds and Insecticidal Plants Be Harnessed for Control of Major Coffee Pests?

    Science.gov (United States)

    Green, Paul W C; Davis, Aaron P; Cossé, Allard A; Vega, Fernando E

    2015-11-04

    Pests and pathogens threaten coffee production worldwide and are difficult to control using conventional methods, such as insecticides. We review the literature on the chemistry of coffee, concentrating on compounds most commonly reported from Coffea arabica and Coffea canephora. Differences in chemistry can distinguish coffee species and varieties, and plants grown under different biogeographic conditions exhibit different chemotypes. A number of chemical groups, such as alkaloids and caffeoylquinic acids, are known to be insecticidal, but most studies have investigated their effects on coffee quality and flavor. More research is required to bridge this gap in knowledge, so that coffee can be bred to be more resistant to pests. Furthermore, we report on some pesticidal plants that have been used for control of coffee pests. Locally sourced pesticidal plants have been underutilized and offer a sustainable alternative to conventional insecticides and could be used to augment breeding for resilience of coffee plants.

  4. Recent applications of Chemical Imaging to pharmaceutical process monitoring and quality control.

    Science.gov (United States)

    Gowen, A A; O'Donnell, C P; Cullen, P J; Bell, S E J

    2008-05-01

    Chemical Imaging (CI) is an emerging platform technology that integrates conventional imaging and spectroscopy to attain both spatial and spectral information from an object. Vibrational spectroscopic methods, such as Near Infrared (NIR) and Raman spectroscopy, combined with imaging are particularly useful for analysis of biological/pharmaceutical forms. The rapid, non-destructive and non-invasive features of CI mark its potential suitability as a process analytical tool for the pharmaceutical industry, for both process monitoring and quality control in the many stages of drug production. This paper provides an overview of CI principles, instrumentation and analysis. Recent applications of Raman and NIR-CI to pharmaceutical quality and process control are presented; challenges facing CI implementation and likely future developments in the technology are also discussed.

  5. Physical and chemical properties of gels. Application to protein nucleation control in the gel acupuncture technique

    Science.gov (United States)

    Moreno, Abel; Juárez-Martínez, Gabriela; Hernández-Pérez, Tomás; Batina, Nikola; Mundo, Manuel; McPherson, Alexander

    1999-09-01

    In this work, we present a new approach using analytical and optical techniques in order to determine the physical and chemical properties of silica gel, as well as the measurement of the pore size in the network of the gel by scanning electron microscopy. The gel acupuncture technique developed by García-Ruiz et al. (Mater. Res. Bull 28 (1993) 541) García-Ruiz and Moreno (Acta Crystallogr. D 50 (1994) 484) was used throughout the history of crystal growth. Several experiments were done in order to evaluate the nucleation control of model proteins (thaumatin I from Thaumatococcus daniellii, lysozyme from hen egg white and catalase from bovine liver) by the porous network of the gel. Finally, it is shown how the number and the size of the crystals obtained inside X-ray capillaries is controlled by the size of the porous structure of the gel.

  6. A survey of process control computers at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Dahl, C.A.

    1989-01-01

    The Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory is charged with the safe processing of spent nuclear fuel elements for the United States Department of Energy. The ICPP was originally constructed in the late 1950s and used state-of-the-art technology for process control at that time. The state of process control instrumentation at the ICPP has steadily improved to keep pace with emerging technology. Today, the ICPP is a college of emerging computer technology in process control with some systems as simple as standalone measurement computers while others are state-of-the-art distributed control systems controlling the operations in an entire facility within the plant. The ICPP has made maximal use of process computer technology aimed at increasing surety, safety, and efficiency of the process operations. Many benefits have been derived from the use of the computers for minimal costs, including decreased misoperations in the facility, and more benefits are expected in the future

  7. Assessing and controlling risks from the emission of organic chemicals from construction products into indoor environments.

    Science.gov (United States)

    Brown, Veronica M; Crump, Derrick R; Harrison, Paul T C

    2013-12-01

    Construction products can be a significant source of indoor pollutants, including volatile organic compounds that may be a risk to the health and well-being of building occupants. There are currently a number of schemes for the labelling of products according to their potential to emit organic compounds. Assessment of the complex mixtures of compounds that may be released has mandated the development of test methods that allow the determination of the concentrations of the chemicals released from products in controlled test chamber environments. In response to concerns about the financial burden faced by manufacturers required to test products according to the various different labelling schemes currently in existence, the European Commission has investigated the scope for greater harmonisation. This initiative has sought to harmonise the process for the assessment of emissions data, complementing work led by the European standards organisation focussed on harmonising the test chamber procedures. The current labelling schemes have a range of requirements with respect to the number of chemicals to be quantified. A comparison of 13 schemes worldwide has identified 15 lists of target compounds, with a total of 611 chemicals occurring on at least one of the target lists. While harmonisation may clarify and perhaps simplify these requirements, at least in Europe, it can be expected that future changes to product formulations, the introduction of new products and our increasing knowledge about the potential risks to health, will require continued development of new and improved measurement techniques. There is, therefore, a particular challenge for analytical chemists to ensure the efficient provision of high quality emissions data and thereby ultimately enable effective control of risks to human health through the prevention or reduction of indoor air pollution.

  8. History of EPI Suite™ and future perspectives on chemical property estimation in US Toxic Substances Control Act new chemical risk assessments.

    Science.gov (United States)

    Card, Marcella L; Gomez-Alvarez, Vicente; Lee, Wen-Hsiung; Lynch, David G; Orentas, Nerija S; Lee, Mari Titcombe; Wong, Edmund M; Boethling, Robert S

    2017-03-22

    Chemical property estimation is a key component in many industrial, academic, and regulatory activities, including in the risk assessment associated with the approximately 1000 new chemical pre-manufacture notices the United States Environmental Protection Agency (US EPA) receives annually. The US EPA evaluates fate, exposure and toxicity under the 1976 Toxic Substances Control Act (amended by the 2016 Frank R. Lautenberg Chemical Safety for the 21 st Century Act), which does not require test data with new chemical applications. Though the submission of data is not required, the US EPA has, over the past 40 years, occasionally received chemical-specific data with pre-manufacture notices. The US EPA has been actively using this and publicly available data to develop and refine predictive computerized models, most of which are housed in EPI Suite™, to estimate chemical properties used in the risk assessment of new chemicals. The US EPA develops and uses models based on (quantitative) structure-activity relationships ([Q]SARs) to estimate critical parameters. As in any evolving field, (Q)SARs have experienced successes, suffered failures, and responded to emerging trends. Correlations of a chemical structure with its properties or biological activity were first demonstrated in the late 19 th century and today have been encapsulated in a myriad of quantitative and qualitative SARs. The development and proliferation of the personal computer in the late 20 th century gave rise to a quickly increasing number of property estimation models, and continually improved computing power and connectivity among researchers via the internet are enabling the development of increasingly complex models.

  9. Evaluation of chemical stabilizers and windscreens for wind erosion control of uranium mill tailings

    International Nuclear Information System (INIS)

    Elmore, M.R.; Hartley, J.N.

    1984-08-01

    Potential wind erosion of uranium mill tailings is a concern for the surface disposal of tailings at uranium mills. Wind-blown tailings may subsequently be redeposited on areas outside the impoundment. Pacific Northwest Laboratory (PNL) is investigating techniques for fugitive dust control at uranium mill tailings piles. Laboratory tests, including wind tunnel studies, were conducted to evaluate the relative effectiveness of 43 chemical stabilizers. Seventeen of the more promising stabilizers were applied to test plots on a uranium tailings pile at the American Nuclear Corporation-Gas Hills Project mill site in central Wyoming. The durabilities of these materials under actual site conditions were evaluated over time. In addition, field testing of commercially available windscreens was conducted. Test panels were constructed of eight different materials at the Wyoming test site to compare their durability. A second test site was established near PNL to evaluate the effectiveness of windscreens at reducing wind velocity, and thereby reduce the potential for wind erosion of mill tailings. Results of the laboratory land field tests of the chemical stabilizers and windscreens are presented, along with costs versus effectiveness of these techniques for control of wind erosion at mill tailings piles. 12 references, 4 figures, 6 tables

  10. Effect of an invasive ant and its chemical control on a threatened endemic Seychelles millipede.

    Science.gov (United States)

    Lawrence, James M; Samways, Michael J; Henwood, Jock; Kelly, Janine

    2011-06-01

    The impact of invasive species on island faunas can be of major local consequence, while their control is an important part of island ecosystem restoration. Among these invasive species are ants, of which some have a disruptive impact on indigenous arthropod populations. Here, we study the impact of the invasive African big-headed ant, Pheidole megacephala, on a small Seychelles island, Cousine, and assess the impact of this ant, and its chemical control, using the commercially available hydramethylnon-based bait, Siege, on the endemic keystone Seychelles giant millipede species, Sechelleptus seychellarum. We found no significant correlations in landscape-scale spatial overlap and abundance between the ant and the millipede. Furthermore, the ant did not attack healthy millipedes, but fed only on dying and dead individuals. The chemical defences of the millipede protected it from ant predation. Ingestion of the bait at standard concentration had no obvious impact on the millipede. The most significant threat to the Seychelles giant millipede in terms of P. megacephala invasion is from possible catastrophic shifts in ecosystem function through ant hemipteran mutualisms which can lead to tree mortality, resulting in alteration of the millipede's habitat.

  11. Chemical Controls of Ozone Dry Deposition to the Sea Surface Microlayer

    Science.gov (United States)

    Carpenter, L.; Chance, R.; Tinel, L.; Saint, A.; Sherwen, T.; Loades, D.; Evans, M. J.; Boxhall, P.; Hamilton, J.; Stolle, C.; Wurl, O.; Ribas-Ribas, M.; Pereira, R.

    2017-12-01

    Oceanic dry deposition of atmospheric ozone (O3) is both the largest and most uncertain O3 depositional sink, and is widely acknowledged to be controlled largely by chemical reactions in the sea surface microlayer (SML) involving iodide (I-) and dissolved organic material (DOM). These reactions not only determine how quickly O3 can be removed from the atmosphere, but also result in emissions of trace gases including volatile organic compounds and may constitute a source of secondary organic aerosols to the marine atmosphere. Iodide concentrations at the sea surface vary by approximately an order of magnitude spatially, leading to more than fivefold variation in ozone deposition velocities (and volatile iodine fluxes). Sea-surface temperature is a reasonable predictor of [I-], however two recent parameterisations for surface I- differ by a factor of two at low latitudes. The nature and reactivity of marine DOM to O3 is almost completely unknown, although studies have suggested approximately equivalent chemical control of I- and DOM on ozone deposition. Here we present substantial new measurements of oceanic I- in both bulk seawater and the overlying SML, and show improved estimates of the global sea surface iodide distribution. We also present analyses of water-soluble DOM isolated from the SML and bulk seawater, and corresponding laboratory studies of ozone uptake to bulk and SML seawater, with the aim of characterizing the reactivity of O3 towards marine DOM.

  12. Improved CO sub 2 enhanced oil recovery -- Mobility control by in-situ chemical precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Ameri, S.; Aminian, K.; Wasson, J.A.; Durham, D.L.

    1991-06-01

    The overall objective of this study has been to evaluate the feasibility of chemical precipitation to improve CO{sub 2} sweep efficiency and mobility control. The laboratory experiments have indicated that carbonate precipitation can alter the permeability of the core samples under reservoir conditions. Furthermore, the relative permeability measurements have revealed that precipitation reduces the gas permeability in favor of liquid permeability. This indicates that precipitation is occurring preferentially in the larger pores. Additional experimental work with a series of connected cores have indicated that the permeability profile can be successfully modified. However, Ph control plays a critical role in propagation of the chemical precipitation reaction. A numerical reservoir model has been utilized to evaluate the effects of permeability heterogeneity and permeability modification on the CO{sub 2} sweep efficiency. The computer simulation results indicate that the permeability profile modification can significantly enhance CO{sub 2} vertical and horizontal sweep efficiencies. The scoping studies with the model have further revealed that only a fraction of high permeability zones need to be altered to achieve sweep efficiency enhancement. 64 refs., 30 figs., 16 tabs.

  13. Secure and Robust Transmission and Verification of Unknown Quantum States in Minkowski Space

    Science.gov (United States)

    Kent, Adrian; Massar, Serge; Silman, Jonathan

    2014-01-01

    An important class of cryptographic applications of relativistic quantum information work as follows. B generates a random qudit and supplies it to A at point P. A is supposed to transmit it at near light speed c to to one of a number of possible pairwise spacelike separated points Q1, …, Qn. A's transmission is supposed to be secure, in the sense that B cannot tell in advance which Qj will be chosen. This poses significant practical challenges, since secure reliable long-range transmission of quantum data at speeds near to c is presently not easy. Here we propose different techniques to overcome these diffculties. We introduce protocols that allow secure long-range implementations even when both parties control only widely separated laboratories of small size. In particular we introduce a protocol in which A needs send the qudit only over a short distance, and securely transmits classical information (for instance using a one time pad) over the remaining distance. We further show that by using parallel implementations of the protocols security can be maintained in the presence of moderate amounts of losses and errors. PMID:24469425

  14. Strategy for control and integrated optimization of chemical processes; Estrategia para o controle e otimizacao integrada de processos quimicos

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Antonio Ignacio de [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Engenharia Quimica]. E-mail: ailac@vm.uff.br; Araujo, Ofelia de Queiroz Fernandes; Medeiros, Jose Luiz de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica]. E-mail: ofelia@eq.ufrj.br; jlm@eq.ufrj.br

    2004-12-01

    The increasingly market competitiveness, the frequent changes in costs of raw materials and imposition of environmental restrictions require quick responses from the industries and better control of their production. The growing increase of the computational systems processing capacity and advances in analysis and instrumentation systems favor the formulation of new strategies geared to the operational optimization of industrial processes. The optimization of a process, within a more rigid context, assumes that it is made through the optimal control theory. In this aspect, comparative studies are carried out between some formulations of the problem in terms of optimal control and a new methodology of economic optimization. The study process was a pyrolysis oven for which an economic function was developed. Such function considers the effects of the oven operation on the other subsequent parts of the Ethylene Plant, taking into account their energy consumptions and their operational restrictions. A rigorous thermal-dynamic analysis was made in the development thereof involving major parts of the product separation system upstream the oven. The results obtained met the expectations and the new optimization criterion tested can be implemented in a relatively simple computational system using personal computers currently available. Although the work is oriented towards the pyrolysis of hydrocarbons the proposed structure may be applied to other types of chemical and petrochemical processes with the same topology: a reaction system and a separation system. (author)

  15. Effect of chemical and mechanical weed control on cassava yield, soil quality and erosion under cassava cropping system

    Science.gov (United States)

    Islami, Titiek; Wisnubroto, Erwin; Utomo, Wani

    2016-04-01

    Three years field experiments were conducted to study the effect of chemical and mechanical weed control on soil quality and erosion under cassava cropping system. The experiment were conducted at University Brawijaya field experimental station, Jatikerto, Malang, Indonesia. The experiments were carried out from 2011 - 2014. The treatments consist of three cropping system (cassava mono culture; cassava + maize intercropping and cassava + peanut intercropping), and two weed control method (chemical and mechanical methods). The experimental result showed that the yield of cassava first year and second year did not influenced by weed control method and cropping system. However, the third year yield of cassava was influence by weed control method and cropping system. The cassava yield planted in cassava + maize intercropping system with chemical weed control methods was only 24 t/ha, which lower compared to other treatments, even with that of the same cropping system used mechanical weed control. The highest cassava yield in third year was obtained by cassava + peanuts cropping system with mechanical weed control method. After three years experiment, the soil of cassava monoculture system with chemical weed control method possessed the lowest soil organic matter, and soil aggregate stability. During three years of cropping soil erosion in chemical weed control method, especially on cassava monoculture, was higher compared to mechanical weed control method. The soil loss from chemical control method were 40 t/ha, 44 t/ha and 54 t/ha for the first, second and third year crop. The soil loss from mechanical weed control method for the same years was: 36 t/ha, 36 t/ha and 38 t/ha. Key words: herbicide, intercropping, soil organic matter, aggregate stability.

  16. Impact of a low intensity controlled-fire in some chemical soil properties.

    Science.gov (United States)

    Martínez-Murillo, Juan F.; Hueso-González, Paloma; Aranda-Gómez, Francisco; Damián Ruiz-Sinoga, José

    2014-05-01

    Some changes in chemical soil properties can be observed after fires of low intensities. pH and electric conductivity tend to increase, while C/N ratio decrease. In the case of organic matter, the content can increase due to the massive incorporation of necromass including, especially, plants and roots. The aim of this study is to assess the impact of low intensity and controlled fire in some soil properties in field conditions. El Pinarillo experimental area is located in South of Spain. Two set of closed plots were installed (24 m2: 12 m length x 2 m width). One of them was remained as control with the original vegetation cover (Mediterranean matorral: Rosmarinus officinalis, Cistus clusii, Lavandula stoechas, Chamaeropos humilis, Thymus baetica), and the other one was burnt in a controlled-fire in 2011. Weather conditions and water content of vegetation influenced in the intensity of fire (low). After the controlled-fire, soil surface sample (0-5 cm) were taken in both set of plots (B, burnt soil samples; C, control soil samples). Some soil chemical properties were analysed: organic matter content (OM), C/N ratio, pH and electrical conductivity (EC). Some changes were observed in B corroborating a controlled-fire of low intensity. pH remained equal after fire (B: pH=7.7±0.11; C: pH=7.7±0.04). An increment was obtained in the case of EC (B: EC=0.45 mScm-1±0.08 mScm-1; C: EC=0.35 mScm-1±0.07 mScm-1) and OM (B: OM=8.7%±3.8%; C: pH=7.3%±1.5%). Finally, C/N ratio decreased after fire respect to the control and initial conditions (B: C/N=39.0±14.6; C: C/N =46.5±10.2).

  17. Chemical and biological control of Sclerotinia stem rot in the soybean crop

    Directory of Open Access Journals (Sweden)

    Ciro Hideki Sumida

    2015-05-01

    Full Text Available It was evaluated the effect of fungicides and the microbial control agent Trichoderma harzianum on the inhibition of the carpogenic and ascospore germination of Sclerotinia sclerotiorum. This study also evaluated the chemical, fungicidal and microbial control of white mold or Sclerotinia stem rot of soybean in the field. Three experiments were conducted, as follows: 1 inhibition of carpogenic germination of sclerotia, 2 inhibition of ascospore germination, and 3 control of Sclerotinia stem rot in a soybean crop under field conditions. The treatments evaluated were fluazinam, procymidone, iprodione, thiophanate-methyl, carbendazim, benzalkonium chloride + fluazinam, and T. harzianum. Procymidone resulted in an inhibition of 13.5% and benzalkonium chloride in an inhibition of 13.9% in an ascospore germination test. Fluazinam and procymidone were the most effective in reducing the production of ascospores/apothecium, representing 65.6% and 82.4% of inhibition. Procymidone and fluazinam if combined or not with benzalkonium chloride were the most effective in controlling sclerotinia stem rot under field conditions when applied at the onset of flowering and 15 days later. In the 2009-10 harvest, these two fungicides reduced the incidence of Sclerotinia stem rot by 73.1 and 71.6% and in the 2010-11 harvest by 75.7 and 77.6%, respectively.

  18. Composition and Morphology Control of Metal Dichalcogenides via Chemical Vapor Deposition for Photovoltaic and Nanoelectronic Applications

    Science.gov (United States)

    Samad, Leith L. J.

    The body of work reviewed here encompasses a variety of metal dichalcogenides all synthesized using chemical vapor deposition (CVD) for solar and electronics applications. The first reported phase-pure CVD synthesis of iron pyrite thin films is presented with detailed structural and electrochemical analysis. The phase-pure thin film and improved crystal growth on a metallic backing material represents one of the best options for potential solar applications using iron pyrite. Large tin-sulfur-selenide solid solution plates with tunable bandgaps were also synthesized via CVD as single-crystals with a thin film geometry. Solid solution tin-sulfur-selenide plates were demonstrated to be a new material for solar cells with the first observed solar conversion efficiencies up to 3.1%. Finally, a low temperature molybdenum disulfide vertical heterostructure CVD synthesis with layered controlled growth was achieved with preferential growth enabled by Van der Waals epitaxy. Through recognition of additional reaction parameters, a fully regulated CVD synthesis enabled the controlled growth of 1-6 molybdenum disulfide monolayers for nanoelectronic applications. The improvements in synthesis and materials presented here were all enabled by the control afforded by CVD such that advances in phase purity, growth, and composition control of several metal dichalcogenides were achieved. Further work will be able to take full advantage of these advances for future solar and electronics technologies.

  19. Effects of simplifying fracture network representation on inert chemical migration in fracture-controlled aquifers

    Science.gov (United States)

    Wellman, Tristan; Shapiro, Allen M.; Hill, Mary C.

    2009-01-01

    While it is widely recognized that highly permeable 'large-scale' fractures dominate chemical migration in many fractured aquifers, recent studies suggest that the pervasive 'small-scale' fracturing once considered of less significance can be equally important for characterizing the spatial extent and residence time associated with transport processes. A detailed examination of chemical migration through fracture-controlled aquifers is used to advance this conceptual understanding. The influence of fracture structure is evaluated by quantifying the effects to transport caused by a systematic removal of fractures from three-dimensional discrete fracture models whose attributes are derived from geologic and hydrologic conditions at multiple field sites. Results indicate that the effects to transport caused by network simplification are sensitive to the fracture network characteristics, degree of network simplification, and plume travel distance, but primarily in an indirect sense since correlation to individual attributes is limited. Transport processes can be 'enhanced' or 'restricted' from network simplification meaning that the elimination of fractures may increase or decrease mass migration, mean travel time, dispersion, and tailing of the concentration plume. The results demonstrate why, for instance, chemical migration may not follow the classic advection-dispersion equation where dispersion approximates the effect of the ignored geologic structure as a strictly additive process to the mean flow. The analyses further reveal that the prediction error caused by fracture network simplification is reduced by at least 50% using the median estimate from an ensemble of simplified fracture network models, and that the error from network simplification is at least 70% less than the stochastic variability from multiple realizations. Copyright 2009 by the American Geophysical Union.

  20. Chemical controls on abiotic and biotic release of geogenic arsenic from Pleistocene aquifer sediments to groundwater.

    Science.gov (United States)

    Gillispie, Elizabeth C; Andujar, Erika; Polizzotto, Matthew L

    2016-08-10

    Over 150 million people in South and Southeast Asia consume unsafe drinking water from arsenic-rich Holocene aquifers. Although use of As-free water from Pleistocene aquifers is a potential mitigation strategy, such aquifers are vulnerable to geogenic As pollution, placing millions more people at potential risk. The goal of this research was to define chemical controls on abiotic and biotic release of geogenic As to groundwater. Batch incubations of sediments with natural chemical variability from a Pleistocene aquifer in Cambodia were conducted to evaluate how interactions among arsenic, manganese and iron oxides, and dissolved and sedimentary organic carbon influenced As mobilization from sediments. The addition of labile dissolved organic carbon produced the highest concentrations of dissolved As after >7 months, as compared to sediment samples incubated with sodium azide or without added carbon, and the extent of As release was positively correlated with the percent of initial extractable Mn released from the sediments. The mode of As release was impacted by the source of DOC supplied to the sediments, with biological processes responsible for 81% to 85% of the total As release following incubations with lactate and acetate but only up to 43% to 61% of the total As release following incubations with humic and fulvic acids. Overall, cycling of key redox-active elements and organic-carbon reactivity govern the potential for geogenic As release to groundwater, and results here may be used to formulate better predictions of the arsenic pollution potential of aquifers in South and Southeast Asia.