WorldWideScience
1

Quantum secure direct communication scheme using a W state and teleportation  

International Nuclear Information System (INIS)

A theoretical scheme for quantum secure direct communication (QSDC) is proposed, where a three-qubit symmetric W state functions as a quantum channel. Two legitimate communicators can transmit their secret information by using quantum teleportation and local measurements.

2006-11-01

2

Two Avowable Quantum Communication Schemes  

International Nuclear Information System (INIS)

Two avowable quantum communication schemes are proposed. One is an avowable teleportation protocol based on the quantum cryptography. In this protocol one teleports a set of one-particle states based on the availability of an honest arbitrator, the keys and the Einstein-Podolsky-Rosen pairs shared by the communication parties and the arbitrator. The key point is that the fact of the teleportation can neither be disavowed by the sender nor be denied by the receiver. Another is an avowable quantum secure direct communication scheme. A one-way Hash function chosen by the communication parties helps the receiver to validate the truth of the information and to avoid disavowing for the sender.

2008-11-15

3

Two Avowable Quantum Communication Schemes  

Science.gov (United States)

Two avowable quantum communication schemes are proposed. One is an avowable teleportation protocol based on the quantum cryptography. In this protocol one teleports a set of one-particle states based on the availability of an honest arbitrator, the keys and the Einstein Podolsky Rosen pairs shared by the communication parties and the arbitrator. The key point is that the fact of the teleportation can neither be disavowed by the sender nor be denied by the receiver. Another is an avowable quantum secure direct communication scheme. A one-way Hash function chosen by the communication parties helps the receiver to validate the truth of the information and to avoid disavowing for the sender.

2008-11-01

4

Efficient quantum secure communication scheme with one-time pad  

Science.gov (United States)

In this paper, we proposed a novel quantum secure direct communication scheme with one-time pad in stabilizer formalism. Based on the reuse of qubit sequence, an efficient secure communication of secret messages without first producing a shared secret key can be achieved. One hence may find that the amount of private key needed for quantum communication is smaller than that in the general case. Therefore, the present protocol which is feasible with the present-day techniques may be applied to quantum communication with short-length encoding.

2009-05-01

5

Controlled Bidirectional Quantum Direct Communication by Using a GHZ State  

Science.gov (United States)

A controlled bidirectional quantum secret direct communication scheme is proposed by using a Greenberger-Horne-Zeilinger (GHZ) state. In the scheme, two users can exchange their secret messages simultaneously with a set of devices under the control of a third party. The security of the scheme is analysed and confirmed.

2006-07-01

6

The enhancement of three-party simultaneous quantum secure direct communication scheme with EPR pairs  

Science.gov (United States)

Recently, Wang et al. proposed a three-party simultaneous quantum secure direct communication (3P-SQSDC) scheme with EPR pairs, which enables three involved parties to exchange their secret messages simultaneously by using an EPR pair. This work proposed an enhancement on Wang et al.'s scheme. With the enhancement, the communications in the improved 3P-SQSDC can be paralleled and thus improves the protocol efficiency.

2011-01-01

7

Limitations of silicon devices for quantum computing  

Energy Technology Data Exchange (ETDEWEB)

There is considerable interest in the use of silicon devices as qubits for quantum computing. The existence of nuclear spin in a silicon isotope and the complex band structure of silicon are unfavourable for this application of silicon devices. (viewpoint)

2004-04-28

8

Quantum Discord and Quantum Computing - An Appraisal  

CERN Document Server

We discuss models of computing that are beyond classical. The primary motivation is to unearth the cause of nonclassical advantages in computation. Completeness results from computational complexity theory lead to the identification of very disparate problems, and offer a kaleidoscopic view into the realm of quantum enhancements in computation. Emphasis is placed on the `power of one qubit' model, and the boundary between quantum and classical correlations as delineated by quantum discord. A recent result by Eastin on the role of this boundary in the efficient classical simulation of quantum computation is discussed. Perceived drawbacks in the interpretation of quantum discord as a relevant certificate of quantum enhancements are addressed.

2011-01-01

9

Quantum secure direct communication by EPR pairs and entanglement swapping  

Science.gov (United States)

We present a quantum secure direct communication scheme achieved by swapping quantum entanglement. In this scheme a set of ordered Einstein-Podolsky-Rosen (EPR) pairs is used as a quantum information channel for sending secret messages directly. After insuring the safety of the quantum channel, the sender Alice encodes the secret messages directly by applying a series local operations on her particle sequences according to their stipulation. Using three EPR pairs, three bits of secret classical information can be faithfully transmitted from Alice to remote Bob without revealing any information to a potential eavesdropper. By both Alice and Bob's GHZ state measurement results, Bob is able to read out the encoded secret messages directly. The protocol is completely secure if perfect quantum channel is used, because there is not a transmission of the qubits ...

2004-03-01

11

Three-Party Simultaneous Quantum Secure Direct Communication Scheme with EPR Pairs  

Science.gov (United States)

We present a scheme for three-party simultaneous quantum secure direct communication by using EPR pairs. In the scheme, three legitimate parties can simultaneously exchange their secret messages. It is also proved to be secure against the intercept-and-resend attack, the disturbance attack and the entangled-and-measure attack.

2007-09-01

12

Centre for Quantum Computation & Communication Technology  

Science.gov (United States)

This is the homepage of "an Australian multi-university collaboration undertaking research on the fundamental physics and technology of building, at the atomic level, a solid state quantum computer in silicon together with other high potential implementations." Although attempts to develop a quantum computer have met with limited success, the centre has substantial resources invested in advancing toward practical uses of quantum computing technology. The site provides a very good introduction to the principles and implications of quantum computing, as well as details about various research projects underway at the Australian universities. Links to conference and journal papers produced by members of the centre, many from 2003, are also provided.

13

Quantum Secure Direct Communication with Four-Particle Genuine Entangled State and Dense Coding  

Science.gov (United States)

A quantum secure direct communication scheme using dense coding is proposed. At first, the sender (Alice) prepares four-particle genuine entangled states and shares them with the receiver (Bob) by sending two particles in each entangled state to him. Secondly, Alice encodes secret information by performing the unitary transformations on her particles and transmits them to Bob. Finally, Bob performs the joint measurements on his particles to decode the secret information. The two-step security test guarantees the security of communication.

2009-07-01

14

Capacity of a Simultaneous Quantum Secure Direct Communication Scheme between the Central Party and Other M Parties  

Science.gov (United States)

We analyse the capacity of a simultaneous quantum secure direct communication scheme between the central party and other M parties via M+1-particle GHZ states and swapping quantum entanglement. It is shown that the encoding scheme should be secret if other M parties wants to transmit M+1 bit classical messages to the centre party secretly. However, when the encoding scheme is announced publicly, we prove that the capacity of the scheme in transmitting the secret messages is 2 bits, no matter how large M is.

2006-10-01

15

An efficient quantum secure direct communication scheme with authentication  

Science.gov (United States)

In this paper an efficient quantum secure direct communication (QSDC) scheme with authentication is presented, which is based on quantum entanglement and polarized single photons. The present protocol uses Einstein-Podolsky-Rosen (EPR) pairs and polarized single photons in batches. A particle of the EPR pairs is retained in the sender's station, and the other is transmitted forth and back between the sender and the receiver, similar to the ``ping-pong'' QSDC protocol. According to the shared information beforehand, these two kinds of quantum states are mixed and then transmitted via a quantum channel. The EPR pairs are used to transmit secret messages and the polarized single photons used for authentication and eavesdropping check. Consequently, because of the dual contributions of the polarized single photons, no classical information is needed. The intrinsic efficiency and total ...

2007-07-01

16

A Simultaneous Quantum Secure Direct Communication Scheme between the Central Party and Other M Parties  

Science.gov (United States)

We propose a simultaneous quantum secure direct communication scheme between one party and other three parties via four-particle GHZ states and swapping quantum entanglement. In the scheme, three spatially separated senders, Alice, Bob and Charlie, transmit their secret messages to a remote receiver Diana by performing a series of local operations on their respective particles according to the quadripartite stipulation. From Alice, Bob, Charlie and Diana's Bell measurement results, Diana can infer the secret messages. If a perfect quantum channel is used, the secret messages are faithfully transmitted from Alice, Bob and Charlie to Diana via initially shared pairs of four-particle GHZ states without revealing any information to a potential eavesdropper. As there is no transmission of the qubits carrying the secret message in the public channel, it is completely secure for the direct secret ...

2005-10-01

17

Secure Direct Communication Based on Non-Orthogonal Entangled Pairs and Local Measurement  

Science.gov (United States)

We propose a quantum secure direct communication scheme based on non-orthogonal entangled pairs and local measurement. In this scheme, we use eight non-orthogonal entangled pairs to act as quantum channels. Due to the non-orthogonality of the quantum channels, the present protocol can availably prohibit from all kinds of valid eavesdropping and acquire a secure quantum channel. By local measurement, the sender acquires a secret random sequence. The process of encoding on the random sequence is identical to the one in one-time-pad. So the present protocol is secure. Even for a highly lossy channel, our scheme is also valid. The scheme is feasible with present-day techniques.

2008-12-01

18

Coherent state quantum key distribution with multi letter phase-shift keying  

International Nuclear Information System (INIS)

We present a protocol for quantum key distribution using discrete modulation of coherent states of light. Information is encoded in the variable phase of coherent states which can be chosen from a regular discrete set ranging from binary to continuous modulation similar to phase-shift keying in classical communication. Information is decoded by simultaneous homodyne measurement of both quadratures and requires no active choice of basis. The protocol utilizes either direct or reverse reconciliation both with and without postselection. We analyze the security of the protocol and show how to enhance it by the optimal choice of all variable parameters of the quantum signal.

2010-05-01

19

Deterministic secure direct communication using GHZ states and swapping quantum entanglement  

International Nuclear Information System (INIS)

We present a deterministic secure direct communication scheme via entanglement swapping, where a set of ordered maximally entangled three-particle states (GHZ states), initially shared by three spatially separated parties, Alice, Bob and Charlie, functions as a quantum information channel. After ensuring the safety of the quantum channel, Alice and Bob apply a series of local operations on their respective particles according to the tripartite stipulation and the secret message they both want to send to Charlie. By three of Alice, Bob and Charlie's Bell measurement results, Charlie is able to infer the secret messages directly. The secret messages are faithfully transmitted from Alice and Bob to Charlie via initially shared pairs of GHZ states without revealing any information to a potential eavesdropper. Since there is no transmission of the qubits carrying the secret message between any two of them in the public channel, ...

2005-06-24

20

Long-lived quantum coherence in photosynthetic complexes at physiological temperature  

UK PubMed Central (United Kingdom)

Photosynthetic antenna complexes capture and concentrate solar radiation by transferring the excitation to the reaction center that stores energy from the photon in chemical bonds. This process occurs...Full Text Available

2010-07-20

21

Quantum Discrete Fourier Transform in an Ion Trap System  

International Nuclear Information System (INIS)

We propose two schemes for the implementation of quantum discrete Fourier transform in the ion trap system. In each scheme we design a tunable two-qubit phase gate as the main ingredient. The experimental implementation of the schemes would be an important step toward complex quantum computation in the ion trap system.

2007-06-15

22

Origin of complex quantum amplitudes and Feynman's rules  

International Nuclear Information System (INIS)

Complex numbers are an intrinsic part of the mathematical formalism of quantum theory and are perhaps its most characteristic feature. In this article, we show that the complex nature of the quantum formalism can be derived directly from the assumption that a pair of real numbers is associated with each sequence of measurement outcomes, with the probability of this sequence being a real-valued function of this number pair. By making use of elementary symmetry conditions, and without assuming that these real number pairs have any other algebraic structure, we show that these pairs must be manipulated according to the rules of complex arithmetic. We demonstrate that these complex numbers combine according to Feynman's sum and product rules, with the modulus-squared yielding the probability of a sequence of outcomes.

2010-02-01

23

Quantum Impurities in the Two-Dimensional Spin One-Half Heisenberg Antiferromagnet  

CERN Document Server

The study of randomness in low-dimensional quantum antiferromagnets is at the forefront of research in the field of strongly correlated electron systems, yet there have been relatively few experimental model systems. Complementary neutron scattering and numerical experiments demonstrate that the spin-diluted Heisenberg antiferromagnet La2Cu(1-z)(Zn,Mg)zO4 is an excellent model material for square-lattice site percolation in the extreme quantum limit of spin one-half. Measurements of the ordered moment and spin correlations provide important quantitative information for tests of theories for this complex quantum-impurity problem.

2002-01-01

24

Generation of number-phase minimum uncertainty states  

Energy Technology Data Exchange (ETDEWEB)

The difference between the two nonclassical lights, i.e., the squeezed state and number-phase minimum uncertainty state (NUS) is discussed. The four different generation principles for NUS are described. They are: unitary evolution using self-phase modulation; nonunitary state reduction by the first kind measurement; controlled state reduction by quantum correlation measurement-feedback, and high saturated laser oscillation with suppressed-pump-noise. The constant current-driven semiconductor laser based on the last principle generated the NUS with photon number noise reduced below the standard quantum limit by 40 percent in the entire frequency region from dc to 1.1 GHz. Several applications of NUS including quantum communication, quantum mechanical computers and interferometric gravitational detection are discussed briefly. This presentation is represented by viewgraphs only.

1987-01-01

25

Multiparty controlled quantum secure direct communication using Greenberger Horne Zeilinger state  

Science.gov (United States)

Based on the idea of dense coding of three-photon entangled state and qubit transmission in blocks, we present a multiparty controlled quantum secret direct communication scheme by using Greenberger Horne Zeilinger state. In the present scheme, the sender transmits three bits of secret message to the receiver directly and the secret message can only be recovered by the receiver under the permission of all the controllers. All three-photon entangled states are used to transmit the secret message except those chosen for eavesdropping check and the present scheme has a high source capacity because Greenberger Horne Zeilinger state forms a large Hilbert space.

2006-10-01

26

HealthKick: a nutrition and physical activity intervention for primary schools in low-income settings  

UK PubMed Central (United Kingdom)

BackgroundThe burden of non-communicable diseases, including type 2 diabetes, is growing in South Africa. This country has a complex mix of over- and under-nutrition, especially...Full Text Available

27

Experimental demonstration of three-color entanglement  

CERN Document Server

Entanglement is the essential quantum resource for a potential speed-up of information processing, as well as for sophisticated quantum communication. Quantum information networks will be required to convey information from one place to another, by using entangled light beams. Many physical systems are under consideration as building blocks, with different merits and faults, so that hybrid systems are likely to be developed. Here we present an important tool for connecting systems that share no common resonance frequencies: we demonstrate the first direct generation of entanglement among more than two bright beams of light, all of different wavelengths (532.251 nm, 1062.102 nm, and 1066.915 nm). We also observe, for the first time, disentanglement for finite channel losses, the continuous variable counterpart to entanglement sudden death.

2010-01-01

28

Antiadiabatic control of Many Body Quantum Systems  

CERN Document Server

Classical control theory has played a major role in the development of present-day technologies. Likewise, recently developed quantum optimal control methods can be applied to emerging quantum technologies, e.g. quantum information processing -- until now, at the level of a few qubits. However, such methods encounter severe limits when applied to many-body quantum systems: due to the complexity of simulating the latter, existing quantum control algorithms (requiring many iterations to converge) usually fail to yield a desired final state within an acceptable computational time. In contrast, we present here a strategy for controlling a vast range of non-integrable one-dimensional systems that is efficiently applicable to quantum many-body systems, as it can be merged with state-of-the-art tensor network simulation methods like the Density ...

2010-01-01

29

Synthesis, luminescence quantum yields, and lifetimes of trischelated ruthenium(II) mixed-ligand complexes including 3,3'-dimethy1-2,2'-bipyridyl  

International Nuclear Information System (INIS)

New five complexes of the type of [RuL sub(3-x)(dmby) sub(x)]X sub(2)(x = 1,2,3, L = 2,2'-bipyridyl or 1,10-phenanthroline, dmby = 3,3'-dimethy1-2,2'-bipyridyl, X = halide ion) have been synthesized in order to investigate the effects of two methyl groups of dmby on the absorption and emission spectra, luminescence quantum yields, and lifetimes. Values of the radiative and nonradiative rate constants have been calculated from these data at 77K. Although the absorption and emission maxima and the lifetimes are not much affected by the dmby ligand substitution, the molar extinction coefficients and emission quantum yields are decreased compared with trischelated complexes of the parent bipyridyl or phenanthroline ligands. At 25"0C the emission yields of the complexes containing dmby decrease by 3 - 4 orders of magnitude than at 77K. Possible causes of the decrease in the ...

1982-01-01

30

Communication and Round Efficient Information Checking Protocol  

CERN Document Server

In this paper, we present a very important primitive called Information Checking Protocol (ICP) which plays an important role in constructing statistical Verifiable Secret Sharing (VSS) and Weak Secret Sharing (WSS) protocols. Informally, ICP is a tool for authenticating messages in the presence of computationally unbounded corrupted parties. Here we extend the basic bare-bone definition of ICP, introduced by Rabin et al. and then present an ICP that attains the best communication complexity and round complexity among all the existing ICPs in the literature. We also show that our ICP satisfies several interesting properties such as linearity property which is an important requirement in many applications of ICP. Though not presented in this paper, we can design communication and round efficient statistical (i.e involves negligible error probability in computation) VSS and Multiparty Computation (MPC) ...

2010-01-01

31

A Time-Slotted On-Demand Routing Protocol for Mobile Ad Hoc Unmanned Vehicle Systems  

Energy Technology Data Exchange (ETDEWEB)

The popularity of UAVs has increased dramatically because of their successful deployment in military operations, their ability to preserve human life, and the continual improvements in wireless communication that serves to increase their capabilities. We believe the usefulness of UAVs would be dramatically increased if formation flight were added to the list of capabilities. Currently, sustained formation flight with a cluster of UAVs has only been achieved with two nodes by the Multi-UAV Testbed at the Massachusetts Institute of Technology. (Park, 2004) Formation flight is a complex operation requiring the ability to adjust the flight patterns on the fly and correct for wind gusts, terrain, and differences in node equipment. All of which increases the amount of inner node communication. Since one of the problems with MANET communication is network congestion, we believe a first step towards formation ...

2007-04-01

32

Quantum query complexity of minor-closed graph properties  

CERN Document Server

We study the quantum query complexity of minor-closed graph properties, which include such problems as determining whether a graph is planar, is a forest, or does not contain a path of a given length. We show that most minor-closed properties---those that cannot be characterized by a finite set of forbidden subgraphs---have quantum query complexity \\Theta(n^{3/2}). To establish this, we prove an adversary lower bound using a detailed analysis of the structure of minor-closed properties with respect to forbidden topological minors and forbidden subgraphs. On the other hand, we show that minor-closed properties (and more generally, sparse graph properties) that can be characterized by finitely many forbidden subgraphs can be solved strictly faster, in o(n^{3/2}) queries. Our algorithms are a novel application of the quantum walk search framework and give improved upper bounds for ...

2010-01-01

33

Effect of V-shaped defects on structural and optical properties of AlGaN/InGaN multiple quantum wells  

International Nuclear Information System (INIS)

We have investigated the correlation between V-shaped defect formation and the optical properties of AlGaN/(In)GaN multiple quantum wells (MQWs) grown under different growth conditions and then demonstrated the characteristics of fabricated ultraviolet (UV) light emitting diodes (LEDs). From the temperature-dependent photoluminescence (PL) measurement, the internal quantum efficiency for 300 K was obtained as 43.6% for a sample with a low density of V-defects in a MQW and 13.7% for a sample with a high density of V-defects. The carrier lifetime based on the time resolved PL measurement at room temperature was 0.32 ns for a sample with a high density of V-defects and 1.26 ns for a sample with a low density of V-defects. And we also found that the density of V-defects affected the external quantum efficiency and wall plug efficiency of the fabricated UV LEDs. (fast track communication)

2008-07-07

34

Leadership, communication and decision making in man-machine systems; Fuehrung, Kommunikation und Entscheidungsfindung in Mensch-Maschine-Systemen  

Energy Technology Data Exchange (ETDEWEB)

The contribution under consideration spans a wide curve from the first deadly accident of motorized aviation in the year 1908 up to newer tendencies of the so-called team resources management on observation points and control stations in order to pursue fundamental questions in man-machine systems. A continuous differentiation in the consideration of the factor human beings in complex technical systems is described. This is illustrated by the example of concepts for leadership, communication and decision making on observation points and control stations.

2008-07-01

36

Quantum information processing in nanostructures[Quantum optics; Quantum computing  

Energy Technology Data Exchange (ETDEWEB)

Since information has been regarded os a physical entity, the field of quantum information theory has blossomed. This brings novel applications, such as quantum computation. This field has attracted the attention of numerous researchers with backgrounds ranging from computer science, mathematics and engineering, to the physical sciences. Thus, we now have an interdisciplinary field where great efforts are being made in order to build devices that should allow for the processing of information at a quantum level, and also in the understanding of the complex structure of some physical processes at a more basic level. This thesis is devoted to the theoretical study of structures at the nanometer-scale, 'nanostructures', through physical processes that mainly involve the solid-state and quantum optics, in order to propose reliable schemes for the processing of ...

2002-07-01

47

Effects of quantum vacuum fluctuations of the electric field on DNA condensation  

British Library Electronic Table of Contents (United Kingdom)

By assuming that not only counter-ions but DNA molecules as well are thermally distributed according to a Boltzmann law, we propose a modified Poisson-Boltzmann equation, at the classical level, as a starting point to compute the effects of quantum fluctuations of the electric field on the interaction among DNA-cation complexes. The latter are modeled here as infinite one-dimensional wires (?-functions). Our goal is to single out such quantum-vacuum-driven interaction from the counterion-induced and water-related interactions. We obtain a universal, frustration-free Casimir-like (codimension 2) interaction that extensive numerical analysis show to be a good candidate to explain the formation and stability of DNA aggregates. Such Casimir energy is computed for a variety of configurations of...

2011-01-01

49

Polyhydroxyflavones as extractants. Communication 7. Solvent extraction of europrium complexes with morin from alkaline media  

Energy Technology Data Exchange (ETDEWEB)

This paper studies the analytical application of europium (III)-morin complex which is formed in alkaline medium and has an intense color. The extent of europium extraction was determined by adding to the extract a morin solution in isoamyl alcohol in a 50-100-fold excess with respect to europium. The dependence of the optical density of the extracts on the ph in the system europium (III)-morin-water-organic solvent for different excesses of the reagent is shown: this indicates formation of two extractable complexes, one being dominant in the pH range 4-7, the other at pH greater than or equal to 8.5. The extraction of the europium (III)-morin complex from alkaline solution is used for direct extraction-photometric determination of europium(III) in compounds of elements having amphoteric properties or forming amines (Zns, Mo0/sub 3/).

1985-09-01

50

Formation of complex Langmuir and Langmuir-Blodgett films of water soluble rosebengal  

British Library Electronic Table of Contents (United Kingdom)

This communication reports the formation of complex Langmuir monolayer at the air-water interface by charge transfer types of interaction with the water soluble N-cetyl Formula Not Shown -trimethyl ammonium bromide (CTAB) molecules doped with rosebengal (RB), with the stearic acid (SA) molecules of a preformed SA Langmuir monolayer. The reaction kinetics of the formation of RB-CTAB-SA complex monolayer was monitored by observing the increase in surface pressure with time while the barrier was kept fixed. Completion of interaction kinetics was confirmed by FTIR study. This complex Langmuir films at the air-water interface was transferred onto solid substrates at a desired surface pressure to form multilayered Langmuir-Blodgett films. Spectroscopic characterizations reveal some molecular lev...

2007-01-01

51

Density functional theory and topological analysis on the hydrogen bonding interactions in cysteine-thymine complexes  

British Library Electronic Table of Contents (United Kingdom)

Abstract Hydrogen bonding interactions between amino acids and nucleic acid bases constitute the most important interactions responsible for the specificity of protein binding. In this study, complexes formed by hydrogen bonding interactions between cysteine and thymine have been studied by density functional theory. The relevant geometries, energies, and IR characteristics of hydrogen bonds (H-bonds) have been systematically investigated. The quantum theory of atoms in molecule and natural bond orbital analysis have also been applied to understand the nature of the hydrogen bonding interactions in complexes. More than 10 kinds of H-bonds including intra- and intermolecular H-bonds have been found in complexes. Most of intermolecular H-bonds involve O (or N) atom as H-acceptor, whereas the...

2011-01-01

52

Quantum computing  

UK PubMed Central (United Kingdom)

Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum...Full Text Available

2001-10-09

53

The holographic principle and the language of genes  

CERN Document Server

We show that the holographic principle in quantum gravity imposes a strong constraint on life. The degrees of freedom of an organism can be estimated according to the theory of Boolean networks, which is constrained by the entropy bound. Hence we can explain the languages in protein sequences or in DNA sequences. The overall evolution of biological complexity can be illustrated. And some general properties of protein length distributions can be explained by a linguistic mechanism.

2008-01-01

54

On Measurement and Computation  

CERN Document Server

Inspired by the work of Feynman, Deutsch, We formally propose the theory of physical computability and accordingly, the physical complexity theory. To achieve this, a framework that can evaluate almost all forms of computation using various physical mechanisms is discussed. Here, we focus on using it to review the theory of Quantum Computation. As a preliminary study on more general problems, some examples of other physical mechanism are also given in this paper.

2011-01-01

55

Synthesis and luminescence of Eu"3"+ and Tb"3"+ complexes with novel calix[4]arene ligands carrying 2,2'-bipyridine subunits  

International Nuclear Information System (INIS)

Eu"3"+ and Tb"3"+ complexes with novel branched calix[4]arene ligands incorporating 2,2' -bipyridine subunits functionalized in the 6- or 5,5'-positions have been synthesized and their photophysical properties investigated. High luminescence intensity was obtained for the Eu"3"+ complex of the calix[4]arene ligand carrying four 5,5' -substituted- 2,2' -bipyridines, which has high molar extinction coefficients (#epsilon#_m_a_x 39 600 M"-"1 cm"-"1) and a high luminescence quantum yield (15%). (authors). 12 refs., 2 figs., 1 tab.

1995-01-01

56

A computational approach to the electronic and optical properties of Ru(II) and Ir(III) polypyridyl complexes: Applications to DSC, OLED and NLO  

British Library Electronic Table of Contents (United Kingdom)

Ruthenium(II) and Iridium(III) polypyridyl complexes have been intensively investigated due to their use in energy conversion and light-emitting devices and materials for non-linear optics. Quantum mechanical computer simulations of molecules and materials have become increasingly popular in the scientific community. Along with experimental investigations, such computational analyses can provide complementary information on the electronic and optical properties of transition metal compounds of interest for optoelectronic applications. Here, we provide a unified review of recent work carried out on computational investigations of a large series of Ruthenium(II) and Iridium(III) polypyridyl complexes, discussing the relations between their electronic structure and optical properties and thei...

2011-01-01

57

Spread spectrum acquisition and tracking performance for Shuttle communication links  

Science.gov (United States)

The spread spectrum acquisition and tracking performance for the Shuttle S-band and Ku-band communication links are analyzed and compared to test results. The S-band link requirements are more severe than those of the Ku-band links, hence, different despreader designs were developed for the two systems. The S-band despreader acquires pseudonoise code lock by examining all possible code phases in half chip steps while the Ku-band despreader acquires pseudonoise code lock by continuously sweeping a tau-jitter loop. Both despreaders employ a tau-jitter loop for code tracking. The code tracking performance is computed for the tau-jitter loop and compared to that of the more complex delay lock loop.

1978-01-01

67

Cluster approach to quantum-chemical calculations of chemisorption and heterogeneous catalytic systems  

Energy Technology Data Exchange (ETDEWEB)

The increasing use of quantum-chemical methods in catalysis has underscored the importance of developing and improving semiempirical approximations oriented toward calculations of the total energy and geometry, offering a means for examining intermolecular interactions. In this article a general approach is proposed, using weighting factors for certain regions of distances, i.e., introducing different parametrization into the various regions. A scheme designated MINDO/3-HB is presented as an extension of the MINDO/3 scheme to the region of hydrogen bonds and ..pi..-complexes of olefins with Broensted acid centers (BACs). Examples of cluster calculations are given for the adsorption of ammonia, pyridine, ethylene, and ethanol on the BACs of zeolites. In the example of the process of zeolite synthesis, the possibilities of the cluster approach are discussed for calculations related to the formation of catalysts.

1987-07-01

68

Clinical-HINTS: integrated intelligent ICU patient monitoring and information management system.  

Science.gov (United States)

Clinical-HINTS (Health Intelligence System) is a horizontally integrated decision support system (DSS) designed to meet the requirements for intelligent real-time clinical information management in critical care medical environments and to lay the foundation for the development of the next generation of intelligent medical instrumentation. The system presented was developed to refine and complement the information yielded by clinical laboratory investigations, thereby benefiting the management of the intensive care unit (ICU) patient. More specifically, Clinical-HINTS was developed to provide computer-based assistance with the acquisition, organisation and display, storage and retrieval, communication and generation of real-time patient-specific clinical information in an ICU. Clinical-HINTS is an object-oriented system developed in C+2 to run under Microsoft Windows as an embryo intelligent agent. Current generic reasoning skills include perception and reactive ...

1997-01-01

69

Observability of complex ghosts and tachyons  

International Nuclear Information System (INIS)

The complex ghost introduced previously by the present author is studied from a standpoint whether its effects are observable by experiments or not. According to the theory of complex ghost the scattering cross section of two real particles shows some particular properties. It has a kind of resonance peak at a certain energy which does not conform to the Breit-Wigner formula. It has also a peak for a certain energy transfer, if there exist tachyons. The tachyon is a kind of ghost and is allowed to exist in the theory. Using these properties the complex ghosts are expected to be detected by experiments. The recently observed resonance psi(3.1) is supposed to be the complex ghost of photon, since they have the same quantum numbers. If it is assumed, some properties of the resonance known by experiments are explained naturally to a certain extent. Along the same line it is not ...

70

Testing of solar cells for communication satellites  

International Nuclear Information System (INIS)

... cadmium sulfides communications electrons performance testing physical

72

Cost savings through effective use of network resources  

Energy Technology Data Exchange (ETDEWEB)

The role of computers has become increasingly important for oil and gas field research and operations support. Today, the computer network is an integral part of the increasingly complex computing environment that exists in many companies. Computer networks allow users to efficiently share information, software, and hardware to support critical global communication needs. Because users are able to share software and hardware, the use of computer networks can also result in significant cost savings. This paper describes typical network loading and demand levels for shared software applications on a computer network that has been used for several years.

1994-12-31

73

The Quantum Vacuum of Complex Media. A Unified Approach to the Dielectric Constant, the Spontaneous Emission and the Zero-Temperature Electromagnetic Pressure  

CERN Document Server

We study from a critical perspective several quantum-electrodynamic phenomena commonly related to vacuum electromagnetic (EM) fluctuations in complex media. We compute the resonance-shift, the spontaneous emission rate, the local density of states and the van-der-Waals-Casimir pressure in a dielectric medium using a microscopic diagrammatic approach. We find, in agreement with some recent works, that these effects cannot be attributed to variations on the energy of the EM vacuum but to variations of the dielectric self-energy. This energy is the result of the interaction of the bare polarizability of the dielectric constituents with the EM fluctuations of an actually polarized vacuum. We have found an exact expression for the spectrum of these fluctuations in a statistically homogeneous dielectric. Those fluctuations turn out to be different to the ones of normal radiative modes. It is the latter that carry the zero-point-energy (ZPE). ...

2009-01-01

74

Antiferromagnetic exchange in a bis(imido) uranium (V) dimeric complex  

Energy Technology Data Exchange (ETDEWEB)

Magnetic coupling between two or more metal centers is an important facet of d- and f-block transition metal chemistry due to its implications in chemical bonding. With respect to actinide metals, magnetic coupling between polymetallic actinide centers is less well-known. Of the few documented examples, only one bimetallic uranium(V) complex, [(MeC{sub 5}H{sub 4}){sub 2}U]{sub 2}[{mu}-1,4-N{sub 2}C{sub 6}H{sub 4}] (1), has unequivocally demonstrated antiferromagnetic coupling. This complex employs a {pi}-conjugated 1,4-phenylenedimide ligand system which bridges the two f{sup 1}-metal centers and enables antiferromagentic coupling between unpaired f-e1ectrons residing in a {pi}-symmetry orbital. In this communication, we report the synthesis of a dimeric bis(imido) uranium(V) iodide complex and demonstrate with magnetic susceptibility measurements and density functional theory (DFT) calculations that ...

2008-01-01

75

Ultrafast fluorescence dynamics of Sybr Green I/DNA complexes  

British Library Electronic Table of Contents (United Kingdom)

The ultrafast dynamics of the DNA fluorescent dye Sybr Green I (SG) has been studied in buffer, single-stranded (ssDNA), double-stranded (dsDNA) and triple-stranded DNA (tsDNA). The fluorescence quantum yield of SG increases dramatically when bound to DNA (including tsDNA). The fluorescence dynamics of the free SG has shown two decay components with 0.15-0.4ps and 1.3-2.1ps time constants, depending on the fluorescence wavelength. Upon binding to DNA, the dynamics becomes slower exhibiting four decay components. This is mainly due to the restriction of the internal motions of the dye caused by the relatively rigid environment of the dye complexed with DNA.

2010-01-01

76

The Minimal Scale Invariant Extension of the Standard Model  

CERN Document Server

We perform a systematic analysis of an extension of the Standard Model that includes a complex singlet scalar field and is scale invariant at the tree level. We call such a model the Minimal Scale Invariant extension of the Standard Model (MSISM). The tree-level scale invariance of the model is explicitly broken by quantum corrections, which can trigger electroweak symmetry breaking and potentially provide a mechanism for solving the gauge hierarchy problem. Even though the scale invariant Standard Model is not a realistic scenario, the addition of a complex singlet scalar field may result in a perturbative and phenomenologically viable theory. We present a complete classification of the flat directions which may occur in the classical scalar potential of the MSISM. After calculating the one-loop effective potential of the MSISM, we investigate a number of representative scenarios and determine their scalar boson mass ...

2010-01-01

77

QCCM - Center for NMR Quantum Information Processing  

Science.gov (United States)

... decoherence. Descriptors : *QUANTUM COMPUTING, NUCLEAR MAGNETIC RESONANCE, JOSEPHSON JUNCTIONS. Subject ...

2011-02-16

78

Synthesis, characterization and antitumor activity study of some cyclometalated organoplatinum(II) complexes containing aromatic N-donor ligands  

British Library Electronic Table of Contents (United Kingdom)

A general approach has been designed to synthesize some mononuclear and binuclear cyclometalated platinum(II) complexes, containing aromatic N-donor ligands with the presence of one Cl- trans to carbon. In this way, cyclometalated platinum(II) complex [Pt(C^N)Cl(dmso)], 1, C^N = N(1),C(2prime)-chelated, deprotonated 2-phenylpyridine and dmso = dimethylsulfoxide, was used as a precursor to react with imidazole derivatives (1-methylimidazole, 2a, imidazole, 2b,), monodentate pyridine derivatives (4-methylpyridine, 2c, pyridine, 2d,) and bidentate pyridine derivative (4,4prime-bipyridine, 3 and 4,). Synthesized complexes were fully characterized by using multinuclear NMR spectroscopy (1H, 13C{1H} and 195Pt), correlation NMR spectroscopy (1H-1H COSY, 13C{1H}-1H Heteronuclear Multiple Quantum C...

2011-01-01

79

A Fast Parallel Algorithm for Selected Inversion of Structured Sparse Matrices with Application to 2D Electronic Structure Calculations  

Energy Technology Data Exchange (ETDEWEB)

We present an efficient parallel algorithm and its implementation for computing the diagonal of $H^-1$ where $H$ is a 2D Kohn-Sham Hamiltonian discretized on a rectangular domain using a standard second order finite difference scheme. This type of calculation can be used to obtain an accurate approximation to the diagonal of a Fermi-Dirac function of $H$ through a recently developed pole-expansion technique \\cite{LinLuYingE2009}. The diagonal elements are needed in electronic structure calculations for quantum mechanical systems \\citeHohenbergKohn1964, KohnSham 1965,DreizlerGross1990. We show how elimination tree is used to organize the parallel computation and how synchronization overhead is reduced by passing data level by level along this tree using the technique of local buffers and relative indices. We analyze the performance of our implementation by examining its load balance and communication overhead. We show that our implementation ...

2009-09-25

80

Evaluation of stability of {sup 99m}Tc-HSA complex during clinical peritoneal dialysis in vivo (short communication); Ocena stabilnosci kompleksu {sup 99m}Tc-HSA in vivo w warunkach klinicznej dializy otrzewnowej (krotkie doniesienie)  

Energy Technology Data Exchange (ETDEWEB)

For the assessment of the intra-dialysis stability of the {sup 99m}Tc-HSA complex, a scintigraphic scanning of the organs accumulation of the free 99mTcO{sub 4}{sup -} was carried out during peritoneal dialysis. 740 MBg {sup 99m}Tc-HSA in dialization fluid was administered during kinetic peritoneal examination of the patient. The organs accumulating the free pertechnetion (head and neck), as well as whole body imaging of pt were carried out. The results show that the radioactivity is accumulated mainly in peritoneal cavity. Minimal radioactivity was indicated in the head and neck ({approx}2.3% of the total whole body radioactivity). Our results show that the {sup 99m}Tc-HSA complex is stable during 3.5 h peritoneal dialysis in vivo. (author) 6 refs, 3 figs

1997-12-31

91
111

Transformational Satellite (TSAT) Communications Systems. ...  

Science.gov (United States)

... The seven existing space/airborne programs are the Defense Satellite Com- munications System (DSCS), Milstar, communications re- lay ...

2007-07-01

112

Orbiting transmitter and antenna for spaceborne communications at ELF/VLF to submerged submarines  

Science.gov (United States)

An orbital emplacement for the transmitter and the antenna of a communications link at ELF (30 to

1993-01-01

113

Milstar Quicklook  

Science.gov (United States)

Milstar picture Milstar is a series of advanced US military communications satellites designed to provide global jam-resistant communications for military users. ...

114

Lunar Communication & Navigation Architecture  

Science.gov (United States)

Prior to this at TRW, Mr. Schier managed flight software development on the MILSTAR Communications Payload and led integration and verification work on ...

115

Global Warming Communications Overview (WMV, 15.09 MB)  

Science.gov (United States)

... insight into the best way to communicate about global warming and it's impact on wildlife to the " ... ...

119

Point contact Andreev reflection spectroscopy of NdFeAsO_0_._8_5  

International Nuclear Information System (INIS)

The newly discovered oxypnictide family of superconductors show very high critical temperatures of up to 55 K. Whilst there is growing evidence that suggests a nodal order parameter, point contact Andreev reflection spectroscopy can provide crucial information such as the gap value and possibly the number of energy gaps involved. For the oxygen deficient NdFeAsO_0_._8_5 with a T_c of 45.5 K, we show that there is clearly a gap value at 4.2 K that is of the order of 7 meV, consistent with previous studies on oxypnictides with lower T_c. In addition, taking the spectra as a function of gold tip contact pressure reveals important changes in the spectra which may be indicative of more complex physics underlying this structure. (rapid communication)

2008-09-01

120

Network management of real-time embedded processors  

International Nuclear Information System (INIS)

The Superconducting super Collider Laboratory is a complex of particle accelerators being built in Ellis County, Texas. It will have a dedicated global communications network that will deliver control messages and provide for general data acquisition. This network will connect thousands of computer nodes over a very large geographic area. In order to meet the demanding availability requirements being levied on the system, it will need comprehensive network management. A large number of the computer nodes are embedded systems that traditionally do not support network management services. This presents unique challenges to standard network management practices. The Simple Network Management Protocol, SNMP, is widely accepted by industry as a tool to manage network devices. In this paper the authors examine the performance characteristics and usefulness of an SNMP agent in a real-time environment.

1993-05-17

121

An Electronic Payment System to Ensure Cost Effectiveness with Easy Security Incorporation for the Developing Countries  

CERN Document Server

With the rapid growth of Information and Communication Technology, Electronic commerce is now acting as a new means of carrying out business transactions through electronic means such as Internet environment. To avoid the complexities associated with the digital cash and electronic cash, consumers and vendors are looking for credit card payments on the Internet as one possible time-tested alternative. This gave rise of the on-line payment processing using a third-party verification; which is not suitable for the developing countries in most of the cases because of the excessive costs associated with it for maintenance and establishment of an online third-party processor. As a remedy of this problem, in this paper, we have proposed a framework for easy security incorporation in credit card based electronic payment system without the use of an on-line third- party processor; which tends to be low cost and effective for the developing countries.

2006-01-01

122

Tachyons as viewed from quantum field theory  

International Nuclear Information System (INIS)

The authors present a summary of the present state of the quantum field theory of tachyons. (W.D.L.).

123

Geometric and topological methods for quantum field theory  

CERN Document Server

An introduction to recent developments in several active topics at the interface between algebra, geometry, topology and quantum field theory

2010-01-01

124

Quantum computing with trapped ions  

Energy Technology Data Exchange (ETDEWEB)

Quantum computers hold the promise of solving certain computational tasks much more efficiently than classical computers. We review recent experimental advances towards a quantum computer with trapped ions. In particular, various implementations of qubits, quantum gates and some key experiments are discussed. Furthermore, we review some implementations of quantum algorithms such as a deterministic teleportation of quantum information and an error correction scheme.

2008-12-15

125

Visible (657 nm) InGaP/InAlGaP strained quantum well vertical-cavity surface-emitting laser  

Science.gov (United States)

We report the first visible (657 nm) vertical-cavity surface-emitting laser. The photopumped undoped structure was grown using low-pressure metalorganic vapor-phase epitaxy in a single-growth sequence on misoriented GaAs substrates. The optical cavity consists of an In{sub 0.54}Ga{sub 0.46}P/In{sub 0.48}(Al{sub 0.7}Ga{sub 0.3}){sub 0.52} P strained quantum-well active region and a lattice-matched In{sub 0.48}(Al{sub {ital y}}Ga{sub 1{minus}{ital y}}){sub 0.52} P (0.7{le}{ital y}{le}1.0) graded spacer region, while the distributed Bragg reflectors are composed of Al{sub 0.5}Ga{sub 0.5}As/AlAs quarter-wave stacks. Room-temperature optically pumped lasing was achieved with a very low-threshold power, clearly demonstrating the viability of this new technology. These results provide the foundation for visible semiconductor laser-diode arrays for a number of applications including laser projection displays, holographic memories, and plastic fiber ...

1992-04-13

126

Propagators and Matrix Basis on Noncommutative Minkowski Space  

CERN Document Server

We describe an analytic continuation of the Euclidean Grosse-Wulkenhaar and LSZ models which defines a one-parameter family of duality covariant noncommutative field theories interpolating between Euclidean and Minkowski space versions of these models, and provides an alternative regularization to the usual Feynman prescription. This regularization allows for a matrix model representation of the field theories in terms of a complex generalization of the usual basis of Landau wavefunctions. The corresponding propagators are calculated and identified with the Feynman propagators of the field theories. The regulated quantum field theories are shown to be UV/IR-duality covariant. We study the asymptotics of the regularized propagators in position and matrix space representations, and confirm that they generically possess a comparably good decay behaviour as in the Euclidean case.

2011-01-01

127

Interplay between coherence and decoherence in LHCII photosynthetic complex  

CERN Document Server

This paper investigates the dynamics of excitonic transport in photocomplex LHCII, the primary component of the photosynthetic apparatus in green plants. The dynamics exhibits a strong interplay between coherent processes mediated by the excitonic Hamiltonian, and incoherent processes due to interactions with the environment. The spreading of the exciton over a single monomer is well described by a proper measure of delocalization that allows one to identify two relevant time scales. An exciton initially localized in one chromophore first spreads coherently to neighboring chromophores. During this initial coherent spreading, quantum effects such as entanglement play a role. As the effects of a decohering environment come into play, coherence and decoherence interact to give rise to efficient and robust excitonic transport, reaching a maximum efficiency at the levels of decoherence found in physiological conditions. We analyze the efficiency for different possible ...

2011-01-01

128

Video equipment of tele dosimetry and audio  

International Nuclear Information System (INIS)

To develop a work in an area with high radiation, it requires of a detailed knowledge of the surroundings work, a communication and effective vision, a near dosimetric control. In a work where the spaces variables and reduced accesses exist, noise that hinders the communication, defendant operative condition, radiation field and taking of decision, it is necessary to have tools that allow a total control of the environment to make opportune and effective decisions, there where the task is developed. Under this elementary concept, it was developed in the Laguna Verde Central a project that it allowed a mechanism, interactive of control in spaces complex; to see, to hear, to speak, to measure. This concept takes to the creation of an equipped system with closed circuit of television, wireless communication systems, tele dosimetry wireless systems, VHS and DVD recording equipment, uninterrupted energy ...

2007-07-01

129

Photoluminescent properties of heteroleptic cyclometalated platinum(II) complexes bearing 1,3-bis(3,4-dibutoxyphenyl)propane-1,3-dionate as an ancillary ligand  

Energy Technology Data Exchange (ETDEWEB)

A new series of heteroleptic cyclometalated platinum(II) complexes Pt-1a-f was synthesized, employing 2-arylpyridine (or 1-arylisoquinoline) (HC{sup L}AMDAN-1) and 1,3-bis(3,4-dibutoxyphenyl)propane-1,3-dione (HO{sup L}AMDAO-1) for cyclometalation and as ancillary ligands, respectively, and photoluminescent properties were investigated. Focusing on red-shifted phosphorescence, C{sup L}AMDAN ligands containing pi-extended aromatics and electron-rich heterocycles were examined. All obtained complexes exhibited photoluminescence at ambient temperature, and the emission maxima ranged from green (lambda{sub PL}=518 nm) to far red (lambda{sub PL}=708 nm). The large Stokes shifts of more than 100 nm and sub-microsecond or microsecond emission lifetimes revealed that these complexes are phosphorescent emissive. The quantum yield of Pt-1 ranged from 0.02 to 0.59 at ambient temperature and decreased as the ...

2010-02-15

130

[Medicine and truth: between science and narrative].  

Science.gov (United States)

To which idea of truth may medicine refer? Evidence-based medicine (EBM) is rooted in the scientific truth. To explain the meaning and to trace the evolution of scientific truth, this article outlines the history of the Scientific Revolution and of the parable of Modernity, up to the arrival of pragmatism and hermeneutics. Here, the concept of truth becomes somehow discomfiting and the momentum leans towards the integration of different points of view. The fuzzy set theory for the definition of disease, as well as the shift from disease to syndrome (which has operational relevance for geriatrics), seems to refer to a more complex perspective on knowledge, albeit one that is less defined as compared to the nosology in use. Supporters of narrative medicine seek the truth in the interpretation of the patients' stories, and take advantage of the medical humanities to find the truth in words, feelings and contact with the patients. Hence, it is possible to mention the ...

131

Semi-empirical calculation of air-broadened half-widths and air pressure-induced frequency shifts of water-vapor absorption lines  

International Nuclear Information System (INIS)

This paper describes a semi-empirical calculation of the air-broadened half-widths and the air pressure-induced frequency shifts for the H_2"1"6O isotopologue. This semi-empirical calculation is based on fits of several recent high-quality measurements and theoretical calculations to the first-order terms in the expansion of the complex Robert-Bonamy (CRB) equations, which yields a second- and first-order polynomial function of the differences in the upper- and lower-state vibrational quantum numbers for the half-width and line shift, respectively. The aim of this work was to obtain a complete set of air-broadened half-widths and air pressure-induced frequency shifts for transitions of H_2"1"6O present in the HITRAN database from microwave to the visible in order to supplement the observed and calculated values. For around 700 sets of rotational quantum numbers (J"'K_a"'K_c"'<-J"''K_a"''K_c"''), semi-empirical ...

2005-12-01

132

How quantum is the big bang?  

CERN Document Server

When quantum gravity is used to discuss the big bang singularity, the most important, though rarely addressed, question is what role genuine quantum degrees of freedom play. Here, complete effective equations are derived for isotropic models with an interacting scalar to all orders in the expansions involved. The resulting coupling terms show that quantum fluctuations do not affect the bounce much. Quantum correlations, however, do have an important role and could even eliminate the bounce. How quantum gravity regularizes the big bang depends crucially on properties of the quantum state.

2008-01-01

133

Research - EU Descartes Prizes for excellence in research and science communication  

Wastenet

...EU Descartes Prizes for excellence in research and science communication descartes, prize, science communication, research, rtd, european commission, ...european union, eu EU Descartes Prizes for excellence in research and science communication Research - EU Descartes Prizes for excellence in research and science ...communication en European Commission Research Descartes Prize Contact | Search ...

134

Luminescent platinum(II) complexes of quinoxaline-2,3-dithiolate  

Energy Technology Data Exchange (ETDEWEB)

The synthesis, characterization, and photophysical properties of several Pt(II) complexes of quinoxaline-2,3-dithiolate (qdt) and 6,7-dimethylquinoxaline-2,3-dithiolate (dmqdt) are described. Specifically, (TBA){sub 2}[Pt(qdt){sub 2}], where TBA = tetra-n-butylammonium, Pt(COD)(qdt), where COD = 1,5-cyclooctadiene, and Pt(phen)(qdt), where phen = 1,10-phenanthroline, and their dmqdt analogs have been prepared and examined with respect to their photophysical properties. Highly structured emission from Pt(COD)(qdt) in frozen glass solution at 77 K has been detected, having a major vibrational progression of 1370 cm{sup {minus}1} corresponding to a C=C stretching frequency of the quinoxalinedithiolate backbone. Solution luminescence from (TBA){sub 2}[Pt(qdt){sub 2}] and Pt(phen)(qdt) has been detected with quantum yields, {Phi}{sub em}, of 10{sup {minus}5} and 10{sup {minus}3}, respectively, although the latter is highly sensitive to solvent ...

1995-04-12

135

Science of quantum phase transitions and quantum criticalities  

International Nuclear Information System (INIS)

Apart from conventional phase transitions driven by the thermal effects, quantum phase transitions generated by quantum fluctuations have their own mechanisms that are reflected in critical phenomena. Quantum phase transitions have an origin from spontaneous symmetry breaking commonly to thermal phase transitions. Even in this case, inherent quantum fluctuations substantially modify and yield new aspects. Quantum phase transitions have, however, another mechanism caused by topology changes, which gives completely new characters. Recently, a mechanism which connects these two has been found. Proimities from first-order transitions and phase separatins as well as from multiphase coexistence also generate characteristic and unconventional quantum criticalities. Understanding novel quantum criticalities offers a firm basis of recent active ...

2011-02-01

136

Quantum Thermodynamic Cycles and quantum heat engines  

CERN Document Server

In order to describe quantum heat engines, here we systematically study isothermal and isochoric processes for quantum thermodynamic cycles. Based on these results the quantum versions of both the Carnot heat engine and the Otto heat engine are defined without ambiguities. We also study the properties of quantum Carnot and Otto heat engines in comparison with their classical counterparts. Relations and mappings between these two quantum heat engines are also investigated by considering their respective quantum thermodynamic processes. In addition, we discuss the role of Maxwell's demon in quantum thermodynamic cycles. We find that there is no violation of the second law, even in the existence of such a demon, when the demon is included correctly as part of the working substance of the heat engine.

2006-01-01

137

Quantum computing and probability  

Energy Technology Data Exchange (ETDEWEB)

Over the past two decades, quantum computing has become a popular and promising approach to trying to solve computationally difficult problems. Missing in many descriptions of quantum computing is just how probability enters into the process. Here, we discuss some simple examples of how uncertainty and probability enter, and how this and the ideas of quantum computing challenge our interpretations of quantum mechanics. It is found that this uncertainty can lead to intrinsic decoherence, and this raises challenges for error correction. (viewpoint)

2009-11-25

138

Quantum Afterburner Improving the Efficiency of an Ideal Heat Engine  

CERN Document Server

By using a laser and maser in tandem, it is possible to obtain laser action in the hot exhaust gases involved in heat engine operation. Such a "quantum afterburner" involves the internal quantum states of working gas atoms or molecules as well as the techniques of cavity quantum electrodynamics and is therefore in the domain of quantum thermodynamics. As an example, it is shown that Otto cycle engine performance can be improved beyond that of the "ideal" Otto heat engine.

2002-01-01

139

Controllable Subspaces of Open Quantum Dynamical Systems  

International Nuclear Information System (INIS)

This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

2008-01-15

141

Correlations of Nursing Communication Network Metrics with Patient Outcomes  

UK PubMed Central (United Kingdom)

Communication problems have been implicated in many safety and quality issues, but tools to examine communication networks and their impact on patient outcomes are only beginning to become available....Full Text Available

2010-01-01

142

The restructured Milstar program  

Science.gov (United States)

This paper discusses the restructure of the Milstar communication satellite program. The resulting system is substantially streamlined, and will provide better utilization by tactical forces without compromising strategic nuclear communications requirements.

1992-03-01

143

Interferons and the Maternal-Conceptus Dialog in Mammals  

UK PubMed Central (United Kingdom)

Two-way communication between the conceptus and the mother during early pregnancy is essential if the pregnancy is to survive. In this review, our primary focus is on biochemical communication...Full Text Available

2008-04-01

144

Design of hybrid mobile communication networks for planetary ...  

Science.gov (United States)

... California where he is currently working on an AS in. Data Communication & Network Management as well as Microsoft. MCSE and Cisco CCNA certifications.

145

Quantum computing for physics research  

Energy Technology Data Exchange (ETDEWEB)

Quantum computers hold great promises for the future of computation. In this paper, this new kind of computing device is presented, together with a short survey of the status of research in this field. The principal algorithms are introduced, with an emphasis on the applications of quantum computing to physics. Experimental implementations are also briefly discussed.

2006-04-01

146

Principles of quantum computing  

Energy Technology Data Exchange (ETDEWEB)

This contribution is intended to introduce the principles of quantum computing to those who always wanted to know about quantum computing but never dared to ask. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

2007-11-15

147

Control and Dynamic Approach to Robust Quantum Computing.  

Science.gov (United States)

During the entire performance period, from 12 May 2003 through 31 December 2006, we have conducted theoretical and computational research on quantum control problems central to quantum computation. In particular we completed a thorough and rigorous analys...

2006-01-01

148

Dephasing of two electron states in a double quantum-dot system irradiated by a microwave field with a nearby Quantum Point Contact  

CERN Document Server

In this work we study the dephasing mechanism of a double quantum-dot system, which includes two electrons and a nearby quantum point contact (QPC) as a measurement device. We obtain that the QPC-induced decoherence is on time scales of microseconds. We also find that the electrons will be delocalized after continuous measurement, irrespectively of the initial conditions, and the frequent repeated measurements will localize the system, which is consistent with the quantum Zeno effect. Further, we consider the situation that the double quantum-dot system is irradiated by a microwave field.

2008-01-01

149

Correlations in Werner States  

International Nuclear Information System (INIS)

Werner states are paradigmatic examples of quantum states and play an innovative role in quantum information theory. In investigating the correlating capability of Werner states, we find the curious phenomenon that quantum correlations, as quantified by the entanglement of formation, may exceed the total correlations, as measured by the quantum mutual information. Consequently, though the entanglement of formation is so widely used in quantifying entanglement, it cannot be interpreted as a consistent measure of quantum correlations per se if we accept the folklore that total correlations are measured (or rather upper bounded) by the quantum mutual information.

2008-02-15

150

Type II Quantum Computing With Superconductors.  

Science.gov (United States)

The results of this research centered on the experimental studies of a single superconducting persistent current qubit, the implementation of type-II algorithms using these qubits, and the proposal for adiabatic quantum computing using these qubits. The m...

2004-01-01

151

The Generalized Quantization Schemes for Games and its Application to Quantum Information  

CERN Document Server

Theory of quantum games is relatively new to the literature and its applications to various areas of research are being explored. It is a novel interpretation of strategies and decisions in quantum domain. In the earlier work on quantum games considerable attention was given to the resolution of dilemmas present in corresponding classical games. Two separate quantum schemes were presented by Eisert et al. and Marinatto and Weber to resolve dilemmas in Prisoners' Dilemma and Battle of Sexes games respectively. However for the latter scheme it was argued that dilemma was not resolved. We have modified the quantization scheme of Marinatto and Weber to resolve the dilemma. We have developed a generalized quantization scheme for two person non-zero sum games which reduces to the existing schemes under certain conditions. Applications of this generalized quantization scheme to quantum ...

2010-01-01

152

Sandia National Labs: PCNSC: Departments: Semiconductor Material...  

Science.gov (United States)

For coupled quantum wires and dots, tunneling effects and coherent transport for quantum computing are being studied. In 2D systems, electron-hole bilayers for exciton...

2011-07-05

153

Quantum chromodynamics with advanced computing  

Energy Technology Data Exchange (ETDEWEB)

We survey results in lattice quantum chromodynamics from groups in the USQCD Collaboration. The main focus is on physics, but many aspects of the discussion are aimed at an audience of computational physicists.

2008-07-01

154

Physics of Quantum Well and Quantum Dot Infrared ...  

Science.gov (United States)

... In this paper we review the recent results concerning physical aspects of QWlP and QDIP operation focusing primarily on the electron transport ...

2000-06-23

155

On the spectroscopy of quantum dots in microcavities  

Energy Technology Data Exchange (ETDEWEB)

At the occasion of the OECS conference in Madrid, we give a succinct account of some recent predictions in the spectroscopy of a quantum dot in a microcavity that remain to be observed experimentally, sometimes within the reach of the current state of the art.

2010-02-01

156

Electrically Tunable Terahertz Quantum-Cascade Lasers  

Science.gov (United States)

Improved quantum-cascade lasers. (QCLs) are being developed as electri- ... These devices would supplant gas lasers as far-infrared sources. ...

157

Comments on the Quantum Afterburner  

CERN Document Server

A process has been proposed to increase the efficiency of an ideal Otto cycle via a quantum heat engine that has no cooler reservoir. We show that such a process is not feasible.

2007-01-01

158

Algebraic Topology Foundations of Supersymmetry and Symmetry Breaking in Quantum Field Theory and Quantum Gravity: A Review  

CERN Document Server

A novel algebraic topology approach to supersymmetry (SUSY) and symmetry breaking in quantum field and quantum gravity theories is presented with a view to developing a wide range of physical applications. These include: controlled nuclear fusion and other nuclear reaction studies in quantum chromodynamics, nonlinear physics at high energy densities, dynamic Jahn-Teller effects, superfluidity, high temperature superconductors, multiple scattering by molecular systems, molecular or atomic paracrystal structures, nanomaterials, ferromagnetism in glassy materials, spin glasses, quantum phase transitions and supergravity. This approach requires a unified conceptual framework that utilizes extended symmetries and quantum groupoid, algebroid and functorial representations of non-Abelian higher dimensional structures pertinent to quantized spacetime topology and state space geometry of ...

2009-01-01

159

(Q-8) Quantum Tunneling  

Science.gov (United States)

Feb 13, 2005 ... Part 8 of a non-mathematical historical review of elementary quantum theory, to help explain processes in the Sun and in stars; part of an ...

160

Usefulness of Computed Tomography in pre-surgical evaluation of maxillo-facial pathology with rapid prototyping and surgical pre-planning by virtual reality  

International Nuclear Information System (INIS)

Purpose. To validate a protocol for creating virtual models to be used in the construction of solid prototypes useful for the planning-simulation of maxillo-facial surgery, in particular for very complex anatomical and pathologic problems. To optimize communications between the radiology, engineering and surgical laboratories. Methods and materials. We studied 16 patients with different clinical problems of the maxillo-facial district. Exams were performed with multidetector computed tomography (MDCT) and single slice computed tomography (SDCT) with axial scans and collimation of 0.5-2 mm, and reconstruction interval of 1 mm. Subsequently we performed 2D multiplanar reconstructions and 3D volume-rendering reconstructions. We exported the DICOM images to the engineering laboratory, to recognize and isolate the bony structures by software. With these data the solid prototypes were generated using stereolitography. To date, surgery has been ...

2005-11-01

161

SRS Public Involvement in Waste Management Has Resulted in Effective Decisions Supported by the Public Including Disposal Changes and Top-to-Bottom Review Initiative Consensus  

Science.gov (United States)

In the Savannah River Site's (SRS') Solid Waste Management Program, a key to success is the Public Involvement Program. The Solid Waste Division at SRS manages the site's transuranic, low-level, mixed, and hazardous wastes. All decisions associated with management of this waste are of interest to the public and successful program implementation would be impossible without a vigorous public involvement program. The SRS Solid Waste Division (SWD) and its Department of Energy (DOE) customer developed, implemented, and maintain a comprehensive public participation and communications program. It is staffed by public participation and technical specialists to ensure information is presented in a manner that is technically accurate while being tailored for understanding by people without a technical background. The program provides the public with accurate, complete, timely information and early meaningful participation opportunities. It also ...

2003-02-27

162

Truck tactics: dispatch from Vancouver  

Energy Technology Data Exchange (ETDEWEB)

Any mine that uses haultrucks has a dispatching system of some sort, even if it is only a very basic and simple arrangement. The larger, more complex operations have found that, if properly applied, automated computerised dispatching improves the productivity of the equipment as well as improving overall control and reporting. However, not every mine can justify going this far; in these cases a computerised monitoring and reporting system with manual dispatching can still give considerable benefits. Wenco International Mining Systems of Vancouver supplies its computerised system to three different specification levels to suit most open pit mining operations. The article describes the 3 PMCSs (Production Monitoring and Control System) available: PMCS 1000, for monitoring and reporting only; PMCS 2000, for dispatching to maximise production; and PMCS 3000, for dispatching with optimised product quality and production. The major components of the PMCS are: mobile data ...

1991-11-01

163

The year 2000 embedded systems problem to maintain the safety of nuclear installations  

International Nuclear Information System (INIS)

The Y2K problem may impact on nuclear installations in a number of ways because embedded systems are used in nuclear routine operation, monitoring and control system. The very simplest embedded systems are capable of performing only a single function or set of functions to meet a single predetermined purpose. In more complex systems the functioning of the embedded system is determined by an application program that enables the embedded system to be used for a particular purpose in a specific application. The simplest devices consist of a single microprocessor which may itself be packaged with other chips in a hybrid system or Application Specific Integrated Circuit (ASIC). Its input comes from a detector or sensor and its output goes to a switch or activator which may start or stop the operation of a positioning motors or, by operating a valve, may control the flow of cooling system to reactor core. Embedded systems in our organization are also be found in Batan ...

1999-02-01

164

Phytoremediation : an industry partner's perspective  

International Nuclear Information System (INIS)

As part of their corporate policy on environmental protection, Chevron, has taken an approach to work collaboratively with other industry members, universities and government agencies in phytoremediation research. The petroleum industry is interested in the integration of phytoremediation with the many biotechnology treatment technologies currently being used by the industry. Phytoremediation is a complex technology that does not just transfer wastes to another site, but offers in-situ final use and disposal treatment at sites anywhere in the world. Sites for potential remediation range from abandoned large refineries, chemical plants, or small urban gas stations. Research has focused on the cleanup of metals and hydrocarbons in diverse types of soil, water and groundwater conditions. This includes research into remediation of petroleum contaminants such as total petroleum hydrocarbon (TPH), polynuclear aromatic hydrocarbons as well as benzene in soil and the ...

165

Design and implementation of the BESIII detector-control system  

Energy Technology Data Exchange (ETDEWEB)

In the upgrade project of the Beijing Electron-Positron Collider (BEPCII), a novel Detector-Control System (DCS) for the Beijing Spectrometer (BESIII) has been built and started its successful operation for the BESIII Commissioning. The main task of the DCS is to monitor and control the status of the BESIII detector and to guarantee a safe operation of the detector. The DCS must provide a uniform and coherent interface to detector operators even though there are a large number of distributed I/O channels from a large variety of equipments. For this reason, the DCS is hierarchically organized and divided into three layers: front-end layer (FEL), local control layer (LCL) and global control layer (GCL). In the FEL, devices ranging from simple sensors up to complex computer-based devices like embedded systems and programmable logical controllers (PLC) are utilized. A LabVIEW-based software framework has been developed for the LCL. Network ...

2008-07-21

166

A Communication Model for Adaptive Service Provisioning in Hybrid Wireless Networks  

CERN Document Server

Mobile entities with wireless links are able to form a mobile ad-hoc network. Such an infrastructureless network does not have to be administrated. However, self-organizing principles have to be applied to deal with upcoming problems, e.g. information dissemination. These kinds of problems are not easy to tackle, requiring complex algorithms. Moreover, the usefulness of pure ad-hoc networks is arguably limited. Hence, enthusiasm for mobile ad-hoc networks, which could eliminate the need for any fixed infrastructure, has been damped. The goal is to overcome the limitations of pure ad-hoc networks by augmenting them with instant Internet access, e.g. via integration of UMTS respectively GSM links. However, this raises multiple questions at the technical as well as the organizational level. Motivated by characteristics of small-world networks that describe an efficient network even without central or organized design, this paper proposes to combine mobile ad-hoc ...

2007-01-01

180

SIMPLIFIED METHODS FOR COMMUNICATING ...  

Science.gov (United States)

... COMBINATION WHICH DISCUSSES AND ILLUSTRATES THE CONSTRUCTION OF AN EXPLODING BRIDGEWIRE ELECTRO-EXPLOSIVE ...

1968-10-01

181

Research - Keyword Index  

Wastenet

...The number of documents that contain the keyword absolute zero is: 2 EU Descartes Prizes for excellence in research and science communication EU Descartes Prizes ...for excellence in research and science communication -Chemistry Close to Absolute Zero - Descartes Prize 2000 - Winner- Ian Smith EU Descartes Prizes for excellence ...in research and science communication EU Descartes Prizes for excellence in research and science communication -Chemistry Close to Absolute Zero - Descartes Prize 2000 ...

203

Implementing Advanced Technologies in the Republic of ...  

Science.gov (United States)

... personal computers low-cost information management capabilities to television's uncanny ability to motivate and communicate. ...

1994-03-01

224

Communicating Mathematics on the Internet: Synchronous and Asynchronous Tools  

British Library Electronic Table of Contents (United Kingdom)

Communicating and collaborating online are becoming common requirements in education. The specialized notations and symbols necessary for some content areas where mathematical expressions are part of the conversation require that users select appropriate communication tools. The purpose of this article is to describe tools that can be used for online, asynchronous or synchronous communication involving mathematical expressions.

2011-01-01

233
235

PICMG xTCA Standards Extensions for Physics: New Developments & Future Plans  

Energy Technology Data Exchange (ETDEWEB)

After several years of planning and workshop meetings, a decision was reached in late 2008 to organize PICMG xTCA for Physics Technical Subcommittees to extend the ATCA and MTCA telecom standards for enhanced system performance, availability and interoperability for physics controls and applications hardware and software. Since formation in May-June 2009, the Hardware Technical Subcommittee has developed a number of ATCA, ARTM, AMC, MTCA and RTM extensions to be completed in mid-to-late 2010. The Software Technical Subcommittee is developing guidelines to promote interoperability of modules designed by industry and laboratories, in particular focusing on middleware and generic application interfaces such as Standard Process Model, Standard Device Model and Standard Hardware API. The paper describes the prototype design work completed by the lab-industry partners to date, the timeline for hardware releases to PICMG for approval, and the status of the software guidelines roadmap. The ...

2010-08-26

236

The thermodynamic characteristics of retention of tricyclo[5.2.1.02,6]decane isomer molecules on different sorbents in gas chromatography  

Science.gov (United States)

The thermodynamic characteristics of sorption of the isomeric tricyclo[5.2.1.02.6]decane (tetrahydrodicyclopentadiene, TDCPD) molecules were for the first time determined experimentally and by molecular statistical methods under the conditions of gas-adsorption chromatography on graphitized thermal carbon black and gas-liquid chromatography on stationary liquid phases of different polarities (Apiezon L and Carbowax 20M). The effects of the chemical nature of sorbents on the retention of the TDCPD isomers are considered. A procedure for calculating the thermodynamic characteristics of adsorption of molecules with a complex structure is suggested within the framework of the atom-atom approximation of the semiempirical molecular statistical theory of adsorption for the example of isostructural norbornane molecules. The procedure involves simultaneous variation of geometric parameters and refinement of the parameters that determine the special features of the ...

2008-07-01

237

Quarkonia and QGP studies  

CERN Document Server

We summarize results of recent studies of heavy quarkonia correlators and spectral functions at finite temperatures from lattice QCD and systematic T-matrix studies using QCD motivated finite-temperature potentials. We argue that heavy quarkonia dissociation shall occur in the temperature range $1.2 \\le T_d/T_c \\le 1.5$ by the interplay of both screening and absorption in the strongly correlated plasma medium. We discuss these effects on the quantum mechanical evolution of quarkonia states within a time-dependent harmonic oscillator model with complex oscillator strength and compare the results with data for $R_{\\rm AA}/R_{\\rm AA}^{\\rm CNM}$ from RHIC and SPS experiments. We speculate whether the suppression pattern of the rather precise NA60 data from In-In collisions may be related to the recently discovered X(3872) state. Theoretical support for this hypothesis comes from the cluster expansion of the plasma Hamiltonian for heavy ...

2011-01-01

238

Photochemistry on surfaces. 2. Intermolecular electron transfer on colloidal alumina-coated silica particles  

Energy Technology Data Exchange (ETDEWEB)

Reductive quenching of two photoexcited ruthenium(II) complexes by an anionic electron donor, 2,2{prime}-azinobis(3-ethyl-benzothiazoline-6-sulfonate) (ABTS{sup 2{minus}}), in aqueous solution was examined by laser flash photolysis before and after adding positively charged colloidal (250-{angstrom} diameter) alumina-coated silica particles. The kinetics and quantum yields of electron transfer with an anionic sensitizer, RuL{sub 3}{sup 4{minus}} (L = bathophenanthroline disulfonate), and a cationic one, Ru(bpy){sub 3}{sup 2+} (bpy = 2,2{prime}-bipyridine), were compared. Coadsorption of ABTS{sup 2{minus}} and RuL{sub 3}{sup 4{minus}} by the particles greatly enhanced the rate of quenching such that only the reaction occurring on the surfaces of the particles was observed. Electron transfer from ABTS{sup 2{minus}} to RuL{sub 3}{sup 4-*} occurred by a static (nondiffusional) process, and the quenching efficiency was maximal when there was close ...

1989-02-23

239

Modelling fragmentations of amino-acids after resonant electron attachment: quantum evidence of possible direct -OH detachment  

International Nuclear Information System (INIS)

We investigate some aspects of the radiation damage mechanisms in biomolecules, focusing on the modelling of resonant fragmentation caused by the attachment of low-energy electrons (LEEs) initially ejected by biological tissues when exposed to ionizing radiation. Scattering equations are formulated within a symmetry-adapted, single-center expansion of both continuum and bound electrons, and the interaction forces are obtained from a combination of ab initio calculations and a nonempirical model of exchange and correlation effects developed in our group. We present total elastic scattering cross-sections and resonance features obtained for the equilibrium geometries of glycine, alanine, proline and valine. Our results at those geometries of the target molecules are briefly shown to qualitatively explain some of the fragmentation patterns obtained in experiments. We further carry out a one-dimensional (1D) modeling for the dynamics of intramolecular energy transfers mediated by the ...

2010-10-01

240

The Quantum Information Revolution: 101 Uses for Schroedingers Cat  

ScienceCinema

...exactly five years ago that english poet ? laws ...

241

Recovering quantum graphs from their Bloch spectrum  

CERN Document Server

We define the Bloch spectrum of a quantum graph to be the collection of the spectra of a family of Schr\\"odinger operators parametrized by the cohomology of the quantum graph. We show that the Bloch spectrum determines the Albanese torus, the block structure and the planarity of the graph. It determines a geometric dual of a planar graph. This enables us to show that the Bloch spectrum completely determines planar 3-connected quantum graphs.

2011-01-01

242
243

Quantum locking of mirrors in interferometric measurements  

International Nuclear Information System (INIS)

We discuss the use of active control to reduce mirror position fluctuations at the quantum level. We have shown in a recent experiment that it is possible to reduce the thermal noise of a mirror by measuring and controlling its motion with an optomechanical sensor based on a high-finesse optical cavity. This approach can be extended to lock the mirror motion at the quantum level, and to suppress the quantum effects of radiation pressure in interferometric measurements such as gravitational-wave detectors. The sensitivity improvement is furthermore independent of losses in the interferometer.

2004-03-07

244

Quantum information approach to the ultimatum game  

CERN Document Server

The paper is devoted to quantization of extensive games with the use of both the Marinatto-Weber and the Eisert-Wilkens-Lewenstein concept of quantum game. We revise the current conception of quantum ultimatum game and we show why the proposal is unacceptable. To support our comment, we present the new idea of the quantum ultimatum game. Our scheme also makes a point of departure for a protocol to quantize extensive games.

2011-01-01

246

Massive parallel generation of indistinguishable single photons via the polaritonic superfluid to Mott-insulator quantum phase transition  

International Nuclear Information System (INIS)

We study the possibility of utilizing the superfluid to Mott-insulator quantum phase transition in an array of quantum well exciton-polariton traps to generate indistinguishable single photons in a massive parallel fashion. By means of analytical and numerical methods, the device operations and system properties are examined using realistic experimental parameters. Such a deterministic, massive parallel generation may find new applications in photonic quantum information processing.

2010-12-01

247

Luminescence of guest - host type organic nanostructures  

International Nuclear Information System (INIS)

... Abstract only 1063-7869 v. 44(10) CLASSICAL AND QUANTUM MECHANICS,

2001-10-31

248

Loop quantum cosmology of Bianchi type IX models  

International Nuclear Information System (INIS)

The loop quantum cosmology 'improved dynamics' of the Bianchi type IX model are studied. The action of the Hamiltonian constraint operator is obtained via techniques developed for the Bianchi type I and type II models, no new input is required. It is shown that the big bang and big crunch singularities are resolved by quantum gravity effects. We also present effective equations which provide quantum geometry corrections to the classical equations of motion.

2010-08-15

250

Choice and meaning in the quantum universe  

Energy Technology Data Exchange (ETDEWEB)

This report discusses whether the events that occur in the universe evolve deterministicly or randomly or both. (LSP).

1992-05-22

251

A magneto-electric quantum wheel  

CERN Document Server

Here we show that self-propulsion in quantum vacuum may be achieved by rotating or aggregating magneto-electric nano-particles. The back-action follows from changes in momentum of electro-magnetic zero-point fluctuations, generated in magneto-electric materials. This effect may provide new tools for investigation of the quantum nature of our world. It might also serve in the future as a "quantum wheel" to correct satellite orientation in space.

2009-01-01

252

Quantum coherence in ion channels: resonances, transport and verification  

Energy Technology Data Exchange (ETDEWEB)

Recently it was demonstrated that long-lived quantum coherence exists during excitation energy transport in photosynthesis. It is a valid question up to which length, time and mass scales quantum coherence may extend, how one may detect this coherence and what, if any, role it plays in the dynamics of the system. Here we suggest that the selectivity filter of ion channels may exhibit quantum coherence, which might be relevant for the process of ion selectivity and conduction. We show that quantum resonances could provide an alternative approach to ultrafast two-dimensional (2D) spectroscopy to probe these quantum coherences. We demonstrate that the emergence of resonances in the conduction of ion channels that are modulated periodically by time-dependent external electric fields can serve as signatures of quantum coherence in such a system. Assessments of ...

2010-08-15

253

Effect of the repulsive core on the exciton spectrum in a quantum ring  

Energy Technology Data Exchange (ETDEWEB)

A theoretical study of an exciton confined in a quantum ring is presented. The quantum ring is described as a two-dimensional circular quantum dot with a repulsive core, which is modelled with the help of two Gaussian functions. We have applied the variational method and investigated the evolution of the low-energy exciton spectrum with the change of the confinement potential. The calculations have been performed for the recently produced self-assembled ring-shaped InGaAs quantum dots. We have shown that the repulsive core strongly increases the radiative transition probability from the exciton ground state at the expense of the decreasing probability of the transitions from the excited states. This effect results from the orthogonality properties of the exciton wavefunctions, which are specific to the quantum-ring confinement potential. We have studied the characteristic features ...

2002-01-14

254

Quantum Teleportation with Continuous Variables: a survey  

CERN Document Server

Very recently we have assisted to a new development of quantum information, the so-called continuous variable (CV) quantum information theory. Such a further development has been mainly due to the experimental and theoretical advantages offered by CV systems, i.e., quantum systems described by a set of observables, like position and momentum, which have a continuous spectrum of eigenvalues. According to this novel trend, quantum information protocols like quantum teleportation have been suitably extended to the CV framework. Here, we briefly review some mathematical tools relative to CV systems and we consequently develop the concepts of quantum entanglement and teleportation in the CV framework, by analogy with the qubit-based approach. Some connections between teleportation fidelity and entanglement properties of the underlying quantum ...

2006-01-01

255

Quantum-dot computing  

Energy Technology Data Exchange (ETDEWEB)

A quantum computer would put the latest PC to shame. Not only would such a device be faster than a conventional computer, but by exploiting the quantum-mechanical principle of superposition it could change the way we think about information processing. However, two key goals need to be met before a quantum computer becomes reality. The first is to be able to control the state of a single quantum bit (or 'qubit') and the second is to build a two-qubit gate that can produce 'entanglement' between the qubit states. (U.K.)

2003-10-01

256

Quantum Darwinism in quantum Brownian motion: the vacuum as a witness  

CERN Document Server

We study quantum Darwinism -- the redundant recording of information about a decohering system by its environment -- in zero-temperature quantum Brownian motion. An initially nonlocal quantum state leaves a record whose redundancy increases rapidly with its spatial extent. Significant delocalization (e.g., a Schroedinger's Cat state) causes high redundancy: many observers can measure the system's position without perturbing it. This explains the objective (i.e. classical) existence of einselected, decoherence-resistant pointer states of macroscopic objects.

2007-01-01

257

Programmed Assembly of Quantum-Dot Arrays on DNA Templates: Hardware for Quantum Computing?  

Energy Technology Data Exchange (ETDEWEB)

This paper reports progress in the fabrication and characterization of an array of 1nm-scale colloidal particles (i.e., quantum-dot array) that can be operated to execute nontrivial and innovative computations, possibly including quantum logic. We discuss the actual fabrication of 2-nm metal clusters as an example of possible quantum dot implementation. Innovative and unconventional paradigms underlie the different stages of this work. For example, regular array geometry is achieved by directing appropriately derivatized metal clusters to preselected locations along a stretched strand of an engineered DNA sequence.

2001-03-23

258

Dirac Fields in Loop Quantum Gravity and Big Bang Nucleosynthesis  

CERN Document Server

Big Bang nucleosynthesis requires a fine balance between equations of state for photons and relativistic fermions. Several corrections to equation of state parameters arise from classical and quantum physics, which are derived here from a canonical perspective. In particular, loop quantum gravity allows one to compute quantum gravity corrections for Maxwell and Dirac fields. Although the classical actions are very different, quantum corrections to the equation of state are remarkably similar. To lowest order, these corrections take the form of an overall expansion-dependent multiplicative factor in the total density. We use these results, along with the predictions of Big Bang nucleosynthesis, to place bounds on these corrections.

2007-01-01

259

Computing the distance between quantum channels: usefulness of the Fano representation  

Energy Technology Data Exchange (ETDEWEB)

The diamond norm measures the distance between two quantum channels. From an operational viewpoint, this norm measures how well we can distinguish between two channels by applying them to the input states of arbitrarily large dimensions. In this paper, we show that the diamond norm can be conveniently, and in a physically transparent way, computed by means of a Monte Carlo algorithm based on the Fano representation of quantum states and quantum operations. The effectiveness of this algorithm is illustrated for several single-qubit quantum channels.

2010-11-14

260

Toward a Conceptual Refinement of Interpersonal Communication Competence: An Analysis of Subjects' Conceptions of Adept and Inept Communicators.  

Science.gov (United States)

A study examined the concept of interpersonal communication competence in order to construct a more refined instrument than those currently used to measure competence. Using 70 items drawn from several existing measures of competence, 660 volunteer subjects from undergraduate communication courses at a large midwestern university provided their conception of adept and inept communicators, defined respectively as the best and worst communicators they know. Direct and multiple step-wise discriminant analyses were performed to determine the extent to which these items best discriminated between subjects' conceptions of adept and inept communicators, and to determine which of the 70 items best discriminated between these conceptions. Canonical discriminant functions revealed that the subjects clearly distinguished between adept and inept communicators. ...

1989-05-01

261

Mode of Communication, Perceived Level of Understanding, and Perceived Quality of Life in Youth Who Are Deaf or Hard of Hearing  

British Library Electronic Table of Contents (United Kingdom)

Given the important role of parent-youth communication in adolescent well-being and quality of life, we sought to examine the relationship between specific communication variables and youth perceived quality of life in general and as a deaf or hard-of-hearing (DHH) individual. A convenience sample of 230 youth (mean age = 14.1, standard deviation = 2.2; 24% used sign only, 40% speech only, and 36% sign + speech) was surveyed on communication-related issues, generic and DHH-specific quality of life, and depression symptoms. Higher youth perception of their ability to understand parents' communication was significantly correlated with perceived quality of life as well as lower reported depressive symptoms and lower perceived stigma. Youth who use speech as their single mode of communication ...

2011-01-01

262

Communication Estimation for Hardware/Software Codesign  

DEFF Research Database (Denmark)

This paper presents a general high level estimation model of communication throughput for the implementation of a given communication protocol. The model, which is part of a larger model that includes component price, software driver object code size and hardware driver area, is intended to be general enough to be able to capture the characteristics of a wide range of communication protocols and yet to be sufficiently detailed as to allow the designer or design tool to efficiently explore tradeoffs between throughput, bus widths, burst/non-burst transfers and data packing strategies. Thus it provides a basis for decision making with respect to communication protocols/components and communication driver design in the initial design space exploration phase of a co-synthesis process where a large number of possibilities must be examined and where fast estimators are therefore ...

1998-01-01

263

Supramolecular selectivity of [60]-fullerene among equivalently photoactive porphyrins  

International Nuclear Information System (INIS)

The photophysical investigation of different para-substituted tetraphenylporphyrins (TP), viz., meso-tetra(4'-hydroxyphenyl)-21H-23H-porphyrin(1),meso-tetrakis (4'-hex-5-enyloxyphenyl)-21H-23H-porphyrin(2), meso-tetrakis(4'-oct-7-enyloxyphenyl)-21H-23H-porphyrin(3) and meso-tetrakis(4'-undecyloxyphenyl)-21H-23H-porphyrin (4) revealed that except for quantum yield (#phi#) the para-substitution has little effect on any other photophysical properties like lifetime, excitation, emission wavelength, etc. The host-guest type interactions of these tetraarylporphyrins (TP 1-4), with [60]-fullerene (F) have been studied with "1H NMR and fluorescence spectrometric techniques in carbon tetrachloride medium. Fluorescence studies revealed that the Q band of the TPs was sufficiently quenched upon addition of F. All the fullerene/porphyrin systems were found to produce stable complexes with 1:1 stoichiometry. Binding constants (K) of all the ...

2010-10-01

265

The Design and Validation of the Quantum Mechanics Conceptual Survey  

CERN Document Server

The Quantum Mechanics Conceptual Survey (QMCS) is a 12-question survey of students' conceptual understanding of quantum mechanics. It is intended to be used to measure the relative effectiveness of different instructional methods in modern physics courses. In this paper we describe the design and validation of the survey, a process that included observations of students, a review of previous literature and textbooks and syllabi, faculty and student interviews, and statistical analysis. We also discuss issues in the development of specific questions, which may be useful both for instructors who wish to use the QMCS in their classes and for researchers who wish to conduct further research of student understanding of quantum mechanics. The QMCS has been most thoroughly tested in, and is most appropriate for assessment of (as a posttest only), sophomore-level modern physics courses. We also describe testing with students in ...

2010-01-01

266

Effective equations of motion for constrained quantum systems: A study of the Bianchi I loop quantum cosmology  

CERN Document Server

A new mathematical framework is formulated to derive the effective equations of motion for the constrained quantum system which possesses an internal clock. In the realm close to classical behavior, the quantum evolution is approximated by a finite system of coupled but ordinary differential equations adhered to the weakly imposed Hamiltonian constraint. For the simplified version of loop quantum cosmology in the Bianchi I model with a free massless scalar filed, the resulting effective equations of motion affirm the bouncing scenario predicted by the previous studies: The big bang singularity is resolved and replaced by the big bounces, which take place up to three times, once in each diagonal direction, whenever the directional density approaches the critical value in the regime of Planckian density. It is also revealed that back-reaction arises from the quantum corrections and modifies the precise ...

2008-01-01

267

Anomaly freedom in perturbative loop quantum gravity  

CERN Document Server

A fully consistent linear perturbation theory for cosmology is derived in the presence of quantum corrections as they are suggested by properties of inverse volume operators in loop quantum gravity. The underlying constraints present a consistent deformation of the classical system, which shows that the discreteness in loop quantum gravity can be implemented in effective equations without spoiling space-time covariance. Nevertheless, non-trivial quantum corrections do arise in the constraint algebra. Since correction terms must appear in tightly controlled forms to avoid anomalies, detailed insights for the correct implementation of constraint operators can be gained. The procedures of this article thus provide a clear link between fundamental quantum gravity and phenomenology.

2008-01-01

268

A generic quantum walk using a coin-embedded shift operator  

CERN Document Server

The study of quantum walk process has been widely divided into the two standard variants, the discrete-time quantum walk (DTQW) and the continuous-time quantum walk (CTQW). The connection between the two variants has been established by considering limiting value of the coin operation parameter in the DTQW and the coin degree of freedom is show to be unnecessary [26]. But the coin degree of freedom is an additional resource which can be exploited to control the dynamics of the QW process. In this paper we present a generic quantum walk (QW) model using a quantum coin-embedded unitary shift operation U_{C}. The standard version of the DTQW and the CTQW can be conveniently retrieved from this generic model retaining the features of the coin degree of freedom in both the variants.

2008-01-01

270

Subtemporal approach to basilar tip aneurysm with division of posterior communicating artery: Technical note  

UK PubMed Central (United Kingdom)

The subtemporal approach with division of the posterior communicating artery (PcomA) is described for treating aneurysms of the basilar tip. When the ipsilateral posterior cerebral artery (PCA) interferes...Full Text Available

2008-08-01

271

Role-Reversal Exercise with Deaf Strong Hospital to Teach Communication Competency and Cultural Awareness  

UK PubMed Central (United Kingdom)

ObjectiveTo implement a role-reversal exercise to increase first-year pharmacy students' awareness of communication barriers in the health care setting, especially for deaf and hard-of-hearing...Full Text Available

2011-04-11

272

RECOD 87  

International Nuclear Information System (INIS)

This fourth volume of the RECOD 87 proceedings contains two parts: 1 - Authors' communications which arrived after the conference. 2 - Authors' corrections concerning communications which were already published in the three first volumes.

273

Comparison of the UHF Follow-on and MILSTAR Satellite Communication Systems.  

Science.gov (United States)

The author compares the UHF Follow-on and MILSTAR satellite communication systems. The comparison uses an analytical hierarchy process. Although the two systems have been tasked with different missions, a comparison of cost, capability, and orbit is condu...

1991-01-01

274

Communicating human biomonitoring results to ensure policy coherence with public health recommendations: analysing breastmilk whilst protecting, promoting and supporting breastfeeding  

UK PubMed Central (United Kingdom)

This article addresses the problem of how to ensure consistency in messages communicating public health recommendations on environmental health and on child health. The World Health Organization states...Full Text Available

275

Alteration of the chemical environment disrupts communication in a freshwater fish  

UK PubMed Central (United Kingdom)

It is well established that changes to the chemical environment can impair development, physiology and reproductive biology; by contrast, impacts on communication have not been widely reported. This...Full Text Available

2006-05-22

276

A Picture Archiving and Communication System Module for Radiology  

UK PubMed Central (United Kingdom)

This paper presents the design and implementation of a clinical picture archiving and communication system (PACS) module within the radiology department of a 700-bed teaching hospital. The system is...Full Text Available

1988-11-09

282

Superconducting Switchable Circulator  

Science.gov (United States)

... as time delay shifters for large-area phased arrays in military (MILSTAR) as well as commercial (Sky phone and other satellite communication) systems, ...

283

Strategic Communication and the Combatant Commander  

Science.gov (United States)

... for International Development representatives. 3. If there is SC policy guidance, use it. If not, ask for it. In many cases, summaries ...

2009-10-01

284

SPACE FLIGHT 1999 - NASA  

Science.gov (United States)

Mission losses were incurred by an early warning satellite and a Milstar-2 communications satellite when their launch vehicles malfunctioned, the first, ...

285

Innovation in Scholarly Communication Vision and Projects from High-Energy Physics  

CERN Document Server

Having always been at the forefront of information management and open access, High-Energy Physics (HEP) proves to be an ideal test-bed for innovations in scholarly communication including new information and communication technologies. Three selected topics of scholarly communication in High-Energy Physics are presented here: A new open access business model, SCOAP3, a world-wide sponsoring consortium for peer-reviewed HEP literature; the design, development and deployment of an e-infrastructure for information management; and the emerging debate on long-term preservation, re-use and (open) access to HEP data.

2008-01-01

292

Defense Science Board 2006 Summer Study of Information ...  

Science.gov (United States)

... Those communications and information management capabilities required in the battlefield should be part of the weapon system. ...

2007-04-01

293

Crisis communication on nuclear facilities and addressing media  

International Nuclear Information System (INIS)

Japanese May 2009 p. 386-390 Japan Mitani, Shinji Japan Nuclear Energy

2009-05-01

294

Commander's Handbook for Strategic Communication and ...  

Science.gov (United States)

... to integrate and synchronize SC efforts and capabilities, as noted in the SC Roadmap, the joint community needs to publish SC policy and expand ...

2009-10-27

295

COMMUNICATION MEDIA AND EDUCATIONAL TECHNOLOGY AN - NASA Technical ...  

Science.gov (United States)

adaptations of analog audio technology Recent developments in tape cassette technolocy have made Itpossible to provide up to ...

296

An Evaluation of the Severity of the January 1998 Ice Storm in ...  

Science.gov (United States)

... storm. There was little damage to high-voltage transmission lines and communication towers in northern New England. ...

1998-04-01

297

A Secure and Efficient Communications Architecture for ...  

Science.gov (United States)

... Milstar Military Strategic and Tactical Relay Satellite ... (EHF) system, composed of the Military Strategic and Tactical Relay Satellite (Milstar) ...

2008-06-19

298

A Comparison of the Technical Communications Practices of ...  

Science.gov (United States)

... Scientists. NASA/DoD Aerospace Knowledge Diffusion Research Project. Descriptive Note : Technical memo. rept. no. 29,. ...

1994-12-01

299

Solar effects on communications  

International Nuclear Information System (INIS)

This paper focuses on potential effects of solar phenomena on communication systems used by the electric utility industry. It begins with a discussion of solar phenomena fundamentals and discussion of the interaction between solar emissions and the earth's ionosphere and magnetosphere. It continues with a discussion of the resulting impacts on communication systems including radio, satellite, wireline, fiber optic, and powerline systems and concludes with a discussion of mitigation techniques and a call for observers to report suspected solar impact experiencexperiences.

300

Secure direct communication using the 'polarization' entangled atomic ensembles  

Energy Technology Data Exchange (ETDEWEB)

We propose a scheme with potential experimental realization to generate 'polarization' entanglement between two atomic ensembles and show one of the applications - a novel secure communication allowing asymptotically key distribution and quasisecure direct communication. The scheme involves laser manipulation of atomic ensembles, adjustable quarter- and half-wave plates, beam splitters, polarizing beam splitters and single-photon detectors, and well fits the status of the current experimental technology.

2004-02-14

301

Proton beam therapy control system  

Energy Technology Data Exchange (ETDEWEB)

A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.

2010-09-21

302

Internal interface for RFC muon trigger electronics at CMS experiment  

CERN Document Server

The paper describes design and practical realization of an internal communication layer referred to as the Internal Interface (II). The system was realized for the RFC Muon Trigger of the CMS experiment. Fully automatic implementation of the communication layer is realized in the FPGA chips and in the control software. The methodology of implementation was presented in the description form of the interface structure from the sides of hardware and software. The examples of the communication layer realizations were given for the RFC Muon Trigger.

2004-01-01

303

Stretched DNA Investigated Using Molecular-Dynamics and Quantum-Mechanical Calculations  

UK PubMed Central (United Kingdom)

AbstractWe combined atomistic molecular-dynamics simulations with quantum-mechanical calculations to investigate the sequence dependence of the stretching behavior of duplex DNA. Our...Full Text Available

2010-01-06

304

Quaternion quantum mechanics as a true 3+1-dimensional theory of tachyons  

International Nuclear Information System (INIS)

Using a new approach to quaternion mechanics based on De Broglie waves, it is shown that such a theory describes tachyons and that the quantum theory of tachyons should be a quaternionic one. (U.K.).

305

Quantum group structure in the unitary minimal model  

Energy Technology Data Exchange (ETDEWEB)

We obtain a symmetry algebra for any unitary minimal model by using the representation of conformal field theories. This symmetry algebra can be interpreted as a quantum group. The generalization to non-unitary minimal models is direct. (orig.).

1989-10-05

306

Quantum group structure in the unitary minimal model  

International Nuclear Information System (INIS)

We obtain a symmetry algebra for any unitary minimal model by using the representation of conformal field theories. This symmetry algebra can be interpreted as a quantum group. The generalization to non-unitary minimal models is direct. (orig.).

307

Quantum computing with solids  

Energy Technology Data Exchange (ETDEWEB)

Science and technology could be revolutionized by quantum computers, but building them from solid-state devices will not be easy. Robert W Keyes of IBM's research division outlines the challenges in scaling up the technology from lab experiments to practical devices. (U.K.)

2002-08-01

308

Quantum computing and the chaotic amplifier  

Energy Technology Data Exchange (ETDEWEB)

A new model for computations is considered which combines the quantum computer with the chaotic dynamics amplifier, based on the logistic map. We discuss the satisfiability problem and argue that the problem can, in principle, be solved in polynomial time if one uses the new model for computations.

2003-12-01

309

Mapping strain exerted on blood vessel walls using deuterium double-quantum-filtered MRI  

UK PubMed Central (United Kingdom)

A technique is described for displaying distinct tissue layers of large blood vessel walls as well as measuring their mechanical strain. The technique is based on deuterium double-quantum-filtered (DQF)...Full Text Available

1998-04-14

310

Lie-algebraic approach to the problem of quasi-exact solubility in quantum mechanics  

Energy Technology Data Exchange (ETDEWEB)

In this paper method of constructing quasi-exactly solvable models of quantum mechanics is proposed. This method is based on the use of infinite-dimensional representations of simple and semi-simple Lie algebras.

1990-09-20

311

Feynman lectures on physics, quantum mechanics; Le cours de physique de Feynman mecanique quantique  

Energy Technology Data Exchange (ETDEWEB)

This course is based upon lectures in physics given by Professor Feynman at the California institute of technology during 1961 and 1962. This volume is dedicated to quantum physics, semiconductors, symmetry and advanced principles of physics.

2000-07-01

312

Ensemble quantum computing by NMR?spectroscopy  

UK PubMed Central (United Kingdom)

A quantum computer (QC) can operate in parallel on all its possible inputs at once, but the amount of information that can be extracted from the result is limited by the phenomenon of wave function...Full Text Available

1997-03-04

313

Asymptotic functions and multiplication of distributions  

International Nuclear Information System (INIS)

Considered is a new type of generalized asymptotic functions, which are not functionals on some space of test functions as the Schwartz distributions. The definition of the generalized asymptotic functions is given. It is pointed out that in future the particular asymptotic functions will be used for solving some topics of quantum mechanics and quantum theory.

1976-01-26

314

Why we don`t need quantum planetary dynamics, or on decoherence and the correspondence principle for chaotic systems  

Energy Technology Data Exchange (ETDEWEB)

Violation of correspondence principle may occur for very macroscopic byt isolated quantum systems on rather short timescales as illustrated by the case of Hyperion, the chaotically tumbling moon of Saturn, for which quantum and classical predictions are expected to diverge on a timescale of approximately 20 years. Motivated by Hyperion, we review salient features of ``quantum chaos`` and show that decoherence is the essential ingredient of the classical limit, as it enables one to solve the apparent paradox caused by the breakdown of the correspondence principle for classically chaotic systems.

1995-08-01

315

Tachyons in field theory  

International Nuclear Information System (INIS)

The conventional treatment of quantum field theories including tachyons is presented, in particular the phi"4 theory. (W.D.L.).

316

Phonon-mediated entanglement for trapped ion quantum computing  

Energy Technology Data Exchange (ETDEWEB)

Trapped ions are a near ideal system to study quantum information processing due to the high degree of control over the ion's external confinement and internal degrees of freedom. We demonstrate the key steps necessary for trapped ion quantum computing and focus on phonon-mediated entangling gates. We highlight several key algorithms implemented over the last decade with these gates and give a detailed description of Grover's quantum database search implemented with two trapped ion qubits.

2010-03-15

317

OCW Physics  

Wastenet

...225J Einstein, Oppenheimer, Feynman: Physics in the 20th Century Fall 2002 8.231 Physics of Solids I Fall 2002 8.251 String Theory for Undergraduates Spring 2003 8.261J Introduction to Computational Neuroscience Spring 2002 8.282J Introduction to Astronomy Spring 2003 8.321 Quantum Theory I Fall 2002 8.322 Quantum Theory II Spring 2003 8.323 Relativistic Quantum Field Theory I Spring 2003 8.324 Quantum Field Theory II ...

318

Integrated photonic qubit quantum computing on a superconducting chip  

International Nuclear Information System (INIS)

We study a quantum computing system using microwave photons in transmission line resonators on a superconducting chip as qubits. We show that linear optics and other controls necessary for quantum computing can be implemented by coupling to Josephson devices on the same chip. By taking advantage of the strong nonlinearities in Josephson junctions, photonic qubit interactions can be realized. We analyze the gate error rate to demonstrate that our scheme is realistic even for Josephson devices with limited decoherence times. As a conceptually innovative solution based on existing technologies, our scheme provides an integrated and scalable approach to the next key milestone for photonic qubit quantum computing.

2010-06-01

319

InP-quantum dots in AlGaInP  

International Nuclear Information System (INIS)

... dpg-tagungen.de Dresden (Germany) 27-31 Mar 2006 0420-0195 VDPEAZ

2006-03-27

320

Go vs. no-go - potential and limitations of continuous-variable quantum computing by measurements  

Energy Technology Data Exchange (ETDEWEB)

In this talk, we explore the feasibility of quantum computation using continuous-variable systems by means of local measurements only. In the first part of the talk, we will identify crucial limitations that arise when starting from Gaussian cluster states. This is done by resorting to a Gaussian projected entangled pair picture as well as to notions of continuous-variable quantum repeater networks. In the second part, we look at instances in which these limitations can be overcome, and how suitable encodings of qubits in oscillators and feasible non-Gaussian resource states give rise to universal schemes for quantum computing.

2010-07-01

321

Entangled quantum currents in distant mesoscopic Josephson junctions  

Energy Technology Data Exchange (ETDEWEB)

Two mesoscopic SQUID rings which are far from each other are considered. A source of two-mode nonclassical microwaves irradiates the two rings with correlated photons. The Josephson currents are in this case quantum mechanical operators, and their expectation values with respect to the density matrix of the microwaves yield the experimentally observed currents. Classically correlated (separable) and quantum mechanically correlated (entangled) microwaves are considered, and their effect on the Josephson currents is quantified. Results for two different examples that involve microwaves in number states and coherent states are derived. It is shown that the quantum statistics of the tunnelling electron pairs through the Josephson junctions in the two rings are correlated.

2004-12-22

323

All Optical Switch of Vacuum Rabi Oscillations: The Ultrafast Quantum Eraser  

CERN Document Server

We study the all-optical time-control of the strong coupling between a single cascade three-level quantum emitter and a microcavity. We find that only specific arrival-times of the control pulses succeed in switching-off the Rabi oscillations. Depending on the arrival times of control pulses, a variety of exotic non-adiabatic cavity quantum electrodynamics effects can be observed. We show that only control pulses with specific arrival times are able to suddenly switch-off and -on first-order coherence of cavity photons, without affecting their strong coupling population dynamics. Such behavior may be understood as a manifestation of quantum complementarity.

2010-01-01

324

Quantum cosmological approach to the cosmic no-hair conjecture in the Bianchi type-IX spacetime  

Energy Technology Data Exchange (ETDEWEB)

The propriety of the cosmic no-hair conjecture to the Bianchi-type-IX spacetime is discussed from a quantum cosmological point of view. It is shown that most, but not all, classical universes which are created quantum cosmologically are inflationary. The probability of inflation among such universes is also discussed.

1990-02-15

325

Quantum cosmological approach to the cosmic no-hair conjecture in the Bianchi type-IX spacetime  

International Nuclear Information System (INIS)

The propriety of the cosmic no-hair conjecture to the Bianchi-type-IX spacetime is discussed from a quantum cosmological point of view. It is shown that most, but not all, classical universes which are created quantum cosmologically are inflationary. The probability of inflation among such universes is also discussed.

326

Optimal Quantum State Estimation by No-Signaling Principle  

CERN Document Server

We obtain a simple derivation of the optimal quantum state estimation of a two-level system using the no-signaling principle. In particular, we show that the no-signaling principle determines the unique form of the guessing probability, independently to a given figure of merit such as the fidelity or the information gain. This proves that optimal measurements for a two-level quantum system is the same for almost all figures of merit.

2010-01-01

327

Investigation of morphology and chemical composition of self-organized semiconductor quantum dots and wires by X-ray scattering  

International Nuclear Information System (INIS)

X-ray scattering methods suitable for the investigation of the morphology and chemical composition of self-organized quantum dots and quantum wires are reviewed. Their application is demonstrated in experimental examples showing that a combination of small angle X-ray scattering with high-resolution X-ray diffraction can reveal both the shape and the chemical composition of the self-organized objects. (author)

2001-09-23

328

Finding two-dimensional peaks  

CERN Document Server

Two-dimensional generalization of the original peak finding algorithm suggested earlier is given. The ideology of the algorithm emerged from the well known quantum mechanical tunneling property which enables small bodies to penetrate through narrow potential barriers. We further merge this ``quantum'' ideology with the philosophy of Particle Swarm Optimization to get the global optimization algorithm which can be called Quantum Swarm Optimization. The functionality of the newborn algorithm is tested on some benchmark optimization problems.

2004-01-01

329

Experimental realization of Dicke states of up to six qubits for multiparty quantum networking  

CERN Document Server

We report the first experimental generation and characterization of a six-photon Dicke state and demonstrate its remarkable versatility by projecting out four- and five-photon Dicke states, in addition to four-photon GHZ- and W-states. These multipartite states are studied by developing experimentally favorable characterization tools. Furthermore, we show that Dicke states have interesting applications in multiparty quantum networking protocols such as open-destination teleportation, telecloning and quantum secret sharing.

2009-01-01

330

Consistent Loop Quantum Cosmology  

CERN Document Server

A consistent combination of quantum geometry effects rules out a large class of models of loop quantum cosmology and their critical densities as they have been used in the recent literature. In particular, the critical density at which an isotropic universe filled with a free, massless scalar field would bounce must be well below the Planck density. In the presence of anisotropy, no model of the Schwarzschild black hole interior analyzed so far is consistent.

2008-01-01

331

Computing quantum eigenvalues made easy  

Energy Technology Data Exchange (ETDEWEB)

An extremely simple and convenient method is presented for computing eigenvalues in quantum mechanics by representing position and momentum operators in matrix form. The simplicity and success of the method is illustrated by numerical results concerning eigenvalues of bound systems and resonances for Hermitian and non-Hermitian Hamiltonians as well as driven quantum systems. Various MATLAB program codes are listed. (author)

2002-07-01

332

Adiabatic quantum computing with phase modulated laser pulses  

Energy Technology Data Exchange (ETDEWEB)

Implementation of quantum logical gates for multilevel systems is demonstrated through decoherence control under the quantum adiabatic method using simple phase modulated laser pulses. We make use of selective population inversion and Hamiltonian evolution with time to achieve such goals robustly instead of the standard unitary transformation language. (letter to the editor)

2005-09-23

333

2D cavity grid quantum computing  

Energy Technology Data Exchange (ETDEWEB)

We propose a novel scheme for scalable solid state quantum computing, where superconducting microwave transmission line resonators (cavities) are arranged in a two-dimensional grid on the surface of a chip, coupling to superconducting qubits (charge or flux) at the intersections. We analyze how tasks of quantum information processing can be implemented in such a topology, including efficient two-qubit gates between any two qubits on the grid and elements of fault-tolerant computation.

2008-07-01

334

TrustMAS: Trusted Communication Platform for Multi-Agent Systems  

CERN Document Server

The paper presents TrustMAS - Trusted Communication Platform for Multi-Agent Systems, which provides trust and anonymity for mobile agents. The platform includes anonymous technique based on random-walk algorithm for providing general purpose anonymous communication for agents. All agents, which take part in the proposed platform, benefit from trust and anonymity that is provided for their interactions. Moreover, in TrustMAS there are StegAgents (SA) that are able to perform various steganographic communication. To achieve that goal, SAs may use methods in different layers of TCP/IP model or specialized middleware enabling steganography that allows hidden communication through all layers of mentioned model. In TrustMAS steganographic channels are used to exchange routing tables between StegAgents. Thus all StegAgents in TrustMAS with their ability to exchange information by using hidden channels form ...

2008-01-01

335

Emerging trends in information and communication technology in mine safety and disaster management  

British Library Electronic Table of Contents (United Kingdom)

There is tremendous growth in the use of Geographic Information Systems (GIS), Global Positioning Systems (GPS), Remote Sensing, Satellite Communication, and Modeling & Simulation techniques. These tools and techniques helps significantly in characterizing infrastructure, risk area and disaster zones, planning and implementation of hazards reduction measures etc. Communication satellites becomes vital for providing emergency communication and timely relief measures. Integration of space technology inputs into natural disaster monitoring and mitigation mechanisms is critical for hazard reduction. This paper mainly focused on all the issues described above. Major emphasis had been given to the recent developments in information & communication technology enabled tools and their applications ...

2010-01-01

336

Determining a bisection bandwidth for a multi-node data communications network  

Energy Technology Data Exchange (ETDEWEB)

Methods, systems, and products are disclosed for determining a bisection bandwidth for a multi-node data communications network that include: partitioning nodes in the network into a first sub-network and a second sub-network in dependence upon a topology of the network; sending, by each node in the first sub-network to a destination node in the second sub-network, a first message having a predetermined message size; receiving, by each node in the first sub-network from a source node in the second sub-network, a second message; measuring, by each node in the first sub-network, the elapsed communications time between the sending of the first message and the receiving of the second message; selecting the longest elapsed communications time; and calculating the bisection bandwidth for the network in dependence upon the number of the nodes in the first sub-network, the predetermined message size of the first test message, and ...

2010-01-26

337

Strong-Weak Coupling Duality in Quantum Mechanics  

CERN Document Server

We present a strong-weak coupling duality for quantum mechanical potentials. Similarly to what happens in quantum field theory, it relates two problems with inverse couplings, leading to a mapping of the strong coupling regime into the weak one, giving information from the nonperturbative region of the parameters space. It can be used to solve exactly power-type potentials and to extract deep information about the energy spectra of polynomial ones. We present a strong-weak coupling duality for quantum mechanical potentials. Similarly to what happens in quantum field theory, it relates two problems with inverse couplings, leading to a mapping of the strong coupling regime into the weak one, giving information from the nonperturbative region of the parameters space. It can be used to solve exactly power-type potentials and to extract deep information about the energy spectra of polynomial ones.

1996-01-01

338

Scalable quantum computing with atomic ensembles  

International Nuclear Information System (INIS)

Atomic ensembles, comprising clouds of atoms addressed by laser fields, provide an attractive system for both the storage of quantum information and the coherent conversion of quantum information between atomic and optical degrees of freedom. We describe a scheme for full-scale quantum computing with atomic ensembles, in which qubits are encoded in symmetric collective excitations of many atoms. We consider the most important sources of error-imperfect exciton-photon coupling and photon losses-and demonstrate that the scheme is extremely robust against these processes: the required photon emission and collection efficiency threshold is #approx#>86%. Our scheme uses similar methods to those already demonstrated experimentally in the context of quantum repeater schemes and yet has information processing capabilities far beyond those proposals.

2010-09-01

339

Quantum probabilities: an information-theoretic interpretation  

CERN Document Server

This Chapter develops a realist information-theoretic interpretation of the nonclassical features of quantum probabilities. On this view, what is fundamental in the transition from classical to quantum physics is the recognition that \\emph{information in the physical sense has new structural features}, just as the transition from classical to relativistic physics rests on the recognition that space-time is structurally different than we thought. Hilbert space, the event space of quantum systems, is interpreted as a kinematic (i.e., pre-dynamic) framework for an indeterministic physics, in the sense that the geometric structure of Hilbert space imposes objective probabilistic or information-theoretic constraints on correlations between events, just as the geometric structure of Minkowski space in special relativity imposes spatio-temporal kinematic constraints on events. The interpretation of quantum ...

2010-01-01

340

Irreversible Performance of a Quantum Harmonic Heat Engine  

CERN Document Server

The unavoidable irreversible losses of power in a heat engine are found to be of quantum origin. Following thermodynamic tradition a model quantum heat engine operating by the Otto cycle is analyzed. The working medium of the model is composed of an ensemble of harmonic oscillators. A link is established between the quantum observables and thermodynamical variables based on the concept of canonical invariance. These quantum variables are sufficient to determine the state of the system and with it all thermodynamical variables. Conditions for optimal work, power and entropy production show that maximum power is a compromise between the quasistatic limit of adiabatic following on the compression and expansion branches and a sudden limit of very short time allocation to these branches. At high temperatures and quasistatic operating conditions the efficiency at maximum power coincides with the ...

2006-01-01

341

In situ ligand exchange of thiol-capped CuInS2/ZnS quantum dots at growth stage without affecting luminescent characteristics  

British Library Electronic Table of Contents (United Kingdom)

An aliphatic thiol ligand of CuInS2/ZnS core/shell quantum dots is replaced with a hydroxyl-terminated thiol ligand by utilizing `on-off state' of ligands during growth stage of the quantum dots. After the ligand-exchange, negligible differences were observed on both photoluminescence spectrum and luminescent quantum efficiency. The reason for the high retention of luminescent efficiency comes from no local agglomeration and no surface deterioration of QDs. It is also observed that 70% of initial ligands are exchanged by the replacing ligand, determined by FT-IR and 1H NMR. The proposed method provides the quantum dots with an excellent dispersibility in polar solvents, supported by identical luminescence decay characteristics of the QDs.

2011-01-01

342

From Bargmann's superselection rule to quantum Newtonian spacetime  

CERN Document Server

Bargmann's superselection rule, which forbids the existence of superpositions of states with different mass and, therefore, implies the impossibility of describing unstable particles in non-relativistic quantum mechanics, arises as a consequence of demanding Galilean covariance of Schr\\"odinger's equation. However, the usual Galilean transformations inadequately describe the symmetries of non-relativistic quantum mechanics since they fail to take into account relativistic time contraction effects which can produce non-relativistic phases in the wavefunction. In this paper we describe the incompatibility between Bargmann's rule and Lorentz transformations in the low-velocities limit, we analyze its classical origin and we show that the Extended Galilei group characterizes better the symmetries of the theory. Furthermore, we claim that a proper description of non-relativistic quantum mechanics requires a modification of the ...

2011-01-01

343

Formation and stability of astatide-mercury complexes  

International Nuclear Information System (INIS)

The formation of astatide-mercury complexes was investigated in aqueous solutions.The obtained complexes were examined by paper electrophoresis. It was found that Hg(OH)At and Hg(OH)I complexes were formed in neutral solution. The stability constants of the obtained complexes were determined by ion-exchange. The preliminary results indicate that the complex of mercury with astatide is much more stable than similar complexes with iodide. (author)

2006-04-01

344

On the integration of technology readiness levels at Sandia National Laboratories.  

Energy Technology Data Exchange (ETDEWEB)

Integrating technology readiness levels (TRL) into the management of engineering projects is critical to the mitigation of risk and improved customer/supplier communications. TRLs provide a common framework and language with which consistent comparisons of different technologies and approaches can be made. At Sandia National Laboratories, where technologies are developed, integrated and deployed into high consequence systems, the use of TRLs may be transformational. They are technology independent and span the full range of technology development including scientific and applied research, identification of customer requirements, modeling and simulation, identification of environments, testing and integration. With this report, we provide a reference set of definitions for TRLs and a brief history of TRLs at Sandia National Laboratories. We then propose and describe two approaches that may be used to integrate TRLs into the NW SMU business practices. In the first ...

2006-09-01

345

LOOP Inc. (Louisiana Offshore Oil Port Inc. ) to start onshore construction this year  

Science.gov (United States)

A discussion covers the LOOP project to construct an offshore pipeline system, which will connect with onshore facilities at Fourchon, La., and two onshore pipelines (26 mi 48 in. Clovelly line and 53 mi 48 in. LOCAP line) connecting Fourchon with the existing Capline system at St. James, La.; the three-phase construction schedule, the first phase due to begin in the third quarter of 1978 with, e.g., onshore pipeline and salt dome storage facility construction which will yield an expected initial throughput of 1.4 million bbl/day; the marine terminal complex, consisting of control and pumping platforms, and three 7000 hp pumps to operate the system at 45,000-100,000 bbl/hr; the offshore lines, including lines between single-point mooring units and the pumping platform, the 21 mi 48 in. pipe to Fourchon, and corrosion protection of lines by an asphalt-sand mixture or a semiplasticized coal-tar enamel; the onshore system, including the Fourchon booster station, ...

1978-06-01

346

Host based internet protocol (IP) packet analysis to enhance network security  

International Nuclear Information System (INIS)

Data communication in a computer network environment is facing serious security threats from numerous sources such as viruses, worms, Zombies etc. These threats can be broadly characterized as internal or external security threats. Internal threats are mainly attributed to sneaker-nets, utility modems and unauthorized users, which can be minimized by skillful network administration, password management and optimum usage policy definition. The external threats need more serious attention as these attacks are mostly coming from public networks such as Internet. Frequency and complexity of such attacks is much higher as compared to internal attacks. This paper presents a host based network layer screening of external and internal IP packets for logging, analyzing and real-time detection of possible IP spoofing and Denial of Service attacks. This work can also be used in tuning security rules definition for gateway firewalls. Software has been ...

2007-01-01

347

DEVELOPMENT OF TECHNOLOGIES AND ANALYTICAL CAPABILITIES FOR VISION 21 ENERGY PLANTS  

Energy Technology Data Exchange (ETDEWEB)

The goal of this DOE Vision-21 project work scope is to develop an integrated suite of software tools that can be used to simulate and visualize advanced plant concepts. Existing process simulation software does not meet the DOE's objective of ''virtual simulation'' which is needed to evaluate complex cycles. The overall intent of the DOE is to improve predictive tools for cycle analysis, and to improve the component models that are used in turn to simulate the cycle. Advanced component models are available; however, a generic coupling capability that will link the advanced component models to the cycle simulation software remains to be developed. In the current project, the coupling of the cycle analysis and cycle component simulation software will be based on an existing suite of programs. The challenge is to develop a general-purpose software and communications link between the cycle analysis ...

2002-08-31

348

Algebraic complexities and algebraic curves over finite fields  

UK PubMed Central (United Kingdom)

We consider the problem of minimal (multiplicative) complexity of polynomial multiplication and multiplication in finite extensions of fields. For infinite fields minimal complexities are known [Winograd,...Full Text Available

1987-04-01

349

Secure data communication for safeguards implementation  

International Nuclear Information System (INIS)

Full text: Secure, reliable and cost-effective communications are becoming an increasingly important tool for safeguards verification. This trend began with the initiation of remote monitoring implementation, where secure and cost effective data communications were required both to satisfy the confidentiality requirements of Member States and in order to meet the rigorous data authenticity requirements which allow the International Atomic Energy Agency (IAEA) to draw credible and independent conclusions. In addition, the implementation of additional protocols and integrated safeguards increases the importance of information (obtained in the course of an inspection, visit, complementary access or design information verification) being analyzed and corroborated with other information sources stored at IAEA Headquarters or Regional Offices, often while the inspector is still on-site. This requires the capability of enabling the inspector, wherever ...

2006-10-16

350

Distribution of quantum information between an atom and two photons  

Energy Technology Data Exchange (ETDEWEB)

The construction of networks consisting of optically interconnected processing units is a promising way to scale up quantum information processing systems. To store quantum information, single trapped atoms are among the most proven candidates. By placing them in high finesse optical resonators, a bidirectional information exchange between the atoms and photons becomes possible with, in principle, unit efficiency. Such an interface between stationary and ying qubits constitutes a possible node of a future quantum network. The results presented in this thesis demonstrate the prospects of a quantum interface consisting of a single atom trapped within the mode of a high-finesse optical cavity. In a two-step process, we distribute entanglement between the stored atom and two subsequently emitted single photons. The long atom trapping times achieved in the system together with the high photon collection ...

2008-11-03

351

Front-End-Electronics Communication software for multiple detectors in the ALICE experiment  

Energy Technology Data Exchange (ETDEWEB)

In the ALICE experiment at CERN, the Detector Control System (DCS) employs several interacting software components to accomplish its task of ensuring the correct operation and monitoring of the experiment. This paper describes the Front-End-Electronics Communication (FeeCommunication) software and its role within the DCS. The FeeCommunication software's central task is passing configuration and monitoring data between the top level DCS process control and the field devices of several detectors within ALICE. The lowest level of the FeeCommunication software runs on the DCS boards, specialized embedded systems which are in direct contact with the field devices and are physically located within the detector. The middle and upper layers run on standard PC hardware located in the counting room or other external locations. This paper focuses on the design and implementation of the ...

2006-02-15

355

DEVELOPMENT OF A GEOGRAPHIC VISUALIZATION AND COMMUNICATIONS SYSTEMS (GVCS) FOR MONITORING REMOTE VEHICLES  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this project is to integrate a variety of geographic information systems capabilities and telecommunication technologies for potential use in geographic network and visualization applications. The specific technical goals of the project were to design, develop, and simulate the components of an audio/visual geographic communications system to aid future real-time monitoring, mapping and managing of transport vehicles. The system components of this feasibility study are collectively referred to as a Geographic Visualization and Communications System (GVCS). State-of-the-art techniques will be used and developed to allow both the vehicle operator and network manager to monitor the location and surrounding environment of a transport vehicle during shipment.

1998-03-30

356

Bechtel Hanford Inc. Network Security Plan for the EnvironmentalRestoration Contract  

Science.gov (United States)

'As part of the Computer Protection Plan, this Network Security Plan identifies the specific security measures used to protect Bechtel Hanford, Inc.'s (BHI's) enterprise network. The network consists of the communication infrastructure and information systems used by BHI to perform work related to the Environmental Restoration Contract (ERC) at the Hanford Site. It provides electronic communication between the ERC-leased facilities in Richland, Washington, and facilities located on the Hanford Site. Network gateways to other site and offsite networks provide electronic communication with the remainder of the Hanford community.'

1999-06-30

357

Complex fluid analysis with the advanced distillation curve approach.  

Science.gov (United States)

An improved method for measuring distillation curves reveals the physicochemical properties of complex fluids such as fuels. PMID:20041713

2010-02-01

358

contents - NASA History Office  

Science.gov (United States)

David N. Spires and Rick W. Sturdevant, "From Advent to Milstar: The United States Air Force and the Challenges of Military Satellite Communications. Chapter 8 ...

359

Volcanoscope: Scoping study for increasing resilience to hazards in volcanic regions  

Environmental Research Database

ObjectivesProject VOLCANOSCOPE will evaluate strategies (1) for applying existing and new forecasting models to volcanic eruptions, and (2) for identifying methods to improve how forecasts are communicated effectively to vulnerable communities. To link forecasting and communication, the interdisciplinary study will assess how to engage all stakeholders - from monitoring scientists, through emergency agencies, to vulnerable communities - to optimize the understanding of forecasts among different end users. [continued...]DescriptionProject VOLCANOSCOPE will evaluate strategies (1) for applying existing and new forecasting models to volcanic eruptions, and (2) for identifying methods to improve how forecasts are communicated effectively to vulnerable communities. To link forecasting and communication, the interdisciplinary study will assess how to engage all stakeholders - from monitoring scientists, ...

2011-01-05

360

United States Space Activities - NASA  

Science.gov (United States)

Mission losses were incurred by an early warning satellite and a Milstar-2 communications satellite when their launch vehicles malfunctioned, the first, ...

361

To talk or not to talk: exploring culturally diverse patients' health information communication choices.  

Science.gov (United States)

As care shifts from institutional to home- and community-based settings, consumer health information technology (IT) must be designed to support patients' new health information management responsibilities. We developed and piloted a new methodology grounded in social network analysis and human factors engineering to explore two often overlooked aspects of this phenomenon: the task of health information communication with members of the social network and the context of culture. Such knowledge is necessary to inform the appropriate design of consumer health IT. We asked a culturally diverse sample of participants to describe what, to whom, why, and how they communicate health information and to provide direct feedback about the methodology. The methodology was acceptable to all participants and able to capture similarities and differences in their health information communication practices. Prior to the main study we will ...

2010-11-13

363

The Current Status of Russian/CIS Communication Satellites  

Science.gov (United States)

... 4302, and to the Office of Management and Budget, Paper-work ... link coverage areas, so it is possible to receive your own ... mestic Ku-band satellite. ...

1994-09-01

364

The Corps Air Assault Brigade: An Integrated Combined Arms ...  

Science.gov (United States)

... communication with the divisions of the Seventh Army ... the 1st Infantry Division could not ... commanding general of the 82nd Airborne Division, landed ...

1988-12-06

366

Strategic Communication: A Department of Defense Approach  

Science.gov (United States)

... development of SC policy within DOD, because it describes the necessary link between DOD ... strategy convolutes USG efforts to develop SC policy. ...

2007-03-28

367

Strategic Communication Meets Public Diplomacy: DoD-DoS ...  

Science.gov (United States)

... PDOD on region- wide SC policy and initiatives, and would liaise with their COCOM colleagues (including the embedded ...

2010-10-27

368

Strategic Communication Enablers for the Regional ...  

Science.gov (United States)

... Joint Publication (JP) 5-0 (Washington DC: CJCS, 29 September ... and Execution System (JOPES) Volume 1. CJCSM 3122.01A (Washington, DC: 6 ...

2008-04-23

371

Single photon emission tomography of the pituitary: preliminary communication.  

UK PubMed Central (United Kingdom)

A specific application of single photon emission tomography to the relative quantitation of the pituitary region is described together with the results obtained in 19 patients with pituitary adenoma...Full Text Available

1981-09-01

373

Regulation of Male Fertility by the Opioid System  

UK PubMed Central (United Kingdom)

Endogenous opioid peptides are substances involved in cell communication. They are present in various organs and tissues of the male and female reproductive tract, suggesting that they may regulate...Full Text Available

2011-07-01

375

Pattern Search Ranking and Selection Algorithms for Mixed ...  

Science.gov (United States)

... 5.12 Terminal Value for Performance Measure P ... As examples, a stochastic communication network containing a buffer queue at each ...

2004-09-01

376

Operation Greenhouse: Communications  

Science.gov (United States)

... 295 VIII Classification Criteria 305 IX List of Applicable JANAP's 307 X Sample Sheets, Eniwetok Consolidated Telephone Directory 309 ...

2011-05-13

377

NHSnet in Scottish primary care: lessons for the future  

UK PubMed Central (United Kingdom)

ObjectiveTo evaluate the primary care communications initiative, which introduced NHSnet to primary care in Scotland.DesignSemi-structured telephone...Full Text Available

2000-10-07

378

N95- 19645 - NASA Technical Report Server (NTRS)  

Science.gov (United States)

Milstar is a flexible, robust satellite communications ... of the Milstar system includes services capable of supporting status reporting, ...

379

Managing Messaging and Data Processing Centers  

Science.gov (United States)

... established in allied communications publications (ACP); DISA circulars (DISAC), Joint Army-Navy-Air Force publications (JANAP), and MAJ- COM ...

1998-03-01

381

Hispanic Cultural Influences on Medical Practice  

UK PubMed Central (United Kingdom)

Because the proportion of Hispanic patients is increasing rapidly, most physicians are now coming into daily contact with Hispanics. In addition to obvious difficulty with oral communication, Hispanics...Full Text Available

1983-10-01

382

HPCC and the National Information Infrastructure: an overview.  

UK PubMed Central (United Kingdom)

The National Information Infrastructure (NII) or "information superhighway" is a high-priority federal initiative to combine communications networks, computers, databases, and consumer electronics to...Full Text Available

1995-01-01

384

Facilitator control as automatic behavior: A verbal behavior analysis  

UK PubMed Central (United Kingdom)

Several studies of facilitated communication have demonstrated that the facilitators were controlling and directing the typing, although they appeared to be unaware of doing so. Such results shift...Full Text Available

1993-01-01

385

Environmental Impact Analysis Process. Final Environmental ...  

Science.gov (United States)

... Abstract : The United States Air Force (USAF) currently operates the Milstar satellite system to provide Military Satellite Communication Systems ...

2001-02-15

387

Emerging global divides in media and communication theory: European universalism versus non-Western reactions  

British Library Electronic Table of Contents (United Kingdom)

What Wallerstein described as European universalism dominated media and communication theory until the end of the twentieth century. The three-tier divide of the global economic system (center, semi-periphery, and periphery) explicated in world-system analysis was equally applicable to the global academic/scholarship structure. The non-traditional fields of study, such as media and (mass) communication, inherited the full flavor of European universalism because they originated in the academic institutions of the center countries. The turn of the century saw a dramatic reaction to the Euro-American rhetoric of power. Organized groups of scholars have begun to question the presumption of European universalism in media and communication theory, encompassing its axiology, epistemology/methodol...

2009-01-01

388

EHF Satellite Communications-on-the-Move Blockage ...  

Science.gov (United States)

... Wheeled Vehicle) equipped with a MILSTAR terminal was driven ... textbooks including Ronald W. Wolff, Stochastic Modeling and The ... Queue Length ...

2004-11-02

389

Dishonest signalling in a fiddler crab.  

UK PubMed Central (United Kingdom)

Animal communication theory predicts that low-frequency cheating should be common in generally honest signalling systems. However, perhaps because cheats are designed to go undetected, there are few...Full Text Available

2000-04-07

391

Cross-sectional survey of users of Internet depression communities  

UK PubMed Central (United Kingdom)

BackgroundInternet-based depression communities provide a forum for individuals to communicate and share information and ideas. There has been little research into the health status...Full Text Available

392

Complementary and alternative medicine in the management of hypertension in an urban Nigerian community  

UK PubMed Central (United Kingdom)

BackgroundHypertension is a common non communicable condition worldwide. In developing countries (including Nigeria), the use of complementary and alternative medicine (CAM) is common....Full Text Available

394

Battle Management Command and Control (BMC2) Human ...  

Science.gov (United States)

... For communication systems that employ spatial audio technology to separate intercom and/or radio channels, configurations of the spatial ...

2005-06-01

395

Attributes of Interactive Online Health Information Systems  

UK PubMed Central (United Kingdom)

The development of online communication systems related to prevention, decision making, and coping with cancer has outpaced theoretical attention to the attributes that appeal to system...Full Text Available

396

Army Communicator. Volume 32, Number 2, Spring 2007  

Science.gov (United States)

... Introduction to the Signal Regiment Cisco Academy 1-4 (CCNA) Engineering Math Basic Electronics/Digital Logic (replaced C Programming ...

2011-05-14

399

49 CFR 130.11 - Communication requirements.  

Science.gov (United States)

...identified as oil when the shipment document accurately describes the material as: aviation fuel, diesel fuel, fuel oil, gasoline, jet fuel, kerosene, motor fuel, or...

2010-10-01

402

Mechanism of zirconium complexing with biphenyl mono- and biscatecholylazo derivatives  

Energy Technology Data Exchange (ETDEWEB)

The complex formation of zirconium with biphenyl mono- and biscatecholyazo derivatives has been studied spectrophotometrically. The composition of the complexes, form and charge of complex-forming zirconium ions have been established. A procedure is suggested for calculation of molar absorptivities and stability constants for each of the complexes formed simultaneously in the system. Possible complex formation schemes have been studied. The data obtained were used to develop a spectrophotometric method of determining zirconium in the presence of large amounts of copper.

1982-05-01

403

The quantum Zeno paradox revisited: the time evolution for a two-level system interacting with a reservoir  

Energy Technology Data Exchange (ETDEWEB)

We revisited the quantum Zeno paradox, which claims that a generic quantum system prepared in a state which is not an eigenstate of the Hamiltonian operator and is continuously observed never decays. Since any perfectly isolated quantum system always interact with a vacuum field, we analyze the possibility of using this fact to solve the above mentioned conceptual problem. Therefore we discuss a two-level system or qubit-Bose field interaction Hamiltonians. We consider the quantum dynamics of this two-level system, prepared in the excited state interacting with a Bose field prepared in the Poincare invariant vacuum state. Using a first-order approximation in time-dependent perturbation theory, we evaluate the probability of spontaneous decay of the two-level system driven by the vacuum field. This probability is evaluated for a finite time interval. Using the standard argument to obtain the ...

2006-12-15

404

Quantum geometrodynamics of the Bianchi IX cosmological model  

Energy Technology Data Exchange (ETDEWEB)

The canonical quantum theory of gravity-quantum geometrodynamics (QG)-is applied to the homogeneous Bianchi type IX cosmological model. As a result, a framework for the quantum theory of homogeneous cosmologies is developed. We show that the theory is internally consistent and prove that it possesses the correct classical limit (the theory of general relativity). To emphasize the special role that the constraints play in this new theory, we compare it to the traditional ADM square-root and Wheeler-DeWitt quantization schemes. We show that, unlike traditional approaches, QG leads to a well-defined Schroedinger equation for the wavefunction of the universe that is inherently coupled to the expectation value of the constraint equations. This coupling to the constraints is responsible for the appearance of a coherent spacetime picture. Thus, the physical meaning of the constraints of the theory is quite different from ...

2006-07-01

405

Quantum geometrodynamics of the Bianchi IX cosmological model  

International Nuclear Information System (INIS)

The canonical quantum theory of gravity-quantum geometrodynamics (QG)-is applied to the homogeneous Bianchi type IX cosmological model. As a result, a framework for the quantum theory of homogeneous cosmologies is developed. We show that the theory is internally consistent and prove that it possesses the correct classical limit (the theory of general relativity). To emphasize the special role that the constraints play in this new theory, we compare it to the traditional ADM square-root and Wheeler-DeWitt quantization schemes. We show that, unlike traditional approaches, QG leads to a well-defined Schroedinger equation for the wavefunction of the universe that is inherently coupled to the expectation value of the constraint equations. This coupling to the constraints is responsible for the appearance of a coherent spacetime picture. Thus, the physical meaning of the constraints of the theory is quite different from Dirac's ...

2006-07-01

406

Quantum Transition State Theory for proton transfer reactions in enzymes  

CERN Document Server

We consider the role of quantum effects in the transfer of hyrogen-like species in enzyme-catalysed reactions. This study is stimulated by claims that the observed magnitude and temperature dependence of kinetic isotope effects imply that quantum tunneling below the energy barrier associated with the transition state significantly enhances the reaction rate in many enzymes. We use a path integral approach which provides a general framework to understand tunneling in a quantum system which interacts with an environment at non-zero temperature. Here the quantum system is the active site of the enzyme and the environment is the surrounding protein and water. Tunneling well below the barrier only occurs for temperatures less than a temperature $T_0$ which is determined by the curvature of potential energy surface near the top of the barrier. We argue that for most enzymes this temperature is less than room ...

2009-01-01

407

Models of continuous-variable quantum computing  

Energy Technology Data Exchange (ETDEWEB)

We discuss strictly efficient models for measurement-based quantum computing using physical continuous variables, such as field modes of light. Such measurement-based quantum computing (MBQC) provides a promising paradigm for quantum computation as it does not require performing unitary gates during the computation, but rather appropriate readout. Here, we introduce novel schemes for which the resource state can be reasonably and efficiently prepared, and which notably do not require having infinite squeezing or mean energy available. What is more, error correction techniques are implementable, as the logical information is stored in finite-dimensional objects grasping correlations of the quantum states. Using the ideas of computational tensor networks we discuss how to sequentially prepare suitable physical resource states with cavity QED or with non-linear optics and how to efficiently implement a ...

2009-07-01

408

Lab-Tutorials for teaching quantum physics (Lab-Tutorials fuer den Quantenphysik Unterricht)  

CERN Document Server

English abstract: In the "Intuitive Quantum Physics" course, we use graphical interpretations of mathematical equations and qualitative reasoning to develop and teach a simplified model of quantum physics. Our course contains three units: Wave physics, Development of a conceptual toolbox, and quantum physics. It also contains three key themes: wave-particle duality, the Schroedinger equation, and tunneling of quantum particles. Students learn most new material in lab-tutorials in which students work in small groups (3 to 3 people) on specially designed worksheets. Lecture reinforces the lab-tutorial content and focuses more on issues about the nature of science. Data show that students are able to learn some of the most difficult concepts in the course, and also that students learn to believe that there is a conceptually accessible structure to the physics in the course. German abstract: Im Kurs ...

2006-01-01

409

Algebraic Principles of Quantum Field Theory II: Quantum Coordinates and WDVV Equation  

CERN Document Server

This paper is about algebro-geometrical structures on a moduli space $\\CM$ of anomaly-free BV QFTs with finite number of inequivalent observables or in a finite superselection sector. We show that $\\CM$ has the structure of F-manifold -- a linear pencil of torsion-free flat connection with unity on the tangent space, in quantum coordinates. We study the notion of quantum coordinates for the family of QFTs, which determines the connection 1-form as well as every quantum correlation function of the family in terms of the 1-point functions of the initial theory. We then define free energy for an unital BV QFT and show that it is another avatar of morphism of QFT algebra. These results are consequences of the solvability of refined quantum master equation of the theory. We also introduce the notion of a QFT integral and study some properties of BV QFT equipped with a QFT integral. We show that BV QFT with ...

2011-01-01

410

Synthesis of histidine-stabilized cadmium sulfide quantum dots: Study of their fluorescence behaviour in the presence of adenine and guanine  

British Library Electronic Table of Contents (United Kingdom)

Cadmium sulfide particles have been synthesized in the aqueous medium using the amino acid histidine as a stabilizing agent. These particles demonstrate the phenomenon of size quantization effect. The fluorescence of histidine-stabilized CdS was found to be enhanced and quenched by the addition of DNA bases adenine and guanine, respectively. The fluorescence enhancement of CdS in the presence of adenine has been explained on the basis of interaction between the quantum dot stabilizer and the amino group of adenine. Quenching of CdS fluorescence by guanine occurs due to interaction of the substrate with the quantum dot surface.

2010-01-01

411

Spin operator matrix elements in the quantum Ising chain: fermion approach  

CERN Document Server

Using some modification of the standard fermion technique we derive factorized formula for spin operator matrix elements (form-factors) between general eigenstates of the Hamiltonian of quantum Ising chain in a transverse field of finite length. The derivation is based on the approach recently used to derive factorized formula for Z_N-spin operator matrix elements between ground eigenstates of the Hamiltonian of the Z_N-symmetric superintegrable chiral Potts quantum chain. The obtained factorized formulas for the matrix elements of Ising chain coincide with the corresponding expressions obtained by the Separation of Variables Method.

2010-01-01

412

Simple Proof of Security of the BB84 Quantum Key Distribution Protocol  

Energy Technology Data Exchange (ETDEWEB)

We prove that the 1984 protocol of Bennett and Brassard (BB84) for quantum key distribution is secure. We first give a key distribution protocol based on entanglement purification, which can be proven secure using methods from Lo and Chau's proof of security for a similar protocol. We then show that the security of this protocol implies the security of BB84. The entanglement purification based protocol uses Calderbank-Shor-Steane codes, and properties of these codes are used to remove the use of quantum computation from the Lo-Chau protocol. (c) 2000 The American Physical Society.

2000-07-10

413

SU(2) potentials in quantum gravity  

CERN Document Server

We present investigations of the potential between static charges from a simulation of quantum gravity coupled to an SU(2) gauge field on 6^{3}\\times 4 and 8^{3}\\times 4 simplicial lattices. In the well-defined phase of the gravity sector where geometrical expectation values are stable, we study the correlations of Polyakov loops and extract the corresponding potentials between a source and sink separated by a distance R. In the confined phase, the potential has a linear form while in the deconfined phase, a screened Coulombic behavior is found. Our results indicate that quantum gravitational effects do not destroy confinement due to non-abelian gauge fields.

1994-01-01

414

Quantum theory of the interaction of Josephson junctions with non-classical microwaves  

Energy Technology Data Exchange (ETDEWEB)

We present a study of the interaction between Josephson junctions in circular superconducting rings and non-classical microwaves, treating both quantum mechanically. A Hamiltonian that describes both inductive and capacitive coupling between the two systems is derived within the external field approximation. Other Hamiltonians which go beyond the external field approximation, and describe explicitly the interaction of the quantum circuit that produces the non-classical microwaves with the Josephson junction circuit, are also presented. A comparison between current experiments which use classical electromagnetic fields and the proposed experiments that use non-classical microwaves, is made. (orig.) With 6 figs., 32 refs.

1997-01-01

415

Quantum electrodynamic and semiclassical interference effects in spontaneous radiation  

International Nuclear Information System (INIS)

The theory of spontaneous decay is studied using both quantum electrodynamics (QED) and semiclassical theories of radiation. There are qualitative differences between the theories in the prediction of interference phenomena. In QED, systems which were excited with pulsed laser light do not exhibit quantum interference effects associated with lower state splittings. On the other hand, semiclassical treatments of spontaneous decay do indicate the existence of interference effects not present in QED. In addition to this, differences are found between the predictions of fluorescence intensity in the presence of lower-state level crossings under continuous excitation. (U.S.).

1975-01-01

416

Quantum Computation with Nonlinear Optics  

International Nuclear Information System (INIS)

We propose a scheme of quantum computation with nonlinear quantum optics. Polarization states of photons are used for qubits. Photons with different frequencies represent different qubits. Single qubit rotation operation is implemented through optical elements like the Faraday polarization rotator. Photons are separated into different optical paths, or merged into a single optical path using dichromatic mirrors. The controlled-NOT gate between two qubits is implemented by the proper combination of parametric up and down conversions. This scheme has the following features: (1) No auxiliary qubits are required in the controlled-NOT gate operation; (2) No measurement is required in the course of the computation; (3) It is resource efficient and conceptually simple.

2008-01-15

417

Observational constraints on loop quantum cosmology  

CERN Document Server

In the inflationary scenario of loop quantum cosmology (LQC) in the presence of inverse-volume corrections, we give analytic formulas for the power spectra of scalar and tensor perturbations convenient to confront with observations. Since inverse-volume corrections can provide strong contributions to the running spectral indices, inclusion of terms higher than the second-order runnings in the power spectra is crucially important. Using the recent data of cosmic microwave background (CMB) and other cosmological experiments, we place bounds on the quantum corrections for a quadratic inflaton potential.

2011-01-01

418

Molecular models in the quantum-chemical investigation of the structure of defect centers on oxide catalysts  

Energy Technology Data Exchange (ETDEWEB)

Several possibilities of the use of molecular models in quantum-chemical investigations of the structure of defect centers on the surfaces of oxides on nontransition elements have been illustrated. There has been a special discussion of the assumption of the local nature of the chemical interactions in these systems, which underlies such an approach, and of the consequent laws governing the formation of their lattices in the example cases of zeolites, kaolinites, and comparable boron- and aluminum-containing oxides. A quantum-chemical interpretation of the body of experimental data from investigations of the dehydroxylation of H forms of zeolites has been given. The structure of the Lewis acid centers formed as a result, and their chemisorption properties, have been discussed.

1987-05-01

419

Incompatibility of the Copenhagen interpretation with quantum formalism and its reasons  

CERN Document Server

It is proved the mathematical theorem, that the wave function describes the statistical ensemble of particles, but not a single particle. Supposition, that the wave function describes a single particle appears to be incompatible with formalism of quantum mechanics. One discusses the reasons, why this very simple statement has not been proved mathematically for many years. The reason lies in application of the trial and error methods for construction of the quantum mechanics. Application of this method as the main tool of investigation during eighty years generated "fitting mentality" of all microwold researchers.

2006-01-01

420

Electrodynamical and quantum-chemical approaches to modeling the electrochemical and catalytic processes on metals, metal alloys, and semiconductors  

British Library Electronic Table of Contents (United Kingdom)

A problem of the catalytic activity definition for metals, binary metallic alloys, and semiconductor materials is considered within new quantum mechanical and electrodynamics approach in the electron theory of catalysis. The quantitative link between the electron structure parameters of the materials and their catalytic activity on example of simple model reactions of the following type are found: H = H+ + e, O2 + e- = O2-. Copyright 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009

2009-01-01

421

Effective Constraints for Quantum Systems  

CERN Document Server

An effective formalism for quantum constrained systems is presented which allows manageable derivations of solutions and observables, including a treatment of physical reality conditions without requiring full knowledge of the physical inner product. Instead of a state equation from a constraint operator, an infinite system of constraint functions on the quantum phase space of expectation values and moments of states is used. The examples of linear constraints as well as the free non-relativistic particle in parameterized form illustrate how standard problems of constrained systems can be dealt with in this framework.

2008-01-01

422

The geometry emerging from the symmetries of a quantum system  

CERN Document Server

We investigate the relation between the symmetries of a quantum system and its topological quantum numbers, in a general C*-algebraic framework. We prove that, under suitable assumptions on the symmetry algebra, there exists a generalization of the Bloch-Floquet transform which induces a direct-integral decomposition of the algebra of observables. Such generalized transform selects uniquely the set of "continuous sections" in the direct integral, thus yielding a Hilbert bundle. The emerging geometric structure provides some topological invariants of the quantum system. Two running examples provide an Ariadne's thread through the paper. For the sake of completeness, we review two related theorems by von Neumann and Maurin and compare them with our result.

2009-01-01

423

Quasienergy description of the driven Jaynes-Cummings model  

CERN Document Server

We analyze the driven resonantly coupled Jaynes-Cummings model in terms of a quasienergy approach by switching to a frame rotating with the external modulation frequency and by using the dressed atom picture. A quasienergy surface in phase space emerges whose level spacing is governed by a rescaled effective Planck constant. Moreover, the well-known multiphoton transitions can be reinterpreted as resonant tunneling transitions from the local maximum of the quasienergy surface. Most importantly, the driving defines a quasienergy well which is nonperturbative in nature. The quantum mechanical quasienergy state localized at its bottom is squeezed. In the Purcell limited regime, the potential well is metastable and the effective local temperature close to its minimum is uniquely determined by the squeezing factor. The activation occurs in this case via dressed spin flip transitions rather than via quantum activation as in other driven nonlinear ...

2010-01-01

424

Quantum simulation of molecular interaction and dynamics at surfaces  

British Library Electronic Table of Contents (United Kingdom)

The interaction between molecules and solid surfaces plays important roles in various applications, including catalysis, sensors, nanoelectronics, and solar cells. Surprisingly, a full understanding of molecule-surface interaction at the quantum mechanical level has not been achieved even for very simple molecules, such as water. In this mini-review, we report recent progresses and current status of studies on interaction between representative molecules and surfaces. Taking water/metal, DNA bases/carbon nanotube, and organic dye molecule/oxide as examples, we focus on the understanding on the microstructure, electronic property, and electron-ion dynamics involved in these systems obtained from first-principles quantum mechanical calculations. We find that a quantum mechanical description ...

2011-01-01

425

Quantum dot micropillars  

International Nuclear Information System (INIS)

This topical review provides an overview of quantum dot micropillars and their application in cavity quantum electrodynamics (cQED) experiments. The development of quantum dot micropillars is motivated by the study of fundamental cQED effects in solid state and their exploitation in novel light sources. In general, light-matter interaction occurs when the dipole of an emitter couples to the ambient light field. The corresponding coupling strength is strongly enhanced in the framework of cQED when the emitter is located inside a low mode volume microcavity providing three-dimensional photon confinement on a length scale of the photon wavelength. In addition, coherent coupling between light and matter, which is essential for applications in quantum information processing, can be achieved when dissipative losses, predominantly due to photon leakage out of the cavity, are strongly reduced. In this paper, we ...

2010-01-27

426

Quantum Information Processing Using Local Control of ...  

Science.gov (United States)

... The insu- lation between gate and nanowire is the high-k dielectric HfO2, deposited by atomic layer depo- sition (ALD). ...

2006-12-31

427

Quantization of coupled 1D vector modes in integrated photonic waveguides  

International Nuclear Information System (INIS)

A quantum mechanical analysis of the guided light in integrated photonics waveguides is presented. The analysis is made starting from one-dimensional (1D) guided vector modes by taking into account the modal orthonormalization property on a cross section of an optical waveguide, the vector structure of the guided optical modes and the reversal-time symmetry in order to quantize the 1D vector modes and to derive the quantum momentum operator and the Heisenberg equations. The results provide a quantum-consistent formulation of the linear and nonlinear quantum light propagations as a function of forward and backward creation and annihilation operators in integrated photonics. As an illustration, an application to an integrated nonlinear directional coupler is given, that is, both the nonlinear momentum and the Heisenberg equations of the nonlinear coupler are derived.

2008-06-01

428

Photon shell game in three-resonator circuit quantum electrodynamics  

CERN Document Server

The generation and control of quantum states of light constitute fundamental tasks in cavity quantum electrodynamics (QED). The superconducting realization of cavity QED, circuit QED, enables on-chip microwave photonics, where superconducting qubits control and measure individual photon states. A long-standing issue in cavity QED is the coherent transfer of photons between two or more resonators. Here, we use circuit QED to implement a three-resonator architecture on a single chip, where the resonators are interconnected by two superconducting phase qubits. We use this circuit to shuffle one- and two-photon Fock states between the three resonators, and demonstrate qubit-mediated vacuum Rabi swaps between two resonators. This illustrates the potential for using multi-resonator circuits as photon quantum registries and for creating multipartite entanglement between delocalized bosonic modes.

2010-01-01

429

One-way quantum computing in a decoherence-free subspace  

Energy Technology Data Exchange (ETDEWEB)

We introduce a novel scheme for one-way quantum computing (QC) based on the use of information encoded qubits in an effective cluster state resource. With the correct encoding structure, we show that it is possible to protect the entangled resource from phase damping decoherence, where the effective cluster state can be described as residing in a decoherence-free subspace (DFS) of its supporting quantum system. One-way QC then requires either single or two-qubit adaptive measurements. As an example where this proposal can be realized, we describe an optical lattice set-up where the scheme provides robust quantum information processing. We also outline how one can adapt the model to provide protection from other types of decoherence.

2007-06-15

431

Image Smearing in a Quantum Well Infrared Photodetector ...  

Science.gov (United States)

... Assuming isotropic emission, the 25' half angle cone represents only -9% [= 1/(2(ngaas/nopticglue) 2)] of the spontaneous radiation. ...

1998-12-01

432

High power GaInP-AlGaInP quantum-well lasers grown by solid source molecular beam epitaxy  

Science.gov (United States)

AlGaInP-based quantum-well laser diodes operating at wavelengths near 680 nm have been grown by all solid source molecular beam epitaxy (SSMBE). The lowest room temperature threshold current densities obtained from shallow rid structures were 300 A/cm{sup 2} and 330 A/cm{sup 2} for pulsed and continuous wave operation, respectively. The dependences of the differential quantum efficiency and threshold current density on the cavity length were also studied in this preliminary SSMBE work. The internal quantum efficiency of 87--89% and the internal losses of 7--10 cm{sup {minus}1} were obtained.

1996-03-01

433

Extended BRS symmetry in non-Abelian gauge theories  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the superfield formulation of quantum gauge theories, recently proposed, is reviewed and developed. The extended BRS symmetry, which comes out quite naturally in this formulation, is investigated.

1981-08-01

434

Excitonic transitions in InGaP/InAlGaP strained quantum wells  

Science.gov (United States)

Excitonic transitions in metalorganic vapor phase epitaxially grown In[sub [ital x

1993-08-30

435

Causality Constrains Higher Curvature Corrections to Gravity  

CERN Document Server

We show that causality constrains the sign of quartic Riemann corrections to the Einstein-Hilbert action. Our constraint constitutes a restriction on candidate theories of quantum gravity.

2006-01-01

436

Brane-world Quantum Gravity  

CERN Document Server

The Arnowitt-Deser-Misner canonical formulation of general relativity is extended to the covariant brane-world theory in arbitrary dimensions. The exclusive probing of the extra dimensions makes a substantial difference, allowing for the construction of a non-constrained canonical theory. The quantum states of the brane-world geometry are defined by the Tomonaga-Schwinger equation, whose integrability conditions are determined by the classical perturbations of submanifolds contained in the Nash's differentiable embedding theorem. In principle, quantum brane-world theory can be tested by current experiments in astrophysics and by near future laboratory experiments at Tev energy. The implications to the black-hole information loss problem, to the accelerating cosmology, and to a quantum mathematical theory of four-sub manifolds are briefly commented.

2007-01-01

437

Black hole horizons from within loop quantum gravity  

CERN Document Server

In general relativity, the fields on a black hole horizon are obtained from those in the bulk by pullback and restriction. Similarly, in quantum gravity, the quantized horizon degrees of freedom should result from restricting, or pulling-back, the quantized bulk degrees of freedom. This is not yet fully realized in the - otherwise very successful - quantization of isolated horizons in loop quantum gravity. In this work we outline a setting in which the quantum horizon degrees of freedom are simply components of the quantized bulk degrees of freedom. There is no need to quantize them separately. We present evidence that for a horizon of sphere topology, the resulting horizon theory is remarkably similar to what has been found before.

2011-01-01

438

BPS Condensates, Matrix Models and Emergent String Theory  

CERN Document Server

A prescription is given for computing anomalous dimensions of single trace operators in SYM at strong coupling and large $N$ using a reduced model of matrix quantum mechanics. The method involves treating some parts of the operators as "BPS condensates" which, in certain limit, have a dual description as null geodesics on the $S^5$. In the gauge theory, the condensate is similar to a representative of the chiral ring and it is described by a background of commuting matrices. Excitations around these condensates correspond to excitations around this background and take the form of ``string bits" which are dual to the "giant magnons" of Hofman and Maldacena. In fact, the matrix model approach gives a {\\it quantum} description of these string configurations and explains why the infinite momentum limit suppresses the quantum effects. This method allows, not only to derive part of the classical sigma model Hamiltonian of the ...

2007-01-01

439

An effective approach to the problem of time: general features and examples  

CERN Document Server

The effective approach to quantum dynamics allows a reformulation of the Dirac quantization procedure for constrained systems in terms of an infinite-dimensional constrained system of classical type. For semiclassical approximations, the quantum constrained system can be truncated to finite size and solved by the reduced phase space or gauge-fixing methods. In particular, the classical feasibility of local internal times is directly generalized to quantum systems, overcoming the main difficulties associated with the general problem of time in the semiclassical realm. The key features of local internal times and the procedure of patching global solutions using overlapping intervals of local internal times are described and illustrated by two quantum mechanical examples. The choice of time is tantamount to a choice of gauge at the effective level and changing the clock is, therefore, equivalent to a gauge ...

2010-01-01

440

An algebraic approach to linear-optical schemes for deterministic quantum computing  

Energy Technology Data Exchange (ETDEWEB)

Linear-optical passive (LOP) devices and photon counters are sufficient to implement universal quantum computation with single photons, and particular schemes have already been proposed. In this paper we discuss the link between the algebraic structure of LOP transformations and quantum computing. We first show how to decompose the Fock space of N optical modes in finite-dimensional subspaces that are suitable for encoding strings of qubits and invariant under LOP transformations (these subspaces are related to the spaces of irreducible unitary representations of U (N). Next we show how to design in algorithmic fashion LOP circuits which implement any quantum circuit deterministically. We also present some simple examples, such as the circuits implementing a cNOT gate and a Bell state generator/analyser.

2005-12-01

441

A classical model for the magnetic field-induced Wigner crystallization in quantum dots  

Energy Technology Data Exchange (ETDEWEB)

A classical model is presented for magnetic field-induced Wigner crystallization in electron systems confined within two-dimensional quantum dots. In contrast to other classical models, this one does not treat an electron as a point charge; the electron density is assumed to take a Gaussian form corresponding to the lowest Landau level. Using a Monte Carlo method we have determined the equilibrium configurations as functions of the magnetic field. We have found a classical counterpart of the quantum maximum density droplet (MDD) and studied the breakdown of the MDD into a Wigner molecule as well as the transformations of the Wigner molecule shape induced by the external magnetic field. The phase diagram for the classical Wigner molecules has been presented and its qualitative agreement with previous quantum mechanical calculations has been shown.

2004-03-03

442

A Quantum-Enhanced Prototype Gravitational-Wave Detector  

CERN Document Server

The quantum nature of the electromagnetic field imposes a fundamental limit on the sensitivity of optical precision measurements such as spectroscopy, microscopy, and interferometry. The so-called quantum limit is set by the zero-point fluctuations of the electromagnetic field, which constrain the precision with which optical signals can be measured. In the world of precision measurement, laser-interferometric gravitational wave (GW) detectors are the most sensitive position meters ever operated, capable of measuring distance changes on the order of 10^-18 m RMS over kilometer separations caused by GWs from astronomical sources. The sensitivity of currently operational and future GW detectors is limited by quantum optical noise. Here we demonstrate a 44% improvement in displacement sensitivity of a prototype GW detector with suspended quasi-free mirrors at frequencies where the sensitivity is shot-noise-limited, by ...

2008-01-01

443

Computational Complexity of Cyclotomic Fast Fourier Transforms over Characteristic-2 Fields  

CERN Document Server

Cyclotomic fast Fourier transforms (CFFTs) are efficient implementations of discrete Fourier transforms over finite fields, which have widespread applications in cryptography and error control codes. They are of great interest because of their low multiplicative and overall complexities. However, their advantages are shown by inspection in the literature, and there is no asymptotic computational complexity analysis for CFFTs. Their high additive complexity also incurs difficulties in hardware implementations. In this paper, we derive the bounds for the multiplicative and additive complexities of CFFTs, respectively. Our results confirm that CFFTs have the smallest multiplicative complexities among all known algorithms while their additive complexities render them asymptotically suboptimal. However, CFFTs remain valuable as they have the smallest overall ...

2011-01-01

444

Complexing of vanadium(3) with chromotropic acid derivatives  

International Nuclear Information System (INIS)

A spectrophotometric study has been made of the complex formation of vanadium (3) with arsenazo(1), arsenazo(3) and some monosubstituted derivatives of chromotropic acid and sulphanylamides. In acid medium vanadium (3) reacts with each of these reagents to produce a 1:1 complex. Optimum conditions of the complex formation was found. The effect of H"+ on the complex formation of vanadium (3) with chromotropic acid derivatives was established. It was found by the graphical method that the formation of the complex is accompanied by the elimination of one proton. Patterns were found of the influence of the nature of substituents in the organic compound on the ionization constants of acid groups and stability of complexes. Molar extinction coefficients, equilibrium constants of the formation reactions and instability constants for the complexes ...

1976-01-01

445

Wireless Sensor Network based Future of Telecom Applications  

CERN Document Server

A system and method for enabling human beings to communicate by way of their monitored brain activity. The brain activity of an individual is monitored and transmitted to a remote location (e.g. by satellite). At the remote location, the monitored brain activity is compared with pre-recorded normalized brain activity curves, waveforms, or patterns to determine if a match or substantial match is found. If such a match is found, then the computer at the remote location determines that the individual was attempting to communicate the word, phrase, or thought corresponding to the matched stored normalized signal.

2010-01-01

446

The software for the USB-based multi-channel analyzer system  

International Nuclear Information System (INIS)

A new type of multi-channel analyzer system is introduced, which takes advantage of Universal Serial Bus to communicate with computer and gets the merit of fast speed, universality and Plug and Play. The authors discussed the framework of the system, primary functions, display of spectrum date and the way of communication with hardware. The environment of the program is Visual Basic 6.0

2002-07-01

447

Public agency partnership: Hanford`s history artifacts as a communications tool  

Energy Technology Data Exchange (ETDEWEB)

The Hanford Site in eastern Washington state currently is engaged in the largest waste cleanup in world history. In order to make informed decisions about remediation options, the public throughout the Pacific Northwest and the nation needs to understand the wastes that are present, their sources of generation, their composition, and their behavior in the environment. The fact that Hanford operations` were conducted in secret for over four decades presents a unique public information challenge to those who currently are responsible for communicating with the public.

1994-02-01

448

Comparison of three methods of remote metering of electrical energy: Telephone line, fiber optic, and radio packet. Final report, June 1995--August 1995  

Energy Technology Data Exchange (ETDEWEB)

This report deals with the selection of a data communication system for a remote metering system. It covers the following three types of systems: fiber optic, telephone line, and radio packet. It provides a methodology for selecting a communication system for a given remote metering system and a method for comparing costs.

1998-07-01

449

On the impact of low power density microwaves in some living tissues  

Energy Technology Data Exchange (ETDEWEB)

The biomedical and ecological interest for the microwave impact on the Earth biosphere is continuously increased since the industrial, military and communication activities strongly contribute to the electromagnetic stress of living bodies. In the next the authors present some of the main results obtained regarding the microwave exposure of various types of biological material: bacteria, fungi, young plant seedlings, dry seeds, animal tissues. The electromagnetic exposure was carried out in open space in well controlled environmental conditions by using 10.75 GHz/1 m W cm{sup -2} microwaves. Biochemical assays and cytogenetic tests have been carried out to reveal the changes induced post irradiation. The response of some pathogen bacteria, have been emphasized by means of turbidimetric measurements - the stimulatory effect being noticed at the level of the microbial population density (the stimulation of the human body microbial flora seems to be one of the side ...

2006-07-01

450

PSDE/SAT-2: Communication system architecture study, executive summary  

Science.gov (United States)

The PSDE/SAT-2 multimission satellite designed to offer a flight opportunity to different experimental communication payloads and verify the feasibility of advanced space technologies is described. It was conceived for expriment in the framework of the European DRS (Data Relay Satellite) program thus providing intersatellite and interorbit communication links, but also experimental and preoperative services. Payloads include optical communication single access payload (LSA); S-Band single access payload; S-Band multiple access payload; land mobile experimental payload; navigation payload; 40/50 GHz communication payload; and millimeter wave propagation payload. The orbital slot and interference analysis identified a limited number of orbital positions for the mission interleaved between Eutelsat satellites (i.e., 14 deg 30 min E and 17 deg 30 min E). A coordination is required in Ku-Band with Eutelsat ...

1988-01-01

451

Dynamic Rating and Underground Monitoring System (DRUMS)  

Energy Technology Data Exchange (ETDEWEB)

Drums is an acronym for Dynamic Rating and Underground Monitoring System, with specific application to high-pressure pipe-type cable systems which are the predominant means of underground electric power transmission in the United States. The primary objective of this EPRI-sponsored feasibility study was to establish the technical feasibility of seven DRUMS functions and two novel DRUMS communication schemes. The seven DRUMS functions which monitor the system's vital and measurable parameters in real time and perform system diagnostics in the event of component deterioration, malfunction or failure are: Real Time Current Monitoring and Rating; Leak Detection and Location; Fault Location; Pothead Monitoring; Oil Monitoring; Pipe Protection; and Splice Monitoring. The two DRUMS communication schemes are internal to the pipe cable system. Mechanical Communication will use pressure pulses to transmit data along the ...

1991-07-01

452

DYMAC communications system  

Energy Technology Data Exchange (ETDEWEB)

The DYMAC Communications System is part of a nuclear safeguards system called DYMAC - short for DYnamic Materials ACcountability - that gathers accountability information at the Los Alamos Scientific Laboratory (LASL) Plutonium Processing Facility. The communications system handles transmissions between data-entry terminals and nondestructive assay (NDA) instruments located in the facility, and a computer located in an adjacent building. System design emphasizes reliability rather than high speed to ensure the integrity of data transmissions. This manual is directed toward the person responsible for maintaining the DYMAC Communication System. It describes the components that make up the communications network, explains how they operate, and gives detailed information about all of the connections. Many of the system components are commercially available; some have been modified at LASL for DYMAC ...

1980-01-01

453

Quantum mechanical interpretation for the role of polyamines in acid corrosion inhibition  

International Nuclear Information System (INIS)

The inhibitor action of unbranched polyamines on corrosion of low-carbon steel in 0.5 M sulfuric acid is studied through potentiostatic polarization curves. It is shown that the inhibitor efficiency I depends on the polyamine concentration and molecular structure. The quantum-mechanical calculations of molecular properties are accomplished through the MNDO method. Correlation between the measured I and physicochemical properties of the polyamine inhibitors in protonized and nonprotonized form is found with application of the general perturbation theory

454

Quantum and semiclassical spin networks: from atomic and molecular physics to quantum computing and gravity  

Energy Technology Data Exchange (ETDEWEB)

The mathematical apparatus of quantum-mechanical angular momentum (re)coupling, developed originally to describe spectroscopic phenomena in atomic, molecular, optical and nuclear physics, is embedded in modern algebraic settings which emphasize the underlying combinatorial aspects. SU(2) recoupling theory, involving Wigner's 3nj symbols, as well as the related problems of their calculations, general properties, asymptotic limits for large entries, nowadays plays a prominent role also in quantum gravity and quantum computing applications. We refer to the ingredients of this theory-and of its extension to other Lie and quantum groups-by using the collective term of 'spin networks'. Recent progress is recorded about the already established connections with the mathematical theory of discrete orthogonal polynomials (the so-called Askey scheme), providing powerful tools based on ...

2008-11-15

455

Quantum Cloning for Absolute Radiometry  

International Nuclear Information System (INIS)

In the quantum regime information can be copied with only a finite fidelity. This fidelity gradually increases to 1 as the system becomes classical. In this Letter we show how this fact can be used to directly measure the amount of radiated power. We demonstrate how these principles can be used to build a practical primary standard.

2010-08-20

456

Model of quantum noise of shadow radiation images  

International Nuclear Information System (INIS)

Correlation characteristics of quantum noise on the shadow radiation image (RI) of the object under nondestructive testing are studied. Mathematical model of RI occasional distortions is derived. The model takes into account the parameters of object under testing and of radiation beam by radiation quanta flux density. The results obtained can be used as a component in the process of investigation of various radiation testing systems

457

Measuring-Basis Encrypted Quantum Key Distribution with Four-State Systems  

International Nuclear Information System (INIS)

A measuring-basis encrypted quantum key distribution scheme is proposed by using twelve nonorthogonal states in a four-state system and the measuring-basis encryption technique. In this scheme, two bits of classical information can be encoded on one four-state particle and the transmitted particles can be fully used.

2007-01-15

458

Global quantum gauge symmetry via reconstruction theorems  

Energy Technology Data Exchange (ETDEWEB)

In this paper we establish that every quantum field theory satisfying some basic axioms possesses a weak quasi Hopf algebra as gauge symmetry. We use a reconstruction theorem to find this symmetry algebra and show how it is sed to build a gauge covariant field algebra. We investigate the question of why this generality is necessary. The non-uniqueness of the reconstruction process is interpreted and a cohomological classification of possible global gauge symmetries is given. (author)

1996-12-21

459

Covariant quantum equations in curved space-time, Lorentz covariance and tachyons  

International Nuclear Information System (INIS)

The author presents his views on the interrelation of quantum theory, space-time, Lorentz covariance and tachyons. He makes general observations on the nature of these topics and in particular on the nature of the mathematics used for their description and, without reaching any definite conclusions, points out some areas which require further critical examination. (W.D.L.).

460

Confinement, chiral symmetry, and the lattice  

CERN Document Server

Two crucial properties of QCD, confinement and chiral symmetry breaking, cannot be understand within the context of conventional Feynman perturbation theory. Non-perturbative phenomena enter the theory in a fundamental way at both the classical and quantum level. Over they years a coherent qualitative picture of the interplay between chiral symmetry, quantum mechanical anomalies, and the lattice has emerged and is reviewed here.

2011-01-01

461

Comment on: 'Critical assessment of the Schroedinger picture of quantum mechanics' [Phys. Lett. A 305 (2002) 322  

Energy Technology Data Exchange (ETDEWEB)

Recently, Faria et al. [Phys. Lett. A 305 (2002) 322] discussed an example in which the Heisenberg and the Schroedinger pictures of quantum mechanics gave different results. We identify the mistake in their reasoning and conclude that the example they discussed does not support the inequivalence of these two pictures.

2004-05-24

462

Coherent oscillator radiation  

International Nuclear Information System (INIS)

Coherent oscillator radiation is considered. A comparison is made with classical particle radiation with gauss distribution. Decay probability for coherent state in spontaneous radiation is estimated. The method suggested for describing harmonic oscillator allows to separate the effect of classical field radiation from quantum description of particle state within the framework of a self-consistent quantum mechanical problem.

1982-04-01

463

Coefficient algebra of the minimal representation of the elliptic quantum group  

International Nuclear Information System (INIS)

The algebra of the coefficients in the minimal representation of the A_n_-_1 quantum group, discussed by Felder and Varchenko, is given. Those coefficients are associated with the Boltzmann weights of A_n_-_1"("1") interaction-round-a-face model. The authors show that the algebra satisfies the Yang-Baxter equation. The PBW base for this algebra is also given

2001-07-01

464

Amplitude-real-phase exact solutions for quantum mixmaster universes  

Energy Technology Data Exchange (ETDEWEB)

We present a set of exact solutions for quantum Bianchi type-IX anisotropic cosmological models (including the Taub model) of the form {Psi}={ital We}{sup {minus}{ital S}}. These solutions are spread over all values of anisotropy near the singularity, but at larger values of the radius of the universe they are strongly peaked around the {ital k}=+1 Friedmann-Robertson-Walker model.

1991-10-15

465

A quantum-statistical-mechanical extension of Gaussian mixture model  

Energy Technology Data Exchange (ETDEWEB)

We propose an extension of Gaussian mixture models in the statistical-mechanical point of view. The conventional Gaussian mixture models are formulated to divide all points in given data to some kinds of classes. We introduce some quantum states constructed by superposing conventional classes in linear combinations. Our extension can provide a new algorithm in classifications of data by means of linear response formulas in the statistical mechanics.

2008-01-15

466

Stable halogen complexes of astatine cations in aqueous solutions  

International Nuclear Information System (INIS)

Halide complexes of astatine cations At"+ and AtO"+ were prepared and their rate of migration was measured. The complexes are of the type AtX_2"- and AtOX_2"- (X = Cl"-, Br"-, I"-). The bromo complexes, AtBr_2"- and AtOBr_2"-, have a higher stability than the chloro complexes. The hydrolysis in weakly alkaline solution of AtX_2"- resulted At"-, and that of AtOX_2"- AtO_2"-. (author).

467

The quantum N-body problem with a minimal length  

CERN Document Server

The quantum $N$-body problem is studied in the context of nonrelativistic quantum mechanics with a one-dimensional deformed Heisenberg algebra of the form $[\\hat x,\\hat p]=i(1+\\beta \\hat p^2)$, leading to the existence of a minimal observable length $\\sqrt\\beta$. For a generic pairwise interaction potential, analytical formulas are obtained that allow to estimate the ground-state energy of the $N$-body system by finding the ground-state energy of a corresponding two-body problem. It is first shown that, in the harmonic oscillator case, the $\\beta$-dependent term grows faster with $N$ than the $\\beta$-independent one. Then, it is argued that such a behavior should be observed also with generic potentials and for $D$-dimensional systems. In consequence, quantum $N$-body bound states might be interesting places to look at nontrivial manifestations of a minimal length since, the more particles are present, the more the ...

2010-01-01

468

Perturbative Quantum Gravity and Yang-Mills Theories in de Sitter Spacetime  

CERN Document Server

This thesis consists of three parts. In the first part we review the quantization of Yang-Mills theories and perturbative quantum gravity in curved spacetime. In the second part we calculate the Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge. In the third part we investigate the physical equivalence of covariant Wightman graviton two-point function with the physical graviton two-point function. The Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge are infrared (IR) divergent in de Sitter spacetime. We point out, that if we regularize these divergences by introducing a finite mass and take the zero mass limit at the end, then the modes responsible for these divergences will not contribute to loop diagrams in computations of time-ordered products in either Yang-Mills ...

2011-01-01

469

Holomorphic wave function of the Universe  

Energy Technology Data Exchange (ETDEWEB)

The quantum behavior of the vacuum Bianchi type-IX universe with the cosmological constant is investigated in terms of the Ashtekar variables. An exact solution to the quantum Hamiltonian constraint in the holomorphic representation is given. This solution reduces to the Hartle-Hawking wave function in the spatially isotropic sector and extends in the triad representation to the classically forbidden region where the determinant of the spatial metric becomes negative. The analysis of the quantum Robertson-Walker universe indicates that if the superspace is extended to such a classically forbidden region, the holomorphic representation picks up some restricted class of solutions in general. This observation leads to a new ansatz on the boundary condition of the Universe. In particular, the behavior of the Lorentzian and Euclidean WKB orbits corresponding to the solution suggests a new picture on the semiclassical behavior of ...

1990-10-15

470

Holomorphic wave function of the Universe  

International Nuclear Information System (INIS)

The quantum behavior of the vacuum Bianchi type-IX universe with the cosmological constant is investigated in terms of the Ashtekar variables. An exact solution to the quantum Hamiltonian constraint in the holomorphic representation is given. This solution reduces to the Hartle-Hawking wave function in the spatially isotropic sector and extends in the triad representation to the classically forbidden region where the determinant of the spatial metric becomes negative. The analysis of the quantum Robertson-Walker universe indicates that if the superspace is extended to such a classically forbidden region, the holomorphic representation picks up some restricted class of solutions in general. This observation leads to a new ansatz on the boundary condition of the Universe. In particular, the behavior of the Lorentzian and Euclidean WKB orbits corresponding to the solution suggests a new picture on the semiclassical behavior of ...

471

Free-field representation of the quantum affine algebra U_q(sl_2) and form factors in the higher-spin XXZ model  

International Nuclear Information System (INIS)

We consider the spin-k/2 XXZ model in the antiferromagnetic regime using the free-field realization of the quantum affine algebra U_q(sl_2) of level k. We give a free-field realization of the type-II q-vertex operator, which describes creation and annihilation of physical particles in the model. By taking a trace of the type-I and type-II q-vertex operators over the irreducible highest-weight representation of U_q(sl_2), we also derive an integral formula for form factors in this model. Investigating the structure of poles, we obtain a residue formula for form factors, which is a lattice analog of the higher-spin extension of Smirnov's formula in the massive integrable quantum field theory. This result as well as the quantum deformation of the Knizhnik-Zamolodchikov equation for form factors shows a deep connection in the mathematical structure of the integrable lattice models and the massive integrable ...

1994-12-01

472

Dissipation and entropy production in open quantum systems  

Energy Technology Data Exchange (ETDEWEB)

A microscopic description of an open system is generally expressed by the Hamiltonian of the form: H{sub tot} = H{sub sys} + H{sub environ} + H{sub sys-environ}. We developed a microscopic theory of entropy and derived a general formula, so-called 'entropy-Hamiltonian relation' (EHR), that connects the entropy of the system to the interaction Hamiltonian represented by H{sub sys-environ} for a nonequilibrium open quantum system. To derive the EHR formula, we mapped the open quantum system to the representation space of the Liouville-space formulation or thermo field dynamics (TFD), and thus worked on the representation space L := H x H-tilde, where H denotes the ordinary Hilbert space while H-tilde the tilde Hilbert space conjugates to H. We show that the natural transformation (mapping) of nonequilibrium open quantum systems is accomplished within the theoretical structure of TFD. By using the obtained ...

2010-11-01

473

The complexity of gene expression dynamics revealed by permutation entropy  

UK PubMed Central (United Kingdom)

BackgroundHigh complexity is considered a hallmark of living systems. Here we investigate the complexity of temporal gene expression patterns using the concept of Permutation Entropy...Full Text Available

474

Subunits of the Drosophila CCR4-NOT complex and their roles in mRNA deadenylation  

UK PubMed Central (United Kingdom)

The CCR4-NOT complex is the main enzyme catalyzing the deadenylation of mRNA. We have investigated the composition of this complex in Drosophila melanogaster by immunoprecipitation...Full Text Available

2010-07-01

475

Rapamycin inhibits trypanosome cell growth by preventing TOR complex 2 formation  

UK PubMed Central (United Kingdom)

Target of rapamycin (TOR) kinases control cell growth through two functionally distinct multiprotein complexes. TOR complex 1 (TORC1) controls temporal cell growth and is sensitive to rapamycin, whereas...Full Text Available

2008-09-23

476

Photochemistry and charge transfer chemistry of the platinum group elements  

Energy Technology Data Exchange (ETDEWEB)

During the past 3 years, progress was made in elucidating the excited state structures of Pt(diimine)(dithiolate) complexes, while more recent efforts focused on the photochemistry of these complexes and electronic structure of other dithiolate systems. A carbonyl-Ir-maleonitrile dithiolate complex is also studied.

1992-12-01

477

On the ease of predicting the thermodynamic properties of beta-cyclodextrin inclusion complexes  

UK PubMed Central (United Kingdom)

BackgroundIn this study we investigated the predictability of three thermodynamic quantities related to complex formation. As a model system we chose the host-guest complexes of...Full Text Available

478

Dynamics of ligand substitution in labile cobalt complexes resolved by ultrafast T-jump  

UK PubMed Central (United Kingdom)

Ligand exchange of hydrated metal complexes is common in chemical and biological systems. Using the ultrafast T-jump, we examined this process, specifically the transformation of aqua cobalt (II) complexes...Full Text Available

2008-09-02

479

Application of ?- and ?-Isomerism of Octahedral Metal Complexes for Inducing Chiral Nematic Phases  

UK PubMed Central (United Kingdom)

The Δ- and Λ-isomerism of octahedral metal complexes is employed as a source of chirality for inducing chiral nematic phases. By applying a wide range of chiral metal complexes as a...Full Text Available

480

Temperature-dependent properties of semiconductor quantum dots in coherent regime; Temperaturabhaengige Eigenschaften einzelner Halbleiter-Quantenpunkte im Kohaerenten Regime  

Energy Technology Data Exchange (ETDEWEB)

Recently, the public has become aware of keywords like ''Quantum computer'' or ''Quantum cryptography''. Regarding their potential application in solid state based quantum information processing and their overall benefit in fundamental research quantum dots have gained more and more public interest. In this context, quantum dots are often referred to as ''artificial atoms'', a term subsuming their physical properties quite nicely and emphasizing the huge potential for further investigations. The basic mechanism to be considered is the theoretical model of a two-level system. A quantum dot itself represents this kind of system quite nicely, provided that only the presence or absence of a single exciton in the ground state of that structure is regarded. This ...

2009-10-15

481

Undergraduate Instruction in Empirical Research Methods in Communication: Assessment and Recommendations  

British Library Electronic Table of Contents (United Kingdom)

This study assesses the current state of undergraduate instruction in empirical research methods in communication and offers recommendations for enhancing such instruction. Responses to an online questionnaire were received from 149 communication-related programs at four-year colleges and universities. Just over 85% of responding programs offered an empirical methods course. Although the course often covered both qualitative and quantitative methods, instruction was heavily slanted toward quantitative methods and topics common to both qualitative and quantitative inquiry. The empirical methods course was usually required for graduation, but it was typically not well integrated with the rest of the curriculum and taken late in students' undergraduate careers. Additional analyses examined st...

2011-01-01

482

Simulating economic effects of disruptions in the telecommunications infrastructure.  

Energy Technology Data Exchange (ETDEWEB)

CommAspen is a new agent-based model for simulating the interdependent effects of market decisions and disruptions in the telecommunications infrastructure on other critical infrastructures in the U.S. economy such as banking and finance, and electric power. CommAspen extends and modifies the capabilities of Aspen-EE, an agent-based model previously developed by Sandia National Laboratories to analyze the interdependencies between the electric power system and other critical infrastructures. CommAspen has been tested on a series of scenarios in which the communications network has been disrupted, due to congestion and outages. Analysis of the scenario results indicates that communications networks simulated by the model behave as their counterparts do in the real world. Results also show that the model could be used to analyze the economic impact of communications congestion and outages.

2004-01-01

483

Proceedings of the 23rd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting  

Energy Technology Data Exchange (ETDEWEB)

A compilation of technical papers, from the 23rd annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting, is presented. Papers were given in the following categories: (1) developments in rubidium, cesium, and hydrogen-based frequency standards, and in cryogenic and trapped-ion technology; (2) international and transnational applications of PTTI technology with emphasis on satellite laser tracking networks, GLONASS timing, comparison of national time scales and international communications; (3) applications of PTTI technology to the telecommunications, power distribution, platform positioning, and geophysical survey industries; (4) applications of PTTI technology to evolving military communications and navigation systems; and (5) dissemination of precise time and frequency by means of GPS, GLONASS, MILSTAR, Loran, and synchronous communications satellites.

1992-07-01

484

Management approaches for improving environmental restoration at the Savannah River Site: Projectization, performance, and communications; Savannah River Site, Aiken, South Carolina  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to communicate how new and established management techniques are applied to environmental restoration projects at the Savannah River Site. Specifically, the paper discusses application of four (4) management approaches: Total Quality Principles; Task Team Structure; Cost Time Management; SAFER (Streamlined Approach for Environmental Restoration). The objective is to share Savannah River Site experience and document case studies where certain approaches have enhanced projects at hand. Each management approach is demonstrated by its project application and impact on performance. The visibility given the project is discussed to emphasize communications as avenues for public information, technical exchange, and employee motivation.

1993-02-01

485

Innovative Elektrizit?tsversorgungssysteme f?r IKT  

British Library Electronic Table of Contents (United Kingdom)

Summary Modern society all over the world depends on information and communication technology (ICT); and security of supply with ICT is an important location factor. In times of increasing anonymity, which makes us more and more dependent on public services such as emergency supports (emergency organizations), communication is existential. Communication also plays an important role for a good functioning of economy and industry, in the course of shorter production and storage times. The usage of ICT is taken for granted. However, the modern society's use of ICT is profoundly dependent on the public power supply. Particularly in highly industrialized countries like e.g. Austria, the ICT sector requires about 10% of the total electric energy demand. One third of these 10% is estimated to be ...

2010-01-01

486

Information security in networked supply chains: impact of network vulnerability and supply chain integration on incentives to invest  

British Library Electronic Table of Contents (United Kingdom)

Recent supply chain reengineering efforts have focused on integrating firms? production, inventory and replenishment activities with the help of communication networks. While communication networks and supply chain integration facilitate optimization of traditional supply chain functions, they also exacerbate the information security risk: communication networks propagate security breaches from one firm to another, and supply chain integration causes breach on one firm to affect other firms in the supply chain. We study the impact of network security vulnerability and supply chain integration on firms? incentives to invest in information security. We find that even though an increase in either the degree of network vulnerability or the degree of supply chain integration increases the secur...

2010-01-01

487

Flexible Session Management in a Distributed Environment  

CERN Document Server

Many secure communication libraries used by distributed systems, such as SSL, TLS, and Kerberos, fail to make a clear distinction between the authentication, session, and communication layers. In this paper we introduce CEDAR, the secure communication library used by the Condor High Throughput Computing software, and present the advantages to a distributed computing system resulting from CEDAR's separation of these layers. Regardless of the authentication method used, CEDAR establishes a secure session key, which has the flexibility to be used for multiple capabilities. We demonstrate how a layered approach to security sessions can avoid round-trips and latency inherent in network authentication. The creation of a distinct session management layer allows for optimizations to improve scalability by way of delegating sessions to other components in the system. This session delegation creates a chain of trust that reduces the ...

2010-01-01

488

Chronic and non-communicable diseases: a critical challenge for nurses globally  

British Library Electronic Table of Contents (United Kingdom)

ALLEYNE G., HANCOCK C. & HUGHES P. (2011) Chronic and non-communicable diseases: a critical challenge for nurses globally. International Nursing Review58, 328-331 Background:- Chronic and non-communicable diseases (NCDs) are a growing and enormous challenge that faces countries across the world. Low- and middle-income countries are disproportionately affected. Contributory factors:- Three risk factors - tobacco use, poor diet (including excessive alcohol intake) and lack of physical activity - contribute to four major chronic diseases - cardiovascular, chronic obstructive pulmonary disease, diabetes and some cancers, which are responsible for over 50% of deaths worldwide. Potential solutions:- International governmental and non-governmental agencies are becoming increasingly concerned and ...

2011-01-01

489

A comparison of the UHF Follow-On and MILSTAR satellite communication systems  

Science.gov (United States)

The author compares the UHF Follow-On and MILSTAR satellite communication systems. The comparison uses an analytical hierarchy process. Although the two systems have been tasked with different missions, a comparison of cost, capability, and orbit is conducted. UFO provides many of the same capabilities as MILSTAR, but on a smaller scale. Since UFO is also a new space system acquisition, it is used to compare dollars spent to field a viable communication system. A review of frequency bands, losses, and problems is conducted to establish the relationship. Cost data is provided to establish the major difference in the systems. While MILSTAR does possess more total capability than UFO, it is 10 times more costly. Additionally, UFO is a satellite that will evolve with new technology while MILSTAR is built to full capability immediately. In the author's opinion, the incremental performance of MILSTAR does not justify its incremental cost.

1991-09-01

490

Targeting a Ruthenium Complex to the Nucleus with Short Peptides  

UK PubMed Central (United Kingdom)

In an effort to develop octahedral metal complexes as chemotherapeutic and diagnostic agents targeted to DNA, it is critical to optimize the properties of their cellular uptake. Appending d-octaarginine...Full Text Available

2010-05-15

492

General Disclaimer One or more of the Following Statements may ...  

Science.gov (United States)

complexe sur paroi non-isotherme, LContri5ution to the Study thermal ... paroi chaude essentiellement non-isotherme, LVaporization in a Complex ...

493

Catalytic hydration of alkynes with platinum(II) complexes  

Energy Technology Data Exchange (ETDEWEB)

Platinum(II) complexes have been investigated in the hydration of alkynes. These catalysts offer improved regioselectivity over Hg(II) counterparts. 1 fig., 2 tabs.

1993-12-17

494

AN EVALUATION OF AN IMPORTANT ADVANCE IN ...  

Science.gov (United States)

... No. 52. Metal Complexes-I. Preparation and Physical Properties of Transition Metal Complexes of 6-Mercaptopurine and 4-Mercapto-6, 7-Diphenyl ...

1965-03-01

495

Hybrid apparatus for Bose-Einstein condensation and cavity quantum electrodynamics: Single atom detection in quantum degenerate gases  

International Nuclear Information System (INIS)

We present and characterize an experimental system in which we achieve the integration of an ultrahigh finesse optical cavity with a Bose-Einstein condensate (BEC). The conceptually novel design of the apparatus for the production of BECs features nested vacuum chambers and an in vacuo magnetic transport configuration. It grants large scale spatial access to the BEC for samples and probes via a modular and exchangeable ''science platform.'' We are able to produce 87Rb condensates of 5x106 atoms and to output couple continuous atom lasers. The cavity is mounted on the science platform on top of a vibration isolation system. The optical cavity works in the strong coupling regime of cavity quantum electrodynamics and serves as a quantum optical detector for single atoms. This system enables us to study atom optics on a single particle level and to further develop the field of quantum atom optics. We describe the technological ...

2006-06-01

496

The MacMahon Master Theorem for right quantum superalgebras and higher Sugawara operators for \\hat gl(m|n)  

CERN Document Server

We prove an analogue of the MacMahon Master Theorem for the right quantum superalgebras. In particular, we obtain a new and simple proof of this theorem for the right quantum algebras. In the super case the theorem is then used to construct higher order Sugawara operators for the affine Lie superalgebra \\hat gl(m|n) in an explicit form. The operators are elements of a completed universal enveloping algebra of \\hat gl(m|n) at the critical level. They occur as the coefficients in the expansion of a noncommutative Berezinian and as the traces of powers of generator matrices. The same construction yields higher Hamiltonians for the Gaudin model associated with the Lie superalgebra gl(m|n).

2009-01-01

497

Isomorphisms of quantizations via quantization of resolutions  

CERN Document Server

In this paper we prove the existence of isomorphisms between certain non-commutative algebras that are interesting from representation theoretic perspective and arise as quantizations of certain Poisson algebras. We show that quantizations of Kleinian resolutions obtained by three different constructions are isomorphic to each other. The constructions are via symplectic reflection algebras, quantum Hamiltonian reduction, and W-algebras. Next, we prove that parabolic W-algebras in type A are isomorphic to quantum Hamiltonian reductions associated to quivers of type A. Finally, we show that the symplectic reflection algebras for wreath-products of the symmetric group and a Kleinian group are isomorphic to certain quantum Hamiltonian reductions. Our results involving W-algebras are new, while for those dealing with symplectic reflection algebras we just give new proofs. A key ingredient in our proofs is the study of ...

2010-01-01

498

High-visibilty two-photon interference at a telecom wavelength using picosecond regime separated sources  

CERN Document Server

We report on a two-photon interference experiment in a quantum relay configuration using two picosecond regime PPLN waveguide based sources emitting paired photons at 1550 nm. The results show that the picosecond regime associated with a guided-wave scheme should have important repercussions for quantum relay implementations in real conditions, essential for improving both the working distance and the efficiency of quantum cryptography and networking systems. In contrast to already reported regimes, namely femtosecond and CW, it allows achieving a 99% net visibility two-photon interference while maintaining a high effective photon pair rate using only standard telecom components and detectors.

2009-01-01

499

AlxGa1-xN/GaN multi-quantum-well ultraviolet detector based on p-i-n heterostructures  

British Library Electronic Table of Contents (United Kingdom)

We report on characterization of a set of AlGaN/GaN multiple-quantum-well (MQW) photodetectors. The model structure used in the calculation is the p-i-n heterojunction with 20 AlGaN/GaN MQW structures in i-region. The MQW structures have 2nm GaN quantum well width and 15nm AlxGa1-xN barrier width. The cutoff wavelength of the MQW photodetectors can be tuned by adjusting the well width and barrier height. Including the polarization field effects, on increasing Al mole fraction, the transition energy decreases, the total noise increases, and the responsivity has a red shift, and so the detectivity decreases and has a red shift.

2009-01-01