Macroscopic quantum resonators (MAQRO)
Kaltenbaek, Rainer; Kiesel, Nikolai; Romero-Isart, Oriol; Johann, Ulrich; Aspelmeyer, Markus
2012-01-01
Quantum physics challenges our understanding of the nature of physical reality and of space-time and suggests the necessity of radical revisions of their underlying concepts. Experimental tests of quantum phenomena involving massive macroscopic objects would provide novel insights into these fundamental questions. Making use of the unique environment provided by space, MAQRO aims at investigating this largely unexplored realm of macroscopic quantum physics. MAQRO has originally been proposed as a medium-sized fundamental-science space mission for the 2010 call of Cosmic Vision. MAQRO unites two experiments: DECIDE (DECoherence In Double-Slit Experiments) and CASE (Comparative Acceleration Sensing Experiment). The main scientific objective of MAQRO, which is addressed by the experiment DECIDE, is to test the predictions of quantum theory for quantum superpositions of macroscopic objects containing more than 10e8 atoms. Under these conditions, deviations due to various suggested alternative models to quantum th...
Covariant Macroscopic Quantum Geometry
Hogan, Craig J
2012-01-01
A covariant noncommutative algebra of position operators is presented, and interpreted as the macroscopic limit of a geometry that describes a collective quantum behavior of the positions of massive bodies in a flat emergent space-time. The commutator defines a quantum-geometrical relationship between world lines that depends on their separation and relative velocity, but on no other property of the bodies, and leads to a transverse uncertainty of the geometrical wave function that increases with separation. The number of geometrical degrees of freedom in a space-time volume scales holographically, as the surface area in Planck units. Ongoing branching of the wave function causes fluctuations in transverse position, shared coherently among bodies with similar trajectories. The theory can be tested using appropriately configured Michelson interferometers.
Quantum equilibria for macroscopic systems
Energy Technology Data Exchange (ETDEWEB)
Grib, A [Department of Theoretical Physics and Astronomy, Russian State Pedagogical University, St. Petersburg (Russian Federation); Khrennikov, A [Centre for Mathematical Modelling in Physics and Cognitive Sciences Vaexjoe University (Sweden); Parfionov, G [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation); Starkov, K [Department of Mathematics, St. Petersburg State University of Economics and Finances (Russian Federation)
2006-06-30
Nash equilibria are found for some quantum games with particles with spin-1/2 for which two spin projections on different directions in space are measured. Examples of macroscopic games with the same equilibria are given. Mixed strategies for participants of these games are calculated using probability amplitudes according to the rules of quantum mechanics in spite of the macroscopic nature of the game and absence of Planck's constant. A possible role of quantum logical lattices for the existence of macroscopic quantum equilibria is discussed. Some examples for spin-1 cases are also considered.
Macroscopic quantum mechanics in a classical spacetime.
Yang, Huan; Miao, Haixing; Lee, Da-Shin; Helou, Bassam; Chen, Yanbei
2013-04-26
We apply the many-particle Schrödinger-Newton equation, which describes the coevolution of a many-particle quantum wave function and a classical space-time geometry, to macroscopic mechanical objects. By averaging over motions of the objects' internal degrees of freedom, we obtain an effective Schrödinger-Newton equation for their centers of mass, which can be monitored and manipulated at quantum levels by state-of-the-art optomechanics experiments. For a single macroscopic object moving quantum mechanically within a harmonic potential well, its quantum uncertainty is found to evolve at a frequency different from its classical eigenfrequency-with a difference that depends on the internal structure of the object-and can be observable using current technology. For several objects, the Schrödinger-Newton equation predicts semiclassical motions just like Newtonian physics, yet quantum uncertainty cannot be transferred from one object to another.
Macroscopic Quantum Resonators (MAQRO): 2015 update
Energy Technology Data Exchange (ETDEWEB)
Kaltenbaek, Rainer [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Aspelmeyer, Markus; Kiesel, Nikolai [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Barker, Peter F.; Bose, Sougato [University College London, Department of Physics and Astronomy, London (United Kingdom); Bassi, Angelo [University of Trieste, Department of Physics, Trieste (Italy); INFN - Trieste Section, Trieste (Italy); Bateman, James [University of Swansea, Department of Physics, College of Science, Swansea (United Kingdom); Bongs, Kai; Cruise, Adrian Michael [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Braxmaier, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Brukner, Caslav [University of Vienna, Vienna Center for Quantum Science and Technology, Vienna (Austria); Austrian Academy of Sciences, Institute of Quantum Optics and Quantum Information (IQOQI), Vienna (Austria); Christophe, Bruno; Rodrigues, Manuel [The French Aerospace Lab, ONERA, Chatillon (France); Chwalla, Michael; Johann, Ulrich [Airbus Defence and Space GmbH, Immenstaad (Germany); Cohadon, Pierre-Francois; Heidmann, Antoine; Lambrecht, Astrid; Reynaud, Serge [ENS-PSL Research University, Laboratoire Kastler Brossel, UPMC-Sorbonne Universites, CNRS, College de France, Paris (France); Curceanu, Catalina [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Dholakia, Kishan; Mazilu, Michael [University of St. Andrews, School of Physics and Astronomy, St. Andrews (United Kingdom); Diosi, Lajos [Wigner Research Center for Physics, P.O. Box 49, Budapest (Hungary); Doeringshoff, Klaus; Peters, Achim [Humboldt-Universitaet zu Berlin, Institut fuer Physik, Berlin (Germany); Ertmer, Wolfgang; Rasel, Ernst M. [Leibniz Universitaet Hannover, Institut fuer Quantenoptik, Hannover (Germany); Gieseler, Jan; Novotny, Lukas; Rondin, Loic [ETH Zuerich, Photonics Laboratory, Zuerich (Switzerland); Guerlebeck, Norman; Herrmann, Sven; Laemmerzahl, Claus [University of Bremen, Center of Applied Space Technology and Micro Gravity (ZARM), Bremen (Germany); Hechenblaikner, Gerald [Airbus Defence and Space GmbH, Immenstaad (Germany); European Southern Observatory (ESO), Garching bei Muenchen (Germany); Hossenfelder, Sabine [KTH Royal Institute of Technology and Stockholm University, Nordita, Stockholm (Sweden); Kim, Myungshik [Imperial College London, QOLS, Blackett Laboratory, London (United Kingdom); Milburn, Gerard J. [University of Queensland, ARC Centre for Engineered Quantum Systems, Brisbane (Australia); Mueller, Holger [University of California, Department of Physics, Berkeley, CA (United States); Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Pikovski, Igor [Harvard-Smithsonian Center for Astrophysics, ITAMP, Cambridge, MA (United States); Pilan Zanoni, Andre [Airbus Defence and Space GmbH, Immenstaad (Germany); CERN - European Organization for Nuclear Research, EN-STI-TCD, Geneva (Switzerland); Riedel, Charles Jess [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); Roura, Albert [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Schleich, Wolfgang P. [Universitaet Ulm, Institut fuer Quantenphysik, Ulm (Germany); Texas A and M University Institute for Advanced Study (TIAS), Institute for Quantum Science and Engineering (IQSE), and Department of Physics and Astronomy, College Station, TX (United States); Schmiedmayer, Joerg [Vienna University of Technology, Vienna Center for Quantum Science and Technology, Institute of Atomic and Subatomic Physics, Vienna (Austria); Schuldt, Thilo [Institute of Space Systems, German Aerospace Center (DLR), Bremen (Germany); Schwab, Keith C. [California Institute of Technology, Applied Physics, Pasadena, CA (United States)
2016-12-15
Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schroedinger's cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments. (orig.)
Black Holes and Quantumness on Macroscopic Scales
Flassig, D; Wintergerst, N
2012-01-01
It has recently been suggested that black holes may be described as condensates of weakly interacting gravitons at a critical point, exhibiting strong quantum effects. In this paper, we study a model system of attractive bosons in one spatial dimension which is known to undergo a quantum phase transition. We demonstrate explicitly that indeed quantum effects are important at the critical point, even if the number of particles is macroscopic. Most prominently, we evaluate the entropy of entanglement between different momentum modes and observe it to become maximal at the critical point. Furthermore, we explicitly see that the leading entanglement is between long wavelength modes and is hence a feature independent of ultraviolet physics. If applicable to black holes, our findings substantiate the conjectured breakdown of semiclassical physics even for large black holes. This can resolve long standing mysteries, such as the information paradox and the no-hair theorem.
Macroscopically-Discrete Quantum Cosmology
Chew, Geoffrey F
2008-01-01
To Milne's Lorentz-group-based spacetime and Gelfand-Naimark unitary representations of this group we associate a Fock space of 'cosmological preons'-quantum-theoretic universe constituents. Milne's 'cosmological principle' relies on Lorentz invariance of 'age'--global time. We divide Milne's spacetime into 'slices' of fixed macroscopic width in age, with 'cosmological rays' defined on (hyperbolic) slice boundaries-Fock space attaching only to these exceptional universe ages. Each (fixed-age) preon locates within a 6-dimensional manifold, one of whose 3 'extra' dimensions associates in Dirac sense to a self-adjoint operator that represents preon (continuous) local time, the operator canonically-conjugate thereto representing preon (total) energy. Self-adjoint-operator expectations at any spacetime-slice boundary prescribe throughout the following slice a non-fluctuating 'mundane reality'- electromagnetic and gravitational potentials 'tethered' to current densities of locally-conserved electric charge and ener...
Assessments of macroscopicity for quantum optical states
DEFF Research Database (Denmark)
Laghaout, Amine; Neergaard-Nielsen, Jonas Schou; Andersen, Ulrik Lund
2015-01-01
With the slow but constant progress in the coherent control of quantum systems, it is now possible to create large quantum superpositions. There has therefore been an increased interest in quantifying any claims of macroscopicity. We attempt here to motivate three criteria which we believe should...... enter in the assessment of macroscopic quantumness: The number of quantum fluctuation photons, the purity of the states, and the ease with which the branches making up the state can be distinguished. © 2014....
Quantum correlations of lights in macroscopic environments
Sua, Yong Meng
This dissertation presents a detailed study in exploring quantum correlations of lights in macroscopic environments. We have explored quantum correlations of single photons, weak coherent states, and polarization-correlated/polarization-entangled photons in macroscopic environments. These included macroscopic mirrors, macroscopic photon number, spatially separated observers, noisy photons source and propagation medium with loss or disturbances. We proposed a measurement scheme for observing quantum correlations and entanglement in the spatial properties of two macroscopic mirrors using single photons spatial compass state. We explored the phase space distribution features of spatial compass states, such as chessboard pattern by using the Wigner function. The displacement and tilt correlations of the two mirrors were manifested through the propensities of the compass states. This technique can be used to extract Einstein-Podolsky-Rosen correlations (EPR) of the two mirrors. We then formulated the discrete-like property of the propensity P b(m,n), which can be used to explore environmental perturbed quantum jumps of the EPR correlations in phase space. With single photons spatial compass state, the variances in position and momentum are much smaller than standard quantum limit when using a Gaussian TEM 00 beam. We observed intrinsic quantum correlations of weak coherent states between two parties through balanced homodyne detection. Our scheme can be used as a supplement to decoy-state BB84 protocol and differential phase-shift QKD protocol. We prepared four types of bipartite correlations +/- cos2(theta1 +/- theta 2) that shared between two parties. We also demonstrated bits correlations between two parties separated by 10 km optical fiber. The bits information will be protected by the large quantum phase fluctuation of weak coherent states, adding another physical layer of security to these protocols for quantum key distribution. Using 10 m of highly nonlinear
Quantum Bell Inequalities from Macroscopic Locality
Yang, Tzyh Haur; Sheridan, Lana; Scarani, Valerio
2010-01-01
We propose a method to generate analytical quantum Bell inequalities based on the principle of Macroscopic Locality. By imposing locality over binary processings of virtual macroscopic intensities, we establish a correspondence between Bell inequalities and quantum Bell inequalities in bipartite scenarios with dichotomic observables. We discuss how to improve the latter approximation and how to extend our ideas to scenarios with more than two outcomes per setting.
A macroscopic challenge for quantum spacetime
Amelino-Camelia, Giovanni
2013-01-01
Over the last decade a growing number of quantum-gravity researchers has been looking for opportunities for the first ever experimental evidence of a Planck-length quantum property of spacetime. These studies are usually based on the analysis of some candidate indirect implications of spacetime quantization, such as a possible curvature of momentum space. Some recent proposals have raised hope that we might also gain direct experimental access to quantum properties of spacetime, by finding evidence of limitations to the measurability of the center-of-mass coordinates of some macroscopic bodies. However I here observe that the arguments that originally lead to speculating about spacetime quantization do not apply to the localization of the center of mass of a macroscopic body. And I also analyze some popular formalizations of the notion of quantum spacetime, finding that when the quantization of spacetime is Planckian for the constituent particles then for the composite macroscopic body the quantization of spa...
Macroscopic superpositions and gravimetry with quantum magnetomechanics
Johnsson, Mattias T.; Brennen, Gavin K.; Twamley, Jason
2016-11-01
Precision measurements of gravity can provide tests of fundamental physics and are of broad practical interest for metrology. We propose a scheme for absolute gravimetry using a quantum magnetomechanical system consisting of a magnetically trapped superconducting resonator whose motion is controlled and measured by a nearby RF-SQUID or flux qubit. By driving the mechanical massive resonator to be in a macroscopic superposition of two different heights our we predict that our interferometry protocol could, subject to systematic errors, achieve a gravimetric sensitivity of Δg/g ~ 2.2 × 10-10 Hz-1/2, with a spatial resolution of a few nanometres. This sensitivity and spatial resolution exceeds the precision of current state of the art atom-interferometric and corner-cube gravimeters by more than an order of magnitude, and unlike classical superconducting interferometers produces an absolute rather than relative measurement of gravity. In addition, our scheme takes measurements at ~10 kHz, a region where the ambient vibrational noise spectrum is heavily suppressed compared the ~10 Hz region relevant for current cold atom gravimeters.
Applying quantum mechanics to macroscopic and mesoscopic systems
T., N Poveda
2012-01-01
There exists a paradigm in which Quantum Mechanics is an exclusively developed theory to explain phenomena on a microscopic scale. As the Planck's constant is extremely small, $h\\sim10^{-34}{J.s}$, and as in the relation of de Broglie the wavelength is inversely proportional to the momentum; for a mesoscopic or macroscopic object the Broglie wavelength is very small, and consequently the undulatory behavior of this object is undetectable. In this paper we show that with a particle oscillating around its classical trajectory, the action is an integer multiple of a quantum of action, $S = nh_{o}$. The quantum of action, $h_{o}$, which plays a role equivalent to Planck's constant, is a free parameter that must be determined and depends on the physical system considered. For a mesoscopic and macroscopic system: $h_{o}\\gg h$, this allows us to describe these systems with the formalism of quantum mechanics.
Toward a superconducting quantum computer. Harnessing macroscopic quantum coherence.
Tsai, Jaw-Shen
2010-01-01
Intensive research on the construction of superconducting quantum computers has produced numerous important achievements. The quantum bit (qubit), based on the Josephson junction, is at the heart of this research. This macroscopic system has the ability to control quantum coherence. This article reviews the current state of quantum computing as well as its history, and discusses its future. Although progress has been rapid, the field remains beset with unsolved issues, and there are still many new research opportunities open to physicists and engineers.
Macroscopic Quantum Criticality in a Circuit QED
Wang, Y D; Nori, F; Quan, H T; Sun, C P; Liu, Yu-xi; Nori, Franco
2006-01-01
Cavity quantum electrodynamic (QED) is studied for two strongly-coupled charge qubits interacting with a single-mode quantized field, which is provided by a on-chip transmission line resonator. We analyze the dressed state structure of this superconducting circuit QED system and the selection rules of electromagnetic-induced transitions between any two of these dressed states. Its macroscopic quantum criticality, in the form of ground state level crossing, is also analyzed, resulting from competition between the Ising-type inter-qubit coupling and the controllable on-site potentials.
Macroscopic Quantum Coherence in Antiferromagnetic Molecular Magnets
Institute of Scientific and Technical Information of China (English)
HU Hui; LO Rong; ZHU Jia-Lin; XIONG Jia-Jiong
2001-01-01
The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model. On the basis of instanton technique in the spin-coherent-state path-integral representation, both the rigorous Wentzel-Kramers-Brillouin exponent and pre-exponential factor for the ground-state tunnel splitting are obtained. We find that the quantum fluctuations around the classical paths can not only induce a new quantum phase previously reported by Chiolero and Loss (Phys. Rev. Lett. 80 (1998) 169), but also have great influence on the intensity of the ground-state tunnel splitting. Those features clearly have no analogue in the ferromagnetic molecular magnets. We suggest that they may be the universal behaviors in all antiferromagnetic molecular magnets. The analytical results are complemented by exact diagonalization calculation.
Macroscopic Quantum Coherence in Antiferromagnetic Molecular Magnets
Institute of Scientific and Technical Information of China (English)
HUHui; LURong; 等
2001-01-01
The macroscopic quantum coherence in a biaxial antiferromagnetic molecular magnet in the presence of magnetic field acting parallel to its hard anisotropy axis is studied within the two-sublattice model.On the basis of instanton technique in the spin-coherent-state path-integral representation,both the rigorous Wentzel-Kramers-Brillouin exponent and pre-exponential factor for the ground-state tunnel splitting are obtained.We find that the quantum fluctuations around the classical paths can not only induce a new quantum phase previously reported by Chiolero and Loss (Phys.Rev.Lett.80(1998)169),but also have great influence on the intensity of the ground-state tunnel splitting.Those features clearly have no analogue in the ferromagnetic molecular magnets.We suggest that they may be the universal behaviors in all antiferromagnetic molecular magnets.The analytical results are complemented by exact diagonalization calculation.
Quantum physics meets biology.
Arndt, Markus; Juffmann, Thomas; Vedral, Vlatko
2009-12-01
Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the past decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world-view of quantum coherences, entanglement, and other nonclassical effects, has been heading toward systems of increasing complexity. The present perspective article shall serve as a "pedestrian guide" to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future "quantum biology," its current status, recent experimental progress, and also the restrictions that nature imposes on bold extrapolations of quantum theory to macroscopic phenomena.
Distributivity breaking and macroscopic quantum games
Grib, A A; Parfionov, G N; Starkov, K A
2005-01-01
Examples of games between two partners with mixed strategies, calculated by the use of the probability amplitude as some vector in Hilbert space are given. The games are macroscopic, no microscopic quantum agent is supposed. The reason for the use of the quantum formalism is in breaking of the distributivity property for the lattice of yes-no questions arising due to the special rules of games. The rules of the games suppose two parts: the preparation and measurement. In the first part due to use of the quantum logical orthocomplemented non-distributive lattice the partners freely choose the wave functions as descriptions of their strategies. The second part consists of classical games described by Boolean sublattices of the initial non-Boolean lattice with same strategies which were chosen in the first part. Examples of games for spin one half are given. New Nash equilibria are found for some cases. Heisenberg uncertainty relations without the Planck constant are written for the "spin one half game".
Casimir effect from macroscopic quantum electrodynamics
Energy Technology Data Exchange (ETDEWEB)
Philbin, T G, E-mail: tgp3@st-andrews.ac.uk [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)
2011-06-15
The canonical quantization of macroscopic electromagnetism was recently presented in (Philbin 2010 New J. Phys. 12 123008). This theory is used here to derive the Casimir effect, by considering the special case of thermal and zero-point fields. The stress-energy-momentum tensor of the canonical theory follows from Noether's theorem, and its electromagnetic part in thermal equilibrium gives the Casimir energy density and stress tensor. The results hold for arbitrary inhomogeneous magnetodielectrics and are obtained from a rigorous quantization of electromagnetism in dispersive, dissipative media. Continuing doubts about the status of the standard Lifshitz theory as a proper quantum treatment of Casimir forces do not apply to the derivation given here. Moreover, the correct expressions for the Casimir energy density and stress tensor inside media follow automatically from the simple restriction to thermal equilibrium, without the need for complicated thermodynamical or mechanical arguments.
Dissipative Optomechanical Preparation of Macroscopic Quantum Superposition States
Abdi, M.; Degenfeld-Schonburg, P.; Sameti, M.; Navarrete-Benlloch, C.; Hartmann, M. J.
2016-06-01
The transition from quantum to classical physics remains an intensely debated question even though it has been investigated for more than a century. Further clarifications could be obtained by preparing macroscopic objects in spatial quantum superpositions and proposals for generating such states for nanomechanical devices either in a transient or a probabilistic fashion have been put forward. Here, we introduce a method to deterministically obtain spatial superpositions of arbitrary lifetime via dissipative state preparation. In our approach, we engineer a double-well potential for the motion of the mechanical element and drive it towards the ground state, which shows the desired spatial superposition, via optomechanical sideband cooling. We propose a specific implementation based on a superconducting circuit coupled to the mechanical motion of a lithium-decorated monolayer graphene sheet, introduce a method to verify the mechanical state by coupling it to a superconducting qubit, and discuss its prospects for testing collapse models for the quantum to classical transition.
Observability of relative phases of macroscopic quantum states
Pati, A K
1998-01-01
After a measurement, to observe the relative phases of macroscopically distinguishable states we have to ``undo'' a quantum measurement. We generalise an earlier model of Peres from two state to N-state quantum system undergoing measurement process and discuss the issue of observing relative phases of different branches. We derive an inequality which is satisfied by the relative phases of macroscopically distinguishable states and consequently any desired relative phases can not be observed in interference setups. The principle of macroscopic complementarity is invoked that might be at ease with the macroscopic world. We illustrate the idea of limit on phase observability in Stern-Gerlach measurements and the implications are discussed.
On the notion of a macroscopic quantum system
Khrenikov, A Yu
2004-01-01
We analyse the notion of macroscopic quantum system from the point of view of the statistical structure of quantum theory. We come to conclusion that the presence of interference of probabilities should be used the main characteristic of quantumness (in the opposition to N. Bohr who permanently emphasized the crucial role of quantum action). In the light of recent experiments with statistical ensembles of people who produced interference of probabilities for special pairs of questions (which can be considered as measurements on people) human being should be considered as a macroscopic quantum system. There is also discussed relation with experiments of A. Zeilinger on interference of probabilities for macromoleculas.
Arndt, Markus; Vedral, Vlatko
2009-01-01
Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the last decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world view of quantum coherences, entanglement and other non-classical effects, has been heading towards systems of increasing complexity. The present perspective article shall serve as a pedestrian guide to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future quantum biology, its current status, recent experimental progress and also the restrictions that nature imposes on bold extrapolat...
An Experimental Proposal for Demonstration of Macroscopic Quantum Effects
Directory of Open Access Journals (Sweden)
Jensen R.
2010-10-01
Full Text Available An experiment is proposed, whose purpose is to determine whether quantum indeterminism can be observed on a truly macroscopic scale. The experiment involves using a double-slit plate or interferometer and a macroscopic mechanical switch. The objective is to determine whether or not the switch can take on an indeterminate state.
An Experimental Proposal for Demonstration of Macroscopic Quantum Effects
Directory of Open Access Journals (Sweden)
Jensen R.
2010-10-01
Full Text Available An experiment is proposed, whose purpose is to determine whether quantum indeter- minism can be observed on a truly macroscopic scale. The experiment involves using a double-slit plate or interferometer and a macroscopic mechanical switch. The objective is to determine whether or not the switch can take on an indeterminate state.
Experimental demonstration of macroscopic quantum coherence in Gaussian states
DEFF Research Database (Denmark)
Marquardt, C.; Andersen, Ulrik Lund; Leuchs, G.
2007-01-01
We witness experimentally the presence of macroscopic coherence in Gaussian quantum states using a recently proposed criterion [E. G. Cavalcanti and M. D. Reid, Phys. Rev. Lett. 97 170405 (2006)]. The macroscopic coherence stems from interference between macroscopically distinct states in phase...... space, and we prove experimentally that a coherent state contains these features with a distance in phase space of 0.51 +/- 0.02 shot noise units. This is surprising because coherent states are generally considered being at the border between classical and quantum states, not yet displaying any...
The quantum interaction of macroscopic objects and gravitons
Piran, Tsvi
2016-09-01
Copious production of gravitational radiation requires a compact source that moves relativistically. Such sources are rare and are found only in extreme cases such as the formation of a black hole in either via a gravitational collapse or via a merger. Noncompact, nonrelativistic objects emit gravitational radiation, however, this emission is extremely weak due to very large value of the Planck energy. The quantum nature of gravitons, namely the fact that a single graviton carries energy of order ℏω implies that macroscopic objects whose kinetic energy is less than the Planck energy emit gravitons quantum mechanically, emitting a single graviton at a time. This is a unique situation in which a macroscopic object behaves quantum mechanically. While it is impossible to check experimentally this quantum gravitational effect, it might be possible to carry out analogous electromagnetic experiments that will shed light on this macroscopic quantum mechanical behavior.
Kobayashi, Tsunehiro
1996-01-01
Quantum macroscopic motions are investigated in the scheme consisting of N-number of harmonic oscillators in terms of ultra-power representations of nonstandard analysis. Decoherence is derived from the large internal degrees of freedom of macroscopic matters.
Quantum statistical derivation of the macroscopic Maxwell equations
Schram, K.
1960-01-01
The macroscopic Maxwell equations in matter are derived on a quantum statistical basis from the microscopic equations for the field operators. Both the density operator formalism and the Wigner distribution function method are discussed. By both methods it can be proved that the quantum statistical
Haroche, Serge
2013-01-01
Mr Administrator,Dear colleagues,Ladies and gentlemen, “I think I can safely say that nobody understands quantum mechanics”. This statement, made by physicist Richard Feynman, expresses a paradoxical truth about the scientific theory that revolutionised our understanding of Nature and made an extraordinary contribution to our means of acting on and gaining information about the world. In this lecture, I will discuss quantum physics with you by attempting to resolve this paradox. And if I don’...
Macroscopic quantum phenomena from the large N perspective
Chou, C. H.; Hu, B. L.; Subaşi, Y.
2011-07-01
Macroscopic quantum phenomena (MQP) is a relatively new research venue, with exciting ongoing experiments and bright prospects, yet with surprisingly little theoretical activity. What makes MQP intellectually stimulating is because it is counterpoised against the traditional view that macroscopic means classical. This simplistic and hitherto rarely challenged view need be scrutinized anew, perhaps with much of the conventional wisdoms repealed. In this series of papers we report on a systematic investigation into some key foundational issues of MQP, with the hope of constructing a viable theoretical framework for this new endeavour. The three major themes discussed in these three essays are the large N expansion, the correlation hierarchy and quantum entanglement for systems of 'large' sizes, with many components or degrees of freedom. In this paper we use different theories in a variety of contexts to examine the conditions or criteria whereby a macroscopic quantum system may take on classical attributes, and, more interestingly, that it keeps some of its quantum features. The theories we consider here are, the O(N) quantum mechanical model, semiclassical stochastic gravity and gauge / string theories; the contexts include that of a 'quantum roll' in inflationary cosmology, entropy generation in quantum Vlasov equation for plasmas, the leading order and next-to-leading order large N behaviour, and hydrodynamic / thermodynamic limits. The criteria for classicality in our consideration include the use of uncertainty relations, the correlation between classical canonical variables, randomization of quantum phase, environment-induced decoherence, decoherent history of hydrodynamic variables, etc. All this exercise is to ask only one simple question: Is it really so surprising that quantum features can appear in macroscopic objects? By examining different representative systems where detailed theoretical analysis has been carried out, we find that there is no a priori
Macroscopic quantum phenomena from the large N perspective
Energy Technology Data Exchange (ETDEWEB)
Chou, C H [department of Physics, National Cheng Kung University, Tainan, Taiwan 701 (China) and National Center for Theoretical Sciences (South), Tainan, Taiwan 701 (China); Hu, B L; Subasi, Y, E-mail: hubeilok@gmail.com [Joint Quantum Institute and Maryland Center for Fundamental Physics, University of Maryland, College Park, Maryland 20742 (United States)
2011-07-08
Macroscopic quantum phenomena (MQP) is a relatively new research venue, with exciting ongoing experiments and bright prospects, yet with surprisingly little theoretical activity. What makes MQP intellectually stimulating is because it is counterpoised against the traditional view that macroscopic means classical. This simplistic and hitherto rarely challenged view need be scrutinized anew, perhaps with much of the conventional wisdoms repealed. In this series of papers we report on a systematic investigation into some key foundational issues of MQP, with the hope of constructing a viable theoretical framework for this new endeavour. The three major themes discussed in these three essays are the large N expansion, the correlation hierarchy and quantum entanglement for systems of 'large' sizes, with many components or degrees of freedom. In this paper we use different theories in a variety of contexts to examine the conditions or criteria whereby a macroscopic quantum system may take on classical attributes, and, more interestingly, that it keeps some of its quantum features. The theories we consider here are, the O(N) quantum mechanical model, semiclassical stochastic gravity and gauge / string theories; the contexts include that of a 'quantum roll' in inflationary cosmology, entropy generation in quantum Vlasov equation for plasmas, the leading order and next-to-leading order large N behaviour, and hydrodynamic / thermodynamic limits. The criteria for classicality in our consideration include the use of uncertainty relations, the correlation between classical canonical variables, randomization of quantum phase, environment-induced decoherence, decoherent history of hydrodynamic variables, etc. All this exercise is to ask only one simple question: Is it really so surprising that quantum features can appear in macroscopic objects? By examining different representative systems where detailed theoretical analysis has been carried out, we find that
The origins of macroscopic quantum coherence in high temperature superconductivity
Energy Technology Data Exchange (ETDEWEB)
Turner, Philip, E-mail: ph.turner@napier.ac.uk [Edinburgh Napier University, 10 Colinton Road, Edinburgh EH10 5DT (United Kingdom); Nottale, Laurent, E-mail: laurent.nottale@obspm.fr [CNRS, LUTH, Observatoire de Paris-Meudon, 5 Place Janssen, 92190 Meudon (France)
2015-08-15
Highlights: • We propose a new theoretical approach to superconductivity in p-type cuprates. • Electron pairing mechanisms in the superconducting and pseudogap phases are proposed. • A scale free network of dopants is key to macroscopic quantum coherence. - Abstract: A new, theoretical approach to macroscopic quantum coherence and superconductivity in the p-type (hole doped) cuprates is proposed. The theory includes mechanisms to account for e-pair coupling in the superconducting and pseudogap phases and their inter relations observed in these materials. Electron pair coupling in the superconducting phase is facilitated by local quantum potentials created by static dopants in a mechanism which explains experimentally observed optimal doping levels and the associated peak in critical temperature. By contrast, evidence suggests that electrons contributing to the pseudogap are predominantly coupled by fractal spin waves (fractons) induced by the fractal arrangement of dopants. On another level, the theory offers new insights into the emergence of a macroscopic quantum potential generated by a fractal distribution of dopants. This, in turn, leads to the emergence of coherent, macroscopic spin waves and a second associated macroscopic quantum potential, possibly supported by charge order. These quantum potentials play two key roles. The first involves the transition of an expected diffusive process (normally associated with Anderson localization) in fractal networks, into e-pair coherence. The second involves the facilitation of tunnelling between localized e-pairs. These combined effects lead to the merger of the super conducting and pseudo gap phases into a single coherent condensate at optimal doping. The underlying theory relating to the diffusion to quantum transition is supported by Coherent Random Lasing, which can be explained using an analogous approach. As a final step, an experimental program is outlined to validate the theory and suggests a new
Macroscopic Quantum Phenomena from the Correlation, Coupling and Criticality Perspectives
Chou, C. H.; Hu, B. L.; Subaşi, Y.
2011-12-01
In this sequel paper we explore how macroscopic quantum phenomena can be measured or understood from the behavior of quantum correlations which exist in a quantum system of many particles or components and how the interaction strengths change with energy or scale, under ordinary situations and when the system is near its critical point. We use the nPI (master) effective action related to the Boltzmann-BBGKY / Schwinger-Dyson hierarchy of equations as a tool for systemizing the contributions of higher order correlation functions to the dynamics of lower order correlation functions. Together with the large N expansion discussed in our first paper [1] we explore 1) the conditions whereby an H-theorem is obtained, which can be viewed as a signifier of the emergence of macroscopic behavior in the system. We give two more examples from past work: 2) the nonequilibrium dynamics of N atoms in an optical lattice under the large Script N (field components), 2PI and second order perturbative expansions, illustrating how N and Script N enter in these three aspects of quantum correlations, coherence and coupling strength. 3) the behavior of an interacting quantum system near its critical point, the effects of quantum and thermal fluctuations and the conditions under which the system manifests infrared dimensional reduction. We also discuss how the effective field theory concept bears on macroscopic quantum phenomena: the running of the coupling parameters with energy or scale imparts a dynamical-dependent and an interaction-sensitive definition of 'macroscopia'.
Gravitational wave echoes from macroscopic quantum gravity effects
Barceló, Carlos; Carballo-Rubio, Raúl; Garay, Luis J.
2017-05-01
New theoretical approaches developed in the last years predict that macroscopic quantum gravity effects in black holes should lead to modifications of the gravitational wave signals expected in the framework of classical general relativity, with these modifications being characterized in certain scenarios by the existence of dampened rep-etitions of the primary signal. Here we use the fact that non-perturbative corrections to the near-horizon external geometry of black holes are necessary for these modifications to exist, in order to classify different proposals and paradigms with respect to this criterion and study in a neat and systematic way their phenomenology. Proposals that lead naturally to the existence of echoes in the late-time ringdown of gravitational wave signals from black hole mergers must share the replacement of black holes by horizonless configurations with a physical surface showing reflective properties in the relevant range of frequencies. On the other hand, proposals or paradigms that restrict quantum gravity effects on the external geometry to be perturbative, such as black hole complementarity or the closely related firewall proposal, do not display echoes. For the sake of completeness we exploit the interplay between the timescales associated with the formation of firewalls and the mechanism behind the existence of echoes in order to conclude that even unconventional distortions of the firewall concept (such as naked firewalls) do not lead to this phenomenon.
Optomechanical entanglement of a macroscopic oscillator by quantum feedback
Wu, E.; Li, Fengzhi; Zhang, Xuefeng; Ma, Yonghong
2016-07-01
We propose a scheme to generate the case of macroscopic entanglement in the optomechanical system, which consist of Fabry-Perot cavity and a mechanical oscillator by applying a homodyne-mediated quantum feedback. We explore the effect of feedback on the entanglement in vacuum and coherent state, respectively. The results show that the introduction of quantum feedback can increase the entanglement effectively between the cavity mode and the oscillator mode.
Macroscopic Quantum Coherence in Magnetic Molecular Clusters
Institute of Scientific and Technical Information of China (English)
JIN Yan-Hong; NIE Yi-Hang; LIANG Jiu-Qing; PU Fu-Cho
2001-01-01
The oscillation of tunnel splitting in Fes molecular clusters is obtained as a function of magnetic field applied along the hard axis by means of the instanton method with both semiclassical treatment and the effective potential field description of the quantum spin system. The theoretical splittings of the instanton method are compared with the numerical result by diagonalization of spin Hamiltonian operators and experimental observations. By taking the appropriate parameters, our theoretical formula yields a result the same as the experimental observation.
Macroscopic quantum oscillator based on a flux qubit
Energy Technology Data Exchange (ETDEWEB)
Singh, Mandip, E-mail: mandip@iisermohali.ac.in
2015-09-25
In this paper a macroscopic quantum oscillator is proposed, which consists of a flux-qubit in the form of a cantilever. The net magnetic flux threading through the flux-qubit and the mechanical degrees of freedom of the cantilever are naturally coupled. The coupling between the cantilever and the magnetic flux is controlled through an external magnetic field. The ground state of the flux-qubit-cantilever turns out to be an entangled quantum state, where the cantilever deflection and the magnetic flux are the entangled degrees of freedom. A variant, which is a special case of the flux-qubit-cantilever without a Josephson junction, is also discussed. - Highlights: • In this paper a flux-qubit-cantilever is proposed. • Coupling can be varied by an external magnetic field. • Ground state is a macroscopic entangled quantum state. • Ground state of the superconducting-loop-oscillator is a macroscopic quantum superposition. • Proposed scheme is based on a generalized quantum approach.
Gazi, Md. Rajjak; Banik, Manik; Das, Subhadipa; Rai, Ashutosh; Kunkri, Samir
2013-11-01
Two physical principles, macroscopic locality (ML) and information causality (IC), so far have been most successful in distinguishing quantum correlations from post-quantum correlations. However, there are also some post-quantum probability distributions which cannot be distinguished with the help of these principles. Thus, it is interesting to see whether consideration of these two principles, separately, along with some additional physically plausible constraints, can explain some interesting quantum features which are otherwise hard to reproduce. In this paper we show that in a Bell-Clauser-Horne-Shimony-Holt scenario, ML along with the constraint of equal bias for the concerned observables, almost reproduces the quantum joint probability distribution corresponding to a maximal quantum Bell violation, which is unique up to relabeling. From this example and earlier work of Cavalcanti, Salles, and Scarani, we conclude that IC and ML are inequivalent physical principles; satisfying one does not imply that the other is satisfied.
Quantum Physics for Beginners.
Strand, J.
1981-01-01
Suggests a new approach for teaching secondary school quantum physics. Reviews traditional approaches and presents some characteristics of the three-part "Quantum Physics for Beginners" project, including: quantum physics, quantum mechanics, and a short historical survey. (SK)
Quantum Physics for Beginners.
Strand, J.
1981-01-01
Suggests a new approach for teaching secondary school quantum physics. Reviews traditional approaches and presents some characteristics of the three-part "Quantum Physics for Beginners" project, including: quantum physics, quantum mechanics, and a short historical survey. (SK)
Approximating macroscopic observables in quantum spin systems with commuting matrices
Ogata, Yoshiko
2011-01-01
Macroscopic observables in a quantum spin system are given by sequences of spatial means of local elements $\\frac{1}{2n+1}\\sum_{j=-n}^n\\gamma_j(A_{i}), \\; n\\in{\\mathbb N},\\; i=1,...,m$ in a UHF algebra. One of their properties is that they commute asymptotically, as $n$ goes to infinity. It is not true that any given set of asymptotically commuting matrices can be approximated by commuting ones in the norm topology. In this paper, we show that for macroscopic observables, this is true.
Quantum-limited heat conduction over macroscopic distances
Partanen, Matti; Tan, Kuan Yen; Govenius, Joonas; Lake, Russell E.; Mäkelä, Miika K.; Tanttu, Tuomo; Möttönen, Mikko
2016-05-01
The emerging quantum technological apparatuses, such as the quantum computer, call for extreme performance in thermal engineering. Cold distant heat sinks are needed for the quantized electric degrees of freedom owing to the increasing packaging density and heat dissipation. Importantly, quantum mechanics sets a fundamental upper limit for the flow of information and heat, which is quantified by the quantum of thermal conductance. However, the short distance between the heat-exchanging bodies in the previous experiments hinders their applicability in quantum technology. Here, we present experimental observations of quantum-limited heat conduction over macroscopic distances extending to a metre. We achieved this improvement of four orders of magnitude in the distance by utilizing microwave photons travelling in superconducting transmission lines. Thus, it seems that quantum-limited heat conduction has no fundamental distance cutoff. This work establishes the integration of normal-metal components into the framework of circuit quantum electrodynamics, which provides a basis for the superconducting quantum computer. Especially, our results facilitate remote cooling of nanoelectronic devices using faraway in situ-tunable heat sinks. Furthermore, quantum-limited heat conduction is important in contemporary thermodynamics. Here, the long distance may lead to ultimately efficient mesoscopic heat engines with promising practical applications.
Macroscopic superposition states and decoherence by quantum telegraph noise
Energy Technology Data Exchange (ETDEWEB)
Abel, Benjamin Simon
2008-12-19
In the first part of the present thesis we address the question about the size of superpositions of macroscopically distinct quantum states. We propose a measure for the ''size'' of a Schroedinger cat state, i.e. a quantum superposition of two many-body states with (supposedly) macroscopically distinct properties, by counting how many single-particle operations are needed to map one state onto the other. We apply our measure to a superconducting three-junction flux qubit put into a superposition of clockwise and counterclockwise circulating supercurrent states and find this Schroedinger cat to be surprisingly small. The unavoidable coupling of any quantum system to many environmental degrees of freedom leads to an irreversible loss of information about an initially prepared superposition of quantum states. This phenomenon, commonly referred to as decoherence or dephasing, is the subject of the second part of the thesis. We have studied the time evolution of the reduced density matrix of a two-level system (qubit) subject to quantum telegraph noise which is the major source of decoherence in Josephson charge qubits. We are able to derive an exact expression for the time evolution of the reduced density matrix. (orig.)
Direct Observation of Spatial Quantum Correlations in the Macroscopic Regime
Kumar, Ashok; Marino, A M
2016-01-01
Spatial quantum correlations in the transverse degree of freedom promise to enhance optical resolution, image detection, and quantum communications through parallel quantum information encoding. In particular, the ability to observe these spatial quantum correlations in a single shot will enable such enhancements in applications that require real time imaging, such as particle tracking and in-situ imaging of atomic systems. Here, we report on the direct measurement of spatial quantum correlations in the macroscopic regime in single images using an electron-multiplying charge-coupled device camera. A four-wave mixing process in hot rubidium atoms is used to generate narrowband-bright-entangled pulsed twin-beams of light with $\\sim10^8$ photons in each beam. Owing to momentum conservation in this process, the twin-beams are momentum correlated, which leads to spatial quantum correlations in far field. We show around 2 dB of spatial quantum noise reduction with respect to the shot noise limit. The spatial squeez...
Two-channel Kondo effect and renormalization flow with macroscopic quantum charge states.
Iftikhar, Z; Jezouin, S; Anthore, A; Gennser, U; Parmentier, F D; Cavanna, A; Pierre, F
2015-10-08
Many-body correlations and macroscopic quantum behaviours are fascinating condensed matter problems. A powerful test-bed for the many-body concepts and methods is the Kondo effect, which entails the coupling of a quantum impurity to a continuum of states. It is central in highly correlated systems and can be explored with tunable nanostructures. Although Kondo physics is usually associated with the hybridization of itinerant electrons with microscopic magnetic moments, theory predicts that it can arise whenever degenerate quantum states are coupled to a continuum. Here we demonstrate the previously elusive 'charge' Kondo effect in a hybrid metal-semiconductor implementation of a single-electron transistor, with a quantum pseudospin of 1/2 constituted by two degenerate macroscopic charge states of a metallic island. In contrast to other Kondo nanostructures, each conduction channel connecting the island to an electrode constitutes a distinct and fully tunable Kondo channel, thereby providing unprecedented access to the two-channel Kondo effect and a clear path to multi-channel Kondo physics. Using a weakly coupled probe, we find the renormalization flow, as temperature is reduced, of two Kondo channels competing to screen the charge pseudospin. This provides a direct view of how the predicted quantum phase transition develops across the symmetric quantum critical point. Detuning the pseudospin away from degeneracy, we demonstrate, on a fully characterized device, quantitative agreement with the predictions for the finite-temperature crossover from quantum criticality.
Tuned Transition from Quantum to Classical for Macroscopic Quantum States
Fedorov, A.; Macha, P.; Feofanov, A.K.; Harmans, C.J.P.M.; Mooij, J.E.
2011-01-01
The boundary between the classical and quantum worlds has been intensely studied. It remains fascinating to explore how far the quantum concept can reach with use of specially fabricated elements. Here we employ a tunable flux qubit with basis states having persistent currents of 1 μA carried by a
Macroscopic Quantum Phenomena from the Correlation, Coupling and Criticality Perspectives
Chou, C H; Subasi, Y
2011-01-01
In this sequel paper we explore how macroscopic quantum phenomena can be measured or understood from the behavior of quantum correlations which exist in a quantum system of many particles or components and how the interaction strengths change with energy or scale, under ordinary situations and when the system is near its critical point. We use the nPI (master) effective action related to the Boltzmann-BBGKY / Schwinger-Dyson hierarchy of equations as a tool for systemizing the contributions of higher order correlation functions to the dynamics of lower order correlation functions. Together with the large N expansion discussed in our first paper(MQP1) we explore 1) the conditions whereby an H-theorem is obtained, which can be viewed as a signifier of the emergence of macroscopic behavior in the system. We give two more examples from past work: 2) the nonequilibrium dynamics of N atoms in an optical lattice under the large $\\cal N$ (field components), 2PI and second order perturbative expansions, illustrating h...
Single-atom quantum control of macroscopic mechanical oscillators
Bariani, F.; Otterbach, J.; Tan, Huatang; Meystre, P.
2014-01-01
We investigate a hybrid electromechanical system consisting of a pair of charged macroscopic mechanical oscillators coupled to a small ensemble of Rydberg atoms. The resonant dipole-dipole coupling between an internal atomic Rydberg transition and the mechanics allows cooling to its motional ground state with a single atom despite the considerable mass imbalance between the two subsystems. We show that the rich electronic spectrum of Rydberg atoms, combined with their high degree of optical control, paves the way towards implementing various quantum-control protocols for the mechanical oscillators.
Experiments testing macroscopic quantum superpositions must be slow
Mari, Andrea; Giovannetti, Vittorio
2015-01-01
We consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication. We give a solution to the paradox which is based on the following fundamental principle: any local experiment, discriminating a coherent superposition from an incoherent statistical mixture, necessarily requires a minimum time proportional to the mass (or charge) of the system. For a charged particle, we consider two examples of such experiments, and show that they are both consistent with the previous limitation. In the first, the measurement requires to accelerate the charge, that can entangle with the emitted photons. In the second, the limitation can be ascribed to the quantum vacuum fluctuations of the electromagnetic field. On the other hand, when applied to massive particles our result provides an indirect evidence for the existence of gravitational vacuum fluctuations an...
De Martini, Francesco
2012-01-01
The present work reports on an extended research endeavor focused on the theoretical and experimental realization of a macroscopic quantum superposition (MQS) made up with photons. As it is well known, this intriguing, fundamental quantum condition is at the core of a famous argument conceived by Erwin Schroedinger, back in 1935. The main experimental challenge to the actual realization of this object resides generally on the unavoidable and uncontrolled interactions with the environment, i.e. the decoherence leading to the cancellation of any evidence of the quantum features associated with the macroscopic system. The present scheme is based on a nonlinear process, the "quantum injected optical parametric amplification", that maps by a linearized cloning process the quantum coherence of a single - particle state, i.e. a Micro - qubit, into a Macro - qubit, consisting in a large number M of photons in quantum superposition. Since the adopted scheme was found resilient to decoherence, the MQS\\ demonstration wa...
Ficek, Zbigniew
2016-01-01
The textbook introduces students to the main ideas of quantum physics and the basic mathematical methods and techniques used in the fields of advanced quantum physics, atomic physics, laser physics, nanotechnology, quantum chemistry, and theoretical mathematics. The textbook explains how microscopic objects (particles) behave in unusual ways, giving rise to what's called quantum effects. It contains a wide range of tutorial problems from simple confidence-builders to fairly challenging exercises that provide adequate understanding of the basic concepts of quantum physics.
Time Symmetric Quantum Mechanics and Causal Classical Physics ?
Bopp, Fritz W.
2017-02-01
A two boundary quantum mechanics without time ordered causal structure is advocated as consistent theory. The apparent causal structure of usual "near future" macroscopic phenomena is attributed to a cosmological asymmetry and to rules governing the transition between microscopic to macroscopic observations. Our interest is a heuristic understanding of the resulting macroscopic physics.
Time Symmetric Quantum Mechanics and Causal Classical Physics
Bopp, Fritz W
2016-01-01
A two boundary quantum mechanics without time ordered causal structure is advocated as consistent theory. The apparent causal structure of usual "near future" macroscopic phenomena is attributed to a cosmological asymmetry and to rules governing the transition between microscopic to macroscopic observations. Our interest is a heuristic understanding of the resulting macroscopic physics.
Experiments testing macroscopic quantum superpositions must be slow
Mari, Andrea; de Palma, Giacomo; Giovannetti, Vittorio
2016-03-01
We consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication. We give a solution to the paradox which is based on the following fundamental principle: any local experiment, discriminating a coherent superposition from an incoherent statistical mixture, necessarily requires a minimum time proportional to the mass (or charge) of the system. For a charged particle, we consider two examples of such experiments, and show that they are both consistent with the previous limitation. In the first, the measurement requires to accelerate the charge, that can entangle with the emitted photons. In the second, the limitation can be ascribed to the quantum vacuum fluctuations of the electromagnetic field. On the other hand, when applied to massive particles our result provides an indirect evidence for the existence of gravitational vacuum fluctuations and for the possibility of entangling a particle with quantum gravitational radiation.
Macroscopic Quantum Phenomena and Topological Phase Interference Effects in Single-Domain Magnets
Institute of Scientific and Technical Information of China (English)
L(U) Rong; ZHU Jialin
2001-01-01
The tunneling of macroscopic object is one of the most fascinating phenomena in condensed matter physics.During the last decade,the problem of quantum tunneling of magnetization in nanometer-scale magnets has attracted a great deal of theoretical and experimental interest.A review of recent theoretical research of the macroscopic quantum phenomena in nanometer-scale single-domain magnets is presented in this paper.It includes macroscopic quantum tunneling (MQT) and coherence (MQC) in single-domain magnetic particles,the topological phase interference or spin-parity effects,and tunneling of magnetization in an arbitrarily directed magnetic field.The general formulas are shown to evaluate the tunneling rate and the tunneling level splitting for single-domain AFM particles.A nontrivial generalization of Kramers degeneracy for double-well system is provided to coherently spin tunneling for spin systems with m-fold rotational symmetry.The effects induced by the external magnetic field have been studied,where the field is along the easy,medium,hard axis,or arbitrary direction.
Macroscopic quantum electrodynamics of high-Q cavities
Energy Technology Data Exchange (ETDEWEB)
Khanbekyan, Mikayel
2009-10-27
In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the
Macroscopic quantum electrodynamics of high-Q cavities
Energy Technology Data Exchange (ETDEWEB)
Khanbekyan, Mikayel
2009-10-27
In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the
A Model for Macroscopic Quantum Tunneling of Bose-Einstein Condensate with Attractive Interaction
Institute of Scientific and Technical Information of China (English)
YAN Ke-Zhu; TAN Wei-Han
2000-01-01
Based on the numerical wave function solutions of neutral atoms with attractive interaction in a harmonic trap, we propose an exactly solvable model for macroscopic quantum tunneling of a Bose condensate with attractive interaction. We calculate the rate of macroscopic quantum tunneling from a metastable condensate state to the collapse state and analyze the stability of the attractive Bose-Einstein condensation.
Tunable Broadband Transparency of Macroscopic Quantum Superconducting Metamaterials
Directory of Open Access Journals (Sweden)
Daimeng Zhang
2015-12-01
Full Text Available Narrow-band invisibility in an otherwise opaque medium has been achieved by electromagnetically induced transparency (EIT in atomic systems. The quantum EIT behavior can be classically mimicked by specially engineered metamaterials via carefully controlled interference with a “dark mode.” However, the narrow transparency window limits the potential applications that require a tunable wideband transparent performance. Here, we present a macroscopic quantum superconducting metamaterial with manipulative self-induced broadband transparency due to a qualitatively novel nonlinear mechanism that is different from conventional EIT or its classical analogs. A near-complete disappearance of resonant absorption under a range of applied rf flux is observed experimentally and explained theoretically. The transparency comes from the intrinsic bistability of the meta-atoms and can be tuned on and off easily by altering rf and dc magnetic fields, temperature, and history. Hysteretic in situ 100% tunability of transparency paves the way for autocloaking metamaterials, intensity-dependent filters, and fast-tunable power limiters.
Holzner, Steve
2013-01-01
Quantum Physics For Dummies, Revised Edition helps make quantum physics understandable and accessible. From what quantum physics can do for the world to understanding hydrogen atoms, readers will get complete coverage of the subject, along with numerous examples to help them tackle the tough equations. Compatible with classroom text books and courses, Quantum Physics For Dummies, Revised Edition lets students study at their own paces and helps them prepare for graduate or professional exams. Coverage includes: The Schrodinger Equation and its Applications The Foundations of Quantum Physics Vector Notation Spin Scattering Theory, Angular Momentum, and more From the Back Cover Your plain-English guide to understanding and working with the micro world Quantum physics -- also called quantum mechanics or quantum field theory -- can be daunting for even the most dedicated student or enthusiast of science, math, or physics. This friendly, concise guide makes this challenging subject understandable and accessible, fr...
Quantum Physics Without Quantum Philosophy
Dürr, Detlef; Zanghì, Nino
2013-01-01
It has often been claimed that without drastic conceptual innovations a genuine explanation of quantum interference effects and quantum randomness is impossible. This book concerns Bohmian mechanics, a simple particle theory that is a counterexample to such claims. The gentle introduction and other contributions collected here show how the phenomena of non-relativistic quantum mechanics, from Heisenberg's uncertainty principle to non-commuting observables, emerge from the Bohmian motion of particles, the natural particle motion associated with Schrödinger's equation. This book will be of value to all students and researchers in physics with an interest in the meaning of quantum theory as well as to philosophers of science.
Quantum physics without quantum philosophy
Energy Technology Data Exchange (ETDEWEB)
Duerr, Detlef [Muenchen Univ. (Germany). Mathematisches Inst.; Goldstein, Sheldon [Rutgers State Univ., Piscataway, NJ (United States). Dept. of Mathematics; Zanghi, Nino [Genova Univ. (Italy); Istituto Nazionale Fisica Nucleare, Genova (Italy)
2013-02-01
Integrates and comments on the authors' seminal papers in the field. Emphasizes the natural way in which quantum phenomena emerge from the Bohmian picture. Helps to answer many of the objections raised to Bohmian quantum mechanics. Useful overview and summary for newcomers and students. It has often been claimed that without drastic conceptual innovations a genuine explanation of quantum interference effects and quantum randomness is impossible. This book concerns Bohmian mechanics, a simple particle theory that is a counterexample to such claims. The gentle introduction and other contributions collected here show how the phenomena of non-relativistic quantum mechanics, from Heisenberg's uncertainty principle to non-commuting observables, emerge from the Bohmian motion of particles, the natural particle motion associated with Schroedinger's equation. This book will be of value to all students and researchers in physics with an interest in the meaning of quantum theory as well as to philosophers of science.
Nonlinear Dynamics In Quantum Physics -- Quantum Chaos and Quantum Instantons
Kröger, H.
2003-01-01
We discuss the recently proposed quantum action - its interpretation, its motivation, its mathematical properties and its use in physics: quantum mechanical tunneling, quantum instantons and quantum chaos.
Nonlinear Dynamics In Quantum Physics -- Quantum Chaos and Quantum Instantons
Kröger, H.
2003-01-01
We discuss the recently proposed quantum action - its interpretation, its motivation, its mathematical properties and its use in physics: quantum mechanical tunneling, quantum instantons and quantum chaos.
Macroscopic Quantum-Type Potentials in Theoretical Systems Biology
Directory of Open Access Journals (Sweden)
Laurent Nottale
2013-12-01
Full Text Available We review in this paper the use of the theory of scale relativity and fractal space-time as a tool particularly well adapted to the possible development of a future genuine systems theoretical biology. We emphasize in particular the concept of quantum-type potentials, since, in many situations, the effect of the fractality of space—or of the underlying medium—can be reduced to the addition of such a potential energy to the classical equations of motion. Various equivalent representations—geodesic, quantum-like, fluid mechanical, stochastic—of these equations are given, as well as several forms of generalized quantum potentials. Examples of their possible intervention in high critical temperature superconductivity and in turbulence are also described, since some biological processes may be similar in some aspects to these physical phenomena. These potential extra energy contributions could have emerged in biology from the very fractal nature of the medium, or from an evolutive advantage, since they involve spontaneous properties of self-organization, morphogenesis, structuration and multi-scale integration. Finally, some examples of applications of the theory to actual biological-like processes and functions are also provided.
Jin, Liang; Wrachtrup, Jörg; Liu, Ren-Bao
2014-01-01
Macroscopic quantum phenomena such as lasers, Bose-Einstein condensates, superfluids, and superconductors are of great importance in foundations and applications of quantum mechanics. In particular, quantum superposition of a large number of spins in solids is highly desirable for both quantum information processing and ultrasensitive magnetometry. Spin ensembles in solids, however, have rather short collective coherence time (typically less than microseconds). Here we demonstrate that under realistic conditions it is possible to maintain macroscopic quantum superposition of a large spin ensemble (such as about ~10^{14} nitrogen-vacancy center electron spins in diamond) with an extremely long coherence time ~10^8 sec under readily accessible conditions. The scheme, following the mechanism of superradiant lasers, is based on superradiant masing due to coherent coupling between collective spin excitations (magnons) and microwave cavity photons. The coherence time of the macroscopic quantum superposition is the ...
Fomin, Vladimir M
2013-01-01
This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is po
Quantum fluctuations, gauge freedom and mesoscopic/macroscopic stability
Energy Technology Data Exchange (ETDEWEB)
Del Giudice, E [Istituto Nazionale di Fisica Nucleare, Via Celoria 16, I-20133 Milan (Italy); Vitiello, G [Dipartimento di Matematica e Informatica, Universita di Salerno and Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Salerno, 84100 Salerno (Italy)
2007-11-15
We study how the mesoscopic/macroscopic stability of coherent extended domains is generated out of the phase locking between gauge field and matter field. The role of the radiative gauge field in sustaining the coherent regime is discussed.
An exploration for the macroscopic physical meaning of entropy
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The macroscopic physical meaning of entropy is analyzed based on the exergy (availability) of a combined system (a closed system and its environment), which is the maximum amount of useful work obtainable from the system and the environment as the system is brought into equilibrium with the environment. The process the system experiences can be divided in two sequent sub-processes, the process at constant volume, which represents the heat interaction of the system with the environment, and the adiabatic process, which represents the work interaction of the system with the environment. It is shown that the macroscopic physical meaning of entropy is a measure of the unavailable energy of a closed system for doing useful work through heat interaction. This statement is more precise than those reported in prior literature. The unavailability function of a closed system can be defined as T0S and p0V in volume constant process and adiabatic process, respectively. Their changes, that is, AiTgS) and A (p0V) represent the unusable parts of the internal energy of a closed system for doing useful work in corresponding processes. Finally, the relation between Clausius entropy and Boltzmann entropy is discussed based on the comparison of their expressions for absolute entropy.
Energy Technology Data Exchange (ETDEWEB)
Fomin, Vladimir M. (ed.) [Leibniz Institute for Solid State and Materials Research, Dresden (Germany)
2014-07-01
Presents the new class of materials of quantum rings. Provides an elemental basis for low-cost high-performance devices promising for electronics, optoelectronics, spintronics and quantum information processing. Explains the physical properties of quantum rings to cover a gap in scientific literature. Presents the application of most advanced nanoengineering and nanocharacterization techniques. This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is possible on the basis of modern characterization methods of nanostructures, such as Scanning Tunneling Microscopy. A high level of complexity is demonstrated to be needed for a dedicated theoretical model to adequately represent the specific features of quantum rings. The findings presented in this book contribute to develop low-cost high-performance electronic, spintronic, optoelectronic and information processing devices based on quantum rings.
Quantum teleportation from light beams to vibrational states of a macroscopic diamond
Hou, P.-Y.; Huang, Y.-Y.; Yuan, X.-X.; Chang, X.-Y.; Zu, C.; He, L.; Duan, L.-M.
2016-05-01
With the recent development of optomechanics, the vibration in solids, involving collective motion of trillions of atoms, gradually enters into the realm of quantum control. Here, building on the recent remarkable progress in optical control of motional states of diamonds, we report an experimental demonstration of quantum teleportation from light beams to vibrational states of a macroscopic diamond under ambient conditions. Through quantum process tomography, we demonstrate average teleportation fidelity (90.6+/-1.0)%, clearly exceeding the classical limit of 2/3. The experiment pushes the target of quantum teleportation to the biggest object so far, with interesting implications for optomechanical quantum control and quantum information science.
Quantum Gravity: physics from supergeometries
Cirilo-Lombardo, Diego Julio
2013-01-01
We show that the metric (line element) is the first geometrical object to be associated to a discrete (quantum) structure of the spacetime without necessity of black hole-entropy-area arguments, in sharp contrast with other attempts in the literature. To this end, an emergent metric solution obtained previously in [Physics Letters B 661, 186-191 (2008)] from a particular non-degenerate Riemmanian superspace is introduced. This emergent metric is described by a physical coherent state belonging to the metaplectic group Mp (n) with a Poissonian distribution at lower n (number basis) restoring the classical thermal continuum behaviour at large n (n ! 1), or leading to non-classical radiation states, as is conjectured in a quite general basis by mean the Bekenstein- Mukhanov effect. Group-dependent conditions that control the behavior of the macroscopic regime spectrum (thermal or not), as the relationship with the problem of area / entropy of the black hole are presented and discussed.
Numerical model for macroscopic quantum superpositions based on phase-covariant quantum cloning
Buraczewski, Adam
2011-01-01
We present a numerical model of macroscopic quantum superpositions generated by universally covariant optimal quantum cloning. It requires fast computation of the Gaussian hypergeometric function for moderate values of its parameters and argument as well as evaluation of infinite sums involving this function. We developed a method of dynamical estimation of cutoff for these sums. We worked out algorithms performing efficient summation of values of orders ranging from $10^{-100}$ to $10^{100}$ which neither lose precision nor accumulate errors, but provide the summation with acceleration. Our model is well adapted to experimental conditions. It optimizes computation by parallelization and choice of the most efficient algorithm. The methods presented here can be adjusted for analysis of similar experimental schemes. Including decoherence and realistic detection greatly improved the reliability and usability of our model for scientific research.
Ogborn, Jon
1974-01-01
Describes the way in which quantum ideas are incorporated into the Nuffield advanced physics course. Quantum theory is presented as an enormous intellectual leap to be excited by, puzzled over and thought about, not as a set of results and equations to be packed away in the mind. (Author/MLH)
Measurement in quantum physics
Energy Technology Data Exchange (ETDEWEB)
Danos, M. [Illinois Univ., Chicago, IL (United States); Kieu, T.D. [Melbourne Univ., Parkville, VIC (Australia). School of Physics]|[Columbia Univ., New York, NY (United States). Dept. of Physics
1997-06-01
The conceptual problems in quantum mechanics - including the collapse of the wave functions, the particle-wave duality, the meaning of measurement-arise from the need to ascribe particle character to the wave function, which describes only the wave aspects. It is demonstrated that all these problems can be resolved when working instead with quantum fields, which have both wave and particle character. The predictions of quantum physics, including Bell`s inequalities, remain unchanged from the standard treatments of quantum mechanics. 16 refs.
Energy Technology Data Exchange (ETDEWEB)
Scheck, Florian [Mainz Univ. (Germany). Inst. fuer Physik, Theoretische Elementarteilchenphysik
2013-11-01
New edition with added sections on nonlinear quantum mechanics and path integral methods in field theory. Contains an encyclopedic coverage from uncertainty relation to many-body systems, from symmetries to electroweak interation. Includes problems, partly with solutions, partly with hints towards solutions. Starting with basic principles and providing the framework all vital elements of nonrelativistic quantum mechanics are explained, even an introduction to quantum electrodynamics is included. Scheck's Quantum Physics presents a comprehensive introductory treatment, ideally suited for a two-semester course. Part One covers the basic principles and prime applications of quantum mechanics, from the uncertainty relations to many-body systems. Part Two introduces to relativistic quantum field theory and ranges from symmetries in quantum physics to electroweak interactions. Numerous worked-out examples as well as exercises, with solutions or hints, enables the book's use as an accompanying text for courses, and also for independent study. For both parts, the necessary mathematical framework is treated in adequate form and detail. The book ends with appendices covering mathematical fundamentals and enrichment topics, plus selected biographical notes on pioneers of quantum mechanics and quantum field theory. The new edition was thoroughly revised and now includes new sections on quantization using the path integral method and on deriving generalized path integrals for bosonic and fermionic fields.
Quantum teleportation from light beams to vibrational states of a macroscopic diamond
Hou, Panyu; Huang, Yuanyuan; Yuan, Xinxing; Chang, Xiuying; Zu, Chong; He, Li; Duan, Luming; CenterQuantum Information, IIIS, Tsinghua University, Beijing 100084, PR China Team; Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA Team
2016-05-01
Quantum teleportation is an unusual disembodied form of quantum information transfer through pre-shared entanglement and classical communication, which has found important applications for realization of various quantum technologies. It is of both fundamental interest and practical importance to push quantum teleportation towards macroscopic objects. With the recent development of optomechanics, the vibration in solids, involving collective motion of trillions of atoms, gradually enters into the realm of quantum control. Built on the recent remarkable progress in optical control of motional states in diamond, we report an experimental demonstration of quantum teleportation from light beams to vibrational states of a macroscopic diamond under ambient conditions. Through quantum state tomography, we demonstrate an average teleportation fidelity (90.6 +/- 1.0)%, exceeding the classical limit of 2/3. The experiment pushes the target of quantum teleportation to the biggest object so far, with interesting implications for quantum foundational studies, optomechanical quantum control and quantum information science. Center for Quantum Information, IIIS, Tsinghua University.
X-ray-generated heralded macroscopical quantum entanglement of two nuclear ensembles
Liao, Wen-Te; Keitel, Christoph H.; Pálffy, Adriana
2016-09-01
Heralded entanglement between macroscopical samples is an important resource for present quantum technology protocols, allowing quantum communication over large distances. In such protocols, optical photons are typically used as information and entanglement carriers between macroscopic quantum memories placed in remote locations. Here we investigate theoretically a new implementation which employs more robust x-ray quanta to generate heralded entanglement between two crystal-hosted macroscopical nuclear ensembles. Mössbauer nuclei in the two crystals interact collectively with an x-ray spontaneous parametric down conversion photon that generates heralded macroscopical entanglement with coherence times of approximately 100 ns at room temperature. The quantum phase between the entangled crystals can be conveniently manipulated by magnetic field rotations at the samples. The inherent long nuclear coherence times allow also for mechanical manipulations of the samples, for instance to check the stability of entanglement in the x-ray setup. Our results pave the way for first quantum communication protocols that use x-ray qubits.
X-ray-generated heralded macroscopical quantum entanglement of two nuclear ensembles.
Liao, Wen-Te; Keitel, Christoph H; Pálffy, Adriana
2016-09-19
Heralded entanglement between macroscopical samples is an important resource for present quantum technology protocols, allowing quantum communication over large distances. In such protocols, optical photons are typically used as information and entanglement carriers between macroscopic quantum memories placed in remote locations. Here we investigate theoretically a new implementation which employs more robust x-ray quanta to generate heralded entanglement between two crystal-hosted macroscopical nuclear ensembles. Mössbauer nuclei in the two crystals interact collectively with an x-ray spontaneous parametric down conversion photon that generates heralded macroscopical entanglement with coherence times of approximately 100 ns at room temperature. The quantum phase between the entangled crystals can be conveniently manipulated by magnetic field rotations at the samples. The inherent long nuclear coherence times allow also for mechanical manipulations of the samples, for instance to check the stability of entanglement in the x-ray setup. Our results pave the way for first quantum communication protocols that use x-ray qubits.
On Macroscopic Quantum Phenomena in Biomolecules and Cells: From Levinthal to Hopfield
Directory of Open Access Journals (Sweden)
Dejan Raković
2014-01-01
Full Text Available In the context of the macroscopic quantum phenomena of the second kind, we hereby seek for a solution-in-principle of the long standing problem of the polymer folding, which was considered by Levinthal as (semiclassically intractable. To illuminate it, we applied quantum-chemical and quantum decoherence approaches to conformational transitions. Our analyses imply the existence of novel macroscopic quantum biomolecular phenomena, with biomolecular chain folding in an open environment considered as a subtle interplay between energy and conformation eigenstates of this biomolecule, governed by quantum-chemical and quantum decoherence laws. On the other hand, within an open biological cell, a system of all identical (noninteracting and dynamically noncoupled biomolecular proteins might be considered as corresponding spatial quantum ensemble of these identical biomolecular processors, providing spatially distributed quantum solution to a single corresponding biomolecular chain folding, whose density of conformational states might be represented as Hopfield-like quantum-holographic associative neural network too (providing an equivalent global quantum-informational alternative to standard molecular-biology local biochemical approach in biomolecules and cells and higher hierarchical levels of organism, as well.
On Macroscopic Quantum Phenomena in Biomolecules and Cells: From Levinthal to Hopfield
Raković, Dejan; Dugić, Miroljub; Jeknić-Dugić, Jasmina; Plavšić, Milenko; Jaćimovski, Stevo; Šetrajčić, Jovan
2014-01-01
In the context of the macroscopic quantum phenomena of the second kind, we hereby seek for a solution-in-principle of the long standing problem of the polymer folding, which was considered by Levinthal as (semi)classically intractable. To illuminate it, we applied quantum-chemical and quantum decoherence approaches to conformational transitions. Our analyses imply the existence of novel macroscopic quantum biomolecular phenomena, with biomolecular chain folding in an open environment considered as a subtle interplay between energy and conformation eigenstates of this biomolecule, governed by quantum-chemical and quantum decoherence laws. On the other hand, within an open biological cell, a system of all identical (noninteracting and dynamically noncoupled) biomolecular proteins might be considered as corresponding spatial quantum ensemble of these identical biomolecular processors, providing spatially distributed quantum solution to a single corresponding biomolecular chain folding, whose density of conformational states might be represented as Hopfield-like quantum-holographic associative neural network too (providing an equivalent global quantum-informational alternative to standard molecular-biology local biochemical approach in biomolecules and cells and higher hierarchical levels of organism, as well). PMID:25028662
Continuity of the entropy of macroscopic quantum systems
Swendsen, Robert H.
2015-11-01
The proper definition of entropy is fundamental to the relationship between statistical mechanics and thermodynamics. It also plays a major role in the recent debate about the validity of the concept of negative temperature. In this paper, I analyze and calculate the thermodynamic entropy for large but finite quantum mechanical systems. A special feature of this analysis is that the thermodynamic energy of a quantum system is shown to be a continuous variable, rather than being associated with discrete energy eigenvalues. Calculations of the entropy as a function of energy can be carried out with a Legendre transform of thermodynamic potentials obtained from a canonical ensemble. The resultant expressions for the entropy are able to describe equilibrium between quantum systems having incommensurate energy-level spacings. This definition of entropy preserves all required thermodynamic properties, including satisfaction of all postulates and laws of thermodynamics. It demonstrates the consistency of the concept of negative temperature with the principles of thermodynamics.
de Vega, H. J.; Sanchez, N. G.
2017-02-01
The Thomas-Fermi approach to galaxy structure determines self-consistently and non-linearly the gravitational potential of the fermionic warm dark matter (WDM) particles given their quantum distribution function f( E). This semiclassical framework accounts for the quantum nature and high number of DM particles, properly describing gravitational bounded and quantum macroscopic systems as neutron stars, white dwarfs and WDM galaxies. We express the main galaxy magnitudes as the halo radius r_h , mass M_h , velocity dispersion and phase space density in terms of the surface density which is important to confront to observations. From these expressions we derive the general equation of state for galaxies, i.e., the relation between pressure and density, and provide its analytic expression. Two regimes clearly show up: (1) Large diluted galaxies for M_h ≳ 2.3 × 10^6 M_⊙ and effective temperatures T_0 > 0.017 K described by the classical self-gravitating WDM Boltzman gas with a space-dependent perfect gas equation of state, and (2) Compact dwarf galaxies for 1.6 × 10^6 M_⊙ ≳ M_h ≳ M_{h,min} ˜eq 3.10 × 10^4 (2 {keV}/m)^{16/5} M_⊙, T_0 < 0.011 K described by the quantum fermionic WDM regime with a steeper equation of state close to the degenerate state. In particular, the T_0 = 0 degenerate or extreme quantum limit yields the most compact and smallest galaxy. In the diluted regime, the halo radius r_h , the squared velocity v^2(r_h) and the temperature T_0 turn to exhibit square-root of M_h scaling laws. The normalized density profiles ρ (r)/ρ (0) and the normalized velocity profiles v^2(r)/ v^2(0) are universal functions of r/r_h reflecting the WDM perfect gas behavior in this regime. These theoretical results contrasted to robust and independent sets of galaxy data remarkably reproduce the observations. For the small galaxies, 10^6 ≳ M_h ≥ M_{h,min} , the equation of state is galaxy mass dependent and the density and velocity profiles are not
Strict Holism in a Quantum Superposition of Macroscopic States
De Barros, J A; Suppes, Patrick
2000-01-01
We show that some N-particle quantum systems are holistic, such that the system is deterministic, whereas its parts are random. The total correlation is not sufficient to determine the probability distribution, showing a need for extra measurements. We propose a formal definition of holism not based on separability.
Kawabata, Shiro; Golubov, Alexander A.
2007-01-01
We theoretically investigate macroscopic quantum tunneling (MQT) in a current-biased π junction with a superconductor (S) and an insulating ferromagnet (IF). By using the functional integral method and the instanton approximation, the influence of the quasiparticle dissipation on MQT is found to be
Jensen, L; Swart, M; van Duijnen, PT
2005-01-01
A polarizable quantum mechanics and molecular mechanics model has been extended to account for the difference between the macroscopic electric field and the actual electric field felt by the solute molecule. This enables the calculation of effective microscopic properties which can be related to mac
Macroscopic Quantum Superposition States in a Model of Photon-Supersonic Phonon Interaction
Institute of Scientific and Technical Information of China (English)
CHAI Jin-Hua; WANG Yan-Bang; LU Yi-Qun
2000-01-01
A model of photon-hypersonic phonon interaction is proposed. The evolution of macroscopic quantum superpo sition states is analyzed, including the wave function and number distribution. It is shown that a superposition state of hypersonic phonon modes can be generated in the case of nondetuning and no losses.
Metastable states and macroscopic quantum tunneling in a cold atom josephson ring
Energy Technology Data Exchange (ETDEWEB)
Solenov, Dmitry [Los Alamos National Laboratory; Mozyrsky, Dmitry [Los Alamos National Laboratory
2009-01-01
We study macroscopic properties of a system of weakly interacting neutral bosons confined in a ring-shaped potential with a Josephson junction. We derive an effective low energy action for this system and evaluate its properties. In particular we find that the system possesses a set of metastable current-carrying states and evaluate the rates of transitions between these states due to macroscopic quantum tunneling. Finally we discuss signatures of different metastable states in the time-of-flight images and argue that the effect is observable within currently available experimental technique.
Generation of a macroscopic entangled coherent state using quantum memories in circuit QED
Liu, Tong; Su, Qi-Ping; Xiong, Shao-Jie; Liu, Jin-Ming; Yang, Chui-Ping; Nori, Franco
2016-01-01
W-type entangled states can be used as quantum channels for, e.g., quantum teleportation, quantum dense coding, and quantum key distribution. In this work, we propose a way to generate a macroscopic W-type entangled coherent state using quantum memories in circuit QED. The memories considered here are nitrogen-vacancy center ensembles (NVEs), each located in a different cavity. This proposal does not require initially preparing each NVE in a coherent state instead of a ground state, which should significantly reduce its experimental difficulty. For most of the operation time, each cavity remains in a vacuum state, thus decoherence caused by the cavity decay and the unwanted inter-cavity crosstalk are greatly suppressed. Moreover, only one external-cavity coupler qubit is needed, which simplifies the circuit. PMID:27562055
Quantum entanglement at ambient conditions in a macroscopic solid-state spin ensemble.
Klimov, Paul V; Falk, Abram L; Christle, David J; Dobrovitski, Viatcheslav V; Awschalom, David D
2015-11-01
Entanglement is a key resource for quantum computers, quantum-communication networks, and high-precision sensors. Macroscopic spin ensembles have been historically important in the development of quantum algorithms for these prospective technologies and remain strong candidates for implementing them today. This strength derives from their long-lived quantum coherence, strong signal, and ability to couple collectively to external degrees of freedom. Nonetheless, preparing ensembles of genuinely entangled spin states has required high magnetic fields and cryogenic temperatures or photochemical reactions. We demonstrate that entanglement can be realized in solid-state spin ensembles at ambient conditions. We use hybrid registers comprising of electron-nuclear spin pairs that are localized at color-center defects in a commercial SiC wafer. We optically initialize 10(3) identical registers in a 40-μm(3) volume (with [Formula: see text] fidelity) and deterministically prepare them into the maximally entangled Bell states (with 0.88 ± 0.07 fidelity). To verify entanglement, we develop a register-specific quantum-state tomography protocol. The entanglement of a macroscopic solid-state spin ensemble at ambient conditions represents an important step toward practical quantum technology.
Thermal Equilibrium of a Macroscopic Quantum System in a Pure State
Goldstein, Sheldon; Huse, David A.; Lebowitz, Joel L.; Tumulka, Roderich
2015-09-01
We consider the notion of thermal equilibrium for an individual closed macroscopic quantum system in a pure state, i.e., described by a wave function. The macroscopic properties in thermal equilibrium of such a system, determined by its wave function, must be the same as those obtained from thermodynamics, e.g., spatial uniformity of temperature and chemical potential. When this is true we say that the system is in macroscopic thermal equilibrium (MATE). Such a system may, however, not be in microscopic thermal equilibrium (MITE). The latter requires that the reduced density matrices of small subsystems be close to those obtained from the microcanonical, equivalently the canonical, ensemble for the whole system. The distinction between MITE and MATE is particularly relevant for systems with many-body localization for which the energy eigenfuctions fail to be in MITE while necessarily most of them, but not all, are in MATE. We note, however, that for generic macroscopic systems, including those with MBL, most wave functions in an energy shell are in both MATE and MITE. For a classical macroscopic system, MATE holds for most phase points on the energy surface, but MITE fails to hold for any phase point.
Quantum dynamics of a macroscopic magnet operating as an environment of a mechanical oscillator
Foti, C.; Cuccoli, A.; Verrucchi, P.
2016-12-01
We study the dynamics of a bipartite quantum system in a way such that its formal description keeps holding even if one of its parts becomes macroscopic; the problem is related to the analysis of the quantum-to-classical crossover, but our approach implies that the whole system stays genuinely quantum. The aim of the work is to understand (1) if, (2) to what extent, and possibly (3) how the evolution of a macroscopic environment testifies to the coupling with its microscopic quantum companion. To this purpose we consider a magnetic environment made of a large number of spin-1/2 particles, coupled with a quantum mechanical oscillator, possibly in the presence of an external magnetic field. We take the value of the total environmental spin S constant and large, which allows us to consider the environment as one single macroscopic system, and further deal with the hurdles of the spin-algebra via approximations that are valid in the large-S limit. We find an insightful expression for the propagator of the whole system, where we identify an effective "back-action" term, i.e., an operator acting on the magnetic environment only, and yet missing in the absence of the quantum principal system. This operator emerges as a time-dependent magnetic anisotropy whose character, whether uniaxial or planar, also depends on the detuning between the frequency of the oscillator and the level splitting in the spectrum of the free magnetic system, induced by the possible presence of the external field. The time dependence of the anisotropy is analyzed, and its effects on the dynamics of the magnet, as well as its relation to the entangling evolution of the overall system, are discussed.
Detecting Current Noise with a Josephson Junction in the Macroscopic Quantum Tunneling Regime
Peltonen, J. T.; Timofeev, A. V.; Meschke, M.; Pekola, J.P.
2006-01-01
We discuss the use of a hysteretic Josephson junction to detect current fluctuations with frequencies below the plasma frequency of the junction. These adiabatic fluctuations are probed by switching measurements observing the noise-affected average rate of macroscopic quantum tunneling of the detector junction out of its zero-voltage state. In a proposed experimental scheme, frequencies of the noise are limited by an on-chip filtering circuit. The third cumulant of current fluctuations at the...
Quantum optics. Gravity meets quantum physics
Energy Technology Data Exchange (ETDEWEB)
Adams, Bernhard W. [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-02-27
Albert Einstein’s general theory of relativity is a classical formulation but a quantum mechanical description of gravitational forces is needed, not only to investigate the coupling of classical and quantum systems but simply to give a more complete description of our physical surroundings. In this issue of Nature Photonics, Wen-Te Liao and Sven Ahrens reveal a link between quantum and gravitational physics. They propose that in the quantum-optical effect of superradiance, the world line of electromagnetic radiation is changed by the presence of a gravitational field.
Energy Technology Data Exchange (ETDEWEB)
Vega, H.J. de [Sorbonne Universites, Universite Pierre et Marie Curie UPMC Paris VI, LPTHE CNRS UMR 7589, Paris Cedex 05 (France); Sanchez, N.G. [Observatoire de Paris PSL Research University, Sorbonne Universites UPMC Paris VI, Observatoire de Paris, LERMA CNRS UMR 8112, Paris (France)
2017-02-15
The Thomas-Fermi approach to galaxy structure determines self-consistently and non-linearly the gravitational potential of the fermionic warm dark matter (WDM) particles given their quantum distribution function f(E). This semiclassical framework accounts for the quantum nature and high number of DM particles, properly describing gravitational bounded and quantum macroscopic systems as neutron stars, white dwarfs and WDM galaxies. We express the main galaxy magnitudes as the halo radius r{sub h}, mass M{sub h}, velocity dispersion and phase space density in terms of the surface density which is important to confront to observations. From these expressions we derive the general equation of state for galaxies, i.e., the relation between pressure and density, and provide its analytic expression. Two regimes clearly show up: (1) Large diluted galaxies for M{sub h} >or similar 2.3 x 10{sup 6} M {sub CircleDot} and effective temperatures T{sub 0} > 0.017 K described by the classical self-gravitating WDM Boltzman gas with a space-dependent perfect gas equation of state, and (2) Compact dwarf galaxies for 1.6 x 10{sup 6} M {sub CircleDot} >or similar M{sub h} >or similar M{sub h,min} ≅ 3.10 x 10{sup 4} (2 keV/m){sup (16)/(5)} M {sub CircleDot}, T{sub 0} < 0.011 K described by the quantum fermionic WDM regime with a steeper equation of state close to the degenerate state. In particular, the T{sub 0} = 0 degenerate or extreme quantum limit yields the most compact and smallest galaxy. In the diluted regime, the halo radius r{sub h}, the squared velocity v{sup 2}(r{sub h}) and the temperature T{sub 0} turn to exhibit square-root of M{sub h} scaling laws. The normalized density profiles ρ(r)/ρ(0) and the normalized velocity profiles v{sup 2}(r)/v{sup 2}(0) are universal functions of r/r{sub h} reflecting the WDM perfect gas behavior in this regime. These theoretical results contrasted to robust and independent sets of galaxy data remarkably reproduce the observations. For
Increasing complexity with quantum physics.
Anders, Janet; Wiesner, Karoline
2011-09-01
We argue that complex systems science and the rules of quantum physics are intricately related. We discuss a range of quantum phenomena, such as cryptography, computation and quantum phases, and the rules responsible for their complexity. We identify correlations as a central concept connecting quantum information and complex systems science. We present two examples for the power of correlations: using quantum resources to simulate the correlations of a stochastic process and to implement a classically impossible computational task.
Towards testing quantum physics in deep space
Kaltenbaek, Rainer
2016-07-01
MAQRO is a proposal for a medium-sized space mission to use the unique environment of deep space in combination with novel developments in space technology and quantum technology to test the foundations of physics. The goal is to perform matter-wave interferometry with dielectric particles of up to 10^{11} atomic mass units and testing for deviations from the predictions of quantum theory. Novel techniques from quantum optomechanics with optically trapped particles are to be used for preparing the test particles for these experiments. The core elements of the instrument are placed outside the spacecraft and insulated from the hot spacecraft via multiple thermal shields allowing to achieve cryogenic temperatures via passive cooling and ultra-high vacuum levels by venting to deep space. In combination with low force-noise microthrusters and inertial sensors, this allows realizing an environment well suited for long coherence times of macroscopic quantum superpositions and long integration times. Since the original proposal in 2010, significant progress has been made in terms of technology development and in refining the instrument design. Based on these new developments, we submitted/will submit updated versions of the MAQRO proposal in 2015 and 2016 in response to Cosmic-Vision calls of ESA for a medium-sized mission. A central goal has been to address and overcome potentially critical issues regarding the readiness of core technologies and to provide realistic concepts for further technology development. We present the progress on the road towards realizing this ground-breaking mission harnessing deep space in novel ways for testing the foundations of physics, a technology pathfinder for macroscopic quantum technology and quantum optomechanics in space.
Scale relativity theory and integrative systems biology: 2. Macroscopic quantum-type mechanics.
Nottale, Laurent; Auffray, Charles
2008-05-01
In these two companion papers, we provide an overview and a brief history of the multiple roots, current developments and recent advances of integrative systems biology and identify multiscale integration as its grand challenge. Then we introduce the fundamental principles and the successive steps that have been followed in the construction of the scale relativity theory, which aims at describing the effects of a non-differentiable and fractal (i.e., explicitly scale dependent) geometry of space-time. The first paper of this series was devoted, in this new framework, to the construction from first principles of scale laws of increasing complexity, and to the discussion of some tentative applications of these laws to biological systems. In this second review and perspective paper, we describe the effects induced by the internal fractal structures of trajectories on motion in standard space. Their main consequence is the transformation of classical dynamics into a generalized, quantum-like self-organized dynamics. A Schrödinger-type equation is derived as an integral of the geodesic equation in a fractal space. We then indicate how gauge fields can be constructed from a geometric re-interpretation of gauge transformations as scale transformations in fractal space-time. Finally, we introduce a new tentative development of the theory, in which quantum laws would hold also in scale space, introducing complexergy as a measure of organizational complexity. Initial possible applications of this extended framework to the processes of morphogenesis and the emergence of prokaryotic and eukaryotic cellular structures are discussed. Having founded elements of the evolutionary, developmental, biochemical and cellular theories on the first principles of scale relativity theory, we introduce proposals for the construction of an integrative theory of life and for the design and implementation of novel macroscopic quantum-type experiments and devices, and discuss their potential
d'Espagnat, Bernard
2011-01-01
Contrary to classical physics, which was strongly objective i.e. could be interpreted as a description of mind-independent reality, standard quantum mechanics (SQM) is only weakly objective, that is to say, its statements, though intersubjectively valid, still merely refer to operations of the mind. Essentially, in fact, they are predictive of observations. On the view that SQM is universal conventional realism is thereby refuted. It is shown however that this does not rule out a broader form of realism, called here 'open realism', restoring the notion of mind-independent reality.
Jensen, L; Swart, Marcel; van Duijnen, Piet Th
2005-01-15
A polarizable quantum mechanics and molecular mechanics model has been extended to account for the difference between the macroscopic electric field and the actual electric field felt by the solute molecule. This enables the calculation of effective microscopic properties which can be related to macroscopic susceptibilities directly comparable with experimental results. By separating the discrete local field into two distinct contribution we define two different microscopic properties, the so-called solute and effective properties. The solute properties account for the pure solvent effects, i.e., effects even when the macroscopic electric field is zero, and the effective properties account for both the pure solvent effects and the effect from the induced dipoles in the solvent due to the macroscopic electric field. We present results for the linear and nonlinear polarizabilities of water and acetonitrile both in the gas phase and in the liquid phase. For all the properties we find that the pure solvent effect increases the properties whereas the induced electric field decreases the properties. Furthermore, we present results for the refractive index, third-harmonic generation (THG), and electric field induced second-harmonic generation (EFISH) for liquid water and acetonitrile. We find in general good agreement between the calculated and experimental results for the refractive index and the THG susceptibility. For the EFISH susceptibility, however, the difference between experiment and theory is larger since the orientational effect arising from the static electric field is not accurately described.
Hidden worlds in quantum physics
Gouesbet, Gérard
2014-01-01
The past decade has witnessed a resurgence in research and interest in the areas of quantum computation and entanglement. This new book addresses the hidden worlds or variables of quantum physics. Author Gérard Gouesbet studied and worked with a former student of Louis de Broglie, a pioneer of quantum physics. His presentation emphasizes the history and philosophical foundations of physics, areas that will interest lay readers as well as professionals and advanced undergraduate and graduate students of quantum physics. The introduction is succeeded by chapters offering background on relevant concepts in classical and quantum mechanics, a brief history of causal theories, and examinations of the double solution, pilot wave, and other hidden-variables theories. Additional topics include proofs of possibility and impossibility, contextuality, non-locality, classification of hidden-variables theories, and stochastic quantum mechanics. The final section discusses how to gain a genuine understanding of quantum mec...
Quantum physics workbook for dummies
Holzner, Steven
2010-01-01
Hands-on practice in solving quantum physics problems Quantum Physics is the study of the behavior of matter and energy at the molecular, atomic, nuclear, and even smaller microscopic levels. Like the other titles in our For Dummies Workbook series, Quantum Physics Workbook For Dummies allows you to hone your skills at solving the difficult and often confusing equations you encounter in this subject. Explains equations in easy-to-understand terms Harmonic Oscillator Operations, Angular Momentum, Spin, Scattering Theory Using a proven practice-and-review approach, Quantum Physics Workbook For Dummies is all you need to get up to speed in problem solving!
Marochnik, Leonid; Vereshkov, Grigory
2013-01-01
We discuss a special class of quantum gravity phenomena that occur on the scale of the Universe as a whole at any stage of its evolution. These phenomena are a direct consequence of the zero rest mass of gravitons, conformal non-invariance of the graviton field, and one-loop finiteness of quantum gravity. The effects are due to graviton-ghost condensates arising from the interference of quantum coherent states. Each of coherent states is a state of gravitons and ghosts of a wavelength of the order of the horizon scale and of different occupation numbers. The state vector of the Universe is a coherent superposition of vectors of different occupation numbers. To substantiate the reliability of macroscopic quantum effects, the formalism of one-loop quantum gravity is discussed in detail. The theory is constructed as follows: Faddeev-Popov path integral in Hamilton gauge -> factorization of classical and quantum variables, allowing the existence of a self-consistent system of equations for gravitons, ghosts and m...
Atomic physics and quantum optics using superconducting circuits.
You, J Q; Nori, Franco
2011-06-29
Superconducting circuits based on Josephson junctions exhibit macroscopic quantum coherence and can behave like artificial atoms. Recent technological advances have made it possible to implement atomic-physics and quantum-optics experiments on a chip using these artificial atoms. This Review presents a brief overview of the progress achieved so far in this rapidly advancing field. We not only discuss phenomena analogous to those in atomic physics and quantum optics with natural atoms, but also highlight those not occurring in natural atoms. In addition, we summarize several prospective directions in this emerging interdisciplinary field.
Quantum computing classical physics.
Meyer, David A
2002-03-15
In the past decade, quantum algorithms have been found which outperform the best classical solutions known for certain classical problems as well as the best classical methods known for simulation of certain quantum systems. This suggests that they may also speed up the simulation of some classical systems. I describe one class of discrete quantum algorithms which do so--quantum lattice-gas automata--and show how to implement them efficiently on standard quantum computers.
The Physics of Quantum Computation
Falci, Giuseppe; Paladino, Elisabette
2015-10-01
Quantum Computation has emerged in the past decades as a consequence of down-scaling of electronic devices to the mesoscopic regime and of advances in the ability of controlling and measuring microscopic quantum systems. QC has many interdisciplinary aspects, ranging from physics and chemistry to mathematics and computer science. In these lecture notes we focus on physical hardware, present day challenges and future directions for design of quantum architectures.
Student views of macroscopic and microscopic energy in physics and biology
Dreyfus, Benjamin W.; Redish, Edward F.; Watkins, Jessica
2012-02-01
Energy concepts are fundamental across the sciences, yet these concepts can be fragmented along disciplinary boundaries, rather than integrated into a coherent whole. To teach physics effectively to biology students, we need to understand students' disciplinary perspectives. We present interview data from an undergraduate student who displays multiple stances towards the concept of energy. At times he views energy in macroscopic contexts as a separate entity from energy in microscopic (particularly biological) contexts, while at other times he uses macroscopic physics phenomena as productive analogies for understanding energy in the microscopic biological context, and he reasons about energy transformations between the microscopic and macroscopic scales. This case study displays preliminary evidence for the context dependence of students' ability to translate energy concepts across scientific disciplines. This points to challenges that must be taken into account in developing curricula for biology students that integrate physics and biology concepts.
Stochastic processes - quantum physics
Energy Technology Data Exchange (ETDEWEB)
Streit, L. (Bielefeld Univ. (Germany, F.R.))
1984-01-01
The author presents an elementary introduction to stochastic processes. He starts from simple quantum mechanics and considers problems in probability, finally presenting quantum dynamics in terms of stochastic processes.
Dielectric Anomaly in Ice near 20 K; Evidence of Macroscopic Quantum Phenomena
Yen, Fei
2015-01-01
H2O is one of the most important substances needed in sustaining life; but yet not much is known about its ground state. Here, a previously unidentified anomaly is identified in the form of a minimum in the imaginary part of the dielectric constant with respect to temperature near 20 K while the real part remains monotonic. Isothermal dispersion and absorption measurements show coinciding results. For the case of heavy ice (D2O), no anomaly was identified confirming an apparent isotope effect. Concerted quantum tunneling of protons is believed to be the main cause behind the reported anomaly. Our findings identify another system that exhibits macroscopic quantum phenomena of which rarely occur in nature.
Pass-through Mach-Zehnder topologies for macroscopic quantum measurements
Khalili, F Ya
2011-01-01
Several relatively small-scale experimental setups aimed on prototyping of future laser gravitational-wave detectors and testing of new methods of quantum measurements with macroscopic mechanical objects, are under development now. In these devices, not devoted directly to the gravitational-wave detection, Mach-Zehnder interferometer with pass-through Fabry-Perot cavities in the arms can be used instead of the standard Michelson/Fabry-Perot one. The advantage of this topology is that it does not contain high-reflectivity end mirrors with multilayer coatings, which Brownian noise could constitute the major part of the noise budget of the Michelson/Fabry-Perot interferometers. We consider here two variants of this topology: the "ordinary" position meter scheme, and a new variant of the quantum speed meter.
Particle physics: Quantum simulation of fundamental physics
Zohar, Erez
2016-06-01
Gauge theories underpin the standard model of particle physics, but are difficult to study using conventional computational methods. An experimental quantum system opens up fresh avenues of investigation. See Letter p.516
Let's call it Nonlocal Quantum Physics
Requardt, M
2000-01-01
In the following we undertake to derive quantum theory as a stochastic low-energy and coarse-grained theory from a more primordial discrete and basically geometric theory living on the Planck scale and which (as we argue) possibly underlies also \\tit{string theory}. We isolate the so-called \\tit{ideal elements} which represent at the same time the cornerstones of the framework of ordinary quantum theory and show how and why they encode the \\tit{non-local} aspects, being ubiquituous in the quantum realm, in a, on the surface, local way. We show that the quantum non-locality emerges in our approach as a natural consequence of the underlying \\tit{two-storey} nature of space-time or the physical vacuum, that is, quantum theory turns out to be a residual effect of the geometric depth structure of space-time on the Planck scale. We indicate how the \\tit{measurement problem} and the emergence of the \\tit{macroscopic sub-regime} can be understood in this framework.
Quantum chaos in nuclear physics
Energy Technology Data Exchange (ETDEWEB)
Bunakov, V. E., E-mail: bunakov@VB13190.spb.edu [St. Petersburg State University (Russian Federation)
2016-07-15
A definition of classical and quantum chaos on the basis of the Liouville–Arnold theorem is proposed. According to this definition, a chaotic quantum system that has N degrees of freedom should have M < N independent first integrals of motion (good quantum numbers) that are determined by the symmetry of the Hamiltonian for the system being considered. Quantitative measures of quantum chaos are established. In the classical limit, they go over to the Lyapunov exponent or the classical stability parameter. The use of quantum-chaos parameters in nuclear physics is demonstrated.
Quantum enigma physics encounters consciousness
Rosenblum, Bruce
2006-01-01
1. Presenting the Enigma2. Einstein Called it ""Spooky""--and I Wish I Had Known3. The Visit to Neg Ahne Poc: A Quantum Parable4. Our Newtonian Worldview: A Universal Law of Motion5. All the Rest of Classical PhysicsHello Quantum Mechanics6. How the Quantum Was Forced on Physics7. Schrodinger's Equation: The New Universal Law of Motion8. One-Third of Our Economy9. Our Skeleton in the Closet10. Wonderful, Wonderful Copenhagen11. Schrodinger's Controversial Cat12. Seeking a Real World: EPR13. Spooky Interactions: Bell's Theorem14. What's Going On?: Interpreting the Quantum Enigma15. The Mystery
Students' Views of Macroscopic and Microscopic Energy in Physics and Biology
Dreyfus, Benjamin W; Watkins, Jessica
2011-01-01
Energy concepts are fundamental across the sciences, yet these concepts can be fragmented along disciplinary boundaries, rather than integrated into a coherent whole. To teach physics effectively to biology students, we need to understand students' disciplinary perspectives. We present interview data from an undergraduate student who displays multiple stances towards the concept of energy. At times he views energy in macroscopic contexts as a separate entity from energy in microscopic (particularly biological) contexts, while at other times he uses macroscopic physics phenomena as productive analogies for understanding energy in the microscopic biological context, and he reasons about energy transformations between the microscopic and macroscopic scales. This case study displays preliminary evidence for the context dependence of students' ability to translate energy concepts across scientific disciplines. This points to challenges that must be taken into account in developing curricula for biology students th...
Lawrence, I.
1996-01-01
Discusses a teaching strategy for introducing quantum ideas into the school classroom using modern devices. Develops the concepts of quantization, wave-particle duality, nonlocality, and tunneling. (JRH)
Physical foundations of quantum electronics
Klyshko, David; Kulik, Sergey
2011-01-01
This concise textbook introduces a graduate student to the various fields of physics related to the interaction between radiation and matter. The scope of the book is very broad, ranging from nonlinear to quantum optics and from quantum transitions in atoms to the dispersion of polaritons in continuous media. The author, Professor David Klyshko (1929-2000), is one of the founders of modern quantum optics, renowned for his theory of Spontaneous Parametric Down-Conversion (SPDC) and its applications in quantum metrology and the optics of nonclassical light. Most parts of the book contain the lec
Physical implementation of quantum walks
Manouchehri, Kia
2013-01-01
Given the extensive application of random walks in virtually every science related discipline, we may be at the threshold of yet another problem solving paradigm with the advent of quantum walks. Over the past decade, quantum walks have been explored for their non-intuitive dynamics, which may hold the key to radically new quantum algorithms. This growing interest has been paralleled by a flurry of research into how one can implement quantum walks in laboratories. This book presents numerous proposals as well as actual experiments for such a physical realization, underpinned by a wide range of
Physical realization of the Glauber quantum oscillator.
Gentilini, Silvia; Braidotti, Maria Chiara; Marcucci, Giulia; DelRe, Eugenio; Conti, Claudio
2015-11-02
More than thirty years ago Glauber suggested that the link between the reversible microscopic and the irreversible macroscopic world can be formulated in physical terms through an inverted harmonic oscillator describing quantum amplifiers. Further theoretical studies have shown that the paradigm for irreversibility is indeed the reversed harmonic oscillator. As outlined by Glauber, providing experimental evidence of these idealized physical systems could open the way to a variety of fundamental studies, for example to simulate irreversible quantum dynamics and explain the arrow of time. However, supporting experimental evidence of reversed quantized oscillators is lacking. We report the direct observation of exploding n = 0 and n = 2 discrete states and Γ0 and Γ2 quantized decay rates of a reversed harmonic oscillator generated by an optical photothermal nonlinearity. Our results give experimental validation to the main prediction of irreversible quantum mechanics, that is, the existence of states with quantized decay rates. Our results also provide a novel perspective to optical shock-waves, potentially useful for applications as lasers, optical amplifiers, white-light and X-ray generation.
Physical realization of the Glauber quantum oscillator
Gentilini, Silvia; Braidotti, Maria Chiara; Marcucci, Giulia; Delre, Eugenio; Conti, Claudio
2015-11-01
More than thirty years ago Glauber suggested that the link between the reversible microscopic and the irreversible macroscopic world can be formulated in physical terms through an inverted harmonic oscillator describing quantum amplifiers. Further theoretical studies have shown that the paradigm for irreversibility is indeed the reversed harmonic oscillator. As outlined by Glauber, providing experimental evidence of these idealized physical systems could open the way to a variety of fundamental studies, for example to simulate irreversible quantum dynamics and explain the arrow of time. However, supporting experimental evidence of reversed quantized oscillators is lacking. We report the direct observation of exploding n = 0 and n = 2 discrete states and Γ0 and Γ2 quantized decay rates of a reversed harmonic oscillator generated by an optical photothermal nonlinearity. Our results give experimental validation to the main prediction of irreversible quantum mechanics, that is, the existence of states with quantized decay rates. Our results also provide a novel perspective to optical shock-waves, potentially useful for applications as lasers, optical amplifiers, white-light and X-ray generation.
Quantum physics a beginner's guide
Rae, Alastair I M
2005-01-01
As Alastair Rae points out in his introduction, ""quantum physics is not rocket science"". It may have gained a reputation as the theory that no one really understands, but its practical applications are all around us in everyday life. If it were not for quantum physics, computers would not function, metals would not conduct electricity, and the power stations that heat our homes would not produce energy. Assuming no prior scientific or mathematical knowledge, this clear and concise introduction provides a step-by-step guide to quantum theory, right from the very basic principles to the most c
Quantum Electronics for Atomic Physics
Nagourney, Warren
2010-01-01
Quantum Electronics for Atomic Physics provides a course in quantum electronics for researchers in atomic physics. The book covers the usual topics, such as Gaussian beams, cavities, lasers, nonlinear optics and modulation techniques, but also includes a number of areas not usually found in a textbook on quantum electronics. It includes such practical matters as the enhancement of nonlinear processes in a build-up cavity, impedance matching into a cavity, laser frequencystabilization (including servomechanism theory), astigmatism in ring cavities, and atomic/molecular spectroscopic techniques
From classical to quantum physics
Stehle, Philip
2017-01-01
Suitable for lay readers as well as students, this absorbing survey explores the twentieth-century transition from classical to quantum physics. Author Philip Stehle traces the shift in the scientific worldview from the work of Galileo, Newton, and Darwin to the modern-day achievements of Max Planck, Albert Einstein, Ernest Rutherford, Niels Bohr, and others of their generation. His insightful overview examines not only the history of quantum physics but also the ways that progress in the discipline changed our understanding of the physical world and forces of nature. This chronicle of the second revolution in the physical sciences conveys the excitement and suspense that new developments produced in the scientific community. The narrative ranges from the classical physics of the seventeenth-century to the emergence of quantum mechanics with the entrance of the electron, the rise of relativity theory, the development of atomic theory, and the recognition of wave-particle duality. Relevant mathematical details...
Macroscopic quantum tunneling induced by a spontaneous field in intrinsic Josephson junctions
Energy Technology Data Exchange (ETDEWEB)
Chizaki, Y., E-mail: y.chizaki@aist.go.jp [Nanosystem Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)] [CREST, Japan Science and Technology Corporation (JST), Kawaguchi, Saitama 332-0012 (Japan); Kashiwaya, H.; Kashiwaya, S. [Nanoelectronics Research Institute (NeRI), AIST, Tsukuba, Ibaraki 305-8568 (Japan); Koyama, T. [CREST, Japan Science and Technology Corporation (JST), Kawaguchi, Saitama 332-0012 (Japan)] [Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Kawabata, S. [Nanosystem Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)] [CREST, Japan Science and Technology Corporation (JST), Kawaguchi, Saitama 332-0012 (Japan)
2011-11-15
Derivation of an effective Hamiltonian in the case that one of the capacitively coupled junctions is in the finite voltage state. Calculation of MQT rate by using the Hamiltonian. The MQT rate is resonantly enhanced and the enhancement is found even when the bias current is off the resonant point. Discussion of the validity of the two types of enhancement. We theoretically study macroscopic quantum tunneling (MQT) in capacitively coupled Josephson junctions in the case that one of the junctions is in the finite voltage state. We find that the system can be mapped into a one dimensional model with a spontaneous periodic perturbation and calculate the MQT rate by using the time-dependent WKB method. Then the MQT rate is found to be resonantly enhanced and the enhancement of MQT rate is found even off the resonant point.
Energy Technology Data Exchange (ETDEWEB)
Asai, Hidehiro, E-mail: hd-asai@aist.go.jp [Electronics and Photonics Research Institute (ESPRIT), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Ota, Yukihiro [CCSE, Japan Atomic Energy Agency, Kashiwa, Chiba 277-8587 (Japan); Kawabata, Shiro [Electronics and Photonics Research Institute (ESPRIT), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Nori, Franco [CEMS, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Physics Department, University of Michigan, Ann Arbor, MI 48109-1040 (United States)
2014-09-15
Highlights: • We study MQT in Josephson junctions composed of multi-gap superconductors. • We derive a formula of the MQT escape rate for multiple phase differences. • We investigate the effect of inter-band phase fluctuation on MQT. • The MQT escape rate is significantly enhanced by the inter-band phase fluctuation. - Abstract: We theoretically investigate macroscopic quantum tunneling (MQT) in a hetero Josephson junction formed by a conventional single-gap superconductor and a multi-gap superconductor. In such Josephson junctions, phase differences for each tunneling channel are defined, and the fluctuation of the relative phase differences appear which is referred to as Josephson–Leggett’s mode. We take into account the effect of the fluctuation in the tunneling process and calculate the MQT escape rate for various junction parameters. We show that the fluctuation of relative phase differences drastically enhances the escape rate.
Quantum Physics Illusion or Reality?
Rae, Alastair I M
2004-01-01
Quantum physics is believed to be the fundamental theory underlying our understanding of the physical universe. However, it is based on concepts and principles that have always been difficult to understand and controversial in their interpretation. This book aims to explain these issues using a minimum of technical language and mathematics. After a brief introduction to the ideas of quantum physics, the problems of interpretation are identified and explained. The rest of the book surveys, describes and criticises a range of suggestions that have been made with the aim of resolving these proble
The physics of quantum mechanics
Binney, James
2014-01-01
The Physics of Quantum Mechanics aims to give students a good understanding of how quantum mechanics describes the material world. It shows that the theory follows naturally from the use of probability amplitudes to derive probabilities. It stresses that stationary states are unphysical mathematical abstractions that enable us to solve the theory's governing equation, the time-dependent Schroedinger equation. Every opportunity is taken to illustrate the emergence of the familiarclassical, dynamical world through the quantum interference of stationary states. The text stresses the continuity be
Uncommon paths in quantum physics
Kazakov, Konstantin V
2014-01-01
Quantum mechanics is one of the most fascinating, and at the same time most controversial, branches of contemporary science. Disputes have accompanied this science since its birth and have not ceased to this day. Uncommon Paths in Quantum Physics allows the reader to contemplate deeply some ideas and methods that are seldom met in the contemporary literature. Instead of widespread recipes of mathematical physics, based on the solutions of integro-differential equations, the book follows logical and partly intuitional derivations of non-commutative algebra. Readers can directly penetrate the
Quantum Simulations of Physics Problems
Somma, R D; Knill, E; Gubernatis, J; Somma, Rolando; Ortiz, Gerardo; Knill, Emanuel; Gubernatis, James
2003-01-01
If a large Quantum Computer (QC) existed today, what type of physical problems could we efficiently simulate on it that we could not simulate on a classical Turing machine? In this paper we argue that a QC could solve some relevant physical "questions" more efficiently. The existence of one-to-one mappings between different algebras of observables or between different Hilbert spaces allow us to represent and imitate any physical system by any other one (e.g., a bosonic system by a spin-1/2 system). We explain how these mappings can be performed showing quantum networks useful for the efficient evaluation of some physical properties, such as correlation functions and energy spectra.
Path Integrals in Quantum Physics
2012-01-01
These lectures aim at giving graduate students an introduction to and a working knowledge of path integral methods in a wide variety of fields in physics. Consequently, the lecture notes are organized in three main parts dealing with non-relativistic quantum mechanics, many-body physics and field theory. In the first part the basic concepts of path integrals are developed in the usual heuristic, non-mathematical way followed by standard examples and special applications including numerical ev...
Goldstein, Sheldon; Lebowitz, Joel L.; Tumulka, Roderich; Zanghi, Nino
2010-01-01
The renewed interest in the foundations of quantum statistical mechanics in recent years has led us to study John von Neumann's 1929 article on the quantum ergodic theorem. We have found this almost forgotten article, which until now has been available only in German, to be a treasure chest, and to be much misunderstood. In it, von Neumann studied the long-time behavior of macroscopic quantum systems. While one of the two theorems announced in his title, the one he calls the "quantum H-theore...
Quantum Processes and Dynamic Networks in Physical and Biological Systems.
Dudziak, Martin Joseph
Quantum theory since its earliest formulations in the Copenhagen Interpretation has been difficult to integrate with general relativity and with classical Newtonian physics. There has been traditionally a regard for quantum phenomena as being a limiting case for a natural order that is fundamentally classical except for microscopic extrema where quantum mechanics must be applied, more as a mathematical reconciliation rather than as a description and explanation. Macroscopic sciences including the study of biological neural networks, cellular energy transports and the broad field of non-linear and chaotic systems point to a quantum dimension extending across all scales of measurement and encompassing all of Nature as a fundamentally quantum universe. Theory and observation lead to a number of hypotheses all of which point to dynamic, evolving networks of fundamental or elementary processes as the underlying logico-physical structure (manifestation) in Nature and a strongly quantized dimension to macroscalar processes such as are found in biological, ecological and social systems. The fundamental thesis advanced and presented herein is that quantum phenomena may be the direct consequence of a universe built not from objects and substance but from interacting, interdependent processes collectively operating as sets and networks, giving rise to systems that on microcosmic or macroscopic scales function wholistically and organically, exhibiting non-locality and other non -classical phenomena. The argument is made that such effects as non-locality are not aberrations or departures from the norm but ordinary consequences of the process-network dynamics of Nature. Quantum processes are taken to be the fundamental action-events within Nature; rather than being the exception quantum theory is the rule. The argument is also presented that the study of quantum physics could benefit from the study of selective higher-scale complex systems, such as neural processes in the brain
Theory of Macroscopic Quantum Tunneling in High-T_c c-Axis Josephson Junctions
Yokoyama, Takehito; Kato, Takeo; Tanaka, Yukio
2007-01-01
We study macroscopic quantum tunneling (MQT) in c-axis twist Josephson junctions made of high-T_c superconductors in order to clarify the influence of the anisotropic order parameter symmetry (OPS) on MQT. The dependence of the MQT rate on the twist angle $\\gamma$ about the c-axis is calculated by using the functional integral and the bounce method. Due to the d-wave OPS, the $\\gamma$ dependence of standard deviation of the switching current distribution and the crossover temperature from thermal activation to MQT are found to be given by $\\cos2\\gamma$ and $\\sqrt{\\cos2\\gamma}$, respectively. We also show that a dissipative effect resulting from the nodal quasiparticle excitation on MQT is negligibly small, which is consistent with recent MQT experiments using Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8 + \\delta}$ intrinsic junctions. These results indicate that MQT in c-axis twist junctions becomes a useful experimental tool for testing the OPS of high-T_c materials at low temperature, and suggest high potential of suc...
Classical and Quantum Thermal Physics
Prasad, R.
2016-11-01
List of figures; List of tables; Preface; Acknowledgement; Dedication; 1. The kinetic theory of gases; 2. Ideal to real gas, viscosity, conductivity and diffusion; 3. Thermodynamics: definitions and Zeroth law; 4. First Law of Thermodynamics and some of its applications; 5. Second Law of Thermodynamics and some of its applications; 6. TdS equations and their applications; 7. Thermodynamic functions, potentials, Maxwell equations, the Third Law and equilibrium; 8. Some applications of thermodynamics to problems of physics and engineering; 9. Application of thermodynamics to chemical reactions; 10. Quantum thermodynamics; 11. Some applications of quantum thermodynamics; 12. Introduction to the thermodynamics of irreversible processes; Index.
The quantum physics of photosynthesis.
Ritz, Thorsten; Damjanović, Ana; Schulten, Klaus
2002-03-12
Biological cells contain nanoscale machineries that exhibit a unique combination of high efficiency, high adaptability to changing environmental conditions, and high reliability. Recent progress in obtaining atomically resolved structures provide an opportunity for an atomic-level explanation of the biological function of cellular machineries and the underlying physical mechanisms. A prime example in this regard is the apparatus with which purple bacteria harvest the light of the sun. Its highly symmetrical architecture and close interplay of biological functionality with quantum physical processes allow an illuminating demonstration of the fact that properties of living beings ultimately rely on and are determined by the laws of physics.
The continuum limit of causal fermion systems from Planck scale structures to macroscopic physics
Finster, Felix
2016-01-01
This monograph introduces the basic concepts of the theory of causal fermion systems, a recent approach to the description of fundamental physics. The theory yields quantum mechanics, general relativity and quantum field theory as limiting cases and is therefore a candidate for a unified physical theory. From the mathematical perspective, causal fermion systems provide a general framework for describing and analyzing non-smooth geometries and "quantum geometries". The dynamics is described by a novel variational principle, called the causal action principle. In addition to the basics, the book provides all the necessary mathematical background and explains how the causal action principle gives rise to the interactions of the standard model plus gravity on the level of second-quantized fermionic fields coupled to classical bosonic fields. The focus is on getting a mathematically sound connection between causal fermion systems and physical systems in Minkowski space. The book is intended for graduate students e...
On foundations of quantum physics
Solov'ev, E A
2010-01-01
Some aspects of the interpretation of quantum theory are discussed. It is emphasized that quantum theory is formulated in the Cartesian coordinate system; in other coordinates the result obtained with the help of the Hamiltonian formalism and commutator relations between 'canonically conjugated' coordinate and momentum operators leads to a wrong version of quantum mechanics. The origin of time is analyzed in detail by the example of atomic collision theory. It is shown that for a closed system like the three-body (two nuclei + electron), time-dependent Schroedinger equation has no physical meaning since in the high impact energy limit it transforms into an equation with two independent time-like variables; the time appears in the stationary Schroedinger equation as a result of extraction of a classical subsystem (two nuclei) from a closed three-body system. Following the Einstein-Rozen-Podolsky experiment and Bell's inequality the wave function is interpreted as an actual field of information in the elementar...
Quantum information and physics: Some future directions
Preskill, John
2000-01-01
I consider some promising future directions for quantum information theory that could influence the development of 21st century physics. Advances in the theory of the distinguishability of superoperators may lead to new strategies for improving the precision of quantum-limited measurements. A better grasp of the properties of multi-partite quantum entanglement may lead to deeper understanding of strongly-coupled dynamics in quantum many-body systems, quantum field theory, and quantum gravity.
Path Integrals in Quantum Physics
Rosenfelder, R
2012-01-01
These lectures aim at giving graduate students an introduction to and a working knowledge of path integral methods in a wide variety of fields in physics. Consequently, the lecture notes are organized in three main parts dealing with non-relativistic quantum mechanics, many-body physics and field theory. In the first part the basic concepts of path integrals are developed in the usual heuristic, non-mathematical way followed by standard examples and special applications including numerical evaluation of (euclidean) path integrals by Monte-Carlo methods with a program for the anharmonic oscillator. The second part deals with the application of path integrals in statistical mechanics and many-body problems treating the polaron problem, dissipative quantum systems, path integrals over ordinary and Grassmannian coherent states and perturbation theory for both bosons and fermions. Again a simple Fortran program is included for illustrating the use of strong-coupling methods. Finally, in the third part path integra...
Some Aspects of Quantum Physics
Directory of Open Access Journals (Sweden)
Newton C. A. da Costa
2007-06-01
Full Text Available I discuss some questions of quantum physics, for instance the validity and limitations of the basic language of set theory to deal with problems related to elementary particles. I also present a sketch of a formalization of a “metaphysics of structures”, which might be useful for a kind of “ontic structural realism”, and briefly review the concept of quasi-truth, which underlies my way of understanding scientific theories and the scientific activity.
Quantum physics in one dimension
Giamarchi, Thierry
2004-01-01
This book presents in a pedagogical yet complete way correlated systems in one dimension. Recent progress in nanotechnology and material research have made one dimensional systems a crucial part of today's physics. After an introduction to the basic concepts of correlated systems, the book gives a step by step description of the techniques needed to treat one dimension, and discusses the resulting physics. Then specific experimental realizations of one dimensional systems such asspin chains, quantum wires, nanotubes, organic superconductors etc. are examined. Given its progressive and pedagogi
Algorithmic approach to quantum physics
Ozhigov, Y
2004-01-01
Algorithmic approach is based on the assumption that any quantum evolution of many particle system can be simulated on a classical computer with the polynomial time and memory cost. Algorithms play the central role here but not the analysis, and a simulation gives a "film" which visualizes many particle quantum dynamics and is demonstrated to a user of the model. Restrictions following from the algorithm theory are considered on a level of fundamental physical laws. Born rule for the calculation of quantum probability as well as the decoherence is derived from the existence of a nonzero minimal value of amplitude module - a grain of amplitude. The limitation on the classical computational resources gives the unified description of quantum dynamics that is not divided to the unitary dynamics and measurements and does not depend on the existence of observer. It is proposed the description of states based on the nesting of particles in each other that permits to account the effects of all levels in the same mode...
Confinement Physics in Quantum Chromodynamics
Suganuma, H; Amemiya, K; Tanaka, A; Suganuma, Hideo; Ichie, Hiroko; Amemiya, Kazuhisa; Tanaka, Atsunori
1998-01-01
We study the confinement physics in QCD in the maximally abelian (MA) gauge using the SU(2) lattice QCD, based on the dual-superconductor picture. In the MA gauge, off-diagonal gluon components are forced to be small, and the off-diagonal angle variable $\\chi_\\mu(s)$ tends to be random. Within the random-variable approximation for $\\chi_\\mu(s)$, we analytically prove the perimeter law of the off-diagonal gluon contribution to the Wilson loop in the MA gauge, which leads to abelian dominance on the string tension. To clarify the origin of abelian dominance for the long-range physics, we study the charged-gluon propagator in the MA gauge using the lattice QCD, and find that the effective mass $m_{ch} \\simeq 0.9 {\\rm GeV}$ of the charged gluon is induced by the MA gauge fixing. In the MA gauge, there appears the macroscopic network of the monopole world-line covering the whole system, which would be identified as monopole condensation at a large scale. To prove monopole condensation in the field-theoretical mann...
Quantum Measurement, Complexity and Discrete Physics
Leckey, Martin
2003-01-01
This paper presents a new modified quantum mechanics, Critical Complexity Quantum Mechanics, which includes a new account of wavefunction collapse. This modified quantum mechanics is shown to arise naturally from a fully discrete physics, where all physical quantities are discrete rather than continuous. I compare this theory with the spontaneous collapse theories of Ghirardi, Rimini, Weber and Pearle and discuss some implications of the theory for a realist view of the quantum realm.
On the fundamental role of dynamics in quantum physics
Hofmann, Holger F.
2016-05-01
Quantum theory expresses the observable relations between physical properties in terms of probabilities that depend on the specific context described by the "state" of a system. However, the laws of physics that emerge at the macroscopic level are fully deterministic. Here, it is shown that the relation between quantum statistics and deterministic dynamics can be explained in terms of ergodic averages over complex valued probabilities, where the fundamental causality of motion is expressed by an action that appears as the phase of the complex probability multiplied with the fundamental constant ħ. Importantly, classical physics emerges as an approximation of this more fundamental theory of motion, indicating that the assumption of a classical reality described by differential geometry is merely an artefact of an extrapolation from the observation of macroscopic dynamics to a fictitious level of precision that does not exist within our actual experience of the world around us. It is therefore possible to completely replace the classical concepts of trajectories with the more fundamental concept of action phase probabilities as a universally valid description of the deterministic causality of motion that is observed in the physical world.
Quantum mechanics for applied physics and engineering
Fromhold, Albert T
2011-01-01
This excellent text, directed to upper-level undergraduates and graduate students in engineering and applied physics, introduces the fundamentals of quantum mechanics, emphasizing those aspects of quantum mechanics and quantum statistics essential to an understanding of solid-state theory. A heavy background in mathematics and physics is not required beyond basic courses in calculus, differential equations, and calculus-based elementary physics.The first three chapters introduce quantum mechanics (using the Schrödinger equations), quantum statistics, and the free-electron theory of metals. Ch
Coherent states in quantum physics
Gazeau, Jean-Pierre
2009-01-01
This self-contained introduction discusses the evolution of the notion of coherent states, from the early works of Schrödinger to the most recent advances, including signal analysis. An integrated and modern approach to the utility of coherent states in many different branches of physics, it strikes a balance between mathematical and physical descriptions.Split into two parts, the first introduces readers to the most familiar coherent states, their origin, their construction, and their application and relevance to various selected domains of physics. Part II, mostly based on recent original results, is devoted to the question of quantization of various sets through coherent states, and shows the link to procedures in signal analysis. Title: Coherent States in Quantum Physics Print ISBN: 9783527407095 Author(s): Gazeau, Jean-Pierre eISBN: 9783527628292 Publisher: Wiley-VCH Dewey: 530.12 Publication Date: 23 Sep, 2009 Pages: 360 Category: Science, Science: Physics LCCN: Language: English Edition: N/A LCSH:
Problems and solutions in quantum physics
Ficek, Zbigniew
2016-01-01
This book contains tutorial problems with solutions for the textbook Quantum Physics for Beginners. The reader studying the abstract field of quantum physics needs to solve plenty of practical, especially quantitative, problems. This book places emphasis on basic problems of quantum physics together with some instructive, simulating, and useful applications. A considerable range of complexity is presented by these problems, and not too many of them can be solved using formulas alone.
Quantum Manybody Physics with Rydberg Polaritons
2016-06-22
AFRL-AFOSR-VA-TR-2017-0033 Quantum Manybody Physics with Rydberg Polaritons Jonathan Simon UNIVERSITY OF CHICAGO THE 5801 S ELLIS AVE CHICAGO, IL...abstract is to be limited. DISTRIBUTION A: Distribution approved for public release. Title: Quantum Manybody Physics with Rydberg Polaritons AFOSR AWARD...developed. In conjunction with synthetic magnetic fields generated through non-planar cavities, we are now poised to explore fractional quantum hall physics
Goldstein, Sheldon; Tumulka, Roderich; Zanghi, Nino
2010-01-01
The renewed interest in the foundations of quantum statistical mechanics in recent years has led us to study John von Neumann's 1929 article on the quantum ergodic theorem. We have found this almost forgotten article, which until now has been available only in German, to be a treasure chest, and to be much misunderstood. In it, von Neumann studied the long-time behavior of macroscopic quantum systems. While one of the two theorems announced in his title, the one he calls the "quantum H-theorem", is actually a much weaker statement than Boltzmann's classical H-theorem, the other theorem, which he calls the "quantum ergodic theorem", is a beautiful and very non-trivial result. It expresses a fact we call "normal typicality" and can be summarized as follows: For a "typical" finite family of commuting macroscopic observables, every initial wave function $\\psi_0$ from a micro-canonical energy shell so evolves that for most times $t$ in the long run, the joint probability distribution of these observables obtained ...
Numerical studies from quantum to macroscopic scales of carbon nanoparticules in hydrogen plasma
Lombardi, Guillaume; Ngandjong, Alain; Mezei, Zsolt; Mougenot, Jonathan; Michau, Armelle; Hassouni, Khaled; Seydou, Mahamadou; Maurel, François
2016-09-01
Dusty plasmas take part in large scientific domains from Universe Science to nanomaterial synthesis processes. They are often generated by growth from molecular precursor. This growth leads to the formation of larger clusters which induce solid germs nucleation. Particle formed are described by an aerosol dynamic taking into account coagulation, molecular deposition and transport processes. These processes are controlled by the elementary particle. So there is a strong coupling between particle dynamics and plasma discharge equilibrium. This study is focused on the development of a multiscale physic and numeric model of hydrogen plasmas and carbon particles around three essential coupled axes to describe the various physical phenomena: (i) Macro/mesoscopic fluid modeling describing in an auto-coherent way, characteristics of the plasma, molecular clusters and aerosol behavior; (ii) the classic molecular dynamics offering a description to the scale molecular of the chains of chemical reactions and the phenomena of aggregation; (iii) the quantum chemistry to establish the activation barriers of the different processes driving the nanopoarticule formation.
Physical synthesis of quantum circuits using templates
Mirkhani, Zahra; Mohammadzadeh, Naser
2016-10-01
Similar to traditional CMOS circuits, quantum circuit design flow is divided into two main processes: logic synthesis and physical design. Addressing the limitations imposed on optimization of the quantum circuit metrics because of no information sharing between logic synthesis and physical design processes, the concept of " physical synthesis" was introduced for quantum circuit flow, and a few techniques were proposed for it. Following that concept, in this paper a new approach for physical synthesis inspired by template matching idea in quantum logic synthesis is proposed to improve the latency of quantum circuits. Experiments show that by using template matching as a physical synthesis approach, the latency of quantum circuits can be improved by more than 23.55 % on average.
Introduction to quantum physics and information processing
Vathsan, Radhika
2016-01-01
An Elementary Guide to the State of the Art in the Quantum Information FieldIntroduction to Quantum Physics and Information Processing guides beginners in understanding the current state of research in the novel, interdisciplinary area of quantum information. Suitable for undergraduate and beginning graduate students in physics, mathematics, or engineering, the book goes deep into issues of quantum theory without raising the technical level too much.The text begins with the basics of quantum mechanics required to understand how two-level systems are used as qubits. It goes on to show how quant
An Introduction to a Realistic Quantum Physics
Preparata, Giuliano
2003-01-01
This book is a remarkable synthesis, a clear and simple introduction to Quantum Physics with a sort of Galilean dialogue on the supreme systems of contemporary Physics. The author, whose research interests and work extended from quarks to liquid systems and from crystals to stars, introduces the common conceptual and mathematical framework of all quantum theories, realistic enough to successfully confront Nature: Quantum Field Theory applied to the study of both dilute and condensed matter. In the dilute limit, quantum mechanics is shown to be a good approximation to Quantum Field Theory. Howe
Innovative quantum technologies for microgravity fundamental physics and biological research
Kierk, I. K.
2002-01-01
This paper presents a new technology program, within the fundamental physics, focusing on four quantum technology areas: quantum atomics, quantum optics, space superconductivity and quantum sensor technology, and quantum field based sensor and modeling technology.
Innovative quantum technologies for microgravity fundamental physics and biological research
Kierk, I. K.
2002-01-01
This paper presents a new technology program, within the fundamental physics, focusing on four quantum technology areas: quantum atomics, quantum optics, space superconductivity and quantum sensor technology, and quantum field based sensor and modeling technology.
Lucas, Andrew
2014-01-01
An elementary understanding of the relevant length, mass and energy scales at the molecular level can be used to explain the order of magnitude of material properties such as mass density, latent heat, surface tension, elastic moduli and beyond in an introductory physics course. These order of magnitude estimates are remarkably easy to derive, and in many instances are the same for many different liquids and solids. This helps students to understand the origin of the zoo of material properties, and to connect molecular physics to the physics of familiar materials like water, metals and plastics. We also note some simple mechanisms by which material properties can easily vary over many orders of magnitude.
Boundary Effects in Quantum Physics
Asorey, M
2013-01-01
We analyze the role of boundaries in the infrared behavior of quantum field theories. By means of a novel method we calculate the vacuum energy for a massless scalar field confined between two homogeneous parallel plates with the most general type of boundary properties. This allows the discrimination between boundary conditions which generate attractive or repulsive Casimir forces between the plates. In the interface between both regimes we find a very interesting family of boundary conditions which do not induce any type of Casimir force. We analyze the effect of the renormalization group flow on these boundary conditions. Even if the Casimirless conformal invariant conditions are physically unstable under renormalization group flow they emerge as a new set of conformally invariant boundary conditions which are anomaly free.
[Quantum physics, medicine and insurance].
Lambeck, M
2007-12-01
Medicine based on natural sciences explains the action of remedies by the chemical bonding of the molecules of the remedy and of the body. This bonding takes place at distances of about 10(-10) m. Several insurance companies pay all medical treatments listed in the Hufeland catalogue of special therapeutical methods. Many of these methods contradict the mechanism mentioned above: Homoeopathy and anthroposophical medicine use substances in which the remedy is not present as matter. Bioenergetic methods like electroacupuncture according to Voll (EAV) and bioresonance use the remedies not inside the body but outside of it. They claim to substitute the chemical bonding of matter waves with the information of electromagnetic waves. The explanation given in the Hufeland catalogue by means of quantum physics is discussed and further investigations are proposed.
Quantum Physics in One Dimension
Energy Technology Data Exchange (ETDEWEB)
Logan, David [University of Oxford (United Kingdom)
2004-05-14
To a casual ostrich the world of quantum physics in one dimension may sound a little one-dimensional, suitable perhaps for those with an unhealthy obsession for the esoteric. Nothing of course could be further from the truth. The field is remarkably rich and broad, and for more than fifty years has thrown up innumerable challenges. Theorists, realising that the role of interactions in 1D is special and that well known paradigms of higher dimensions (Fermi liquid theory for example) no longer apply, took up the challenge of developing new concepts and techniques to understand the undoubted peculiarities of one-dimensional systems. And experimentalists have succeeded in turning pipe dreams into reality, producing an impressive and ever increasing array of experimental realizations of 1D systems, from the molecular to the mesoscopic - spin and ladder compounds, organic superconductors, carbon nanotubes, quantum wires, Josephson junction arrays and so on. Many books on the theory of one-dimensional systems are however written by experts for experts, and tend as such to leave the non-specialist a touch bewildered. This is understandable on both fronts, for the underlying theoretical techniques are unquestionably sophisticated and not usually part of standard courses in many-body theory. A brave author it is then who aims to produce a well rounded, if necessarily partial, overview of quantum physics in one dimension, accessible to a beginner yet taking them to the edge of current research, and providing en route a thorough grounding in the fundamental ideas, basic methods and essential phenomenology of the field. It is of course the brave who succeed in this world, and Thierry Giamarchi does just that with this excellent book, written by an expert for the uninitiated. Aimed in particular at graduate students in theoretical condensed matter physics, and assuming little theoretical background on the part of the reader (well just a little), Giamarchi writes in a
A quantum physics poetry competition
Susanna Wong
2014-01-01
What do you think happened when six world-renowned poets from six European countries met eight famous CERN scientists to talk about the Universe and the Higgs boson? Six poems about new quantum physics discoveries were born from this exciting collision of literature and science in an intimate and spontaneous setting! Express yourself through poetry: this is the call from POPScience, a European Researchers' Night 2014-15 project supported by CERN. The general public can discover the mysteries of particle physics using a series of texts and thematic videos as well as clips of the meetings of the poets and CERN scientists available on the POPScience website. The Big Bang, an expanding Universe, dark energy, matter, antimatter and supersymmetry: what are they and do they exist? The general public is welcome to give an answer in a poem by signing up to the competition. Poems can be submitted in English, French, Italian, Danish and Spanish; the selected entries will be translated ...
Interference of macroscopic superpositions
Vecchi, I
2000-01-01
We propose a simple experimental procedure based on the Elitzur-Vaidman scheme to implement a quantum nondemolition measurement testing the persistence of macroscopic superpositions. We conjecture that its implementation will reveal the persistence of superpositions of macroscopic objects in the absence of a direct act of observation.
Entangled Systems New Directions in Quantum Physics
Audretsch, Jürgen
2007-01-01
An introductory textbook for advanced students of physics, chemistry and computer science, covering an area of physics that has lately witnessed rapid expansion. The topics treated here include quantum information, quantum communication, quantum computing, teleportation and hidden parameters, thus imparting not only a well-founded understanding of quantum theory as such, but also a solid basis of knowledge from which readers can follow the rapid development of the topic or delve deeper into a more specialized branch of research. Commented recommendations for further reading as well as end-of-chapter problems help the reader to quickly access the theoretical basics of future key technologies
Quantum coding theory with realistic physical constraints
Yoshida, Beni
2010-01-01
The following open problems, which concern a fundamental limit on coding properties of quantum codes with realistic physical constraints, are analyzed and partially answered here: (a) the upper bound on code distances of quantum error-correcting codes with geometrically local generators, (b) the feasibility of a self-correcting quantum memory. To investigate these problems, we study stabilizer codes supported by local interaction terms with translation and scale symmetries on a $D$-dimensional lattice. Our analysis uses the notion of topology emerging in geometric shapes of logical operators, which sheds a surprising new light on theory of quantum codes with physical constraints.
Development of quantum perspectives in modern physics
Charles Baily; Noah D. Finkelstein
2009-01-01
Introductory undergraduate courses in classical physics stress a perspective that can be characterized as realist; from this perspective, all physical properties of a classical system can be simultaneously specified and thus determined at all future times. Such a perspective can be problematic for introductory quantum physics students, who must develop new perspectives in order to properly interpret what it means to have knowledge of quantum systems. We document this evolution in student thin...
The emerging quantum the physics behind quantum mechanics
Pena, Luis de la; Valdes-Hernandez, Andrea
2014-01-01
This monograph presents the latest findings from a long-term research project intended to identify the physics behind Quantum Mechanics. A fundamental theory for quantum mechanics is constructed from first physical principles, revealing quantization as an emergent phenomenon arising from a deeper stochastic process. As such, it offers the vibrant community working on the foundations of quantum mechanics an alternative contribution open to discussion. The book starts with a critical summary of the main conceptual problems that still beset quantum mechanics. The basic consideration is then introduced that any material system is an open system in permanent contact with the random zero-point radiation field, with which it may reach a state of equilibrium. Working from this basis, a comprehensive and self-consistent theoretical framework is then developed. The pillars of the quantum-mechanical formalism are derived, as well as the radiative corrections of nonrelativistic QED, while revealing the underlying physi...
Macroscopicity of quantum superpositions on a one-parameter unitary path in Hilbert space
Volkoff, T. J.; Whaley, K. B.
2014-12-01
We analyze quantum states formed as superpositions of an initial pure product state and its image under local unitary evolution, using two measurement-based measures of superposition size: one based on the optimal quantum binary distinguishability of the branches of the superposition and another based on the ratio of the maximal quantum Fisher information of the superposition to that of its branches, i.e., the relative metrological usefulness of the superposition. A general formula for the effective sizes of these states according to the branch-distinguishability measure is obtained and applied to superposition states of N quantum harmonic oscillators composed of Gaussian branches. Considering optimal distinguishability of pure states on a time-evolution path leads naturally to a notion of distinguishability time that generalizes the well-known orthogonalization times of Mandelstam and Tamm and Margolus and Levitin. We further show that the distinguishability time provides a compact operational expression for the superposition size measure based on the relative quantum Fisher information. By restricting the maximization procedure in the definition of this measure to an appropriate algebra of observables, we show that the superposition size of, e.g., NOON states and hierarchical cat states, can scale linearly with the number of elementary particles comprising the superposition state, implying precision scaling inversely with the total number of photons when these states are employed as probes in quantum parameter estimation of a 1-local Hamiltonian in this algebra.
Lesovik, G B; Lebedev, A V; Sadovskyy, I A; Suslov, M V; Vinokur, V M
2016-09-12
Remarkable progress of quantum information theory (QIT) allowed to formulate mathematical theorems for conditions that data-transmitting or data-processing occurs with a non-negative entropy gain. However, relation of these results formulated in terms of entropy gain in quantum channels to temporal evolution of real physical systems is not thoroughly understood. Here we build on the mathematical formalism provided by QIT to formulate the quantum H-theorem in terms of physical observables. We discuss the manifestation of the second law of thermodynamics in quantum physics and uncover special situations where the second law can be violated. We further demonstrate that the typical evolution of energy-isolated quantum systems occurs with non-diminishing entropy.
Lesovik, G. B.; Lebedev, A. V.; Sadovskyy, I. A.; Suslov, M. V.; Vinokur, V. M.
2016-09-01
Remarkable progress of quantum information theory (QIT) allowed to formulate mathematical theorems for conditions that data-transmitting or data-processing occurs with a non-negative entropy gain. However, relation of these results formulated in terms of entropy gain in quantum channels to temporal evolution of real physical systems is not thoroughly understood. Here we build on the mathematical formalism provided by QIT to formulate the quantum H-theorem in terms of physical observables. We discuss the manifestation of the second law of thermodynamics in quantum physics and uncover special situations where the second law can be violated. We further demonstrate that the typical evolution of energy-isolated quantum systems occurs with non-diminishing entropy.
Quantum optics and frontiers of physics: the third quantum revolution
Celi, Alessio; Sanpera, Anna; Ahufinger, Veronica; Lewenstein, Maciej
2017-01-01
The year 2015 was the International Year of Light. However, it also marked, the 20th anniversary of the first observation of Bose-Einstein condensation in atomic vapors by Eric Cornell, Carl Wieman and Wolfgang Ketterle. This discovery could be considered as one of the greatest achievements of quantum optics that has triggered an avalanche of further seminal discoveries and achievements. For this reason we devote this essay for the focus issue on ‘Quantum Optics in the International Year of Light’ to the recent revolutionary developments in quantum optics at the frontiers of all physics: atomic physics, molecular physics, condensed matter physics, high energy physics and quantum information science. We follow here the lines of the introduction to our book ‘Ultracold atoms in optical lattices: Simulating quantum many-body systems’ (Lewenstein et al 2012 Ultracold Atoms in Optical Lattices: Simulating Quantum Many-body Systems (Oxford: University Press)), and to a lesser extent the review article M Lewenstein et al (2007 Adv. Phys. 56 243). The book, however, was published in 2012, and many things has happened since then—the present essay is therefore upgraded to include the latest developments.
An Introduction to Quantum Mechanics ... for those who dwell in the macroscopic world
Barletta, Antonio
2012-01-01
There is a huge number of excellent and comprehensive textbooks on quantum mechanics. They mainly differ for the approach, more or less oriented to the formalism rather than to the phenomenology, as well as for the topics covered. These lectures have been based mainly on the classical textbook by Gasiorowicz (1974). I must confess that the main reason for my choice of Gasiorowicz (1974) is affective, as it was the textbook were I first learned the basic principles of quantum mechanics. Beyond my personal taste, I now recognize that Gasiorowicz (1974) is still a very good textbook on quantum mechanics, with a rigorous theoretical approach accompanied by a wide collection of applications. If the textbook by Gasiorowicz was my main basis, I have taken much also from other textbooks such as Phillips (2003), as well as from the excellent classical textbook by Dirac (1981).
Physics: Quantum problems solved through games
Maniscalco, Sabrina
2016-04-01
Humans are better than computers at performing certain tasks because of their intuition and superior visual processing. Video games are now being used to channel these abilities to solve problems in quantum physics. See Letter p.210
Simulating Physical Phenomena by Quantum Networks
Somma, R D; Gubernatis, J E; Knill, E H; Laflamme, R
2002-01-01
Physical systems, characterized by an ensemble of interacting elementary constituents, can be represented and studied by different algebras of observables or operators. For example, a fully polarized electronic system can be investigated by means of the algebra generated by the usual fermionic creation and annihilation operators, or by using the algebra of Pauli (spin-1/2) operators. The correspondence between the two algebras is given by the Jordan-Wigner isomorphism. As we previously noted similar one-to-one mappings enable one to represent any physical system in a quantum computer. In this paper we evolve and exploit this fundamental concept in quantum information processing to simulate generic physical phenomena by quantum networks. We give quantum circuits useful for the efficient evaluation of the physical properties (e.g, spectrum of observables or relevant correlation functions) of an arbitrary system with Hamiltonian $H$.
Quantum Gravity: The View From Particle Physics
Nicolai, Hermann
This lecture reviews aspects of and prospects for progress towards a theory of quantum gravity from a particle physics perspective, also paying attention to recent findings of the LHC experiments at CERN.
Philosophy and logic of quantum physics
Dapprich, Jan Philipp
2015-01-01
The book investigates the ontology and logic of quantum physics. The first part discusses the relationship of theory and observation and different views on the ontological status of scientific theories. It introduces the fundamentals of quantum mechanics and some of its interpretations and their compatibility with various ontological positions. In the second part, implications of quantum mechanics on classical logic, especially on the distributive law and bivalence, as discussed by Garrett Birkhoff & John von Neumann (1936) and Hilary Putnam (1968), and their counterarguments are reconstructed and discussed. It is concluded that classical logic is sufficient for dealing with quantum mechanical propositions.
Quantum Physics in a different ontology
de Silva, Nalin
2010-01-01
It is shown that neither the wave picture nor the ordinary particle picture offers a satisfactory explanation of the double-slit experiment. The Physicists who have been successful in formulating theories in the Newtonian Paradigm with its corresponding ontology find it difficult to interpret Quantum Physics which deals with particles that are not sensory perceptible. A different interpretation of Quantum Physics based in a different ontology is presented in what follows. According to the new interpretation Quantum particles have different properties from those of Classical Newtonian particles. The interference patterns are explained in terms of particles each of which passes through both slits.
Quantum circuit physical design methodology with emphasis on physical synthesis
Mohammadzadeh, Naser; Saheb Zamani, Morteza; Sedighi, Mehdi
2013-11-01
In our previous works, we have introduced the concept of "physical synthesis" as a method to consider the mutual effects of quantum circuit synthesis and physical design. While physical synthesis can involve various techniques to improve the characteristics of the resulting quantum circuit, we have proposed two techniques (namely gate exchanging and auxiliary qubit selection) to demonstrate the effectiveness of the physical synthesis. However, the previous contributions focused mainly on the physical synthesis concept, and the techniques were proposed only as a proof of concept. In this paper, we propose a methodological framework for physical synthesis that involves all previously proposed techniques along with a newly introduced one (called auxiliary qubit insertion). We will show that the entire flow can be seen as one monolithic methodology. The proposed methodology is analyzed using a large set of benchmarks. Experimental results show that the proposed methodology decreases the average latency of quantum circuits by about 36.81 % for the attempted benchmarks.
2011-01-01
technological perspective, the most important quantum well is that that occurs in silicon MOSFETs ad- jacent to oxide interfaces. Because the barrier...harder to make. From the experimental (a) (b) Fig. 4.5.2 Energy band diagram and carrier profiles in the DGT ap- proximation for an n+-poly MOSFET ...device design using well-understood materials or predicting ultimate performance of some new material like graphene ). As a tactical choice for
Holism, Physical Theories and Quantum Mechanics
Seevinck, M P
2004-01-01
Motivated by the question what it is that makes quantum mechanics a holistic theory (if so), I try to define for general physical theories what we mean by `holism'. I propose an operational criterion to decide whether or not a physical theory is holistic, namely: a physical theory is holistic if and only if some determination (measurement) of the global properties in the theory which can be determined by global measurements, can not be implemented by local operations and classical communication. This approach is contrasted with the well known approaches to holism in terms of supervenience. I will argue that the latter have a limited scope and need to be extended using the criterion for holism proposed here in order to satisfactory address the issue for physical theories. I formalize this criterion for classical particle physics and Bohmian mechanics as represented on a Cartesian phase and configuration space, and for quantum mechanics (in the orthodox interpretation) using the formalism of general quantum ope...
Baladrón, Carlos; Khrennikov, Andrei
2016-12-01
The similarities between biological and physical systems as respectively defined in quantum information biology (QIB) and in a Darwinian approach to quantum mechanics (DAQM) have been analysed. In both theories the processing of information is a central feature characterising the systems. The analysis highlights a mutual support on the thesis contended by each theory. On the one hand, DAQM provides a physical basis that might explain the key role played by quantum information at the macroscopic level for bio-systems in QIB. On the other hand, QIB offers the possibility, acting as a macroscopic testing ground, to analyse the emergence of quantumness from classicality in the terms held by DAQM. As an added result of the comparison, a tentative definition of quantum information in terms of classical information flows has been proposed. The quantum formalism would appear from this comparative analysis between QIB and DAQM as an optimal information scheme that would maximise the stability of biological and physical systems at any scale.
1991-01-01
The following personnel have worked on the project A. Principal Investigators 1. Stephen D. Antolovich Fracture Mechanics analytical studies...Physical Processes of Crack Closure of Al-Li Alloy 2090," T.M. Breunig, S.R. Stock, S.D. Antolovich , J.H. Kinney, W.N. Massey and M.C. Nichols, to appear in...Relating Macroscopic Measures and Physical Processes of Crack Closure of Al-Li Alloy 2090," T.M. Breunig, S.R. Stock, S.D. Antolovich , J.H. Kinney, W.N
Classical approach in quantum physics
Solov'ev, Evgeni A
2010-01-01
The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom recently discovered with the help of Poincar$\\acute{\\mathrm{e}}$ section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treating as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semicla...
Quantum physics what everyone needs to know
Raymer, Michael G
2017-01-01
Around 1900, physicists started to discover particles like electrons, protons, and neutrons, and with these discoveries believed they could predict the internal behavior of the atom. However, once their predictions were compared to the results of experiments in the real world, it became clear that the principles of classical physics and mechanics were far from capable of explaining phenomena on the atomic scale. With this realization came the advent of quantum physics, one of the most important intellectual movements in human history. Today, quantum physics is everywhere: it explains how our computers work, how lasers transmit information across the Internet, and allows scientists to predict accurately the behavior of nearly every particle in nature. Its application continues to be fundamental in the investigation of the most expansive questions related to our world and the universe. However, while the field and principles of quantum physics are known to have nearly limitless applications, the fundamental rea...
Quantum enigma physics encounters consciousness
Rosenblum, Bruce
2012-01-01
Everyone knows that sub-atomic particles have some very strange qualities. Light sometimes behaves like a particle, sometimes like a wave. Objects separated by vast distances interact faster than the speed of light what Einstein called spooky action at a distance'. Most strangely, the behaviour of objects somehow seems to be determined in retrospect, depending on what the observer is looking for. In this ground-breaking work the authors show how these quantum properties are being observed in larger and larger objects. They set out carefully and cautiously exactly what quantum theory
The quantum world philosophical debates on quantum physics
Zwirn, Hervé
2017-01-01
In this largely nontechnical book, eminent physicists and philosophers address the philosophical impact of recent advances in quantum physics. These are shown to shed new light on profound questions about realism, determinism, causality or locality. The participants contribute in the spirit of an open and honest discussion, reminiscent of the time when science and philosophy were inseparable. After the editors’ introduction, the next chapter reveals the strangeness of quantum mechanics and the subsequent discussions examine our notion of reality. The spotlight is then turned to the topic of decoherence. Bohm’s theory is critically examined in two chapters, and the relational interpretation of quantum mechanics is likewise described and discussed. The penultimate chapter presents a proposal for resolving the measurement problem, and finally the topic of loop quantum gravity is presented by one of its founding fathers, Carlo Rovelli. The original presentations and discussions on which this volume is based t...
Quantum Entropy and Its Applications to Quantum Communication and Statistical Physics
Directory of Open Access Journals (Sweden)
Masanori Ohya
2010-05-01
Full Text Available Quantum entropy is a fundamental concept for quantum information recently developed in various directions. We will review the mathematical aspects of quantum entropy (entropies and discuss some applications to quantum communication, statistical physics. All topics taken here are somehow related to the quantum entropy that the present authors have been studied. Many other fields recently developed in quantum information theory, such as quantum algorithm, quantum teleportation, quantum cryptography, etc., are totally discussed in the book (reference number 60.
Directory of Open Access Journals (Sweden)
Eduardo Maurício Mendes de Lima
2009-06-01
Full Text Available The region of esophagus-gastric transition of equines was studied since distinct factors can cause injuries in this region as well as in the glandular region of the stomach of these animals. The objective of this work was to identify whether different types of physical and alimentary handling determine alterations in the macroscopic structure of the region of esophagus-gastric transition of the equines. We used 15 sets consisting of the regions of esophagus-gastric transition of adult equines whose race, sex and age were unidentified, divided into three groups in accordance with the diet and developed physical activity: Group I, five sets of equines in intensive training and fed mainly on the basis of concentrate; Group II, five sets of equines that did not engage in intense physical activity and were fed mainly on the basis of concentrate; and Group III with five sets of equines kept on pasture that did not engage in intense physical activity. The results showed that the staining of the mucosa, as well as the wall thickness of the region of transition, varied among groups. Gastric ulcers were found in all the groups studied, but most of them were identified in the transitions of the equines of Group II. The study concludes that no correlation existed between the macroscopic diet/physical activity and the presence of ulcers in the wall of esophagus-gastric transition of the equines.
Teaching Quantum Physics without Paradoxes
Hobson, Art
2007-01-01
Although the resolution to the wave-particle paradox has been known for 80 years, it is seldom presented. Briefly, the resolution is that material particles and photons are the quanta of extended spatially continuous but energetically quantized fields. But because the resolution resides in quantum field theory and is not usually spelled out in…
Teaching Quantum Physics without Paradoxes
Hobson, Art
2007-01-01
Although the resolution to the wave-particle paradox has been known for 80 years, it is seldom presented. Briefly, the resolution is that material particles and photons are the quanta of extended spatially continuous but energetically quantized fields. But because the resolution resides in quantum field theory and is not usually spelled out in…
Béné, G J; Bene, Gyula; Dieks, Dennis
2001-01-01
We study the process of observation (measurement), within the framework of a `perspectival' (`relational', `relative state') version of the modal interpretation of quantum mechanics. We show that if we assume certain features of discreteness and determinism in the operation of the measuring device (which could be a part of the observer's nerve system), this gives rise to classical characteristics of the observed properties, in the first place to spatial localization. We investigate to what extent semi-classical behavior of the object system itself (as opposed to the observational system) is needed for the emergence of classicality. Decoherence is an essential element in the mechanism of observation that we assume, but it turns out that in our approach no environment-induced decoherence on the level of the object system is required for the emergence of classical properties.
Directory of Open Access Journals (Sweden)
Antipov A.
2015-01-01
Full Text Available The nanostructures with different morphology have been obtained by us by methods of both direct laser modification (from cw to fs laser radiation of the target surface/thin films and laser evaporation of the target substance in liquid to produce the colloid systems, and then – to deposite substance on substrate from colloid, and also – by a single drop deposition technique. The analysis of induced nanostructures has been carried out by absorption spectroscopy, scanning electron microscopy and transmission electron microscopy. The island conductivity is dominant for the nanocluster semiconductor systems induced by laser ablation technique, and electroresistance can dramatically decrease due to spontaneous selected multichannel/parallel electron transportation trajectories. A tunneling quantum coherent effect takes place for electron conductivity for the case.
Energy Technology Data Exchange (ETDEWEB)
Rech, J
2006-06-15
It took several years after the idea of a zero-temperature phase transition emerged to realize the impact of such a quantum critical point over a large region of the phase diagram. Observed in many experimental examples, this quantum critical regime is not yet understood in details theoretically, and one needs to develop new approaches. In the first part, we focused on the ferromagnetic quantum critical point. After constructing a controlled approach allowing us to describe the quantum critical regime, we show through the computation of the static spin susceptibility that the ferromagnetic quantum critical point is unstable, destroyed internally by an effective dynamic long-range interaction generated by the Landau damping. In the second part, we revisit the exactly screened single impurity Kondo model, using a bosonic representation of the local spin and treating it in the limit of large spin degeneracy N. We show that, in this regime, the ground-state is a non-trivial Fermi liquid, unlike what was advocated by previous similar studies. We then extend our method to encompass the physics of two coupled impurities, for which our results are qualitatively comparable to the ones obtained from various approaches carried out in the past. We also develop a Luttinger-Ward formalism, enabling us to cure some of the drawbacks of the original method used to describe the single impurity physics. Finally, we present the main ideas and the first results for an extension of the method towards the description of a Kondo lattice, relevant for the understanding of the quantum critical regime of heavy fermion materials. (authors)
Beyond relativity and quantum mechanics: space physics
Lindner, Henry H.
2011-09-01
Albert Einstein imposed an observer-based epistemology upon physics. Relativity and Quantum Mechanics limit physics to describing and modeling the observer's sensations and measurements. Their "underlying reality" consists only of ideas that serve to model the observer's experience. These positivistic models cannot be used to form physical theories of Cosmic phenomena. To do this, we must again remove the observer from the center of physics. When we relate motion to Cosmic space instead of to observers and we attempt to explain the causes of Cosmic phenomena, we are forced to admit that Cosmic space is a substance. We need a new physics of space. We can begin by replacing Relativity with a modified Lorentzian-Newtonian model of spatial flow, and Quantum Mechanics with a wave-based theory of light and electrons. Space physics will require the reinterpretation of all known phenomena, concepts, and mathematical models.
Canonical quantization of macroscopic electromagnetism
Energy Technology Data Exchange (ETDEWEB)
Philbin, T G, E-mail: tgp3@st-andrews.ac.u [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)
2010-12-15
Application of the standard canonical quantization rules of quantum field theory to macroscopic electromagnetism has encountered obstacles due to material dispersion and absorption. This has led to a phenomenological approach to macroscopic quantum electrodynamics where no canonical formulation is attempted. In this paper macroscopic electromagnetism is canonically quantized. The results apply to any linear, inhomogeneous, magnetodielectric medium with dielectric functions that obey the Kramers-Kronig relations. The prescriptions of the phenomenological approach are derived from the canonical theory.
Canonical quantization of macroscopic electromagnetism
Philbin, T G
2010-01-01
Application of the standard canonical quantization rules of quantum field theory to macroscopic electromagnetism has encountered obstacles due to material dispersion and absorption. This has led to a phenomenological approach to macroscopic quantum electrodynamics where no canonical formulation is attempted. In this paper macroscopic electromagnetism is canonically quantized. The results apply to any linear, inhomogeneous, magnetoelectric medium with dielectric functions that obey the Kramers-Kronig relations. The prescriptions of the phenomenological approach are derived from the canonical theory.
Cosmic Censorship: the Role of Quantum Physics
Hod, Shahar
1999-01-01
The cosmic censorship hypothesis introduced by Penrose thirty years ago is still one of the most important open questions in {\\it classical} general relativity. The main goal of this paper is to put forward the idea that cosmic censorship is intrinsically a {\\it quantum} phenomena. We construct a gedanken experiment which seems to violate the cosmic censorship principle within the purely {\\it classical} framework of general relativity. We prove, however, that {\\it quantum} physics restores th...
Physical models of semiconductor quantum devices
Fu, Ying
2013-01-01
The science and technology relating to nanostructures continues to receive significant attention for its applications to various fields including microelectronics, nanophotonics, and biotechnology. This book describes the basic quantum mechanical principles underlining this fast developing field. From the fundamental principles of quantum mechanics to nanomaterial properties, from device physics to research and development of new systems, this title is aimed at undergraduates, graduates, postgraduates, and researchers.
Advanced Level Physics Students' Conceptions of Quantum Physics.
Mashhadi, Azam
This study addresses questions about particle physics that focus on the nature of electrons. Speculations as to whether they are more like particles or waves or like neither illustrate the difficulties with which students are confronted when trying to incorporate the concepts of quantum physics into their overall conceptual framework. Such…
Was Einstein Wrong on Quantum Physics?
Bhaumik, Mani
2015-01-01
Einstein is considered by many as the father of quantum physics in some sense. Yet there is an unshakable view that he was wrong on quantum physics. Although it may be a subject of considerable debate, the core of his allegedly wrong demurral was the insistence on finding an objective reality underlying the manifestly bizarre behavior of quantum objects. The uncanny wave-particle duality of a quantum particle is a prime example. In view of the latest developments, particularly in quantum field theory, objections of Einstein are substantially corroborated. Careful investigation suggests that a travelling quantum particle is a holistic wave packet consisting of an assemblage of irregular disturbances in quantum fields. It acts as a particle because only the totality of all the disturbances in the wave packet yields the energy momentum with the mass of a particle, along with its other conserved quantities such as charge and spin. Thus the wave function representing a particle is not just a fictitious mathematica...
Toward a physical theory of quantum cognition.
Takahashi, Taiki
2014-01-01
Recently, mathematical models based on quantum formalism have been developed in cognitive science. The target articles in this special issue of Topics in Cognitive Science clearly illustrate how quantum theoretical formalism can account for various aspects of human judgment and decision making in a quantitatively and mathematically rigorous manner. In this commentary, we show how future studies in quantum cognition and decision making should be developed to establish theoretical foundations based on physical theory, by introducing Taketani's three-stage theory of the development of science. Also, implications for neuroeconomics (another rapidly evolving approach to human judgment and decision making) are discussed.
Development of quantum perspectives in modern physics
Directory of Open Access Journals (Sweden)
Charles Baily
2009-03-01
Full Text Available Introductory undergraduate courses in classical physics stress a perspective that can be characterized as realist; from this perspective, all physical properties of a classical system can be simultaneously specified and thus determined at all future times. Such a perspective can be problematic for introductory quantum physics students, who must develop new perspectives in order to properly interpret what it means to have knowledge of quantum systems. We document this evolution in student thinking in part through pre- and post-instruction evaluations using the Colorado Learning Attitudes about Science Survey. We further characterize variations in student epistemic and ontological commitments by examining responses to two essay questions, coupled with responses to supplemental quantum attitude statements. We find that, after instruction in modern physics, many students are still exhibiting a realist perspective in contexts where a quantum-mechanical perspective is needed. We further find that this effect can be significantly influenced by instruction, where we observe variations for courses with differing learning goals. We also note that students generally do not employ either a realist or a quantum perspective in a consistent manner.
Raghavan, S.; Smerzi, A.; Fantoni, S.; Shenoy, S. R.
1999-01-01
We discuss the coherent atomic oscillations between two weakly coupled Bose-Einstein condensates. The weak link is provided by a laser barrier in a (possibly asymmetric) double-well trap or by Raman coupling between two condensates in different hyperfine levels. The boson Josephson junction (BJJ) dynamics is described by the two-mode nonlinear Gross-Pitaevskii equation that is solved analytically in terms of elliptic functions. The BJJ, being a neutral, isolated system, allows the investigations of dynamical regimes for the phase difference across the junction and for the population imbalance that are not accessible with superconductor Josephson junctions (SJJ's). These include oscillations with either or both of the following properties: (i) the time-averaged value of the phase is equal to π (π-phase oscillations); (ii) the average population imbalance is nonzero, in states with macroscopic quantum self-trapping. The (nonsinusoidal) generalization of the SJJ ac and plasma oscillations and the Shapiro resonance can also be observed. We predict the collapse of experimental data (corresponding to different trap geometries and the total number of condensate atoms) onto a single universal curve for the inverse period of oscillations. Analogies with Josephson oscillations between two weakly coupled reservoirs of 3He-B and the internal Josephson effect in 3He-A are also discussed.
Workshop on quantum stochastic differential equations for the quantum simulation of physical systems
2016-09-22
SECURITY CLASSIFICATION OF: This is a report on the “Workshop on quantum stochastic differential equations for the quantum simulation of physical ...mathematical tools to the quantum simulation of physical systems of interest to the Army. There were participants from US Government agencies, industry, and... quantum stochastic differential equations for the quantum simulation of physical systems Report Title This is a report on the “Workshop on quantum
Certified randomness in quantum physics.
Acín, Antonio; Masanes, Lluis
2016-12-07
The concept of randomness plays an important part in many disciplines. On the one hand, the question of whether random processes exist is fundamental for our understanding of nature. On the other, randomness is a resource for cryptography, algorithms and simulations. Standard methods for generating randomness rely on assumptions about the devices that are often not valid in practice. However, quantum technologies enable new methods for generating certified randomness, based on the violation of Bell inequalities. These methods are referred to as device-independent because they do not rely on any modelling of the devices. Here we review efforts to design device-independent randomness generators and the associated challenges.
Certified randomness in quantum physics
Acín, Antonio; Masanes, Lluis
2016-12-01
The concept of randomness plays an important part in many disciplines. On the one hand, the question of whether random processes exist is fundamental for our understanding of nature. On the other, randomness is a resource for cryptography, algorithms and simulations. Standard methods for generating randomness rely on assumptions about the devices that are often not valid in practice. However, quantum technologies enable new methods for generating certified randomness, based on the violation of Bell inequalities. These methods are referred to as device-independent because they do not rely on any modelling of the devices. Here we review efforts to design device-independent randomness generators and the associated challenges.
Nuclear Physics from Lattice Quantum Chromodynamics
Savage, Martin J
2015-01-01
Quantum Chromodynamics and Quantum Electrodynamics, both renormalizable quantum field theories with a small number of precisely constrained input parameters, dominate the dynamics of the quarks and gluons - the underlying building blocks of protons, neutrons, and nuclei. While the analytic techniques of quantum field theory have played a key role in understanding the dynamics of matter in high energy processes, they encounter difficulties when applied to low-energy nuclear structure and reactions, and dense systems. Expected increases in computational resources into the exascale during the next decade will provide the ability to determine a range of important strong interaction processes directly from QCD using the numerical technique of Lattice QCD. This will complement the nuclear physics experimental program, and in partnership with new thrusts in nuclear many-body theory, will enable unprecedented understanding and refinement of nuclear forces and, more generally, the visible matter in our universe. In th...
Quantum photonic network and physical layer security.
Sasaki, Masahide; Endo, Hiroyuki; Fujiwara, Mikio; Kitamura, Mitsuo; Ito, Toshiyuki; Shimizu, Ryosuke; Toyoshima, Morio
2017-08-06
Quantum communication and quantum cryptography are expected to enhance the transmission rate and the security (confidentiality of data transmission), respectively. We study a new scheme which can potentially bridge an intermediate region covered by these two schemes, which is referred to as quantum photonic network. The basic framework is information theoretically secure communications in a free space optical (FSO) wiretap channel, in which an eavesdropper has physically limited access to the main channel between the legitimate sender and receiver. We first review a theoretical framework to quantify the optimal balance of the transmission efficiency and the security level under power constraint and at finite code length. We then present experimental results on channel characterization based on 10 MHz on-off keying transmission in a 7.8 km terrestrial FSO wiretap channel.This article is part of the themed issue 'Quantum technology for the 21st century'. © 2017 The Author(s).
Quantum photonic network and physical layer security
Sasaki, Masahide; Endo, Hiroyuki; Fujiwara, Mikio; Kitamura, Mitsuo; Ito, Toshiyuki; Shimizu, Ryosuke; Toyoshima, Morio
2017-06-01
Quantum communication and quantum cryptography are expected to enhance the transmission rate and the security (confidentiality of data transmission), respectively. We study a new scheme which can potentially bridge an intermediate region covered by these two schemes, which is referred to as quantum photonic network. The basic framework is information theoretically secure communications in a free space optical (FSO) wiretap channel, in which an eavesdropper has physically limited access to the main channel between the legitimate sender and receiver. We first review a theoretical framework to quantify the optimal balance of the transmission efficiency and the security level under power constraint and at finite code length. We then present experimental results on channel characterization based on 10 MHz on-off keying transmission in a 7.8 km terrestrial FSO wiretap channel. This article is part of the themed issue 'Quantum technology for the 21st century'.
Embedded random matrix ensembles in quantum physics
Kota, V K B
2014-01-01
Although used with increasing frequency in many branches of physics, random matrix ensembles are not always sufficiently specific to account for important features of the physical system at hand. One refinement which retains the basic stochastic approach but allows for such features consists in the use of embedded ensembles. The present text is an exhaustive introduction to and survey of this important field. Starting with an easy-to-read introduction to general random matrix theory, the text then develops the necessary concepts from the beginning, accompanying the reader to the frontiers of present-day research. With some notable exceptions, to date these ensembles have primarily been applied in nuclear spectroscopy. A characteristic example is the use of a random two-body interaction in the framework of the nuclear shell model. Yet, topics in atomic physics, mesoscopic physics, quantum information science and statistical mechanics of isolated finite quantum systems can also be addressed using these ensemb...
Quantum Well Infrared Photodetectors Physics and Applications
Schneider, Harald
2007-01-01
Addressed to both students as a learning text and scientists/engineers as a reference, this book discusses the physics and applications of quantum-well infrared photodetectors (QWIPs). It is assumed that the reader has a basic background in quantum mechanics, solid-state physics, and semiconductor devices. To make this book as widely accessible as possible, the treatment and presentation of the materials is simple and straightforward. The topics for the book were chosen by the following criteria: they must be well-established and understood; and they should have been, or potentially will be, used in practical applications. The monograph discusses most aspects relevant for the field but omits, at the same time, detailed discussions of specialized topics such as the valence-band quantum wells.
The mathematical representation of physical objects and relativistic Quantum Mechanics
Romay, Enrique Ordaz
2004-01-01
The mathematical representation of the physical objects determines which mathematical branch will be applied during the physical analysis in the systems studied. The difference among non-quantum physics, like classic or relativistic physics, and quantum physics, especially in quantum field theory, is nothing else than the difference between the mathematics that is used on both branches of the physics. A common physical and mathematical origin for the analysis of the different systems brings b...
Parables of Physics and a Quantum Romance
Machacek, A. C.
2014-01-01
Teachers regularly use stories to amplify the concepts taught and to encourage student engagement. The literary form of a parable is particularly suitable for classroom use, and examples are given, including a longer one intended to stimulate discussion on the nature of quantum physics (and the wave-particle duality in particular).
Parables of physics and a quantum romance
Machacek, A. C.
2014-01-01
Teachers regularly use stories to amplify the concepts taught and to encourage student engagement. The literary form of a parable is particularly suitable for classroom use, and examples are given, including a longer one intended to stimulate discussion on the nature of quantum physics (and the wave-particle duality in particular).
Parables of Physics and a Quantum Romance
Machacek, A. C.
2014-01-01
Teachers regularly use stories to amplify the concepts taught and to encourage student engagement. The literary form of a parable is particularly suitable for classroom use, and examples are given, including a longer one intended to stimulate discussion on the nature of quantum physics (and the wave-particle duality in particular).
Holism, physical theories and quantum mechanics
Seevinck, M. P.
Motivated by the question what it is that makes quantum mechanics a holistic theory (if so), I try to define for general physical theories what we mean by `holism'. For this purpose I propose an epistemological criterion to decide whether or not a physical theory is holistic, namely: a physical theory is holistic if and only if it is impossible in principle to infer the global properties, as assigned in the theory, by local resources available to an agent. I propose that these resources include at least all local operations and classical communication. This approach is contrasted with the well-known approaches to holism in terms of supervenience. The criterion for holism proposed here involves a shift in emphasis from ontology to epistemology. I apply this epistemological criterion to classical physics and Bohmian mechanics as represented on a phase and configuration space respectively, and for quantum mechanics (in the orthodox interpretation) using the formalism of general quantum operations as completely positive trace non-increasing maps. Furthermore, I provide an interesting example from which one can conclude that quantum mechanics is holistic in the above mentioned sense, although, perhaps surprisingly, no entanglement is needed.
Mathematics of classical and quantum physics
Byron, Frederick W
Well-organized text designed to complement graduate-level physics texts in classical mechanics, electricity, magnetism, and quantum mechanics. Topics include theory of vector spaces, analytic function theory, Green's function method of solving differential and partial differential equations, theory of groups, more. Many problems, suggestions for further reading.
Summer Workshop on Physics, Mathematics, and All That Quantum Jazz
Bando, Masamitsu; Güngördü, Utkan; Physics, Mathematics, and All That Quantum Jazz
2014-01-01
This book is a collection of contributions from a Summer Workshop on Physics, Mathematics, and All That Quantum Jazz . Subjects of the symposium include quantum information theory, quantum annealing, Bose gases, and thermodynamics from a viewpoint of quantum physics. Contributions to this book are prepared in a self-contained manner so that readers with a modest background may understand the subjects.
Quantum physics reimagined for the general public
Bobroff, Julien
2015-03-01
Quantum Physics has always been a challenging issue for outreach. It is invisible, non-intuitive and written in sophisticated mathematics. In our ``Physics Reimagined'' research group, we explore new ways to present that field to the general public. Our approach is to develop close collaborations between physicists and designers or graphic artists. By developing this new kind of dialogue, we seek to find new ways to present complex phenomena and recent research topics to the public at large. For example, we created with web-illustrators a series of 3D animations about basic quantum laws and research topics (graphene, Bose-Einstein condensation, decoherence, pump-probe techniques, ARPES...). We collaborated with designers to develop original setups, from quantum wave animated models or foldings to a superconducting circus with levitating animals. With illustrators, we produced exhibits, comic strips or postcards displaying the physicists in their labs, either famous ones or even our own colleagues in their daily life as researchers. With artists, we recently made a stop-motion picture to explain in an esthetic way the process of discovery and scientific publication. We will discuss how these new types of outreach projects allowed us to engage the public with modern physics both on a scientific and cultural level and how the concepts and process can easily be replicated and expanded by other physicists. We are at the precise time when creative tools, interfaces, and ways of sharing and learning are rapidly evolving (wikipedia, MOOCs, smartphones...). If scientists don't step forward to employ these tools and develop new resources, other people will, and the integrity of the science and underlying character of research risks being compromised. All our productions are free to use and can be downloaded at www.PhysicsReimagined.com (for 3D quantum videos, specific link: www.QuantumMadeSimple.com) This work benefited from the support of the Chair ``Physics Reimagined
Physics of strained quantum well lasers
Loehr, John P
1998-01-01
When this publisher offered me the opportunity to \\\\Tite a book, some six years ago, I did not hesitate to say yes. I had just spent the last four years of graduate school struggling to understand the physics of strained quantum well lasers, and it seemed to me the whole experience was much more difficult that it should have been. For although many of the results I needed were easy to locate, the underlying physical premises and intervening steps were not. If only I had a book providing the derivations, I could have absorbed them and gone on my way. Such a book lies before you. It provides a unified and self-contained descrip tion of the essential physics of strained quantum well lasers, starting from first principles whenever feasible. The presentation I have chosen requires only the standard introductory background in quantum mechanics, solid state physics, and electromagnetics expected of entering graduate students in physics or elec trical engineering. A single undergraduate course in each of these su...
Theoretical physics 6 quantum mechanics : basics
Nolting, Wolfgang
2017-01-01
This textbook offers a clear and comprehensive introduction to the basics of quantum mechanics, one of the core components of undergraduate physics courses. It follows on naturally from the previous volumes in this series, thus developing the physical understanding further on to quantized states. The first part of the book introduces wave equations while exploring the Schrödinger equation and the hydrogen atom. More complex themes are covered in the second part of the book, which describes the Dirac formulism of quantum mechanics. Ideally suited to undergraduate students with some grounding in classical mechanics and electrodynamics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful German editions, the eight volumes of this...
The physical principles of the quantum theory
Heisenberg, Werner
1949-01-01
The contributions of few contemporary scientists have been as far reaching in their effects as those of Nobel Laureate Werner Heisenberg. His matrix theory is one of the bases of modern quantum mechanics, while his ""uncertainty principle"" has altered our whole philosophy of science.In this classic, based on lectures delivered at the University of Chicago, Heisenberg presents a complete physical picture of quantum theory. He covers not only his own contributions, but also those of Bohr, Dirac, Bose, de Broglie, Fermi, Einstein, Pauli, Schrodinger, Somerfield, Rupp, ·Wilson, Germer, and others
Quantum electronics for atomic physics and telecommunication
Nagourney, Warren G
2014-01-01
Nagourney provides a course in quantum electronics for researchers in atomic physics and other related areas (including telecommunications). The book covers the usual topics, such as Gaussian beams, optical cavities, lasers, non-linear optics, modulation techniques and fibre optics, but also includes a number of areas not usually found in a textbook on quantum electronics, such as the enhancement of non-linear processes in a build-up cavity or periodically poled waveguide, impedance matching into a cavity and astigmatism in ring cavities.
VANDENBERG, IP
1991-01-01
We present a mathematical model for the ''river-phenomenon'': striking concentrations of trajectories of ordinary differential equations. This model of ''macroscopic rivers'' is formulated within nonstandard analysis, and stated in terms of macroscopes and singular perturbations. For a subclass, the
Nonrelativistic quantum X-ray physics
Hau-Riege, Stefan P
2015-01-01
Providing a solid theoretical background in photon-matter interaction, Nonrelativistic Quantum X-Ray Physics enables readers to understand experiments performed at XFEL-facilities and x-ray synchrotrons. As a result, after reading this book, scientists and students will be able to outline and perform calculations of some important x-ray-matter interaction processes. Key features of the contents are that the scope reaches beyond the dipole approximation when necessary and that it includes short-pulse interactions. To aid the reader in this transition, some relevant examples are discussed in detail, while non-relativistic quantum electrodynamics help readers to obtain an in-depth understanding of the formalisms and processes. The text presupposes a basic (undergraduate-level) understanding of mechanics, electrodynamics, and quantum mechanics. However, more specialized concepts in these fields are introduced and the reader is directed to appropriate references. While primarily benefiting users of x-ray light-sou...
Hilbert Space Operators in Quantum Physics
Blank, Jiří; Havlíček, Miloslav
2008-01-01
The second edition of this course-tested book provides a detailed and in-depth discussion of the foundations of quantum theory as well as its applications to various systems. The exposition is self-contained; in the first part the reader finds the mathematical background in chapters about functional analysis, operators on Hilbert spaces and their spectral theory, as well as operator sets and algebras. This material is used in the second part to a systematic explanation of the foundations, in particular, states and observables, properties of canonical variables, time evolution, symmetries and various axiomatic approaches. In the third part, specific physical systems and situations are discussed. Two chapters analyze Schrödinger operators and scattering, two others added in the second edition are devoted to new important topics, quantum waveguides and quantum graphs. Some praise for the previous edition: "I really enjoyed reading this work. It is very well written, by three real experts in the field. It stands...
Quantum algorithms for computational nuclear physics
Directory of Open Access Journals (Sweden)
Višňák Jakub
2015-01-01
Full Text Available While quantum algorithms have been studied as an efficient tool for the stationary state energy determination in the case of molecular quantum systems, no similar study for analogical problems in computational nuclear physics (computation of energy levels of nuclei from empirical nucleon-nucleon or quark-quark potentials have been realized yet. Although the difference between the above mentioned studies might seem negligible, it will be examined. First steps towards a particular simulation (on classical computer of the Iterative Phase Estimation Algorithm for deuterium and tritium nuclei energy level computation will be carried out with the aim to prove algorithm feasibility (and extensibility to heavier nuclei for its possible practical realization on a real quantum computer.
Discovery Mondays: Quantum physics - incredible but true
2006-01-01
Physicists use two main theories to describe the world around us - the general theory of relativity to describe the infinitely large and quantum theory to describe the infinitesimally small, at the scale of the atom and its constituent parts. Quantum physics is as fascinating as it is bewildering. And yet it's used in many practical applications - medical imaging, lasers and computers, to name but a few. Over the course of the evening, you'll become acquainted with strange phenomena such as super-fluidity, teleportation and quantum cryptography. And through some amazing sleights-of-hand and experiments, you'll be taken on a journey into the mysteries of the infinitesimally small... The event will be conducted in French. Come to Microcosm, (Reception Building 33, Meyrin site), on Monday 3 July from 7.30 p.m. to 9.00 p.m. Entrance is free http://www.cern.ch/LundisDecouverte/
Fillaux, François; Cousson, Alain
2016-03-01
Neutron diffraction by single-crystals KH2(1- ρ)D2 ρ PO4 at 293 K reveal quantum interferences consistent with a static lattice of entangled proton-deuteron scatterers. These crystals are represented by a macroscopic-scale condensate of phonons with continuous space-time-translation symmetry and zero-entropy. This state is energetically favored and decoherence-free over a wide temperature-range. Projection of the crystal state onto a basis of four electrically- and isotopically-distinct state-vectors accounts for isotope and pressure effects on the temperature of the ferroelectric-dielectric transition, as well as for the latent heat. At the microscopic level, an incoming wave realizes a transitory state either in the space of static positional parameters (elastic scattering) or in that of the symmetry species (energy transfer). Neutron diffraction, vibrational spectroscopy, relaxometry and neutron Compton scattering support the conclusion that proton and deuteron scatterers are separable exclusively through resonant energy-transfer.
Qigong meets quantum physics experiencing cosmic oneness
Bock-Möbius, Imke
2012-01-01
Quantum physicists have reached a point commonly only attained by mystics: they understand something with amazing clarity yet can only talk about it in parables and metaphors. In this context, qigong with its Daoist background is a powerful way to integrate these apparently opposing ways of apperception and understanding. It allows us to realise cosmic oneness in the activities of daily life. This book succeeds in presenting both an easily accessible outline of quantum physics and also an appreciation of mysticism beyond vagueness and obscurity. From here it describes the physical and mental movements of qigong as a way of integrating body and mind, head and heart, detailing specific exercises and outlining their rationale and effects.
Relativity and quantum physics for beginners
Manly, Steven L
2009-01-01
As we humans have expanded our horizons to see things vastly smaller, faster, larger, and farther than ever before, we have been forced to confront preconceptions born of the human experience and create wholly new ways of looking at the world around us. The theories of relativity and quantum physics were developed out of this need and have provided us with phenomenal, mind-twisting insights into the strange and exciting reality show of our universe.Relativity and Quantum Physics For Beginners is an entertaining and accessible introduction to the bizarre concepts that fueled the scientific revolution of the 20th century and led to amazing advances in our understanding of the universe.
EPR Paradox, Quantum Nonlocality and Physical Reality
Kupczynski, Marian
2016-01-01
Eighty years ago Einstein demonstrated that a particular interpretation of the reduction of wave function led to a paradox and that this paradox disappeared if statistical interpretation of quantum mechanics was adopted. According to the statistical interpretation a wave function describes only an ensemble of identically prepared physical systems. Searching for an intuitive explanation of long range correlations between outcomes of distant measurements, performed on pairs of physical systems prepared in a spin singlet state, John Bell analysed local realistic hidden variable models and proved that correlations consistent with these models satisfy Bell inequalities which are violated by some predictions of quantum mechanics. Several different local models were constructed, various inequalities proven and shown to be violated by experimental data. Some physicists concluded that Nature is definitely not local. We strongly disagree with this conclusion and we critically analyze some influential finite sample proo...
Refined Characterization of Student Perspectives on Quantum Physics
Charles Baily; Noah D. Finkelstein
2011-01-01
The perspectives of introductory classical physics students can often negatively influence how those students later interpret quantum phenomena when taking an introductory course in modern physics. A detailed exploration of student perspectives on the interpretation of quantum physics is needed, both to characterize student understanding of physics concepts, and to inform how we might teach traditional content. Our previous investigations of student perspectives on quantum physics have indica...
Directory of Open Access Journals (Sweden)
U. V. S. Seshavatharam
2013-08-01
Full Text Available In this paper an attempt is made to emphasize the major shortcomings of standard cosmology. It can be suggested that, the current cosmological changes can be understood by studying the atom and the atomic nucleus through ground based experiments. If light is coming from the atoms of the gigantic galaxy, then redshift can be interpreted as an index of the galactic atomic ‘light emission mechanism’. In no way it seems to be connected with ‘galaxy receding’. With ‘cosmological increasing (emitted photon energy’, observed cosmic redshift can be considered as a measure of the age difference between our galaxy and any observed galaxy. If it is possible to show that, (from the observer older galaxy’s distance increases with its ‘age’, then ‘galaxy receding’ and ‘accelerating universe’ concepts can be put for a revision at fundamental level. At any given cosmic time, the product of ‘critical density’ and ‘Hubble volume’ gives a characteristic cosmic mass and it can be called as the ‘Hubble mass’. Interesting thing is that, Schwarzschild radius of the ‘Hubble mass’ again matches with the ‘Hubble length’. Most of the cosmologists believe that this is merely a coincidence. At any given cosmic time,’Hubble length’ can be considered as the gravitational or electromagnetic interaction range. If one is willing to think in this direction, by increasing the number of applications of Hubble mass and Hubble volume in other areas of fundamental physics like quantum physics, nuclear physics, atomic physics and particle physics - slowly and gradually - in a progressive way, concepts of ‘Black hole Cosmology’ can be strengthened and can also be confirmed.
Physics of Quantum Structures in Photovoltaic Devices
Raffaelle, Ryne P.; Andersen, John D.
2005-01-01
There has been considerable activity recently regarding the possibilities of using various nanostructures and nanomaterials to improve photovoltaic conversion of solar energy. Recent theoretical results indicate that dramatic improvements in device efficiency may be attainable through the use of three-dimensional arrays of zero-dimensional conductors (i.e., quantum dots) in an ordinary p-i-n solar cell structure. Quantum dots and other nanostructured materials may also prove to have some benefits in terms of temperature coefficients and radiation degradation associated with space solar cells. Two-dimensional semiconductor superlattices have already demonstrated some advantages in this regard. It has also recently been demonstrated that semiconducting quantum dots can also be used to improve conversion efficiencies in polymeric thin film solar cells. Improvement in thin film cells utilizing conjugated polymers has also be achieved through the use of one-dimensional quantum structures such as carbon nanotubes. It is believed that carbon nanotubes may contribute to both the disassociation as well as the carrier transport in the conjugated polymers used in certain thin film photovoltaic cells. In this paper we will review the underlying physics governing some of the new photovoltaic nanostructures being pursued, as well as the the current methods being employed to produce III-V, II-VI, and even chalcopyrite-based nanomaterials and nanostructures for solar cells.
Teaching Quantum Physics in Upper Secondary School in France:
Lautesse, Philippe; Vila Valls, Adrien; Ferlin, Fabrice; Héraud, Jean-Loup; Chabot, Hugues
2015-01-01
One of the main problems in trying to understand quantum physics is the nature of the referent of quantum theory. This point is addressed in the official French curriculum in upper secondary school. Starting in 2012, after about 20 years of absence, quantum physics has returned to the national program. On the basis of the historical construction…
Teaching Quantum Physics in Upper Secondary School in France:
Lautesse, Philippe; Vila Valls, Adrien; Ferlin, Fabrice; Héraud, Jean-Loup; Chabot, Hugues
2015-01-01
One of the main problems in trying to understand quantum physics is the nature of the referent of quantum theory. This point is addressed in the official French curriculum in upper secondary school. Starting in 2012, after about 20 years of absence, quantum physics has returned to the national program. On the basis of the historical construction…
Geometrical Lorentz Violation and Quantum Mechanical Physics
Mignani, R; Cardone, F
2013-01-01
On the basis of the results of some experiments dealing with the violation of Local Lorentz Invariance (LLI) and on the formalism of the Deformed Special Relativity (DSR), we examine the connections between the local geometrical structure of space-time and the foundation of Quantum Mechanics. We show that Quantum Mechanics, beside being an axiomatic theory, can be considered also a deductive physical theory, deducted from the primary physical principle of Relativistic Correlation. This principle is synonym of LLI and of a rigid and at minkowskian space-time. The results of the experiments mentioned above show the breakdown of LLI and hence the violation of the principle of Relativistic Correlation. The formalism of DSR allows to highlight the deep meaning of LLI breakdown in terms of the geometrical structure of local space-time which, far from being rigid and at, is deformed by the energy of the physical phenomena that take place and in this sense it has an active part in the dynamics of the whole physical p...
Quantum Dots: An Experiment for Physical or Materials Chemistry
Winkler, L. D.; Arceo, J. F.; Hughes, W. C.; DeGraff, B. A.; Augustine, B. H.
2005-01-01
An experiment is conducted for obtaining quantum dots for physical or materials chemistry. This experiment serves to both reinforce the basic concept of quantum confinement and providing a useful bridge between the molecular and solid-state world.
Measurement theory in local quantum physics
Energy Technology Data Exchange (ETDEWEB)
Okamura, Kazuya, E-mail: okamura@math.cm.is.nagoya-u.ac.jp; Ozawa, Masanao, E-mail: ozawa@is.nagoya-u.ac.jp [Graduate School of Information Science, Nagoya University, Chikusa-ku, Nagoya 464-8601 (Japan)
2016-01-15
In this paper, we aim to establish foundations of measurement theory in local quantum physics. For this purpose, we discuss a representation theory of completely positive (CP) instruments on arbitrary von Neumann algebras. We introduce a condition called the normal extension property (NEP) and establish a one-to-one correspondence between CP instruments with the NEP and statistical equivalence classes of measuring processes. We show that every CP instrument on an atomic von Neumann algebra has the NEP, extending the well-known result for type I factors. Moreover, we show that every CP instrument on an injective von Neumann algebra is approximated by CP instruments with the NEP. The concept of posterior states is also discussed to show that the NEP is equivalent to the existence of a strongly measurable family of posterior states for every normal state. Two examples of CP instruments without the NEP are obtained from this result. It is thus concluded that in local quantum physics not every CP instrument represents a measuring process, but in most of physically relevant cases every CP instrument can be realized by a measuring process within arbitrary error limits, as every approximately finite dimensional von Neumann algebra on a separable Hilbert space is injective. To conclude the paper, the concept of local measurement in algebraic quantum field theory is examined in our framework. In the setting of the Doplicher-Haag-Roberts and Doplicher-Roberts theory describing local excitations, we show that an instrument on a local algebra can be extended to a local instrument on the global algebra if and only if it is a CP instrument with the NEP, provided that the split property holds for the net of local algebras.
The Physics of Quantum Well Infrared Photodetectors
Choi, K K
1999-01-01
In the past, infrared imaging has been used exclusively for military applications. In fact, it can also be useful in a wide range of scientific and commercial applications. However, its wide spread use was impeded by the scarcity of the imaging systems and its high cost. Recently, there is an emerging infrared technology based on quantum well intersubband transition in III-V compound semiconductors. With the new technology, these impedances can be eliminated and a new era of infrared imaging is in sight. This book is designed to give a systematic description on the underlying physics of the ne
The Qubit as Key to Quantum Physics Part II: Physical Realizations and Applications
Dür, Wolfgang; Heusler, Stefan
2016-01-01
Using the simplest possible quantum system--the qubit--the fundamental concepts of quantum physics can be introduced. This highlights the common features of many different physical systems, and provides a unifying framework when teaching quantum physics at the high school or introductory level. In a previous "TPT" article and in a…
The Qubit as Key to Quantum Physics Part II: Physical Realizations and Applications
Dür, Wolfgang; Heusler, Stefan
2016-01-01
Using the simplest possible quantum system--the qubit--the fundamental concepts of quantum physics can be introduced. This highlights the common features of many different physical systems, and provides a unifying framework when teaching quantum physics at the high school or introductory level. In a previous "TPT" article and in a…
Baily, Charles; Finkelstein, Noah D.
2015-01-01
Most introductory quantum physics instructors would agree that transitioning students from classical to quantum thinking is an important learning goal, but may disagree on whether or how this can be accomplished. Although (and perhaps because) physicists have long debated the physical interpretation of quantum theory, many instructors choose to…
Baily, Charles; Finkelstein, Noah D.
2015-01-01
Most introductory quantum physics instructors would agree that transitioning students from classical to quantum thinking is an important learning goal, but may disagree on whether or how this can be accomplished. Although (and perhaps because) physicists have long debated the physical interpretation of quantum theory, many instructors choose to…
BOOK REVIEW: Quantum Physics in One Dimension
Logan, David
2004-05-01
To a casual ostrich the world of quantum physics in one dimension may sound a little one-dimensional, suitable perhaps for those with an unhealthy obsession for the esoteric. Nothing of course could be further from the truth. The field is remarkably rich and broad, and for more than fifty years has thrown up innumerable challenges. Theorists, realising that the role of interactions in 1D is special and that well known paradigms of higher dimensions (Fermi liquid theory for example) no longer apply, took up the challenge of developing new concepts and techniques to understand the undoubted pecularities of one-dimensional systems. And experimentalists have succeeded in turning pipe dreams into reality, producing an impressive and ever increasing array of experimental realizations of 1D systems, from the molecular to the mesoscopic---spin and ladder compounds, organic superconductors, carbon nanotubes, quantum wires, Josephson junction arrays and so on. Many books on the theory of one-dimensional systems are however written by experts for experts, and tend as such to leave the non-specialist a touch bewildered. This is understandable on both fronts, for the underlying theoretical techniques are unquestionably sophisticated and not usually part of standard courses in many-body theory. A brave author it is then who aims to produce a well rounded, if necessarily partial, overview of quantum physics in one dimension, accessible to a beginner yet taking them to the edge of current research, and providing en route a thorough grounding in the fundamental ideas, basic methods and essential phenomenology of the field. It is of course the brave who succeed in this world, and Thierry Giamarchi does just that with this excellent book, written by an expert for the uninitiated. Aimed in particular at graduate students in theoretical condensed matter physics, and assumimg little theoretical background on the part of the reader (well just a little), Giamarchi writes in a refreshingly
Fillaux, François
2011-01-01
The crystal of benzoic acid is comprised of tautomeric centrosymmetric dimers linked through bistable hydrogen bonds. Statistical disorder of the bonding protons is excluded by neutron diffraction from 6 K to 293 K. In addition to diffraction data, vibrational spectra and relaxation rates measured with solid-state-NMR and quasi-elastic neutron scattering are consistent with wave-like, rather than particle-like protons. We present a macroscopic-scale quantum theory for the bonding protons represented by a periodic lattice of fermions. The adiabatic separation, the exclusion principle, and the antisymmetry postulate yield a static lattice-state immune to decoherence. According to the theory of quantum measurements, vibrational spectroscopy and relaxometry involve realizations of decoherence-free Bloch states for nonlocal symmetry species that did not exist before the measurement. The eigen states are fully determined by three temperature-independent parameters which are effectively measured: the energy differen...
Refined Characterization of Student Perspectives on Quantum Physics
Baily, Charles; Finkelstein, Noah D.
2010-01-01
The perspectives of introductory classical physics students can often negatively influence how those students later interpret quantum phenomena when taking an introductory course in modern physics. A detailed exploration of student perspectives on the interpretation of quantum physics is needed, both to characterize student understanding of…
Designing Learning Environments to Teach Interactive Quantum Physics
Puente, Sonia M. Gomez; Swagten, Henk J. M.
2012-01-01
This study aims at describing and analysing systematically an interactive learning environment designed to teach Quantum Physics, a second-year physics course. The instructional design of Quantum Physics is a combination of interactive lectures (using audience response systems), tutorials and self-study in unit blocks, carried out with small…
Designing Learning Environments to Teach Interactive Quantum Physics
Puente, Sonia M. Gomez; Swagten, Henk J. M.
2012-01-01
This study aims at describing and analysing systematically an interactive learning environment designed to teach Quantum Physics, a second-year physics course. The instructional design of Quantum Physics is a combination of interactive lectures (using audience response systems), tutorials and self-study in unit blocks, carried out with small…
Refined Characterization of Student Perspectives on Quantum Physics
Baily, Charles; Finkelstein, Noah D.
2010-01-01
The perspectives of introductory classical physics students can often negatively influence how those students later interpret quantum phenomena when taking an introductory course in modern physics. A detailed exploration of student perspectives on the interpretation of quantum physics is needed, both to characterize student understanding of…
Teaching and understanding of quantum interpretations in modern physics courses
Noah D. Finkelstein; Charles Baily
2010-01-01
Just as expert physicists vary in their personal stances on interpretation in quantum mechanics, instructors vary on whether and how to teach interpretations of quantum phenomena in introductory modern physics courses. In this paper, we document variations in instructional approaches with respect to interpretation in two similar modern physics courses recently taught at the University of Colorado, and examine associated impacts on student perspectives regarding quantum physics. We find studen...
Photonic dark matter portal and quantum physics
Alavi, S A
2016-01-01
To identify the nature and properties of dark matter is one of the most serious open problems in modern physics. We study a model of dark matter in which the hidden sector interacts with ordinary matter (standard model particles) via photonic portal(hidden photonic portal). We search for the effects of this new interaction in quantum physics, therefore we study its effects on hydrogen atom because it is a simple and a well-studied quantum system so it can be considered as an outstanding test for dark matter signatures. Using the accuracy of the measurement of energy, we obtain an upper bound for the coupling constant of the model. We also calculate the contribution to the anomalous magnetic moment of muon due to the hidden photonic portal. At the moment there is a deviation between the standard model prediction for muon anomalous magnetic moment and its experimental value so the anomalous magnetic moment of muon can provide an important test of the standard model and the theories beyond it.
Atomic physics: A milestone in quantum computing
Bartlett, Stephen D.
2016-08-01
Quantum computers require many quantum bits to perform complex calculations, but devices with more than a few bits are difficult to program. A device based on five atomic quantum bits shows a way forward. See Letter p.63
Schuch, Dieter
2014-04-01
Theoretical physics seems to be in a kind of schizophrenic state. Many phenomena in the observable macroscopic world obey nonlinear evolution equations, whereas the microscopic world is governed by quantum mechanics, a fundamental theory that is supposedly linear. In order to combine these two worlds in a common formalism, at least one of them must sacrifice one of its dogmas. I claim that linearity in quantum mechanics is not as essential as it apparently seems since quantum mechanics can be reformulated in terms of nonlinear Riccati equations. In a first step, it will be shown where complex Riccati equations appear in time-dependent quantum mechanics and how they can be treated and compared with similar space-dependent Riccati equations in supersymmetric quantum mechanics. Furthermore, the time-independent Schrödinger equation can also be rewritten as a complex Riccati equation. Finally, it will be shown that (real and complex) Riccati equations also appear in many other fields of physics, like statistical thermodynamics and cosmology.
The Knight of the Quantum: On the Contribution of D.I. Blokhintsev to Quantum Physics
Kuzemsky, A. L.
2008-01-01
A concise survey of the contribution of D.I. Blokhintsev to the quantum physics, including solid state physics, physics of metals, surface physics, statistical physics and optics is given. These achievements have been considered in the context of modern development of these fields of physics.
Non-selfadjoint operators in quantum physics mathematical aspects
Gazeau, Jean Pierre; Szafraniec, Franciszek Hugon; Znojil, Miloslav
2015-01-01
A unique discussion of mathematical methods with applications to quantum mechanics Non-Selfadjoint Operators in Quantum Physics: Mathematical Aspects presents various mathematical constructions influenced by quantum mechanics and emphasizes the spectral theory of non-adjoint operators. Featuring coverage of functional analysis and algebraic methods in contemporary quantum physics, the book discusses recent emergence of the unboundedness of metric operators, which is a serious issue in the study of parity-time-symmetric quantum mechanics. The book also answers mathematical questions that are currently the subject of rigorous analysis, with potentially significant physical consequences. In addition to prompting a discussion of the role of mathematical methods in the contemporary development of quantum physics, the book features: * Chapter contributions written by well-known mathematical physicists who clarify numerous misunderstandings and misnomers while shedding light on new approaches in this growing area *...
Exceptional quantum geometry and particle physics
Dubois-Violette, Michel
2016-11-01
Based on an interpretation of the quark-lepton symmetry in terms of the unimodularity of the color group SU (3) and on the existence of 3 generations, we develop an argumentation suggesting that the "finite quantum space" corresponding to the exceptional real Jordan algebra of dimension 27 (the Euclidean Albert algebra) is relevant for the description of internal spaces in the theory of particles. In particular, the triality which corresponds to the 3 off-diagonal octonionic elements of the exceptional algebra is associated to the 3 generations of the Standard Model while the representation of the octonions as a complex 4-dimensional space C ⊕C3 is associated to the quark-lepton symmetry (one complex for the lepton and 3 for the corresponding quark). More generally it is suggested that the replacement of the algebra of real functions on spacetime by the algebra of functions on spacetime with values in a finite-dimensional Euclidean Jordan algebra which plays the role of "the algebra of real functions" on the corresponding almost classical quantum spacetime is relevant in particle physics. This leads us to study the theory of Jordan modules and to develop the differential calculus over Jordan algebras (i.e. to introduce the appropriate notion of differential forms). We formulate the corresponding definition of connections on Jordan modules.
Exceptional quantum geometry and particle physics
Directory of Open Access Journals (Sweden)
Michel Dubois-Violette
2016-11-01
Full Text Available Based on an interpretation of the quark–lepton symmetry in terms of the unimodularity of the color group SU(3 and on the existence of 3 generations, we develop an argumentation suggesting that the “finite quantum space” corresponding to the exceptional real Jordan algebra of dimension 27 (the Euclidean Albert algebra is relevant for the description of internal spaces in the theory of particles. In particular, the triality which corresponds to the 3 off-diagonal octonionic elements of the exceptional algebra is associated to the 3 generations of the Standard Model while the representation of the octonions as a complex 4-dimensional space C⊕C3 is associated to the quark–lepton symmetry (one complex for the lepton and 3 for the corresponding quark. More generally it is suggested that the replacement of the algebra of real functions on spacetime by the algebra of functions on spacetime with values in a finite-dimensional Euclidean Jordan algebra which plays the role of “the algebra of real functions” on the corresponding almost classical quantum spacetime is relevant in particle physics. This leads us to study the theory of Jordan modules and to develop the differential calculus over Jordan algebras (i.e. to introduce the appropriate notion of differential forms. We formulate the corresponding definition of connections on Jordan modules.
Kizilcik, Hasan Sahin; Yavas, Pervin Ünlü
2017-01-01
The aim of this study is to identify the opinions of pre-service physics teachers about the difficulties in introductory quantum physics topics. In this study conducted with twenty-five pre-service physics teachers, the case study method was used. The participants were interviewed about introductory quantum physics topics. The interviews were…
Quantum dynamics as a physical resource
Nielsen, M A; Dodd, J L; Gilchrist, A; Mortimer, D; Osborne, T J; Bremner, M J; Harrow, A W; Hines, A; Nielsen, Michael A.; Dawson, Christopher M.; Dodd, Jennifer L.; Gilchrist, Alexei; Mortimer, Duncan; Osborne, Tobias J.; Bremner, Michael J.; Harrow, Aram W.; Hines, Andrew
2003-01-01
How useful is a quantum dynamical operation for quantum information processing? Motivated by this question we investigate several strength measures quantifying the resources intrinsic to a quantum operation. We develop a general theory of such strength measures, based on axiomatic considerations independent of state-based resources. The power of this theory is demonstrated with applications to quantum communication complexity, quantum computational complexity, and entanglement generation by unitary operations.
Cognitive Mapping of Advanced Level Physics Students' Conceptions of Quantum Physics.
Mashhadi, Azam; Woolnough, Brian
This paper presents findings from a study that investigated students' understanding of quantum phenomena and focused on how students incorporate the ideas of quantum physics into their overall cognitive framework. The heuristic metaphor of the map is used to construct graphic representations of students' understanding of quantum physics. The…
Designing quantum information processing via structural physical approximation
Bae, Joonwoo
2017-10-01
In quantum information processing it may be possible to have efficient computation and secure communication beyond the limitations of classical systems. In a fundamental point of view, however, evolution of quantum systems by the laws of quantum mechanics is more restrictive than classical systems, identified to a specific form of dynamics, that is, unitary transformations and, consequently, positive and completely positive maps to subsystems. This also characterizes classes of disallowed transformations on quantum systems, among which positive but not completely maps are of particular interest as they characterize entangled states, a general resource in quantum information processing. Structural physical approximation offers a systematic way of approximating those non-physical maps, positive but not completely positive maps, with quantum channels. Since it has been proposed as a method of detecting entangled states, it has stimulated fundamental problems on classifications of positive maps and the structure of Hermitian operators and quantum states, as well as on quantum measurement such as quantum design in quantum information theory. It has developed efficient and feasible methods of directly detecting entangled states in practice, for which proof-of-principle experimental demonstrations have also been performed with photonic qubit states. Here, we present a comprehensive review on quantum information processing with structural physical approximations and the related progress. The review mainly focuses on properties of structural physical approximations and their applications toward practical information applications.
Quantum Chaos in Physical Systems: from Super Conductors to Quarks
Bittner, Elmar; Markum, Harald; Pullirsch, Rainer
2001-01-01
This article is the written version of a talk delivered at the Bexbach Colloquium of Science 2000 and starts with an introduction into quantum chaos and its relationship to classical chaos. The Bohigas-Giannoni-Schmit conjecture is formulated and evaluated within random-matrix theory. Several examples of physical systems exhibiting quantum chaos ranging from nuclear to solid state physics are presented. The presentation concludes with recent research work on quantum chromodynamics and the qua...
Process Physics From Quantum Foam to General Relativity
Cahill, R T
2002-01-01
Progress in the new information-theoretic process physics is reported in which the link to the phenomenology of general relativity is made. In process physics the fundamental assumption is that reality is to be modelled as self-organising semantic (or internal or relational) information using a self-referentially limited neural network model. Previous progress in process physics included the demonstration that space and quantum physics are emergent and unified, with time a distinct non-geometric process, that quantum phenomena are caused by fractal topological defects embedded in and forming a growing three-dimensional fractal process-space, which is essentially a quantum foam. Other features of the emergent physics were: quantum field theory with emergent flavour and confined colour, limited causality and the Born quantum measurement metarule, inertia, time-dilation effects, gravity and the equivalence principle, a growing universe with a cosmological constant, black holes and event horizons, and the emergen...
Wang, Hong-Fu; Zhu, Ai-Dong; Zhang, Shou
2013-05-20
We propose an efficient protocol for optimizing the physical implementation of three-qubit quantum error correction with spatially separated quantum dot spins via virtual-photon-induced process. In the protocol, each quantum dot is trapped in an individual cavity and each two cavities are connected by an optical fiber. We propose the optimal quantum circuits and describe the physical implementation for correcting both the bit flip and phase flip errors by applying a series of one-bit unitary rotation gates and two-bit quantum iSWAP gates that are produced by the long-range interaction between two distributed quantum dot spins mediated by the vacuum fields of the fiber and cavity. The protocol opens promising perspectives for long distance quantum communication and distributed quantum computation networks.
Exploring quantum physics through hands-on projects
Prutchi, David
2012-01-01
Build an intuitive understanding of the principles behind quantum mechanics through practical construction and replication of original experiments With easy-to-acquire, low-cost materials and basic knowledge of algebra and trigonometry, Exploring Quantum Physics through Hands-on Projects takes readers step by step through the process of re-creating scientific experiments that played an essential role in the creation and development of quantum mechanics. From simple measurements of Planck's constant to testing violations of Bell's inequalities using entangled photons, Exploring Quantum Physics through Hands-on Projects not only immerses readers in the process of quantum mechanics, it provides insight into the history of the field--how the theories and discoveries apply to our world not only today, but also tomorrow. By immersing readers in groundbreaking experiments that can be performed at home, school, or in the lab, this first-ever, hands-on book successfully demystifies the world of quantum physics for...
Hermann Weyl's Phenomenological Contribution to Quantum Physics
Mastrobisi, Giorgio J.
On examining carefully Weyl's writings one realizes that the great mathematician from Göttingen in his researches follows the programmatic scheme of the binomial of "wissenschaftliche Erkenntnis" (scientific Knowledge) and "philosophische Besinnung" (philosophical Reflection). In 1954 in a retrospective writing he affirmed: «The formulation of Einstein's Theory of Relativity and the Laws of Gravitation, valid in this context and corroborated by experimental proofs turning to experience, constitute a method which combines "Wesenanalyse" with "mathematische Konstruktion" of convincing and excellent exemplarity». This conviction has conducted him to a close collaboration with A. Einstein (documented by punctual correspondence) for the decisive formulation of the "General Theory of Relativity", but also of the Theory of unified Field of Gravitation and Electromagnetism and therefore the following formulation of some fundamental principles of Quantum Physics. So Weyl's theoretical formation was marked by the devotion toward a mathematical formalization ("mathematische Konstruktion") of physical phenomena, reporting each of them to the causal structure of the "mathematical thinking" and geometry, contemporarely to a strong inclination toward the phenomenological "Analysis of essence". He brings really a notable quantity of considerations in that 1954 essay by the point of view of the decisive role that the "pure Phenomenology" of Edmund Husserl developed in the determination of his scientific activity.
Links between quantum physics and thought.
Robson, Barry
2009-01-01
Quantum mechanics (QM) provides a variety of ideas that can assist in developing Artificial Intelligence for healthcare, and opens the possibility of developing a unified system of Best Practice for inference that will embrace both QM and classical inference. Of particular interest is inference in the hyperbolic-complex plane, the counterpart of the normal i-complex plane of basic QM. There are two reasons. First, QM appears to rotate from i-complex Hilbert space to hyperbolic-complex descriptions when observations are made on wave functions as particles, yielding classical results, and classical laws of probability manipulation (e.g. the law of composition of probabilities) then hold, whereas in the i-complex plane they do not. Second, i-complex Hilbert space is not the whole story in physics. Hyperbolic complex planes arise in extension from the Dirac-Clifford calculus to particle physics, in relativistic correction thereby, and in regard to spinors and twisters. Generalization of these forms resemble grammatical constructions and promote the idea that probability-weighted algebraic elements can be used to hold dimensions of syntactic and semantic meaning. It is also starting to look as though when a solution is reached by an inference system in the hyperbolic-complex, the hyperbolic-imaginary values disappear, while conversely hyperbolic-imaginary values are associated with the un-queried state of a system and goal seeking behavior.
Quantum entanglement in random physical states
Hamma, Alioscia; Zanardi, Paolo
2011-01-01
Most states in the Hilbert space are maximally entangled. This fact has proven useful to investigate - among other things - the foundations of statistical mechanics. Unfortunately, most states in the Hilbert space of a quantum many body system are not physically accessible. We define physical ensembles of states by acting on random factorized states by a circuit of length k of random and independent unitaries with local support. This simulates an evolution for finite time k generated by a local (time-dependent) Hamiltonian. We apply group theoretic methods to study these statistical ensemble. In particular, we study the typicality of entanglement by means of the purity of the reduced state. We find that for a time k=O(1) the typical purity obeys the area law, while for a time k \\sim O(L) the purity obeys a volume law, with L the linear size of the system. Moreover, we show that for large values of k the reduced state becomes very close to the completely mixed state.
Santos, Emilio
2012-01-01
It is stressed the advantage of a realistic interpretation of quantum mechanics providing a physical model of the quantum world. After some critical comments on the most popular interpretations, the difficulties for a model are pointed out and possible solutions proposed. In particular the existence of discrete states, the quantum jumps, the alleged lack of objective properties, measurement theory, the probabilistic character of quantum physics, the wave-particle duality and the Bell inequalities are commented. It is conjectured that an intuitive picture of the quantum world could be obtained compatible with the quantum predictions for actual experiments, although maybe incompatible with alleged predictions for ideal, unrealizable, experiments.
Design of Quantum Algorithms Using Physics Tools
2014-06-02
spin chains, the development of a novel quantum money scheme, a study of quantum interactive proof systems , research on Hamiltonians on graphs...in the Hamiltonians . The states of a quantum spin chain are naturally represented in the Matrix Product States (MPS) framework. Using imaginary time...worked on a wide range of topics with some common themes related by the study of quantum Hamiltonians . Ground state properties of Hamiltonians and the
Marochnik, Leonid; Vereshkov, Grigory
2008-01-01
We show that cosmological acceleration, Dark Energy (DE) effect is a consequence of the zero rest mass, conformal non-invariance of gravitons, and 1-loop finiteness of quantum gravity (QG). The effect is due to graviton-ghost condensates arising from the interference of quantum coherent states. The theory is constructed as follows: De Witt-Faddeev-Popov gauged path integral -> factorization of classical and quantum variables -> transition to the 1-loop approximation -> choice of ghost sector, satisfying 1-loop finiteness of the theory off the mass shell. The Bogolyubov-Born-Green-Kirckwood-Yvon (BBGKY) chain for the spectral function of gravitons renormalized by ghosts is used to build a theory of gravitons in the isotropic Universe. We found three exact solutions of the equations that describe virtual graviton and ghost condensates as well as condensates of instanton fluctuations. Exact solutions correspond to various condensates with different graviton-ghost compositions. The formalism of the BBGKY chain ta...
Refined Characterization of Student Perspectives on Quantum Physics
Baily, Charles
2011-01-01
The perspectives of introductory classical physics students can often negatively influence how those students later interpret quantum phenomena when taking an introductory course in modern physics. A detailed exploration of student perspectives on the interpretation of quantum physics is needed, both to characterize student understanding of physics concepts, and to inform how we might teach traditional content. Our previous investigations of student perspectives on quantum physics have indicated they can be highly nuanced, and may vary both within and across contexts. In order to better understand the contextual and often seemingly contradictory stances of students on matters of interpretation, we interviewed 19 students from four introductory modern physics courses taught at the University of Colorado. We find that students have attitudes and opinions that often parallel the stances of expert physicists when arguing for their favored interpretations of quantum mechanics, allowing for more nuanced characteriz...
Scattering and structures essentials and analogies in quantum physics
Povh, Bogdan
2017-01-01
Quantum physics may appear complicated, especially if one forgets the "big picture" and gets lost in the details. However, it can become clearer and less tangled if one applies a few fundamental concepts so that simplified approaches can emerge and estimated orders of magnitude become clear. Povh and Rosina’s Scattering and Structures presents the properties of quantum systems (elementary particles, nucleons, atoms, molecules, quantum gases, quantum liquids, stars, and early universe) with the help of elementary concepts and analogies between these seemingly different systems. In this new edition, sections on quantum gases and an up to date overview of elementary particles have been added.
Recovering the quantum formalism from physically realist axioms.
Auffèves, Alexia; Grangier, Philippe
2017-03-03
We present a heuristic derivation of Born's rule and unitary transforms in Quantum Mechanics, from a simple set of axioms built upon a physical phenomenology of quantization. This approach naturally leads to the usual quantum formalism, within a new realistic conceptual framework that is discussed in details. Physically, the structure of Quantum Mechanics appears as a result of the interplay between the quantized number of "modalities" accessible to a quantum system, and the continuum of "contexts" that are required to define these modalities. Mathematically, the Hilbert space structure appears as a consequence of a specific "extra-contextuality" of modalities, closely related to the hypothesis of Gleason's theorem, and consistent with its conclusions.
Quantum monadology: a consistent world model for consciousness and physics.
Nakagomi, Teruaki
2003-04-01
The NL world model presented in the previous paper is embodied by use of relativistic quantum mechanics, which reveals the significance of the reduction of quantum states and the relativity principle, and locates consciousness and the concept of flowing time consistently in physics. This model provides a consistent framework to solve apparent incompatibilities between consciousness (as our interior experience) and matter (as described by quantum mechanics and relativity theory). Does matter have an inside? What is the flowing time now? Does physics allow the indeterminism by volition? The problem of quantum measurement is also resolved in this model.
Open quantum physics and environmental heat conversion into usable energy
Stefanescu, Eliade
2014-01-01
A Quantum system can be viewed as a larger closed system comprising of two components: an open quantum system and its surrounding environment. These two components interact with each other, and in the realm of theoretical physics, this interaction cannot be neglected. This eBook A Quantum system can be viewed as a larger closed system comprising of two components: an open quantum system and its surrounding environment. These two components interact with each other, and in the realm of theoretical physics, this interaction cannot be neglected. This eBook explains mathematical and statistical co
Meixner, Uwe
2014-01-01
Quantum physics, unlike classical physics, suggests a non-physicalistic metaphysics. Whereas physicalism implies a reductive position in the philosophy of mind, quantum physics is compatible with non-reductionism, and actually seems to support it. The essays in this book explore, from various points of view, the possibilities of basing a non-reductive philosophy of mind on quantum physics.
Statistical thermodynamics understanding the properties of macroscopic systems
Fai, Lukong Cornelius
2012-01-01
Basic Principles of Statistical PhysicsMicroscopic and Macroscopic Description of StatesBasic PostulatesGibbs Ergodic AssumptionGibbsian EnsemblesExperimental Basis of Statistical MechanicsDefinition of Expectation ValuesErgodic Principle and Expectation ValuesProperties of Distribution FunctionRelative Fluctuation of an Additive Macroscopic ParameterLiouville TheoremGibbs Microcanonical EnsembleMicrocanonical Distribution in Quantum MechanicsDensity MatrixDensity Matrix in Energy RepresentationEntropyThermodynamic FunctionsTemperatureAdiabatic ProcessesPressureThermodynamic IdentityLaws of Th
Interpretive Themes in Quantum Physics: Curriculum Development and Outcomes
Baily, Charles
2011-01-01
A common learning goal for modern physics instructors is for students to recognize a difference between the experimental uncertainty of classical physics and the fundamental uncertainty of quantum mechanics. Our prior work has shown that student perspectives on the physical interpretation of quantum mechanics can be characterized, and are differentially influenced by the myriad ways instructors approach interpretive themes in their introductory courses. We report how a transformed modern physics curriculum (recently implemented at the University of Colorado) has positively impacted student perspectives on quantum physics, by making questions of classical and quantum reality a central theme of the course, but also by making the beliefs of students (and not just those of scientists) an explicit topic of discussion.
DEFF Research Database (Denmark)
Eitelberger, Johannes; Svensson, Staffan; Hofstetter, Karin
2011-01-01
The macroscopic formulation of moisture transport in wood below the fiber saturation point has motivated many research efforts in the past two decades. Many experiments demonstrated the difference in steady state and transient moisture transport and the inadequacy of models derived for steady state...
Inverse Problems in Classical and Quantum Physics
Almasy, Andrea A
2009-01-01
The subject of this thesis is in the area of Applied Mathematics known as Inverse Problems. Inverse problems are those where a set of measured data is analysed in order to get as much information as possible on a model which is assumed to represent a system in the real world. We study two inverse problems in the fields of classical and quantum physics: QCD condensates from tau-decay data and the inverse conductivity problem. We use a functional method which allows us to extract within rather general assumptions phenomenological parameters of QCD (the condensates) from a comparison of the time-like experimental data with asymptotic space-like results from theory. The price to be paid for the generality of assumptions is relatively large errors in the values of the extracted parameters. Although we do not claim that our method is superior to other approaches, we hope that our results lend additional confidence to the numerical results obtained with the help of methods based on QCD sum rules. In this thesis, als...
Are quantum-mechanical-like models possible, or necessary, outside quantum physics?
Plotnitsky, Arkady
2014-12-01
This article examines some experimental conditions that invite and possibly require recourse to quantum-mechanical-like mathematical models (QMLMs), models based on the key mathematical features of quantum mechanics, in scientific fields outside physics, such as biology, cognitive psychology, or economics. In particular, I consider whether the following two correlative features of quantum phenomena that were decisive for establishing the mathematical formalism of quantum mechanics play similarly important roles in QMLMs elsewhere. The first is the individuality and discreteness of quantum phenomena, and the second is the irreducibly probabilistic nature of our predictions concerning them, coupled to the particular character of the probabilities involved, as different from the character of probabilities found in classical physics. I also argue that these features could be interpreted in terms of a particular form of epistemology that suspends and even precludes a causal and, in the first place, realist description of quantum objects and processes. This epistemology limits the descriptive capacity of quantum theory to the description, classical in nature, of the observed quantum phenomena manifested in measuring instruments. Quantum mechanics itself only provides descriptions, probabilistic in nature, concerning numerical data pertaining to such phenomena, without offering a physical description of quantum objects and processes. While QMLMs share their use of the quantum-mechanical or analogous mathematical formalism, they may differ by the roles, if any, the two features in question play in them and by different ways of interpreting the phenomena they considered and this formalism itself. This article will address those differences as well.
Simulating Zeno physics by a quantum quench with superconducting circuits
Tong, Qing-Jun; An, Jun-Hong; Kwek, L. C.; Luo, Hong-Gang; Oh, C. H.
2014-06-01
Studying out-of-equilibrium physics in quantum systems under quantum quench is of vast experimental and theoretical interest. Using periodic quantum quenches, we present an experimentally accessible scheme to simulate the quantum Zeno and anti-Zeno effects in an open quantum system of a single superconducting qubit interacting with an array of transmission line resonators. The scheme is based on the following two observations: First, compared with conventional systems, the short-time nonexponential decay in our superconducting circuit system is readily observed; and second, a quench-off process mimics an ideal projective measurement when its time duration is sufficiently long. Our results show the active role of quantum quench in quantum simulation and control.
Critical Missing Equation of Quantum Physics for Understanding Atomic Structures
Huang, Xiaofei
2013-01-01
This paper presents an optimization approach to explain why and how a quantum system evolves from an arbitrary initial state to a stationary state, satisfying the time-independent Schr\\"{o}dinger equation. It also points out the inaccuracy of this equation, which is critial important in quantum mechanics and quantum chemistry, due to a fundamental flaw in it conflicting with the physical reality. The some directions are suggested on how to modify the equation to fix the problem
Critical Missing Equation of Quantum Physics for Understanding Atomic Structures
Huang, Xiaofei
2015-01-01
This paper presents an optimization approach to explain why and how a quantum system evolves from an arbitrary initial state to a stationary state, satisfying the time-independent Schr\\"{o}dinger equation. It also points out the inaccuracy of this equation, which is critial important in quantum mechanics and quantum chemistry, due to a fundamental flaw in it conflicting with the physical reality. The some directions are suggested on how to modify the equation to fix the problem
International Conference on Laser Physics and Quantum Optics
Xie, Shengwu; Zhu, Shi-Yao; Scully, Marlan
2000-01-01
Since the advent of the laser about 40 years ago, the field of laser physics and quantum optics have evolved into a major discipline. The early studies included the optical coherence theory and the semiclassical and quantum mechanical theories of the laser. More recently many new and interesting effects have been predicted. These include the role of coherent atomic effects in lasing without inversion and electromagnetically induced transparency, atom optics, laser cooling and trapping, teleportation, the single-atom micromaser and its role in quantum measurement theory, to name a few. The International Conference on Laser Physics and Quantum Optics was held in Shanghai from August 25 to August 28, 1999, to discuss these and many other exciting developments in laser physics and quantum optics. The international character of the conference was manifested by the fact that scientists from over 13 countries participated and lectured at the conference. There were four keynote lectures delivered by Nobel laureate Wi...
Compendium of quantum physics concepts, experiments, history and philosophy
Hentschel, Klaus; Weinert, Friedel
2009-01-01
With contributions by many of today's leading quantum physicists, philosophers and historians, including three Nobel laureates, this comprehensive A to Z of quantum physics provides a lucid understanding of the key concepts of quantum theory and experiment. It covers technical and interpretational aspects alike, and includes both traditional topics and newer areas such as quantum information and its relatives. The central concepts that have shaped contemporary understanding of the quantum world are clearly defined, with illustrations where helpful, and discussed at a level suitable for undergraduate and graduate students of physics, history of science, and philosophy of physics. All articles share three main aims: (1) to provide a clear definition and understanding of the term concerned; (2) where possible, to trace the historical origins of the concept; and (3) to provide a small but optimal selection of references to the most relevant literature, including pertinent historical studies. Also discussed are th...
Quantum-like behavior without quantum physics I : Kinematics of neural-like systems.
Selesnick, S A; Rawling, J P; Piccinini, Gualtiero
2017-07-13
Recently there has been much interest in the possible quantum-like behavior of the human brain in such functions as cognition, the mental lexicon, memory, etc., producing a vast literature. These studies are both empirical and theoretical, the tenets of the theory in question being mainly, and apparently inevitably, those of quantum physics itself, for lack of other arenas in which quantum-like properties are presumed to obtain. However, attempts to explain this behavior on the basis of actual quantum physics going on at the atomic or molecular level within some element of brain or neuronal anatomy (other than the ordinary quantum physics that underlies everything), do not seem to survive much scrutiny. Moreover, it has been found empirically that the usual physics-like Hilbert space model seems not to apply in detail to human cognition in the large. In this paper we lay the groundwork for a theory that might explain the provenance of quantum-like behavior in complex systems whose internal structure is essentially hidden or inaccessible. The approach is via the logic obeyed by these systems which is similar to, but not identical with, the logic obeyed by actual quantum systems. The results reveal certain effects in such systems which, though quantum-like, are not identical to the kinds of quantum effects found in physics. These effects increase with the size of the system.
Quantum simulations with photons and polaritons merging quantum optics with condensed matter physics
2017-01-01
This book reviews progress towards quantum simulators based on photonic and hybrid light-matter systems, covering theoretical proposals and recent experimental work. Quantum simulators are specially designed quantum computers. Their main aim is to simulate and understand complex and inaccessible quantum many-body phenomena found or predicted in condensed matter physics, materials science and exotic quantum field theories. Applications will include the engineering of smart materials, robust optical or electronic circuits, deciphering quantum chemistry and even the design of drugs. Technological developments in the fields of interfacing light and matter, especially in many-body quantum optics, have motivated recent proposals for quantum simulators based on strongly correlated photons and polaritons generated in hybrid light-matter systems. The latter have complementary strengths to cold atom and ion based simulators and they can probe for example out of equilibrium phenomena in a natural driven-dissipative sett...
The Second Law and Quantum Physics
Bennett, Charles H.
2008-08-01
In this talk, I discuss the mystery of the second law and its relation to quantum information. There are many explanations of the second law, mostly satisfactory and not mutually exclusive. Here, I advocate quantum mechanics and quantum information as something that, through entanglement, helps resolve the paradox or the puzzle of the origin of the second law. I will discuss the interpretation called quantum Darwinism and how it helps explain why our world seems so classical, and what it has to say about the permanence or transience of information. And I will discuss a simple model illustrating why systems away from thermal equilibrium tend to be more complicated.
Proof of Bekenstein-Mukhanov ansatz in loop quantum gravity
Majhi, Abhishek
2016-01-01
A simple proof of Bekenstein-Mukhanov(BM) ansatz is given within the loop quantum gravity(LQG) framework. The macroscopic area of an equilibrium black hole horizon indeed manifests a linear quantization. The quantum number responsible for this discreteness of the macroscopic area has a physical meaning in the LQG framework, unlike the ad hoc one that remained unexplained in BM ansatz.
Teaching and Understanding of Quantum Interpretations in Modern Physics Courses
Baily, Charles; Finkelstein, Noah D.
2010-01-01
Just as expert physicists vary in their personal stances on interpretation in quantum mechanics, instructors vary on whether and how to teach interpretations of quantum phenomena in introductory modern physics courses. In this paper, we document variations in instructional approaches with respect to interpretation in two similar modern physics…
How to teach quantum physics to your dog
Orzel, Chad
2010-01-01
In this international bestseller, Orzel explains the key theories of quantum physics, taking his dog Emmy's anarchic behaviour as a starting point. Could she use quantum tunnelling to get through the neighbour's fence? How about diffracting round a tree to chase squirrels? From quarks and gluons to Heisenberg's uncertainty principle, this is a uniquely entertaining way to unlock the secrets of the universe.
Teaching and Understanding of Quantum Interpretations in Modern Physics Courses
Baily, Charles; Finkelstein, Noah D.
2010-01-01
Just as expert physicists vary in their personal stances on interpretation in quantum mechanics, instructors vary on whether and how to teach interpretations of quantum phenomena in introductory modern physics courses. In this paper, we document variations in instructional approaches with respect to interpretation in two similar modern physics…
From Dualism to Unity in Quantum Physics
Landé, Alfred
2016-02-01
Preface; Introduction; 1. Causality, chance, continuity; 2. States, observables, probabilities; 3. The metric law of probabilities; 4. Quantum dynamics; 5. Quantum fact and fiction; Retrospect. From dualism to unity, from positivism to realism; Appendix 1. Survey of elementary postulates; Appendix 2. Two problems of uniqueness; References; Index.
Quantum physics: Photons paired with phonons
Blencowe, Miles
2016-02-01
The force exerted by light on an object has been used to pair photons with quantum units of mechanical vibration. This paves the way for mechanical oscillators to act as interfaces between photons and other quantum systems. See Letter p.313
Quantum Physics A First Encounter Interference, Entanglement, and Reality
Scarani, Valerio
2006-01-01
The essential features of quantum physics, largely debated since its discovery, are presented in this book, through the description (without mathematics) of recent experiments. Putting the accent on physical phenomena, this book clarifies the historical issues (delocalisation, interferences) and reaches out to modern topics (quantum cryptography, non-locality and teleportation); the debate on interpretations is serenely reviewed. - ;Quantum physics is often perceived as a weird and abstract theory, which physicists must use in order to make correct predictions. But many recent experiments have shown that the weirdness of the theory simply mirrors the weirdness of phenomena: it is Nature itself, and not only our description of it, that behaves in an astonishing way. This book selects those, among these typical quantum phenomena, whose rigorous description requires neither the formalism, nor an important. background in physics. The first part of the book deals with the phenomenon of single-particle interference...
Quantum potential physics, geometry and algebra
Licata, Ignazio
2014-01-01
Recently the interest in Bohm realist interpretation of quantum mechanics has grown. The important advantage of this approach lies in the possibility to introduce non-locality ab initio, and not as an “unexpected host”. In this book the authors give a detailed analysis of quantum potential, the non-locality term and its role in quantum cosmology and information. The different approaches to the quantum potential are analysed, starting from the original attempt to introduce a realism of particles trajectories (influenced by de Broglie’s pilot wave) to the recent dynamic interpretation provided by Goldstein, Durr, Tumulka and Zanghì, and the geometrodynamic picture, with suggestion about quantum gravity. Finally we focus on the algebraic reading of Hiley and Birkbeck school, that analyse the meaning of the non-local structure of the world, bringing important consequences for the space, time and information concepts.
International Conference on Quantum Mathematical Physics : a Bridge between Mathematics and Physics
Kleiner, Johannes; Röken, Christian; Tolksdorf, Jürgen
2016-01-01
Quantum physics has been highly successful for more than 90 years. Nevertheless, a rigorous construction of interacting quantum field theory is still missing. Moreover, it is still unclear how to combine quantum physics and general relativity in a unified physical theory. Attacking these challenging problems of contemporary physics requires highly advanced mathematical methods as well as radically new physical concepts. This book presents different physical ideas and mathematical approaches in this direction. It contains a carefully selected cross-section of lectures which took place in autumn 2014 at the sixth conference ``Quantum Mathematical Physics - A Bridge between Mathematics and Physics'' in Regensburg, Germany. In the tradition of the other proceedings covering this series of conferences, a special feature of this book is the exposition of a wide variety of approaches, with the intention to facilitate a comparison. The book is mainly addressed to mathematicians and physicists who are interested in fu...
Beyond Quantum Theory: A Realist Psychobiological Interpretation of Physical Reality
Conrad, Michael; Josephson, Brian
2016-01-01
Stapp and others have proposed that reality involves a fundamental life process, or creative process. It is shown how this process description may be unified with the description that derives from quantum physics. The methods of the quantum physicist and of the biological sciences are seen to be two alternative approaches to the understanding of nature, involving two distinct modes of description which can usefully supplement each other, and neither on its own contains the full story. The unified view explains the major features of quantum mechanics and suggests that biological systems may function more effectively than would be expected on the basis of quantum mechanics alone.
Chiao, R Y; Chiao, Raymond Y.; Fitelson, Walter J.
2006-01-01
Measurements of the tunneling time are briefly reviewed. Next, time and matter in general relativity and quantum mechanics is examined. In particular, the question arises: How does gravitational radiation interact with a coherent quantum many-body system (a ``quantum fluid'')? A minimal coupling rule for the coupling of the electron spin to curved spacetime in general relativity implies the possibility of a coupling between electromagnetic (EM) and gravitational (GR) radiation mediated by a quantum Hall fluid. This suggests that quantum transducers between these two kinds of radiation fields might exist. We report here on a first attempt at a Hertz-type experiment, in which a high-$\\rm{T_c}$ superconductor (YBCO) was the material used as a quantum transducer to convert EM into GR microwaves, and a second piece of YBCO in a separate apparatus was used to back-convert GR into EM microwaves. An upper limit on the conversion efficiency of YBCO was measured to be $1.6\\times10^{-5}$.
Computational physics simulation of classical and quantum systems
Scherer, Philipp O J
2017-01-01
This textbook presents basic numerical methods and applies them to a large variety of physical models in multiple computer experiments. Classical algorithms and more recent methods are explained. Partial differential equations are treated generally comparing important methods, and equations of motion are solved by a large number of simple as well as more sophisticated methods. Several modern algorithms for quantum wavepacket motion are compared. The first part of the book discusses the basic numerical methods, while the second part simulates classical and quantum systems. Simple but non-trivial examples from a broad range of physical topics offer readers insights into the numerical treatment but also the simulated problems. Rotational motion is studied in detail, as are simple quantum systems. A two-level system in an external field demonstrates elementary principles from quantum optics and simulation of a quantum bit. Principles of molecular dynamics are shown. Modern bounda ry element methods are presented ...
Quantum Chaos in Physical Systems from Super Conductors to Quarks
Bittner, E; Pullirsch, R; Bittner, Elmar; Markum, Harald; Pullirsch, Rainer
2001-01-01
This article is the written version of a talk delivered at the Bexbach Colloquium of Science 2000 and starts with an introduction into quantum chaos and its relationship to classical chaos. The Bohigas-Giannoni-Schmit conjecture is formulated and evaluated within random-matrix theory. Several examples of physical systems exhibiting quantum chaos ranging from nuclear to solid state physics are presented. The presentation concludes with recent research work on quantum chromodynamics and the quark-gluon plasma. In the case of a chemical potential the eigenvalue spectrum becomes complex and one has to deal with non-Hermitian random-matrix theory.
Transnational Quantum: Quantum Physics in India through the Lens of Satyendranath Bose
Banerjee, Somaditya
2016-08-01
This paper traces the social and cultural dimensions of quantum physics in colonial India where Satyendranath Bose worked. By focusing on Bose's approach towards the quantum and his collaboration with Albert Einstein, I argue that his physics displayed both the localities of doing science in early twentieth century India as well as a cosmopolitan dimension. He transformed the fundamental new concept of the light quantum developed by Einstein in 1905 within the social and political context of colonial India. This cross-pollination of the local with the global is termed here as the locally rooted cosmopolitan nature of Bose's science. The production of new knowledge through quantum statistics by Bose show the co-constructed nature of physics and the transnational nature of the quantum.
Senokos, E.; Reguero, V.; Palma, J.; Vilatela, J. J.; Marcilla, Rebeca
2016-02-01
In this work we present a combined electrochemical and mechanical study of mesoporous electrodes based on CNT fibres in the context of electric double layer capacitors. We show that through control of the synthetic and assembly processes of the fibres, it is possible to obtain an active material that combines a surface area of 250 m2 g-1, high electrical conductivity (3.5 × 105 S m-1) and mechanical properties in the high-performance range including toughness (35 J g-1) comparable to that of aramid fibre (e.g. Kevlar). These properties are a consequence of the predominant orientation of the CNTs, observed by wide- and small-angle X-ray diffraction, and to the exceptionally long CNT length on the millimetre scale. Cyclic voltammetry measurements in a three-electrode configuration and using 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR14TFSI) ionic liquid electrolyte, show that the CNT fibres have a large quantum capacitance, evidenced by the near linear dependence of geometric capacitance (and conductivity) on potential bias. This reflects the low dimensionality of the CNT building blocks, which were purposely synthesised to have 1-5 layers and a high degree of graphitization. From the charge-discharge measurements of supercapacitor devices with symmetric CNT fibre electrodes we obtain power and energy densities as high as 58 kW kg-1 and 14 Wh kg-1, respectively. These record-high values for CNT fibre-based supercapacitors, are a consequence of the low equivalent series resistance due to the high conductivity of the fibres, the large contribution from quantum capacitance, and the wide stability window of the ionic liquid (3.5 V). Cycle life experiments demonstrate stable capacitance and energy retention over 10 000 cycles of charge-discharge at 3.5 V.In this work we present a combined electrochemical and mechanical study of mesoporous electrodes based on CNT fibres in the context of electric double layer capacitors. We show that through
Quantum physics: Destruction of discrete charge
Nazarov, Yuli V.
2016-08-01
Electric charge is quantized in units of the electron's charge. An experiment explores the suppression of charge quantization caused by quantum fluctuations and supports a long-standing theory that explains this behaviour. See Letter p.58
Attention, Intention and Will in Quantum Physics
Stapp, Henry P
1999-01-01
The need for a self-observing quantum system to pose questions leads to a tripartite quantum process involving a Schroedinger process that is local deterministic, a Heisenberg process that poses the question, and a Dirac process that picks the answer. In the classical limit where Planck's constant is set to zero these three processes reduce to one single deterministic classical process: the fine structure wherein lies the effect of mind upon matter is obliterated.
Could nanostructure be unspeakable quantum system?
Aristov, V V
2010-01-01
Heisenberg, Bohr and others were forced to renounce on the description of the objective reality as the aim of physics because of the paradoxical quantum phenomena observed on the atomic level. The contemporary quantum mechanics created on the base of their positivism point of view must divide the world into speakable apparatus which amplifies microscopic events to macroscopic consequences and unspeakable quantum system. Examination of the quantum phenomena corroborates the confidence expressed by creators of quantum theory that the renunciation of realism should not apply on our everyday macroscopic world. Nanostructures may be considered for the present as a boundary of realistic description for all phenomena including the quantum one.
Refined characterization of student perspectives on quantum physics
Directory of Open Access Journals (Sweden)
Charles Baily
2010-09-01
Full Text Available The perspectives of introductory classical physics students can often negatively influence how those students later interpret quantum phenomena when taking an introductory course in modern physics. A detailed exploration of student perspectives on the interpretation of quantum physics is needed, both to characterize student understanding of physics concepts, and to inform how we might teach traditional content. Our previous investigations of student perspectives on quantum physics have indicated they can be highly nuanced, and may vary both within and across contexts. In order to better understand the contextual and often seemingly contradictory stances of students on matters of interpretation, we interviewed 19 students from four introductory modern physics courses taught at the University of Colorado. We find that students have attitudes and opinions that often parallel the stances of expert physicists when arguing for their favored interpretations of quantum mechanics, allowing for more nuanced characterizations of student perspectives in terms of three key interpretive themes. We present a framework for characterizing student perspectives on quantum mechanics, and demonstrate its utility in interpreting the sometimes contradictory nature of student responses to previous surveys. We further find that students most often vacillate in their responses when what makes intuitive sense to them is not in agreement with what they consider to be a correct response, underscoring the need to distinguish between the personal and the public perspectives of introductory modern physics students.
Physical quantities and dimensional analysis: from mechanics to quantum gravity
Trancanelli, Diego
2015-01-01
Physical quantities and physical dimensions are among the first concepts encountered by students in their undergraduate career. In this pedagogical review, I will start from these concepts and, using the powerful tool of dimensional analysis, I will embark in a journey through various branches of physics, from basic mechanics to quantum gravity. I will also discuss a little bit about the fundamental constants of Nature, the so-called "cube of Physics", and the natural system of units.
Macroscopic realism, wave-particle duality and the superposition principle for entangled states
Chuprikov, N L
2006-01-01
On the basis of our model of a one-dimensional (1D) completed scattering (Russian Physics, 49, p.119 and p.314 (2006)) we argue that the linear formalism of quantum mechanics (QM) respects the principles of the macroscopic realism (J. Phys.: Condens. Matter, 14, R415-R451 (2002)). In QM one has to distinguish two kinds of pure ensembles: pure unentangled ensembles to be macroscopically inseparable, and pure entangled ones to be macroscopically separable. A pure entangled ensemble is an intermediate link between a pure unentangled ensemble and classical mixture. Like the former it strictly respects the linear formalism of QM. Like the latter it is decomposable into macroscopically distinct subensembles, in spite of interference between them; our new model exemplifies how to perform such a decomposition in the case of a 1D completed scattering. To respect macroscopic realism, the superposition principle must be reformulated: it must forbid introducing observables for entangled states.
Nori, Franco
2012-02-01
This talk will present an overview of some of our recent results on atomic physics and quantum optics using superconducting circuits. Particular emphasis will be given to photons interacting with qubits, interferometry, the Dynamical Casimir effect, and also studying Majorana fermions using superconducting circuits.[4pt] References available online at our web site:[0pt] J.Q. You, Z.D. Wang, W. Zhang, F. Nori, Manipulating and probing Majorana fermions using superconducting circuits, (2011). Arxiv. J.R. Johansson, G. Johansson, C.M. Wilson, F. Nori, Dynamical Casimir effect in a superconducting coplanar waveguide, Phys. Rev. Lett. 103, 147003 (2009). [0pt] J.R. Johansson, G. Johansson, C.M. Wilson, F. Nori, Dynamical Casimir effect in superconducting microwave circuits, Phys. Rev. A 82, 052509 (2010). [0pt] C.M. Wilson, G. Johansson, A. Pourkabirian, J.R. Johansson, T. Duty, F. Nori, P. Delsing, Observation of the Dynamical Casimir Effect in a superconducting circuit. Nature, in press (Nov. 2011). P.D. Nation, J.R. Johansson, M.P. Blencowe, F. Nori, Stimulating uncertainty: Amplifying the quantum vacuum with superconducting circuits, Rev. Mod. Phys., in press (2011). [0pt] J.Q. You, F. Nori, Atomic physics and quantum optics using superconducting circuits, Nature 474, 589 (2011). [0pt] S.N. Shevchenko, S. Ashhab, F. Nori, Landau-Zener-Stuckelberg interferometry, Phys. Reports 492, 1 (2010). [0pt] I. Buluta, S. Ashhab, F. Nori. Natural and artificial atoms for quantum computation, Reports on Progress in Physics 74, 104401 (2011). [0pt] I.Buluta, F. Nori, Quantum Simulators, Science 326, 108 (2009). [0pt] L.F. Wei, K. Maruyama, X.B. Wang, J.Q. You, F. Nori, Testing quantum contextuality with macroscopic superconducting circuits, Phys. Rev. B 81, 174513 (2010). [0pt] J.Q. You, X.-F. Shi, X. Hu, F. Nori, Quantum emulation of a spin system with topologically protected ground states using superconducting quantum circuit, Phys. Rev. A 81, 063823 (2010).
Inverse problems in classical and quantum physics
Energy Technology Data Exchange (ETDEWEB)
Almasy, A.A.
2007-06-29
The subject of this thesis is in the area of Applied Mathematics known as Inverse Problems. Inverse problems are those where a set of measured data is analysed in order to get as much information as possible on a model which is assumed to represent a system in the real world. We study two inverse problems in the fields of classical and quantum physics: QCD condensates from tau-decay data and the inverse conductivity problem. Despite a concentrated effort by physicists extending over many years, an understanding of QCD from first principles continues to be elusive. Fortunately, data continues to appear which provide a rather direct probe of the inner workings of the strong interactions. We use a functional method which allows us to extract within rather general assumptions phenomenological parameters of QCD (the condensates) from a comparison of the time-like experimental data with asymptotic space-like results from theory. The price to be paid for the generality of assumptions is relatively large errors in the values of the extracted parameters. Although we do not claim that our method is superior to other approaches, we hope that our results lend additional confidence to the numerical results obtained with the help of methods based on QCD sum rules. EIT is a technology developed to image the electrical conductivity distribution of a conductive medium. The technique works by performing simultaneous measurements of direct or alternating electric currents and voltages on the boundary of an object. These are the data used by an image reconstruction algorithm to determine the electrical conductivity distribution within the object. In this thesis, two approaches of EIT image reconstruction are proposed. The first is based on reformulating the inverse problem in terms of integral equations. This method uses only a single set of measurements for the reconstruction. The second approach is an algorithm based on linearisation which uses more then one set of measurements. A
Reitz, Meredith; Stark, Colin; Hung, Chi-Yao; Smith, Breannan; Grinspin, Eitan; Capart, Herve; Li, Liming; Crone, Timothy; Hsu, Leslie; Ling, Hoe
2014-05-01
A complete theoretical understanding of geophysical granular flow is essential to the reliable assessment of landslide and debris flow hazard and for the design of mitigation strategies, but several key challenges remain. Perhaps the most basic is a general treatment of the processes of internal energy dissipation, which dictate the runout velocity and the shape and scale of the affected area. Currently, dissipation is best described by macroscopic, empirical friction coefficients only indirectly related to the grain-scale physics. Another challenge is describing the forces exerted at the boundaries of the flow, which dictate the entrainment of further debris and the erosion of cohesive surfaces. While the granular effects on these boundary forces have been shown to be large compared to predictions from continuum approximations, the link between granular effects and erosion or entrainment rates has not been settled. Here we present preliminary results of a multi-disciplinary study aimed at improving our understanding of granular flow energy dissipation and boundary forces, through an effort to connect grain-scale physics to macroscopic behaviors. Insights into grain-scale force distributions and energy dissipation mechanisms are derived from discrete contact-dynamics simulations. Macroscopic erosion and flow behaviors are documented from a series of granular flow experiments, in which a rotating drum half-filled with grains is placed within a centrifuge payload, in order to drive effective gravity levels up to ~100g and approach the forces present in natural systems. A continuum equation is used to characterize the flowing layer depth and velocity resulting from the force balance between the down-slope pull of gravity and the friction at the walls. In this presentation we will focus on the effect of granular-specific physics such as force chain networks and grain-grain collisions, derived from the contact dynamics simulations. We will describe our efforts to
Making the Transition from Classical to Quantum Physics
Dutt, Amit
2011-01-01
This paper reports on the nature of the conceptual understandings developed by Year 12 Victorian Certificate of Education (VCE) physics students as they made the transition from the essentially deterministic notions of classical physics, to interpretations characteristic of quantum theory. The research findings revealed the fact that the…
Pre-Service Physics Teachers' Comprehension of Quantum Mechanical Concepts
Didis, Nilufer; Eryilmaz, Ali; Erkoc, Sakir
2010-01-01
When quantum theory caused a paradigm shift in physics, it introduced difficulties in both learning and teaching of physics. Because of its abstract, counter-intuitive and mathematical structure, students have difficulty in learning this theory, and instructors have difficulty in teaching the concepts of the theory. This case study investigates…
Pre-Service Physics Teachers' Comprehension of Quantum Mechanical Concepts
Didis, Nilufer; Eryilmaz, Ali; Erkoc, Sakir
2010-01-01
When quantum theory caused a paradigm shift in physics, it introduced difficulties in both learning and teaching of physics. Because of its abstract, counter-intuitive and mathematical structure, students have difficulty in learning this theory, and instructors have difficulty in teaching the concepts of the theory. This case study investigates…
Making the Transition from Classical to Quantum Physics
Dutt, Amit
2011-01-01
This paper reports on the nature of the conceptual understandings developed by Year 12 Victorian Certificate of Education (VCE) physics students as they made the transition from the essentially deterministic notions of classical physics, to interpretations characteristic of quantum theory. The research findings revealed the fact that the…
50 quantum physics ideas you really need to know
Baker, Joanne
2013-01-01
Following on from the highly successful 50 Physics Ideas You Really Need to Know, author Joanne Baker consolidates the foundation concepts of physics and moves on to present clear explanations of the most cutting-edge area of science: quantum physics. With 50 concise chapters covering complex theories and their advanced applications - from string theory to black holes, and quarks to quantum computing - alongside informative two-colour illustrations, this book presents key ideas in straightforward, bite-sized chunks. Ideal for the layperson, this book will challenge the way you understand the world. The ideas explored include: Theory of relativity; Schrodinger's cat; Nuclear forces: fission and fusion; Antimatter; Superconductivity.
One hundred years of quantum physics.
Kleppner, D; Jackiw, R
2000-08-11
This year marks the 100th anniversary of Max Planck's creation of the quantum concept, an idea so revolutionary that it took nearly 30 years for scientists to develop it into the theory that has transformed the way scientists view reality. In this month's essay, Daniel Kleppner and Roman Jackiw recount how quantum theory, which they rate as "the most precisely tested and most successful theory in the history of science," came to be, how it changed the world, and how it might continue to evolve to make the dream of ultimate understanding of the universe come true.
The Two-Time Interpretation and Macroscopic Time-Reversibility
Directory of Open Access Journals (Sweden)
Yakir Aharonov
2017-03-01
Full Text Available The two-state vector formalism motivates a time-symmetric interpretation of quantum mechanics that entails a resolution of the measurement problem. We revisit a post-selection-assisted collapse model previously suggested by us, claiming that unlike the thermodynamic arrow of time, it can lead to reversible dynamics at the macroscopic level. In addition, the proposed scheme enables us to characterize the classical-quantum boundary. We discuss the limitations of this approach and its broad implications for other areas of physics.
On some links between quantum physics and gravitation
Ilyin, Aleksey V
2016-01-01
It is widely believed that quantum gravity effects are negligible in a conventional laboratory experiment because quantum gravity should play its role only at a distance of about Planck's length ($\\sim10^{-33}$ cm). Sometimes that is not the case as shown in this article. We discuss two new ideas about quantum physics connections with gravity. First, the Hong-Ou-Mandel effect relation to quantum gravity is examined. Second, it is shown that the very existence of gravitons is an inevitable consequence of quantum statistics. Moreover, since the Bose-Einstein statistics is a special case of Compound Poisson Distribution, it predicts the existence of an infinite family of high-spin massless particles that should be involved in gravitational interaction.
The Oxford Questions on the foundations of quantum physics.
Briggs, G A D; Butterfield, J N; Zeilinger, A
2013-09-08
The twentieth century saw two fundamental revolutions in physics-relativity and quantum. Daily use of these theories can numb the sense of wonder at their immense empirical success. Does their instrumental effectiveness stand on the rock of secure concepts or the sand of unresolved fundamentals? Does measuring a quantum system probe, or even create, reality or merely change belief? Must relativity and quantum theory just coexist or might we find a new theory which unifies the two? To bring such questions into sharper focus, we convened a conference on Quantum Physics and the Nature of Reality. Some issues remain as controversial as ever, but some are being nudged by theory's secret weapon of experiment.
Recovering the quantum formalism from physically realist axioms
Auffèves, Alexia; Grangier, Philippe
2017-01-01
We present a heuristic derivation of Born’s rule and unitary transforms in Quantum Mechanics, from a simple set of axioms built upon a physical phenomenology of quantization. This approach naturally leads to the usual quantum formalism, within a new realistic conceptual framework that is discussed in details. Physically, the structure of Quantum Mechanics appears as a result of the interplay between the quantized number of “modalities” accessible to a quantum system, and the continuum of “contexts” that are required to define these modalities. Mathematically, the Hilbert space structure appears as a consequence of a specific “extra-contextuality” of modalities, closely related to the hypothesis of Gleason’s theorem, and consistent with its conclusions. PMID:28256539
Scattering and Structures Essentials and Analogies in Quantum Physics
Povh, Bogdan
2005-01-01
Quantum physics may appear complicated, especially if one forgets the "big picture" and gets lost in the details. However, it can become clearer and less tangled if one applies a few fundamental concepts so that simplified approaches can emerge and estimated orders of magnitude become clear. Povh and Rosina’s "Scattering and Structures" presents the properties of quantum systems (elementary particles, nucleons, atoms, molecules, quantum gases, quantum liquids, stars, and early universe) with the help of elementary concepts and analogies between these seemingly different systems. The original German-language edition of this book was written for students preparing for their final oral examination in physics. By and large, the scope of the book in English has been essentially enlarged and thus will also be of interest for physicists in general.
Baily, Charles
2014-01-01
Most introductory quantum physics instructors would agree that transitioning students from classical to quantum thinking is an important learning goal, but may disagree on whether or how this can be accomplished. Although (and perhaps because) physicists have long debated the interpretation of quantum theory, many instructors choose to avoid emphasizing interpretive themes; or they discuss the views of scientists but do not adequately attend to student interpretations. This paper provides evidence-based arguments for an instructional approach that explicitly integrates the physical interpretation of quantum mechanics into introductory modern physics courses. In this synthesis and extension of prior work, we demonstrate: (1) instructors vary in their approaches to teaching interpretive themes; (2) specific instructional approaches can have significant impacts on student thinking; (3) when student interpretations go unattended, they often develop their own (sometimes scientifically undesirable) views; and (4) e...
Quantum physics and linguistics a compositional, diagrammatic discourse
Grefenstette, Edward; Heunen, Chris
2013-01-01
New scientific paradigms typically consist of an expansion of the conceptual language with which we describe the world. Over the past decade, theoretical physics and quantum information theory have turned to category theory to model and reason about quantum protocols. This new use of categorical and algebraic tools allows a more conceptual and insightful expression of elementary events such as measurements, teleportation and entanglement operations, that were obscured in previous formalisms.
Non-Commutative Geometry, Categories and Quantum Physics
Bertozzini, Paolo; Lewkeeratiyutkul, Wicharn
2008-01-01
After an introduction to some basic issues in non-commutative geometry (Gel'fand duality, spectral triples), we present a "panoramic view" of the status of our current research program on the use of categorical methods in the setting of A.Connes' non-commutative geometry: morphisms/categories of spectral triples, categorification of Gel'fand duality. We conclude with a summary of the expected applications of "categorical non-commutative geometry" to structural questions in relativistic quantum physics: (hyper)covariance, quantum space-time, (algebraic) quantum gravity.
On the Physical Explanation for Quantum Computational Speedup
Cuffaro, Michael E
2013-01-01
The aim of this dissertation is to clarify the debate over the explanation of quantum speedup and to submit a tentative resolution to it. In particular, I argue that the physical explanation for quantum speedup is precisely the fact that the phenomenon of quantum entanglement enables a quantum computer to fully exploit the representational capacity of Hilbert space. This is impossible for classical systems, joint states of which must always be representable as product states. Chapter 2 begins with a discussion of the most popular of the candidate physical explanations for quantum speedup: the many worlds explanation. I argue that unlike the neo-Everettian interpretation of quantum mechanics it does not have the conceptual resources required to overcome the `preferred basis objection'. I further argue that the many worlds explanation, at best, can serve as a good description of the physical process which takes place in so-called network-based computation, but that it is incompatible with other models of comput...
Understanding quantum physics; Verstehen in der Quantenphysik
Energy Technology Data Exchange (ETDEWEB)
Spillner, Vera
2011-07-01
This thesis presents a bundle definition for 'scientific understanding' through which the empirically equivalent interpretations of quantum mechanics can be evaluated with respect to the understanding they generate. The definition of understanding is based on a sufficient and necessary criterion, as well as a bundle of conditions - where a theory can be called most understandable whenever it fulfills the highest number of bundle criteria. Thereby the definition of understanding is based on the one hand on the objective number of criteria a theory fulfills, as well as, on the other hand, on the individual's preference of bundle criteria. Applying the definition onto three interpretations of quantum mechanics, the interpretation of David Bohm appears as most understandable, followed by the interpretation of Tim Maudlin and the Kopenhagen interpretation. These three interpretations are discussed in length in my thesis. (orig.)
Classical and quantum physics of hydrogen clusters.
Mezzacapo, Fabio; Boninsegni, Massimo
2009-04-22
We present results of a comprehensive theoretical investigation of the low temperature (T) properties of clusters of para-hydrogen (p-H(2)), both pristine as well as doped with isotopic impurities (i.e., ortho-deuterium, o-D(2)). We study clusters comprising up to N = 40 molecules, by means of quantum simulations based on the continuous-space Worm algorithm. Pristine p-H(2) clusters are liquid-like and superfluid in the [Formula: see text] limit. The superfluid signal is uniform throughout these clusters; it is underlain by long cycles of permutation of molecules. Clusters with more than 22 molecules display solid-like, essentially classical behavior at temperatures down to T∼1 K; some of them are seen to turn liquid-like at sufficiently low T (quantum melting).
Quark Confinement Physics from Quantum Chromodynamics
Suganuma, H; Tanaka, A; Ichie, H
2016-01-01
We show the construction of the dual superconducting theory for the confinement mechanism from QCD in the maximally abelian (MA) gauge using the lattice QCD Monte Carlo simulation. We find that essence of infrared abelian dominance is naturally understood with the off-diagonal gluon mass $m_{\\rm off} \\simeq 1.2 {\\rm GeV}$ induced by the MA gauge fixing. In the MA gauge, the off-diagonal gluon amplitude is forced to be small, and the off-diagonal gluon phase tends to be random. As the mathematical origin of abelian dominance for confinement, we demonstrate that the strong randomness of the off-diagonal gluon phase leads to abelian dominance for the string tension. In the MA gauge, there appears the macroscopic network of the monopole world-line covering the whole system. We investigate the monopole-current system in the MA gauge by analyzing the dual gluon field $B_\\mu$. We evaluate the dual gluon mass as $m_B = 0.4 \\sim$ 0.5GeV in the infrared region, which is the lattice-QCD evidence of the dual Higgs mechan...
Decision theory and information propagation in quantum physics
Forrester, Alan
In recent papers, Zurek [(2005). Probabilities from entanglement, Born's rule p k =| ψ k | 2 from entanglement. Physical Review A, 71, 052105] has objected to the decision-theoretic approach of Deutsch [(1999) Quantum theory of probability and decisions. Proceedings of the Royal Society of London A, 455, 3129-3137] and Wallace [(2003). Everettian rationality: defending Deutsch's approach to probability in the Everett interpretation. Studies in History and Philosophy of Modern Physics, 34, 415-438] to deriving the Born rule for quantum probabilities on the grounds that it courts circularity. Deutsch and Wallace assume that the many worlds theory is true and that decoherence gives rise to a preferred basis. However, decoherence arguments use the reduced density matrix, which relies upon the partial trace and hence upon the Born rule for its validity. Using the Heisenberg picture and quantum Darwinism-the notion that classical information is quantum information that can proliferate in the environment pioneered in Ollivier et al. [(2004). Objective properties from subjective quantum states: Environment as a witness. Physical Review Letters, 93, 220401 and (2005). Environment as a witness: Selective proliferation of information and emergence of objectivity in a quantum universe. Physical Review A, 72, 042113]-I show that measurement interactions between two systems only create correlations between a specific set of commuting observables of system 1 and a specific set of commuting observables of system 2. This argument picks out a unique basis in which information flows in the correlations between those sets of commuting observables. I then derive the Born rule for both pure and mixed states and answer some other criticisms of the decision theoretic approach to quantum probability.
Quantum Mechanics for Beginning Physics Students
Schneider, Mark B.
2010-01-01
The past two decades of attention to introductory physics education has emphasized enhanced development of conceptual understanding to accompany calculational ability. Given this, it is surprising that current texts continue to rely on the Bohr model to develop a flawed intuition, and introduce correct atomic physics on an ad hoc basis. For…
The role of quantum measurements in physical processes and protocols
Cruikshank, Benjamin; Jacobs, Kurt
2017-09-01
In this mainly pedagogical article, we discuss under what circumstances measurements play a special role in quantum processes. In particular, we discuss the following facts that appear to be a common area of confusion. (i) From a fundamental point of view, measurements play no special role whatsoever: all dynamics that can be generated by measurements can be generated by unitary processes (for which post-selection is no exception). (ii) From a purely physical point of view, measurements are not ‘outside’ of quantum mechanics. (iii) The only difference between the abilities of measurement-based protocols and unitary circuits for quantum computing comes from practical (technology dependent) constraints. We emphasise the importance of distinguishing between differences that are (i) fundamental but without physical import; (ii) fundamental and possess physical import; and (iii) are not fundamental but have practical import. We also emphasise the importance of separating theoretical and experimental elements of measurement, primarily projection and amplification, which are physically very different. Note that since we are concerned with facts regarding physical processes, this article has little if anything to do with interpretations of quantum mechanics.
The geometric phase in quantum physics
Energy Technology Data Exchange (ETDEWEB)
Bohm, A.
1993-03-01
After an explanatory introduction, a quantum system in a classical time-dependent environment is discussed; an example is a magnetic moment in a classical magnetic field. At first, the general abelian case is discussed in the adiabatic approximation. Then the geometric phase for nonadiabatic change of the environment (Anandan--Aharonov phase) is introduced, and after that general cyclic (nonadiabatic) evolution is discussed. The mathematics of fiber bundles is introduced, and some of its results are used to describe the relation between the adiabatic Berry phase and the geometric phase for general cyclic evolution of a pure state. The discussion is restricted to the abelian, U(1) phase.
The Oxford Questions on the foundations of quantum physics
Briggs, G. A. D.; Butterfield, J. N.; Zeilinger, A.
2013-01-01
The twentieth century saw two fundamental revolutions in physics—relativity and quantum. Daily use of these theories can numb the sense of wonder at their immense empirical success. Does their instrumental effectiveness stand on the rock of secure concepts or the sand of unresolved fundamentals? Does measuring a quantum system probe, or even create, reality or merely change belief? Must relativity and quantum theory just coexist or might we find a new theory which unifies the two? To bring such questions into sharper focus, we convened a conference on Quantum Physics and the Nature of Reality. Some issues remain as controversial as ever, but some are being nudged by theory's secret weapon of experiment. PMID:24062626
Hamiltonian and physical Hilbert space in polymer quantum mechanics
Corichi, A; Zapata, R J A; Corichi, Alejandro; Vukasinac, Tatjana; Zapata, Jose A.
2006-01-01
In this paper, a version of polymer quantum mechanics, which is inspired by loop quantum gravity, is considered and shown to be equivalent, in a precise sense, to the standard, experimentally tested, Schroedinger quantum mechanics. The kinematical cornerstone of our framework is the so called polymer representation of the Heisenberg-Weyl (H-W) algebra, which is the starting point of the construction. The dynamics is constructed as a continuum limit of effective theories characterized by a scale, and requires a renormalization of the inner product. The result is a physical Hilbert space in which the continuum Hamiltonian can be represented and that is unitarily equivalent to the Schroedinger representation of quantum mechanics. As a concrete implementation of our formalism, the simple harmonic oscillator is fully developed.
Physics Colloquium: The optical route to quantum information processing
Université de Genève
2011-01-01
Geneva University Physics Department 24, Quai Ernest Ansermet CH-1211 Geneva 4 Monday 11 April 2011 17h00 - Ecole de Physique, Auditoire Stückelberg The optical route to quantum information processing Prof. Terry Rudolph/Imperial College, London Photons are attractive as carriers of quantum information both because they travel, and can thus transmit information, but also because of their good coherence properties and ease in undergoing single-qubit manipulations. The main obstacle to their use in information processing is inducing an effective interaction between them in order to produce entanglement. The most promising approach in photon-based information processing architectures is so-called measurement-based quantum computing. This relies on creating upfront a multi-qubit highly entangled state (the cluster state) which has the remarkable property that, once prepared, it can be used to perform quantum computation by making only single qubit measurements. In this talk I will discuss generically the...
Principles of physics from quantum field theory to classical mechanics
Jun, Ni
2014-01-01
This book starts from a set of common basic principles to establish the formalisms in all areas of fundamental physics, including quantum field theory, quantum mechanics, statistical mechanics, thermodynamics, general relativity, electromagnetic field, and classical mechanics. Instead of the traditional pedagogic way, the author arranges the subjects and formalisms in a logical-sequential way, i.e. all the formulas are derived from the formulas before them. The formalisms are also kept self-contained. Most of the required mathematical tools are also given in the appendices. Although this book covers all the disciplines of fundamental physics, the book is concise and can be treated as an integrated entity. This is consistent with the aphorism that simplicity is beauty, unification is beauty, and thus physics is beauty. The book may be used as an advanced textbook by graduate students. It is also suitable for physicists who wish to have an overview of fundamental physics. Readership: This is an advanced gradua...
Relational time in quantum physics; Relationale Zeit in der Quantenphysik
Energy Technology Data Exchange (ETDEWEB)
Hoge, Marc Oliver
2008-12-15
In this diploma thesis a relational and intrinsic description of the external time parameter in non-relativistic quantum mechanics is given using two separate methods. Firstly, the dynamics of a system is expressed in terms of a collection of physical observables, so called ''clock'' variables, which are themselves part of the system. In particular it is studied how the position of one particle can be used as a ''clock'' for parameterising the motion of another particle. Secondly, a formal generalisation is developed which implements time as a physical observable into quantum mechanics. This leads to a formalism which is more general than the ''clock'' variable approach. Using this formalism a novel analysis of a particular problem in quantum cosmology is carried out. (orig.)
The infamous boundary seven decades of controversy in quantum physics
Wick, David
1995-01-01
reprinted in the British trade journal Physics World in 1990, three separate and 5 lengthy replies from establishment physicists were printed in subsequent issues. For outsiders, especially scientists who rely on physicist's theories in their own fields, this situation is disquieting. Moreover, many recall their introduction to quantum mechanics as a startling, if not shocking, experience. A molecular biologist related how he had started in theoretical physics but, after hearing the ideology of quantum mechanics, marched straight to the Reg istrar's office and switched fields. A colleague recalled how her undergraduate chemistry professor religiously entertained queries from the class - until one day he began with the words: "No questions will be permitted on today's lecture." The topic, of course, was quantum mechanics. My father, an organic chemist at a Midwestern university, also had to give that dreaded annual lecture. Around age 16, I picked up a little book he used to prepare and was perplexed by the ...
Theoretical physics 7 quantum mechanics : methods and applications
Nolting, Wolfgang
2017-01-01
This textbook offers a clear and comprehensive introduction to methods and applications in quantum mechanics, one of the core components of undergraduate physics courses. It follows on naturally from the previous volumes in this series, thus developing the understanding of quantized states further on. The first part of the book introduces the quantum theory of angular momentum and approximation methods. More complex themes are covered in the second part of the book, which describes multiple particle systems and scattering theory. Ideally suited to undergraduate students with some grounding in the basics of quantum mechanics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful German editions, the eight volumes of this seri...
Presenting particle physics and quantum mechanics to the general public
Strauss, J
2015-01-01
The job of a physicist is to describe Nature. General features, hypotheses and theories help to describe physics phenomena at a more abstract, fundamental level, and are sometimes tacitly assigned some sort of real existence; doing so appears to be of little harm in most of classical physics. However, missing any tangible connection to everyday experience, one better always bears in mind the descriptive nature of any efforts to grasp the quantum. And elementary particles interact in the quantum world, of course. When communicating the world of elementary particles to the general public, the Bayesian approach of an ever ongoing updating of the depiction of reality turns out to be virtually indispensable. The human experience of providing a series of increasingly better descriptions generates plenty of personal pleasures, for researchers as well as for amateurs. A suggestive analogy for improving our understanding of the world, even the seemingly paradoxical quantum world, may be found in recent insight into ho...
Macroscopic Quantum Coherence and Computing
2010-02-17
A. Gubrud, A. J. Berkley, J. R. Anderson, C. J. Lobb, and F. C. Wellstood, IEEE Trans AppI Supr 11,998 (2001) [2] J. M. Martinis, S. Nam, J. Aumentado...al., Phys. Rev. Lett. 87, 217003 (2001) [5] M. Savolainen, et. al., to be published in Appi . Phys. A (2004), cond-mat/031 1383 Modelling the current
Quantum Physics and Mental Health Counseling: The Time Is...!
Gerstein, Lawrence H.; Bennett, Matt
1999-01-01
Introduces a new framework of mental health counseling based on quantum physics. The framework stresses systemic thinking and intervention, interdependence, and the importance of adopting a novel perspective about time, space, reality, and change. This framework has the potential of modifying mental health counseling practice and training. Offers…
A Quantum Chemistry Concept Inventory for Physical Chemistry Classes
Dick-Perez, Marilu; Luxford, Cynthia J.; Windus, Theresa L.; Holme, Thomas
2016-01-01
A 14-item, multiple-choice diagnostic assessment tool, the quantum chemistry concept inventory or QCCI, is presented. Items were developed based on published student misconceptions and content coverage and then piloted and used in advanced physical chemistry undergraduate courses. In addition to the instrument itself, data from both a pretest,…
Electron-hole quantum physics in ZnO
Versteegh, M.A.M.
2011-01-01
This dissertation describes several new aspects of the quantum physics of electrons and holes in zinc oxide (ZnO), including a few possible applications. Zinc oxide is a II-VI semiconductor with a direct band gap in the ultraviolet. Experimental and theoretical studies have been performed, both on b
Electron-hole quantum physics in ZnO
Versteegh, M.A.M.
2011-01-01
This dissertation describes several new aspects of the quantum physics of electrons and holes in zinc oxide (ZnO), including a few possible applications. Zinc oxide is a II-VI semiconductor with a direct band gap in the ultraviolet. Experimental and theoretical studies have been performed, both on b
A Quantum Chemistry Concept Inventory for Physical Chemistry Classes
Dick-Perez, Marilu; Luxford, Cynthia J.; Windus, Theresa L.; Holme, Thomas
2016-01-01
A 14-item, multiple-choice diagnostic assessment tool, the quantum chemistry concept inventory or QCCI, is presented. Items were developed based on published student misconceptions and content coverage and then piloted and used in advanced physical chemistry undergraduate courses. In addition to the instrument itself, data from both a pretest,…
Exceptional quantum geometry and particle physics
Dubois-Violette, Michel
2016-01-01
Based on an interpretation of the quark-lepton symmetry in terms of the unimodularity of the color group $SU(3)$ and on the existence of 3 generations, we develop an argumentation suggesting that the "finite quantum space" corresponding to the exceptional real Jordan algebra of dimension 27 (the Euclidean Albert algebra) is relevant for the description of internal spaces in the theory of particles. In particular, the triality which corresponds to the 3 off-diagonal octonionic elements of the exceptional algebra is associated to the 3 generations of the Standard Model while the representation of the octonions as a complex 4-dimensional space $\\mathbb C\\oplus\\mathbb C^3$ is associated to the quark-lepton symmetry, (one complex for the lepton and 3 for the corresponding quark). More generally it is is suggested that the replacement of the algebra of real functions on spacetime by the algebra of functions on spacetime with values in a finite-dimensional Euclidean Jordan algebra which plays the role of "the algebr...
The pivotal role of causality in local quantum physics
Energy Technology Data Exchange (ETDEWEB)
Schroer, Bert [Freie Univ. Berlin (Germany). Inst. fuer Theoretische Physik
1999-04-01
In this article an attempt is made to present very recent conceptual and computational developments in QFT as new manifestation of old well established physical principles. The vehicle for converting the quantum-algebraic aspects of local quantum physics into more classical geometric structures is the modular theory of Tomita. As the above named laureate together with his collaborator showed for the first time, in sufficient generality, its use in physics goes through Einstein causality. This line of research recently gained momentum when it was realized that it is not only of great structural and conceptual innovative power (see section 4), but also promises a new computational road into nonperturbative QFT (section 5) which, picturesquely speaking, enters the subject on the extreme opposite (noncommutative) side relative to (Lagrangian) quantization. (author)
Bao, Lei; Redish, Edward F.
2002-01-01
Explains the critical role of probability in making sense of quantum physics and addresses the difficulties science and engineering undergraduates experience in helping students build a model of how to think about probability in physical systems. (Contains 17 references.) (Author/YDS)
Large numbers hypothesis. IV - The cosmological constant and quantum physics
Adams, P. J.
1983-01-01
In standard physics quantum field theory is based on a flat vacuum space-time. This quantum field theory predicts a nonzero cosmological constant. Hence the gravitational field equations do not admit a flat vacuum space-time. This dilemma is resolved using the units covariant gravitational field equations. This paper shows that the field equations admit a flat vacuum space-time with nonzero cosmological constant if and only if the canonical LNH is valid. This allows an interpretation of the LNH phenomena in terms of a time-dependent vacuum state. If this is correct then the cosmological constant must be positive.
Thirty years that shook physics the story of quantum theory
Gamow, George A
1966-01-01
""Dr. Gamow, physicist and gifted writer, has sketched an intriguing portrait of the scientists and clashing ideas that made the quantum revolution."" - Christian Science MonitorIn 1900, German physicist Max Planck postulated that light, or radiant energy, can exist only in the form of discrete packages or quanta. This profound insight, along with Einstein's equally momentous theories of relativity, completely revolutionized man's view of matter, energy, and the nature of physics itself.In this lucid layman's introduction to quantum theory, an eminent physicist and noted popularizer of scien
Large numbers hypothesis. IV - The cosmological constant and quantum physics
Adams, P. J.
1983-01-01
In standard physics quantum field theory is based on a flat vacuum space-time. This quantum field theory predicts a nonzero cosmological constant. Hence the gravitational field equations do not admit a flat vacuum space-time. This dilemma is resolved using the units covariant gravitational field equations. This paper shows that the field equations admit a flat vacuum space-time with nonzero cosmological constant if and only if the canonical LNH is valid. This allows an interpretation of the LNH phenomena in terms of a time-dependent vacuum state. If this is correct then the cosmological constant must be positive.
Photon physics: from wave mechanics to quantum electrodynamics
Keller, Ole
2009-05-01
When rewritten in an appropriate manner, the microscopic Maxwell-Lorentz equations appear as a wave-mechanical theory for photons, and their quantum physical interaction with matter. A natural extension leads from photon wave mechanics to quantum electrodynamics (QED). In its modern formulation photon wave mechanics has given us valuable new insight in subjects such as spatial photon localization, near-field photon dynamics, transverse photon mass, photon eikonal theory, photon tunneling, and rim-zone electrodynamics. The present review is based on my plenary lecture at the SPIE-Europe 2009 Optics and Optoelectronics International Symposium in Prague.
Thirty years that shook physics the story of quantum theory
Gamow, George
1985-01-01
""Dr. Gamow, physicist and gifted writer, has sketched an intriguing portrait of the scientists and clashing ideas that made the quantum revolution."" - Christian Science MonitorIn 1900, German physicist Max Planck postulated that light, or radiant energy, can exist only in the form of discrete packages or quanta. This profound insight, along with Einstein's equally momentous theories of relativity, completely revolutionized man's view of matter, energy, and the nature of physics itself.In this lucid layman's introduction to quantum theory, an eminent physicist and noted popularizer of scien
Foundations of quantum mechanics an exploration of the physical meaning of quantum theory
Norsen, Travis
2017-01-01
Authored by an acclaimed teacher of quantum physics and philosophy, this textbook pays special attention to the aspects that many courses sweep under the carpet. Traditional courses in quantum mechanics teach students how to use the quantum formalism to make calculations. But even the best students - indeed, especially the best students - emerge rather confused about what, exactly, the theory says is going on, physically, in microscopic systems. This supplementary textbook is designed to help such students understand that they are not alone in their confusions (luminaries such as Albert Einstein, Erwin Schroedinger, and John Stewart Bell having shared them), to sharpen their understanding of the most important difficulties associated with interpreting quantum theory in a realistic manner, and to introduce them to the most promising attempts to formulate the theory in a way that is physically clear and coherent. The text is acces sible to students with at least one semester of prior exposure to quantum (or...
Edge physics of the quantum spin Hall insulator from a quantum dot excited by optical absorption.
Vasseur, Romain; Moore, Joel E
2014-04-11
The gapless edge modes of the quantum spin Hall insulator form a helical liquid in which the direction of motion along the edge is determined by the spin orientation of the electrons. In order to probe the Luttinger liquid physics of these edge states and their interaction with a magnetic (Kondo) impurity, we consider a setup where the helical liquid is tunnel coupled to a semiconductor quantum dot that is excited by optical absorption, thereby inducing an effective quantum quench of the tunneling. At low energy, the absorption spectrum is dominated by a power-law singularity. The corresponding exponent is directly related to the interaction strength (Luttinger parameter) and can be computed exactly using boundary conformal field theory thanks to the unique nature of the quantum spin Hall edge.
Quantum Information in Non-physics Departments at Liberal Arts Colleges
Westmoreland, Michael
2012-02-01
Quantum information and quantum computing have changed our thinking about the basic concepts of quantum physics. These fields have also introduced exciting new applications of quantum mechanics such as quantum cryptography and non-interactive measurement. It is standard to teach such topics only to advanced physics majors who have completed coursework in quantum mechanics. Recent encounters with teaching quantum cryptography to non-majors and a bout of textbook-writing suggest strategies for teaching this interesting material to those without the standard quantum mechanics background. This talk will share some of those strategies.
Space-based research in fundamental physics and quantum technologies
Turyshev, S G; Shao, M; Yu, N; Kusenko, A; Wright, E L; Everitt, C W F; Kasevich, M A; Lipa, J A; Mester, J C; Reasenberg, R D; Walsworth, R L; Ashby, N; Gould, H; Paik, H -J
2007-01-01
Space-based experiments today can uniquely address important questions related to the fundamental laws of Nature. In particular, high-accuracy physics experiments in space can test relativistic gravity and probe the physics beyond the Standard Model; they can perform direct detection of gravitational waves and are naturally suited for precision investigations in cosmology and astroparticle physics. In addition, atomic physics has recently shown substantial progress in the development of optical clocks and atom interferometers. If placed in space, these instruments could turn into powerful high-resolution quantum sensors greatly benefiting fundamental physics. We discuss the current status of space-based research in fundamental physics, its discovery potential, and its importance for modern science. We offer a set of recommendations to be considered by the upcoming National Academy of Sciences' Decadal Survey in Astronomy and Astrophysics. In our opinion, the Decadal Survey should include space-based research ...
Cybernetical Physics From Control of Chaos to Quantum Control
Fradkov, Alexander L
2007-01-01
The control of complex systems is one of the most important aspects in dealing with systems exhibiting nonlinear behaviour or similar features that defy traditional control techniques. This specific subject is gradually becoming known as cybernetical physics, borrowing methods from both theoretical physics and control engineering. This book is, perhaps, the first attempt to present a unified exposition of the subject and methodology of cybernetical physics as well as solutions to some of its problems. Emphasis of the book is on the examination of fundamental limits on energy transformation by means of control procedures in both conservative and dissipative systems. A survey of application in physics includes the control of chaos, synchronisation of coupled oscillators, pendulum chains, reactions in physical chemistry and of quantum systems such as the dissociation of diatomic molecules. This book has been written having researchers from various backgrounds in physics, mathematics and engineering in mind and i...
Becker, Nicole; Stanford, Courtney; Towns, Marcy; Cole, Renee
2015-01-01
In physical chemistry classrooms, mathematical and graphical representations are critical tools for reasoning about chemical phenomena. However, there is abundant evidence that to be successful in understanding complex thermodynamics topics, students must go beyond rote mathematical problem solving in order to connect their understanding of…
Becker, Nicole; Stanford, Courtney; Towns, Marcy; Cole, Renee
2015-01-01
In physical chemistry classrooms, mathematical and graphical representations are critical tools for reasoning about chemical phenomena. However, there is abundant evidence that to be successful in understanding complex thermodynamics topics, students must go beyond rote mathematical problem solving in order to connect their understanding of…
Na\\"ive Physics and Quantum Mechanics: The Cognitive Bias of Everett's Many-Worlds Interpretation
Lang, Andrew Sid
2016-01-01
We discuss the role that intuitive theories of physics play in the interpretation of quantum mechanics. We compare and contrast na\\"ive physics with quantum mechanics and argue that quantum mechanics is not just hard to understand but that it is difficult to believe, often appearing magical in nature. Quantum mechanics is often discussed in the context of "quantum weirdness" and quantum entanglement is known as "spooky action at a distance." This spookiness is more than just because quantum mechanics doesn't match everyday experience; it ruffles the feathers of our na\\"ive physics cognitive module. In Everett's many-worlds interpretation of quantum mechanics, we preserve a form of deterministic thinking that can alleviate some of the perceived weirdness inherent in other interpretations of quantum mechanics, at the cost of having the universe split into parallel worlds at every quantum measurement. By examining the role cognitive modules play in interpreting quantum mechanics, we conclude that the many-worlds...
Beyond quantum probability: another formalism shared by quantum physics and psychology.
Dzhafarov, Ehtibar N; Kujala, Janne V
2013-06-01
There is another meeting place for quantum physics and psychology, both within and outside of cognitive modeling. In physics it is known as the issue of classical (probabilistic) determinism, and in psychology it is known as the issue of selective influences. The formalisms independently developed in the two areas for dealing with these issues turn out to be identical, opening ways for mutually beneficial interactions.
Quantum Dot Semiconductor Optical Amplifiers - Physics and Applications
DEFF Research Database (Denmark)
Berg, Tommy Winther
2004-01-01
This thesis describes the physics and applications of quantum dot semiconductor optical amplifiers based on numerical simulations. These devices possess a number of unique properties compared with other types of semiconductor amplifiers, which should allow enhanced performance of semiconductor...... devices in communication systems in the future. The basic properties of quantum dot devices are investigated, especially regarding the potential of realizing amplification and signal processing without introducing pattern dependence. Also the gain recovery of a single short pulse is modeled...... and an explanation for the fast gain recovery observed experimentally is given. The properties of quantum dot amplifiers operating in the linear regime are investigated. The devices are predicted to show high device gain, high saturated output power, and low noise figure, resulting in a performance, that in some...
Barnes, Marianne B.; Garner, James; Reid, David
2004-01-01
In this article we use the pendulum as the vehicle for discussing the transition from classical to quantum physics. Since student knowledge of the classical pendulum can be generalized to all harmonic oscillators, we propose that a quantum analysis of the pendulum can lead students into the unanticipated consequences of quantum phenomena at the…
Barnes, Marianne B.; Garner, James; Reid, David
2004-01-01
In this article we use the pendulum as the vehicle for discussing the transition from classical to quantum physics. Since student knowledge of the classical pendulum can be generalized to all harmonic oscillators, we propose that a quantum analysis of the pendulum can lead students into the unanticipated consequences of quantum phenomena at the…
Semiotic aspects of quantum physics; Semiotische Aspekte der Quantenphysik
Energy Technology Data Exchange (ETDEWEB)
Januschke, Eugen
2010-07-01
By means of semiotics it is studied, how it succeeds in quantum physics to make formulas plausible, the basic physical facts of which are not accessible for a common understanding respectively an understanding in the sense of classical physics. Thereby it deals with a generally acknowledged kind of making understandable of certain physical formulas beyond the individual marking distinctly of abilities of explaining and understanding of social phenomena and historical developments, whereby to these formulas each a certain experiment is put on side. The experiment is thereby such chosen that the physical phenomenon, which is described in the formula, is studied in the experiment, so that the formula then results as evaluation of the experiment.
Tales of the quantum understanding physics' most fundamental theory
Hobson, Art
2017-01-01
Everybody has heard that we live in a world made of atoms. But far more fundamentally, we live in a universe made of quanta. Many things are not made of atoms: light, radio waves, electric current, magnetic fields, Earth's gravitational field, not to mention exotica such a neutron stars, black holes, dark energy, and dark matter. But everything, including atoms, is made of highly unified or "coherent" bundles of energy called "quanta" that (like everything else) obey certain rules. In the case of the quantum, these rules are called "quantum physics." This is a book about quanta and their unexpected, some would say peculiar, behavior--tales, if you will, of the quantum. The quantum has developed the reputation of being capricious, bewildering, even impossible to understand. The peculiar habits of quanta are certainly not what we would have expected to find at the foundation of physical reality, but these habits are not necessarily bewildering and not at all impossible or paradoxical. This book explains those h...
Nori, Franco
2008-03-01
Superconducting (SC) circuits can behave like atoms making transitions between a few energy levels. Such circuits can test quantum mechanics at macroscopic scales and be used to conduct atomic-physics experiments on a silicon chip. This talk overviews a few of our theoretical studies on SC circuits and quantum information processing (QIP) including: SC qubits for single photon generation and for lasing; controllable couplings among qubits; how to increase the coherence time of qubits using a capacitor in parallel to one of the qubit junctions; hybrid circuits involving both charge and flux qubits; testing Bell's inequality in SC circuits; generation of GHZ states; quantum tomography in SC circuits; preparation of macroscopic quantum superposition states of a cavity field via coupling to a SC qubit; generation of nonclassical photon states using a SC qubit in a microcavity; scalable quantum computing with SC qubits; and information processing with SC qubits in a microwave field. Controllable couplings between qubits can be achieved either directly or indirectly. This can be done with and without coupler circuits, and with and without data-buses like EM fields in cavities (e.g., we will describe both the variable-frequency magnetic flux approach and also a generalized double-resonance approach that we introduced). It is also possible to ``turn a quantum bug into a feature'' by using microscopic defects as qubits, and the macroscopic junction as a controller of it. We have also studied ways to implement radically different approaches to QIP by using ``cluster states'' in SC circuits. For a general overview of this field, see, J.Q. You and F. Nori, Phys. Today 58 (11), 42 (2005)
Baily, Charles
2011-01-01
A common learning goal for modern physics instructors is for students to recognize a difference between the experimental uncertainty of classical physics and the fundamental uncertainty of quantum mechanics. Our studies suggest this notoriously difficult task may be frustrated by the intuitively realist perspectives of introductory students, and a lack of ontological flexibility in their conceptions of light and matter. We have developed a framework for understanding and characterizing student perspectives on the physical interpretation of quantum mechanics, and demonstrate the differential impact on student thinking of the myriad ways instructors approach interpretive themes in their introductory courses. Like expert physicists, students interpret quantum phenomena differently, and these interpretations are significantly influenced by their overall stances on questions central to the so-called measurement problem: Is the wave function physically real, or simply a mathematical tool? Is the collapse of the wav...
Randomness in Quantum Mechanics: Philosophy, Physics and Technology
Bera, Manabendra Nath; Kuś, Marek; Mitchell, Morgan; Lewenstein, Maciej
2016-01-01
This progress report covers recent developments in the area of quantum randomness, which is an extraordinarily interdisciplinary area that belongs not only to physics, but also to philosophy, mathematics, computer science, and technology. For this reason the article contains three parts that will be essentially devoted to different aspects of quantum randomness, and even directed, although not restricted, to various audiences: a philosophical part, a physical part, and a technological part. For these reasons the article is written on an elementary level, combining very elementary and non-technical descriptions with a concise review of more advanced results. In this way readers of various provenances will be able to gain while reading the article.
Wess, J; Physics Enrico Fermi : Quantum Groups and their Applications in Physics
1996-01-01
This book focuses on quantum groups, i.e., continuous deformations of Lie groups, and their applications in physics. These algebraic structures have been studied in the last decade by a growing number of mathematicians and physicists, and are found to underlie many physical systems of interest. They do provide, in fact, a sort of common algebraic ground for seemingly very different physical problems. As it has happened for supersymmetry, the q-group symmetries are bound to play a vital role in physics, even in fundamental theories like gauge theory or gravity. In fact q-symmetry can be considered itself as a generalization of supersymmetry, evident in the q-commutator formulation. The hope that field theories on q-groups are naturally reguralized begins to appear founded, and opens new perspectives for quantum gravity. The topics covered in this book include: conformal field theories and quantum groups, gauge theories of quantum groups, anyons, differential calculus on quantum groups and non-commutative geome...
Spinorial space-time and the origin of Quantum Mechanics. The dynamical role of the physical vacuum
Gonzalez-Mestres, Luis
2016-11-01
Is Quantum Mechanics really and ultimate principle of Physics described by a set of intrinsic exact laws? Are standard particles the ultimate constituents of matter? The two questions appear to be closely related, as a preonic structure of the physical vacuum would have an influence on the properties of quantum particles. Although the first preon models were just « quark-like » and assumed preons to be direct constituents of the conventional « elementary » particles, we suggested in 1995 that preons could instead be constituents of the physical vacuum (the superbradyon hypothesis). Standard particles would then be excitations of the preonic vacuum and have substantially different properties from those of preons themselves (critical speed…). The standard laws of Particle Physics would be approximate expressions generated from basic preon dynamics. In parallel, the mathematical properties of space-time structures such as the spinoral space-time (SST) we introduced in 1996-97 can have strong implications for Quantum Mechanics and even be its real origin. We complete here our recent discussion of the subject by pointing out that: i) Quantum Mechanics corresponds to a natural set of properties of vacuum excitations in the presence of a SST geometry ; ii) the recently observed entanglement at long distances would be a logical property if preons are superluminal (superbradyons), so that superluminal signals and correlations can propagate in vacuum ; iii) in a specific description, the function of space-time associated to the extended internal structure of a spin-1/2 particle at very small distances may be incompatible with a continuous motion at space and time scales where the internal structure of vacuum can be felt. In the dynamics associated to iii), and using the SST approach to space-time, a contradiction can appear between macroscopic and microscopic space-times due to an overlap in the time variable directly related to the fact that a spinorial function takes
Macroscopic-microscopic mass models
Nix, J R; Nix, J Rayford; Moller, Peter
1995-01-01
We discuss recent developments in macroscopic-microscopic mass models, including the 1992 finite-range droplet model, the 1992 extended-Thomas-Fermi Strutinsky-integral model, and the 1994 Thomas-Fermi model, with particular emphasis on how well they extrapolate to new regions of nuclei. We also address what recent developments in macroscopic-microscopic mass models are teaching us about such physically relevant issues as the nuclear curvature energy, a new congruence energy arising from a greater-than-average overlap of neutron and proton wave functions, the nuclear incompressibility coefficient, and the Coulomb redistribution energy arising from a central density depression. We conclude with a brief discussion of the recently discovered rock of metastable superheavy nuclei near 272:110 that had been correctly predicted by macroscopic-microscopic models, along with a possible new tack for reaching an island near 290:110 beyond our present horizon.
A proposed physical analog for a quantum probability amplitude
Boyd, Jeffrey
What is the physical analog of a probability amplitude? All quantum mathematics, including quantum information, is built on amplitudes. Every other science uses probabilities; QM alone uses their square root. Why? This question has been asked for a century, but no one previously has proposed an answer. We will present cylindrical helices moving toward a particle source, which particles follow backwards. Consider Feynman's book QED. He speaks of amplitudes moving through space like the hand of a spinning clock. His hand is a complex vector. It traces a cylindrical helix in Cartesian space. The Theory of Elementary Waves changes direction so Feynman's clock faces move toward the particle source. Particles follow amplitudes (quantum waves) backwards. This contradicts wave particle duality. We will present empirical evidence that wave particle duality is wrong about the direction of particles versus waves. This involves a paradigm shift; which are always controversial. We believe that our model is the ONLY proposal ever made for the physical foundations of probability amplitudes. We will show that our ``probability amplitudes'' in physical nature form a Hilbert vector space with adjoints, an inner product and support both linear algebra and Dirac notation.
Ensembles of physical states and random quantum circuits on graphs
Hamma, Alioscia; Zanardi, Paolo
2012-01-01
In this paper we continue and extend the investigations of the ensembles of random physical states introduced in A. Hamma et al arXiv:1109.4391. These ensembles are constructed by finite-length random quantum circuits (RQC) acting on (hyper)edges of an underlying (hyper)graph structure. The latter encodes for the locality structure associated with finite-time quantum evolutions generated by physical i.e., local, Hamiltonians. Our goal is to analyze physical properties of typical states in these ensembles, in particular here we focus on proxies of quantum entanglement as purity and $\\alpha$-Renyi entropies. The problem is formulated in terms of matrix elements of superoperators which depend on the graph structure, choice of probability measure over the local unitaries and circuit length. In the $\\alpha=2$ case these superoperators act on a restricted multi-qubit space generated by permutation operators associated to the subsets of vertices of the graph. For permutationally invariant interactions the dynamics c...
Quantum generations: a history of physics in the twentieth century
Energy Technology Data Exchange (ETDEWEB)
Rechenberg, H
2000-11-01
Full text: The author attempts to handle the most important physics development of the twentieth century, namely that of quantum theory, in one, not too bulky, volume. This heroic task is split into 29 chapters, each treating a topic that forms a well defined subpart of the big theme embracing quantum theory itself (and also some of its companions), and the experimental discoveries, technology, sociology and science politics connected with it. The contents of Part One cover roughly the first twenty years of the century. There are also chapters on the introduction of the quantum of action and atomic constitution, on discharge in gases, low-temperature research and the interaction of science with industrial and military affairs in World War I. Part Two, leading up to the Hiroshima bomb, includes, beyond such central chapters as the rise of nuclear physics, quantum field theory and the physical and philosophical interpretation of quantum mechanics, further accounts of the Eddington-Milne cosmology, physics in the dictatorial regimes of National Socialism, Fascism and Stalinism, and the intellectual immigration during the 1930s into the USA. Part Three brings the story up to the end of the century, embracing great topics like nuclear energy, Big Science (i.e. physics in military and civil projects), fundamental particle theories up to speculations about 'grand unification', quantum electronics, or the increasingly hostile attitude toward science in the past 30 years. The short Part Four contains two chapters on a century in retrospect, which was really the century of physics. An enormous amount of material has been addressed in this book, and one wonders how one person can say anything reasonable about all these topics. The overall organization and the selection of chapters appears to be well planned and carried out quite successfully. In this reviewer's opinion, some chapters, e.g. on Dirac's theoretical work or cosmology (on which the author has
Franceschetti, Donald R; Gire, Elizabeth
2013-06-01
Quantum probability theory offers a viable alternative to classical probability, although there are some ambiguities inherent in transferring the quantum formalism to a less determined realm. A number of physicists are now looking at the applicability of quantum ideas to the assessment of physics learning, an area particularly suited to quantum probability ideas.
Fundamentals of physics II electromagnetism, optics, and quantum mechanics
Shankar, R
2016-01-01
R. Shankar, a well-known physicist and contagiously enthusiastic educator, was among the first to offer a course through the innovative Open Yale Course program. His popular online video lectures on introductory physics have been viewed over a million times. In this second book based on his online Yale course, Shankar explains essential concepts, including electromagnetism, optics, and quantum mechanics. The book begins at the simplest level, develops the basics, and reinforces fundamentals, ensuring a solid foundation in the principles and methods of physics. It provides an ideal introduction for college-level students of physics, chemistry, and engineering; for motivated AP Physics students; and for general readers interested in advances in the sciences.
Physics on all scales. Scalar-tensor theories of quantum gravity in particle physics and cosmology
Energy Technology Data Exchange (ETDEWEB)
Henz, Tobias
2016-05-10
In this thesis, we investigate dilaton quantum gravity using a functional renormalization group approach. We derive and discuss flow equations both in the background field approximation and using a vertex expansion as well as solve the fixed point equations globally to show how realistic gravity, connecting ultraviolet and infrared physics, can be realized on a pure fixed point trajectory by virtue of spontaneous breaking of scale invariance. The emerging physical system features a dynamically generated moving Planck scale resembling the Newton coupling as well as slow roll inflation with an exponentially decreasing effective cosmological constant that vanishes completely in the infrared. The moving Planck scale might make quantum gravity experimentally accessible at a different energy scale than previously believed. We therefore not only provide further evidence for the existence of a consistent quantum theory of gravity based on general relativity, but also offer potential solutions towards the hierarchy and cosmological constant problems, thereby opening up exciting opportunities for further research.
Becchi, Carlo Maria
2016-01-01
This is the third edition of a well-received textbook on modern physics theory. This book provides an elementary but rigorous and self-contained presentation of the simplest theoretical framework that will meet the needs of undergraduate students. In addition, a number of examples of relevant applications and an appropriate list of solved problems are provided.Apart from a substantial extension of the proposed problems, the new edition provides more detailed discussion on Lorentz transformations and their group properties, a deeper treatment of quantum mechanics in a central potential, and a closer comparison of statistical mechanics in classical and in quantum physics. The first part of the book is devoted to special relativity, with a particular focus on space-time relativity and relativistic kinematics. The second part deals with Schrödinger's formulation of quantum mechanics. The presentation concerns mainly one-dimensional problems, but some three-dimensional examples are discussed in detail. The third...
Understanding quantum phase transitions
Carr, Lincoln
2010-01-01
Quantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivity and display fundamental aspects of quantum theory, such as strong correlations and entanglement. Over the last two decades, our understanding of QPTs has increased tremendously due to a plethora of experimental examples, powerful new numerical meth
Space-Based Research in Fundamental Physics and Quantum Technologies
Turyshev, Slava G.; Israelsson, Ulf E.; Shao, Michael; Yu, Nan; Kusenko, Alexander; Wright, Edward L.; Everitt, C. W. Francis; Kasevich, Mark; Lipa, John A.; Mester, John C.; Reasenberg, Robert D.; Walsworth, Ronald L.; Ashby, Neil; Gould, Harvey; Paik, Ho Jung
Space offers unique experimental conditions and a wide range of opportunities to explore the foundations of modern physics with an accuracy far beyond that of ground-based experiments. Space-based experiments today can uniquely address important questions related to the fundamental laws of Nature. In particular, high-accuracy physics experiments in space can test relativistic gravity and probe the physics beyond the Standard Model; they can perform direct detection of gravitational waves and are naturally suited for investigations in precision cosmology and astroparticle physics. In addition, atomic physics has recently shown substantial progress in the development of optical clocks and atom interferometers. If placed in space, these instruments could turn into powerful high-resolution quantum sensors greatly benefiting fundamental physics. We discuss the current status of space-based research in fundamental physics, its discovery potential, and its importance for modern science. We offer a set of recommendations to be considered by the upcoming National Academy of Sciences' Decadal Survey in Astronomy and Astrophysics. In our opinion, the Decadal Survey should include space-based research in fundamental physics as one of its focus areas. We recommend establishing an Astronomy and Astrophysics Advisory Committee's interagency "Fundamental Physics Task Force" to assess the status of both ground- and space-based efforts in the field, to identify the most important objectives, and to suggest the best ways to organize the work of several federal agencies involved. We also recommend establishing a new NASA-led interagency program in fundamental physics that will consolidate new technologies, prepare key instruments for future space missions, and build a strong scientific and engineering community. Our goal is to expand NASA's science objectives in space by including "laboratory research in fundamental physics" as an element in the agency's ongoing space research efforts.
Goyal, Ketan; Kawai, Ryoichi
As nanotechnology advances, understanding of the thermodynamic properties of small systems becomes increasingly important. Such systems are found throughout physics, biology, and chemistry manifesting striking properties that are a direct result of their small dimensions where fluctuations become predominant. The standard theory of thermodynamics for macroscopic systems is powerless for such ever fluctuating systems. Furthermore, as small systems are inherently quantum mechanical, influence of quantum effects such as discreteness and quantum entanglement on their thermodynamic properties is of great interest. In particular, the quantum fluctuations due to quantum uncertainty principles may play a significant role. In this talk, we investigate thermodynamic properties of an autonomous quantum heat engine, resembling a quantum version of the Feynman Ratchet, in non-equilibrium condition based on the theory of open quantum systems. The heat engine consists of multiple subsystems individually contacted to different thermal environments.
Computational physics simulation of classical and quantum systems
Scherer, Philipp O J
2013-01-01
This textbook presents basic and advanced computational physics in a very didactic style. It contains very-well-presented and simple mathematical descriptions of many of the most important algorithms used in computational physics. Many clear mathematical descriptions of important techniques in computational physics are given. The first part of the book discusses the basic numerical methods. A large number of exercises and computer experiments allows to study the properties of these methods. The second part concentrates on simulation of classical and quantum systems. It uses a rather general concept for the equation of motion which can be applied to ordinary and partial differential equations. Several classes of integration methods are discussed including not only the standard Euler and Runge Kutta method but also multistep methods and the class of Verlet methods which is introduced by studying the motion in Liouville space. Besides the classical methods, inverse interpolation is discussed, together with the p...
The physical underpinning of security proofs for quantum key distribution
Boileau, Jean Christian
The dawn of quantum technology unveils a plethora of new possibilities and challenges in the world of information technology, one of which is the quest for secure information transmission. A breakthrough in classical algorithm or the development of a quantum computer could threaten the security of messages encoded using public key cryptosystems based on one-way function such as RSA. Quantum key distribution (QKD) offers an unconditionally secure alternative to such schemes, even in the advent of a quantum computer, as it does not rely on mathematical or technological assumptions, but rather on the universality of the laws of quantum mechanics. Physical concepts associated with quantum mechanics, like the uncertainty principle or entanglement, paved the way to the first successful security proof for QKD. Ever since, further development in security proofs for QKD has been remarkable. But the connection between entanglement distillation and the uncertainty principle has remained hidden under a pile of mathematical burden. Our main goal is to dig the physics out of the new advances in security proofs for QKD. By introducing an alternative definition of private state, which elaborates the ideas of Mayers and Koashi, we explain how the security of all QKD protocols follows from an entropic uncertainty principle. We show explicitly how privacy amplification protocol can be reduced to a private state distillation protocol constructed from our observations about the uncertainty principle. We also derive a generic security proof for one-way permutation-invariant QKD protocols. Considering collective attack, we achieve the same secret key generation rate as the Devetak-Winter's bound. Generalizing an observation from Kraus, Branciard and Renner, we have provided an improved version of the secret key generation rates by considering a different symmetrization. In certain situations, we argue that Azuma's inequality can simplify the security proof considerably, and we explain
How does Planck’s constant influence the macroscopic world?
Yang, Pao-Keng
2016-09-01
In physics, Planck’s constant is a fundamental physical constant accounting for the energy-quantization phenomenon in the microscopic world. The value of Planck’s constant also determines in which length scale the quantum phenomenon will become conspicuous. Some students think that if Planck’s constant were to have a larger value than it has now, the quantum effect would only become observable in a world with a larger size, whereas the macroscopic world might remain almost unchanged. After reasoning from some basic physical principles and theories, we found that doubling Planck’s constant might result in a radical change on the geometric sizes and apparent colors of macroscopic objects, the solar spectrum and luminosity, the climate and gravity on Earth, as well as energy conversion between light and materials such as the efficiency of solar cells and light-emitting diodes. From the discussions in this paper, students can appreciate how Planck’s constant affects various aspects of the world in which we are living now.
Macroscopic transport by synthetic molecular machines
Berna, J; Leigh, DA; Lubomska, M; Mendoza, SM; Perez, EM; Rudolf, P; Teobaldi, G; Zerbetto, F
2005-01-01
Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with - and perform physical tasks in - the macroscopic world represents a significant hurdle
Blanchard, Philippe
2015-01-01
The second edition of this textbook presents the basic mathematical knowledge and skills that are needed for courses on modern theoretical physics, such as those on quantum mechanics, classical and quantum field theory, and related areas. The authors stress that learning mathematical physics is not a passive process and include numerous detailed proofs, examples, and over 200 exercises, as well as hints linking mathematical concepts and results to the relevant physical concepts and theories. All of the material from the first edition has been updated, and five new chapters have been added on such topics as distributions, Hilbert space operators, and variational methods. The text is divided into three main parts. Part I is a brief introduction to distribution theory, in which elements from the theories of ultradistributions and hyperfunctions are considered in addition to some deeper results for Schwartz distributions, thus providing a comprehensive introduction to the theory of generalized functions. P...
Causal ubiquity in quantum physics a superluminal and local-causal physical ontology
Neelamkavil, Raphael
2014-01-01
A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly non-causal processes, something exists processually in extension-motion, between the causal and the non-causal. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That
The cosmic code quantum physics as the language of nature
Pagels, Heinz R
2012-01-01
""The Cosmic Code can be read by anyone. I heartily recommend it!"" - The New York Times Book Review""A reliable guide for the nonmathematical reader across the highest ridges of physical theory. Pagels is unfailingly lighthearted and confident."" - Scientific American""A sound, clear, vital work that deserves the attention of anyone who takes an interest in the relationship between material reality and the human mind."" - Science 82This is one of the most important books on quantum mechanics ever written for general readers. Heinz Pagels, an eminent physicist and science writer, discusses and
Tomonaga-Luttinger physics in electronic quantum circuits.
Jezouin, S; Albert, M; Parmentier, F D; Anthore, A; Gennser, U; Cavanna, A; Safi, I; Pierre, F
2013-01-01
In one-dimensional conductors, interactions result in correlated electronic systems. At low energy, a hallmark signature of the so-called Tomonaga-Luttinger liquids is the universal conductance curve predicted in presence of an impurity. A seemingly different topic is the quantum laws of electricity, when distinct quantum conductors are assembled in a circuit. In particular, the conductances are suppressed at low energy, a phenomenon called dynamical Coulomb blockade. Here we investigate the conductance of mesoscopic circuits constituted by a short single-channel quantum conductor in series with a resistance, and demonstrate a proposed link to Tomonaga-Luttinger physics. We reformulate and establish experimentally a recently derived phenomenological expression for the conductance using a wide range of circuits, including carbon nanotube data obtained elsewhere. By confronting both conductance data and phenomenological expression with the universal Tomonaga-Luttinger conductance curve, we demonstrate experimentally the predicted mapping between dynamical Coulomb blockade and the transport across a Tomonaga-Luttinger liquid with an impurity.
15th International Conference on Non-Hermitian Hamiltonians in Quantum Physics
Passante, Roberto; Trapani, Camillo
2016-01-01
This book presents the Proceedings of the 15th International Conference on Non-Hermitian Hamiltonians in Quantum Physics, held in Palermo, Italy, from 18 to 23 May 2015. Non-Hermitian operators, and non-Hermitian Hamiltonians in particular, have recently received considerable attention from both the mathematics and physics communities. There has been a growing interest in non-Hermitian Hamiltonians in quantum physics since the discovery that PT-symmetric Hamiltonians can have a real spectrum and thus a physical relevance. The main subjects considered in this book include: PT-symmetry in quantum physics, PT-optics, Spectral singularities and spectral techniques, Indefinite-metric theories, Open quantum systems, Krein space methods, and Biorthogonal systems and applications. The book also provides a summary of recent advances in pseudo-Hermitian Hamiltonians and PT-symmetric Hamiltonians, as well as their applications in quantum physics and in the theory of open quantum systems.
Quantum states preparation in cavity optomechanics
Ge, Wenchao
Quantum entanglement and quantum superposition are fundamental properties of quantum mechanics, which underline quantum information and quantum computation. Preparing quantum states in the macroscopic level is both conceptually interesting for extending quantum physics to a broader sense and fundamentally important for testing the validity of quantum mechanics. In this dissertation, schemes of preparing macroscopic entanglement and macroscopic superposition states in cavity optomechanics are studied using the unitary evolution method in the nonlinear regime or Lyapunov equation in the linearized regime. Quantum entanglement and quantum superposition states can be realized using experimentally feasible parameters with the proposals in this dissertation. Firstly, a scheme of entangling two movable end mirrors in a Fabry-Perot cavity that are coupled to a common single photon superposition state is studied. It is shown that strong entanglement can be obtained either in the single-photon strong coupling regime deterministically or in the single-photon weak coupling regime conditionally. Secondly, a scheme of entangling two movable end mirrors, that are coupled to two-mode entangled fields generated from a correlated-emission laser is investigated. By tuning the input driving laser frequencies at the Stokes sidebands of the cavity, the radiation-pressure coupling can be linearized as an effective beam-splitter-like interaction. Hence entanglement can be transferred from the two-mode fields to the two mechanical mirrors. Macroscopic entanglement between macroscopic mirrors persists at temperature ~ 1K. Thirdly, a scheme of creating macroscopic quantum superpositions of a mechanical mirror via periodically flipping a photonic qubit is proposed. Quantum superposition states of a mechanical mirror can be obtained via the nonlinear radiation coupling with a single-photon superposition state. However, the difference between two superposed mechanical states is very small due
A Synthetic Approach to the Transfer Matrix Method in Classical and Quantum Physics
Pujol, O.; Perez, J. P.
2007-01-01
The aim of this paper is to propose a synthetic approach to the transfer matrix method in classical and quantum physics. This method is an efficient tool to deal with complicated physical systems of practical importance in geometrical light or charged particle optics, classical electronics, mechanics, electromagnetics and quantum physics. Teaching…
A Synthetic Approach to the Transfer Matrix Method in Classical and Quantum Physics
Pujol, O.; Perez, J. P.
2007-01-01
The aim of this paper is to propose a synthetic approach to the transfer matrix method in classical and quantum physics. This method is an efficient tool to deal with complicated physical systems of practical importance in geometrical light or charged particle optics, classical electronics, mechanics, electromagnetics and quantum physics. Teaching…
Quantum physics for dummies. 2. rev. and enl. ed.; Quantenphysik fuer Dummies
Energy Technology Data Exchange (ETDEWEB)
Holzner, Steven
2012-07-01
Quantum physics is a central and fascinating, albeit unpopular by many students theme of physics. Steven Holzner explains understandably and alively, what must be known about quantum physics. He explains the foundations of angular momentum and spin, gives tips how complex equations can be solved. Thereby he works with examples, which he explains extensively.
Dislocations in the Spacetime Continuum: Framework for Quantum Physics
Directory of Open Access Journals (Sweden)
Millette P. A.
2015-10-01
Full Text Available This paper provides a framework for the physical description of physical processes at the quantum level based on dislocations in the spacetime continuum within STCED (Spacetime Continuum Elastodynamics. In this framework, photon and particle self- energies and interactions are mediated by the strain energy density of the dislocations, replacing the role played by virtual particles in QED. We postulate that the spacetime continuum has a granularity characterized by a length b 0 corresponding to the smallest STC elementary Burgers dislocation-displacement vector. Screw dislocations corre- sponding to transverse displacements are identified with photons, and edge dislocations corresponding to longitudinal displacements are identified with particles. Mixed dislo- cations give rise to wave-particle duality. The strain energy density of the dislocations are calculated and proposed to explain the QED problem of mass renormalization.
Quantum physics in the nanoworld Schrödinger's cat and the dwarfs
Lüth, Hans
2015-01-01
The second edition deals with all essential aspects of non-relativistic quantum physics up to the quantisation of fields. In contrast to common textbooks of quantum mechanics, modern experiments are described both for the purpose of foundation of the theory and in relation to recent applications. Links are made to important research fields and applications such as elementary particle physics, solid state physics and nuclear magnetic resonance in medicine, biology and material science. Special emphasis is paid to quantum physics in nanoelectronics such as resonant tunnelling, Coulomb blockade and the realisation of quantum bits. This second edition also considers quantum transport through quantum point contacts and its application as charge detectors in nanoelectronic circuits. Also the realization and the study of electronic properties of an artificial quantum dot molecule are presented. Because of its recent interest a brief discussion of Bose-Einstein condensation has been included, as well as the rece...
Separation of the Microscopic and Macroscopic Domains
Van Zandt, L. L.
1977-01-01
Examines the possibility of observing interference in quantum magnification experiments such as the celebrated "Schroedinger cat". Uses the possibility of observing interference for separating the realm of microscopic from macroscopic dynamics; estimates the dividing line to fall at system sizes of about 100 Daltons. (MLH)
Al-Khalili, Jim
2003-01-01
In this lively look at quantum science, a physicist takes you on an entertaining and enlightening journey through the basics of subatomic physics. Along the way, he examines the paradox of quantum mechanics--beautifully mathematical in theory but confoundingly unpredictable in the real world. Marvel at the Dual Slit experiment as a tiny atom passes through two separate openings at the same time. Ponder the peculiar communication of quantum particles, which can remain in touch no matter how far apart. Join the genius jewel thief as he carries out a quantum measurement on a diamond without ever touching the object in question. Baffle yourself with the bizzareness of quantum tunneling, the equivalent of traveling partway up a hill, only to disappear then reappear traveling down the opposite side. With its clean, colorful layout and conversational tone, this text will hook you into the conundrum that is quantum mechanics.
Quantum Humor: The Playful Side of Physics at Bohr's Institute for Theoretical Physics
Halpern, Paul
2012-09-01
From the 1930s to the 1950s, a period of pivotal developments in quantum, nuclear, and particle physics, physicists at Niels Bohr's Institute for Theoretical Physics in Copenhagen took time off from their research to write humorous articles, letters, and other works. Best known is the Blegdamsvej Faust, performed in April 1932 at the close of one of the Institute's annual conferences. I also focus on the Journal of Jocular Physics, a humorous tribute to Bohr published on the occasions of his 50th, 60th, and 70th birthdays in 1935, 1945, and 1955. Contributors included Léon Rosenfeld, Victor Weisskopf, George Gamow, Oskar Klein, and Hendrik Casimir. I examine their contributions along with letters and other writings to show that they offer a window into some issues in physics at the time, such as the interpretation of complementarity and the nature of the neutrino, as well as the politics of the period.
Emergence of string-like physics from Lorentz invariance in loop quantum gravity
Gambini, Rodolfo
2014-01-01
We consider a quantum field theory on a spherically symmetric quantum space time described by loop quantum gravity. The spin network description of space time in such a theory leads to equations for the quantum field that are discrete. We show that to avoid significant violations of Lorentz invariance one needs to consider specific non-local interactions in the quantum field theory similar to those that appear in string theory. This is the first sign that loop quantum gravity places restrictions on the type of matter considered, and points to a connection with string theory physics.
Lab-Tutorials for teaching quantum physics (Lab-Tutorials fuer den Quantenphysik Unterricht)
Wittmann, M C
2006-01-01
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 "Intuitive Quantum Physics" werden graphische Interpretationen mathematischer Gleichungen und qualitatives Denken d...
Synchronization of interacting quantum dipoles
Zhu, B.; Schachenmayer, J.; Xu, M.; Herrera, F.; Restrepo, J. G.; Holland, M. J.; Rey, A. M.
2015-08-01
Macroscopic ensembles of radiating dipoles are ubiquitous in the physical and natural sciences. In the classical limit the dipoles can be described as damped-driven oscillators, which are able to spontaneously synchronize and collectively lock their phases in the presence of nonlinear coupling. Here we investigate the corresponding phenomenon with arrays of quantized two-level systems coupled via long-range and anisotropic dipolar interactions. Our calculations demonstrate that by incoherently driving dense packed arrays of strongly interacting dipoles, the dipoles can overcome the decoherence induced by quantum fluctuations and inhomogeneous coupling and reach a synchronized steady-state characterized by a macroscopic phase coherence. This steady-state bears much similarity to that observed in classical systems, and yet also exhibits genuine quantum properties such as quantum correlations and quantum phase diffusion (reminiscent of lasing). Our predictions could be relevant for the development of better atomic clocks and a variety of noise tolerant quantum devices.
Quantum simulations and many-body physics with light.
Noh, Changsuk; Angelakis, Dimitris G
2017-01-01
In this review we discuss the works in the area of quantum simulation and many-body physics with light, from the early proposals on equilibrium models to the more recent works in driven dissipative platforms. We start by describing the founding works on Jaynes-Cummings-Hubbard model and the corresponding photon-blockade induced Mott transitions and continue by discussing the proposals to simulate effective spin models and fractional quantum Hall states in coupled resonator arrays (CRAs). We also analyse the recent efforts to study out-of-equilibrium many-body effects using driven CRAs, including the predictions for photon fermionisation and crystallisation in driven rings of CRAs as well as other dynamical and transient phenomena. We try to summarise some of the relatively recent results predicting exotic phases such as super-solidity and Majorana like modes and then shift our attention to developments involving 1D nonlinear slow light setups. There the simulation of strongly correlated phases characterising Tonks-Girardeau gases, Luttinger liquids, and interacting relativistic fermionic models is described. We review the major theory results and also briefly outline recent developments in ongoing experimental efforts involving different platforms in circuit QED, photonic crystals and nanophotonic fibres interfaced with cold atoms.
Quantum simulations and many-body physics with light
Noh, Changsuk; Angelakis, Dimitris G.
2017-01-01
In this review we discuss the works in the area of quantum simulation and many-body physics with light, from the early proposals on equilibrium models to the more recent works in driven dissipative platforms. We start by describing the founding works on Jaynes-Cummings-Hubbard model and the corresponding photon-blockade induced Mott transitions and continue by discussing the proposals to simulate effective spin models and fractional quantum Hall states in coupled resonator arrays (CRAs). We also analyse the recent efforts to study out-of-equilibrium many-body effects using driven CRAs, including the predictions for photon fermionisation and crystallisation in driven rings of CRAs as well as other dynamical and transient phenomena. We try to summarise some of the relatively recent results predicting exotic phases such as super-solidity and Majorana like modes and then shift our attention to developments involving 1D nonlinear slow light setups. There the simulation of strongly correlated phases characterising Tonks-Girardeau gases, Luttinger liquids, and interacting relativistic fermionic models is described. We review the major theory results and also briefly outline recent developments in ongoing experimental efforts involving different platforms in circuit QED, photonic crystals and nanophotonic fibres interfaced with cold atoms.
QUANTUM PHYSICS and HUMAN RESOURCE MANAGEMENT – DEFINING THE FIELD
Directory of Open Access Journals (Sweden)
Andronicus TORP
2014-11-01
Full Text Available This paper argues that it is possible, based on the universal principles revealed by Quantum Physics, to construct an energetic profile of a human being, using the ElectroPhotonic Imaging/Gas Discharge Visualisation-camera, where different frequency domains are connected with different clusters of skills, competences, and qualities, and that the amplitude of the energy within these domains indicates how much the specific person manifests these skills, competences, and qualities. Furthermore, this measurement also indicates the persons stress and energy level. In this way it is possible to compare two or more people objectively and quantitatively, which may find use for example in a Recruitment and Selection situation.
Local State and Sector Theory in Local Quantum Physics
Ojima, Izumi; Okamura, Kazuya; Saigo, Hayato
2016-06-01
We define a new concept of local states in the framework of algebraic quantum field theory (AQFT). Local states are a natural generalization of states and give a clear vision of localization in the context of QFT. In terms of them, we can find a condition from which follows automatically the famous DHR selection criterion in DHR-DR theory. As a result, we can understand the condition as consequences of physically natural state preparations in vacuum backgrounds. Furthermore, a theory of orthogonal decomposition of completely positive (CP) maps is developed. It unifies a theory of orthogonal decomposition of states and order structure theory of CP maps. Using it, localized version of sectors is formulated, which gives sector theory for local states with respect to general reference representations.
QUANTUM PHYSICS and HUMAN RESOURCE MANAGEMENT – DEFINING THE FIELD
Directory of Open Access Journals (Sweden)
Andronicus TORP
2014-11-01
Full Text Available This paper argues that it is possible, based on the universal principles revealed by Quantum Physics, to construct an energetic profile of a human being, using the ElectroPhotonic Imaging/Gas Discharge Visualisation-camera, where different frequency domains are connected with different clusters of skills, competences, and qualities, and that the amplitude of the energy within these domains indicates how much the specific person manifests these skills, competences, and qualities. Furthermore, this measurement also indicates the persons stress and energy level. In this way it is possible to compare two or more people objectively and quantitatively, which may find use for example in a Recruitment and Selection situation.
Probing University Students' Pre-Knowledge in Quantum Physics with QPCS Survey
Asikainen, Mervi A.
2017-01-01
The study investigated the use of Quantum Physics Conceptual Survey (QPCS) in probing student understanding of quantum physics. Altogether 103 Finnish university students responded to QPCS. The mean scores of the student responses were calculated and the test was evaluated using common five indices: Item difficulty index, Item discrimination…
Theorems on Estimating Perturbative Coefficients in Quantum Field Theory and Statistical Physics
Energy Technology Data Exchange (ETDEWEB)
Samuel, Mark
2003-06-25
The authors present rigorous proofs for several theorems on using Pade approximants to estimate coefficients in Perturbative Quantum Field Theory and Statistical Physics. As a result, they find new trigonometric and other identities where the estimates based on this approach are exact. They discuss hypergeometric functions, as well as series from both Perturbative Quantum Field Theory and Statistical Physics.
Causal ubiquity in quantum physics. A superluminal and local-causal physical ontology
Energy Technology Data Exchange (ETDEWEB)
Neelamkavil, Raphael
2014-07-01
A fixed highest criterial velocity (of light) in STR (special theory of relativity) is a convention for a layer of physical inquiry. QM (Quantum Mechanics) avoids action-at-a-distance using this concept, but accepts non-causality and action-at-a-distance in EPR (Einstein-Podolsky-Rosen-Paradox) entanglement experiments. Even in such allegedly [non-causal] processes, something exists processually in extension-motion, between the causal and the [non-causal]. If STR theoretically allows real-valued superluminal communication between EPR entangled particles, quantum processes become fully causal. That is, the QM world is sub-luminally, luminally and superluminally local-causal throughout, and the Law of Causality is ubiquitous in the micro-world. Thus, ''probabilistic causality'' is a merely epistemic term.
``Who Thinks Abstractly?'': Quantum Theory and the Architecture of Physical Concepts
Plotnitsky, Arkady
2011-03-01
Beginning with its introduction by W. Heisenberg, quantum mechanics was often seen as an overly abstract theory, mathematically and physically, vis-à-vis classical physics or relativity. This perception was amplified by the fact that, while the quantum-mechanical formalism provided effective predictive algorithms for the probabilistic predictions concerning quantum experiments, it appeared unable to describe, even by way idealization, quantum processes themselves in space and time, in the way classical mechanics or relativity did. The aim of the present paper is to reconsider the nature of mathematical and physical abstraction in modern physics by offering an analysis of the concept of "physical fact" and of the concept of "physical concept," in part by following G. W. F. Hegel's and G. Deleuze's arguments concerning the nature of conceptual thinking. In classical physics, relativity, and quantum physics alike, I argue, physical concepts are defined by the following main features—1) their multi-component multiplicity; 2) their essential relations to problems; 3) and the interactions between physical, mathematical, and philosophical components within each concept. It is the particular character of these interactions in quantum mechanics, as defined by its essentially predictive (rather than descriptive) nature, that distinguishes it from classical physics and relativity.
Quantum Plasmas An Hydrodynamic Approach
Haas, Fernando
2011-01-01
This book provides an overview of the basic concepts and new methods in the emerging scientific area known as quantum plasmas. In the near future, quantum effects in plasmas will be unavoidable, particularly in high density scenarios such as those in the next-generation intense laser-solid density plasma experiment or in compact astrophysics objects. Currently, plasmas are in the forefront of many intriguing questions around the transition from microscopic to macroscopic modeling of charged particle systems. Quantum Plasmas: an Hydrodynamic Approach is devoted to the quantum hydrodynamic model paradigm, which, unlike straight quantum kinetic theory, is much more amenable to investigate the nonlinear realm of quantum plasmas. The reader will have a step-by-step construction of the quantum hydrodynamic method applied to plasmas. The book is intended for specialists in classical plasma physics interested in methods of quantum plasma theory, as well as scientists interested in common aspects of two major areas of...
The quantum beat the physical principles of atomic clocks
Major, F G
1998-01-01
One of the indicators of the level of technological development of a society has been, throughout history, the precision of clocks it was able to build. This book examines the physical principles underlying the workings of clocks--from the earliest mechanical clocks to the present-day sophisticated clocks based on the properties of individual atoms. Intended for non-specialists with some knowledge of physics or engineering,the book treats the material in a broad intuitive manner, with a minimum of mathematical formalism. The presentation covers a broad range of salient topics relevant to the measurement of frequency and time intervals. The main focus is on electronic time-keeping: clocks based on quartz crystal oscillators and, at greater length, atomic clocks based on quantum resonance in rubidium, cesium, and hydrogen atoms, and, more recently, mercury ions. The book treats the revolutionary changes that the optical laser has wrought on atomic standards through laser cooling and optical pumping, and it disc...
The physical Church-Turing thesis and the principles of quantum theory
Arrighi, Pablo
2011-01-01
Notoriously, quantum computation shatters complexity theory, but is innocuous to computability theory. Yet several works have shown how quantum theory as it stands could breach the physical Church-Turing thesis. We draw a clear line as to when this is the case, in a way that is inspired by Gandy. Gandy formulates postulates about physics, such as homogeneity of space and time, bounded density and velocity of information --- and proves that the physical Church-Turing thesis is a consequence of these postulates. We provide a quantum version of the theorem. Thus this approach exhibits a formal non-trivial interplay between theoretical physics symmetries and computability assumptions.
Quantum theory and the schism in physics from the postscript to the logic of scientific discovery
Popper, Karl Raimund
1982-01-01
Quantum Theory and the Schism in Physics is one of the three volumes of Karl Popper's Postscript to the Logic of scientific Discovery. The Postscript is the culmination of Popper's work in the philosophy of physics and a new famous attack on subjectivist approaches to philosophy of science.Quantum Theory and the Schism in Physics is the third volume of the Postscript. It may be read independently, but it also forms part of Popper's interconnected argument in the Postscript. It presents Popper's classic statement on quantum physics a
Condensed-matter physics: Quantum mechanics in a spin
Balents, Leon
2016-12-01
Quantum spin liquids are exotic states of matter first predicted more than 40 years ago. An inorganic material has properties consistent with these predictions, revealing details about the nature of quantum matter. See Letter p.559
Chemical physics: Quantum control of light-induced reactions
Chandler, David W.
2016-07-01
An investigation of how ultracold molecules are broken apart by light reveals surprising, previously unobserved quantum effects. The work opens up avenues of research in quantum optics. See Letter p.122
Quantum physics: Squeezed ions in two places at once
Northup, Tracy
2015-05-01
Experiments on a trapped calcium ion have again exposed the strange nature of quantum phenomena, and could pave the way for sensitive techniques to explore the boundary between the quantum and classical worlds. See Letter p.336
Barbara, Bernard; Sawatzky, G; Stamp, P. C. E
2008-01-01
This book is based on some of the lectures during the Pacific Institute of Theoretical Physics (PITP) summer school on "Quantum Magnetism", held during June 2006 in Les Houches, in the French Alps. The school was funded jointly by NATO, the CNRS, and PITP, and entirely organized by PITP. Magnetism is a somewhat peculiar research field. It clearly has a quantum-mechanical basis – the microsopic exchange interactions arise entirely from the exclusion principle, in conjunction with respulsive interactions between electrons. And yet until recently the vast majority of magnetism researchers and users of magnetic phenomena around the world paid no attention to these quantum-mechanical roots. Thus, eg., the huge ($400 billion per annum) industry which manufactures hard discs, and other components in the information technology sector, depends entirely on room-temperature properties of magnets - yet at the macroscopic or mesoscopic scales of interest to this industry, room-temperature magnets behave entirely classic...
Yes-no experiments and ordered structures in quantum physics
Energy Technology Data Exchange (ETDEWEB)
Garola, C.; Solombrino, L. (Lecce Univ. (Italy). Ist. di Fisica)
1983-09-11
We consider the set E of all the yes-no experiments that can be performed on a given physical system and the related posets (E,<=) of the ''effects'' and (L,<=) of the ''propositions'', illustrate by means of examples the relations <= and <= and give counter examples for properties that one might suspect to hold in (E,<=); in particular, we show that Mackey's axiom V does not usually hold either in (E,<=) or in its greatest subposet (E/sub 0/,<=) which can be orthocomplemented with standard methods in quantum logic. Following on the suggestions arising from the examples, we associate with every observable T, by means of the concept of ''efficiency'', a family Esub(T) of yes-no experiments, hence a family Esub(T) of effects parameterized by the Borel fuzzy sets on the real line, and show that the description of the effects by means of operators, which is usual in some axiomatic approaches, can be recovered in standard Hilbert-space quantum theory as an immediate consequence of simple, ''intuitive'' assumptions on E. This description is used in order to explicitly display (possibly in the presence of superselection rules) some properties of the representations of (E,<=) and (L,<=), and the links between some different axiomatic approaches (in particular, Mackey and Piron). Finally, we point out some mathematical properties of the lattice of the operators that describe Esub(T).
Yes-no experiments and ordered structures in quantum physics
Energy Technology Data Exchange (ETDEWEB)
Garola, C.; Solombrino, L. (Lecce Univ. (Italy). Ist. di Fisica)
1983-09-11
The set E of all the yes-no experiments that can be performed on a given physical system and the related posets (E, <=) of the 'effects' and (L, '<=') of the propositions are considered. The relations <= and '<=' are illustrated by means of examples, and counterexamples for properties that one might suspect to hold in (E, '<=') are given. In particular it is shown that Mackey's axiom V does not usually hold either in (E, <=) or in its greatest subposet (E/sub 0/, <=) which can be orthocomplemented with standard methods in quantum logic. Following on the suggestions arising from the examples, it is associated with every observable T, by means of the concept of 'efficiency', a family Esub(T) of yes-no experiments, hence a family Esub(T) of effects parametrized by the Borel fuzzy sets on the real line, and it is shown that the description of the effects by means of operators, which is usual in some axiomatic approaches, can be recovered in standard Hilbert-space quantum theory as an immediate consequence of simple, 'intuitive' assumptions on E. This description is used in order to explicitly display (possibly in the presence of superselection rules) some properties of the representations of (E, <=) and (L, '<='), and the links between some different axiomatic approaches (in particular, Mackey and Piron). Finally, some mathematical properties of the lattice of the operators that describe Esub(T) are pointed out.
ReleQuant – Improving teaching and learning in quantum physics through educational design research
Directory of Open Access Journals (Sweden)
Berit Bungum
2015-05-01
Full Text Available Quantum physics and relativity are demanding for teachers and students, but have the potential for students to experience physics as fascinating and meaningful. Project ReleQuant engaged in educational design research to improve teaching and learning in these topics in Norwegian upper secondary schools. The paper focuses on the first cycle of development of a teaching module on quantum physics and how design principles were developed. We construct the design principles by reviewing relevant research literature and conducting three pilot studies. The process resulted in the following principles for designing the quantum physics teaching module: 1 clarify how quantum physics breaks with classical physics; 2 use simulations of phenomena that cannot be experienced directly; 3 provide students to use written and oral language; 4 address and discuss wave-particle duality and the uncertainty
A Complete Physical Germanium-on-Silicon Quantum Dot Self-Assembly Process
Alkhatib, Amro; Nayfeh, Ammar
2013-06-01
Achieving quantum dot self-assembly at precise pre-defined locations is of vital interest. In this work, a novel physical method for producing germanium quantum dots on silicon using nanoindentation to pre-define nucleation sites is described. Self-assembly of ordered ~10 nm height germanium quantum dot arrays on silicon substrates is achieved. Due to the inherent simplicity and elegance of the proposed method, the results describe an attractive technique to manufacture semiconductor quantum dot structures for future quantum electronic and photonic applications.
Michelsen, Eric L
2014-01-01
Quirky Quantum Concepts explains the more important and more difficult concepts in theoretical quantum mechanics, especially those which are consistently neglected or confusing in many common expositions. The emphasis is on physical understanding, which is necessary for the development of new, cutting edge science. In particular, this book explains the basis for many standard quantum methods, which are too often presented without sufficient motivation or interpretation. The book is not a simplification or popularization: it is real science for real scientists. Physics includes math, and this book does not shy away from it, but neither does it hide behind it. Without conceptual understanding, math is gibberish. The discussions here provide the experimental and theoretical reasoning behind some of the great discoveries, so the reader may see how discoveries arise from a rational process of thinking, a process which Quirky Quantum Concepts makes accessible to its readers. Quirky Quantum Concepts is therefore a s...
Classical Physics and the Bounds of Quantum Correlations.
Frustaglia, Diego; Baltanás, José P; Velázquez-Ahumada, María C; Fernández-Prieto, Armando; Lujambio, Aintzane; Losada, Vicente; Freire, Manuel J; Cabello, Adán
2016-06-24
A unifying principle explaining the numerical bounds of quantum correlations remains elusive, despite the efforts devoted to identifying it. Here, we show that these bounds are indeed not exclusive to quantum theory: for any abstract correlation scenario with compatible measurements, models based on classical waves produce probability distributions indistinguishable from those of quantum theory and, therefore, share the same bounds. We demonstrate this finding by implementing classical microwaves that propagate along meter-size transmission-line circuits and reproduce the probabilities of three emblematic quantum experiments. Our results show that the "quantum" bounds would also occur in a classical universe without quanta. The implications of this observation are discussed.
Landsman, N P
2005-01-01
The relationship between classical and quantum theory is of central importance to the philosophy of physics, and any interpretation of quantum mechanics has to clarify it. Our discussion of this relationship is partly historical and conceptual, but mostly technical and mathematically rigorous, including over 500 references. On the assumption that quantum mechanics is universal and complete, we discuss three ways in which classical physics has so far been believed to emerge from quantum physics, namely in the limit h -> 0 of small Planck's constant (in a finite system), in the limit of a large system, and through decoherence and consistent histores. The first limit is closely related to modern quantization theory and microlocal analysis, whereas the second involves methods of C*-algebras and the concepts of superselection sectors and macroscopic observables. In these limits, the classical world does not emerge as a sharply defined objective reality, but rather as an approximate appearance relative to certain "...
Paredes, María Alejandra; Montecino, Vivian; Anic, Vinka; Egaña, Miguel; Guzmán, Leonardo
2014-12-01
The distribution of planktonic organisms remains a central focus of research due to the fact that physical and biological interactions affect the marine pelagic ecosystem in different ways and at different scales. Therefore, different patterns in the structure of phytoplankton community emerge according to the observation scale. In the Chilean fjords systems, suggested to be autotrophic and showing neither a nitrate nor a phosphate deficit, we studied the phytoplankton structures from data sets obtained in four seasonal cruises across a large geographical region in Patagonia and Tierra del Fuego, including the biogeographic Magellan District and a portion of the Fuegian District (48-55°S) separated in three sectors. We also processed a database from a spring cruise at a sub-regional spatial scale, which covers a portion of the central and southern Magellan sectors (52-55° S) separated in seven areas with distinctive geographic characteristics. More defined patterns of microphytoplankton at large spatial scales were predicted, with greater heterogeneity and differences between assemblages at a smaller scale. Therefore, at a smaller scale particular local zones with characteristic phytoplankton assemblage are expected as a result of particular environmental conditions of the different geographical areas. In order to evaluate the phytoplankton community structure in both data bases, statistical tools such as multidimensional scaling (MDS), analysis of similarities (ANOSIM), Similarity Percentages (SIMPER) and Cluster Analysis were used when required. At a sub-regional mesoscale, principal component (PCA) and factor analysis were used for environmental data in order to determine if their distribution patterns influences the formation of local zones with similar microphytoplankton assemblages. A Canonical Correspondence Analysis (CCA) was performed to find the relationship between environmental variables and diatom and dinoflagellate grouped by genera. At the regional
Quantum physics in the nanoworld Schrödinger's cat and the dwarfs
Lüth, Hans
2013-01-01
The book deals with all essential aspects of non-relativistic quantum physics up to the quantization of fields. In contrast to common textbooks of quantum mechanics, modern experiments are described both for the purpose of foundation of the theory and in relation to recent applications. In this respect applications to nano-electronics as well as the realization of quantum-bits are presented and discussed. Furthermore, links are made to other important research fields and applications, such as elementary particle physics, solid state physics and nuclear magnetic resonance tomography in medicine. Even though the representation of the topics is largely performed in terms of Dirac´s bra-ket notation and by use of commutator algebra, the concrete description of the physical basis and the corresponding theoretical concepts are emphasized. Because of little requirement of complex mathematics, the book is suitable as an introduction into quantum physics, not only for physicists but also for chemists, biologists, eng...
Quantum rules how the laws of physics explain love, success, and everyday life
Das, Kunal K
2015-01-01
Learn how quantum physics affects your daily life and learn practical ways to put that knowledge to good use! Ever feel guilty that you always seem to seek the easiest and shortest way to accomplish something? And why is it so satisfying to drive along a road hitting every green light as if by magic? The Quantum Rules applies the laws of physics to explain everything from relationships and human nature to the effects of globalization. It achieves the impossible task of making quantum physics deeply relevant to all readerseven those with no interest in science.With a lively
``Simplest Molecule'' Clarifies Modern Physics II. Relativistic Quantum Mechanics
Harter, William; Reimer, Tyle
2015-05-01
A ``simplest molecule'' consisting of CW- laser beam pairs helps to clarify relativity from poster board - I. In spite of a seemingly massless evanescence, an optical pair also clarifies classical and quantum mechanics of relativistic matter and antimatter. Logical extension of (x,ct) and (ω,ck) geometry gives relativistic action functions of Hamiltonian, Lagrangian, and Poincare that may be constructed in a few ruler-and-compass steps to relate relativistic parameters for group or phase velocity, momentum, energy, rapidity, stellar aberration, Doppler shifts, and DeBroglie wavelength. This exposes hyperbolic and circular trigonometry as two sides of one coin connected by Legendre contact transforms. One is Hamiltonian-like with a longitudinal rapidity parameter ρ (log of Doppler shift). The other is Lagrange-like with a transverse angle parameter σ (stellar aberration). Optical geometry gives recoil in absorption, emission, and resonant Raman-Compton acceleration and distinguishes Einstein rest mass, Galilean momentum mass, and Newtonian effective mass. (Molecular photons appear less bullet-like and more rocket-like.) In conclusion, modern space-time physics appears as a simple result of the more self-evident Evenson's axiom: ``All colors go c.''
"simplest Molecule" Clarifies Modern Physics II. Relativistic Quantum Mechanics
Reimer, T. C.; Harter, W. G.
2014-06-01
A "simplest molecule" consisting of CW-laser beam pairs helps to clarify relativity in Talk I. In spite of a seemingly massless evanescence, an optical pair also clarifies classical and quantum mechanics of relativistic matter and anti-matter. *Logical extension of (x,ct) and (ω,ck) geometry gives relativistic action functions of Hamiltonian, Lagrangian, and Poincare that may be constructed in a few ruler-and-compass steps to relate relativistic parameters for group or phase velocity, momentum, energy, rapidity, stellar aberration, Doppler shifts, and DeBroglie wavelength. This exposes hyperbolic and circular trigonometry as two sides of one coin connected by Legendre contact transforms. One is Hamiltonian-like with a longitudinal rapidity parameter ρ (log of Doppler shift). The other is Lagrange-like with a transverse angle parameter σ (stellar aberration). Optical geometry gives recoil in absorption, emission, and resonant Raman-Compton acceleration and distinguishes Einstein rest mass, Galilean momentum mass, and Newtonian effective mass. (Molecular photons appear less bullet-like and more rocket-like.) In conclusion, modern space-time physics appears as a simple result of the more self-evident Evenson's axiom: "All colors go c."
Macroscopic Objects, Intrinsic Spin, and Lorentz Violation
Atkinson, David W; Tasson, Jay D
2013-01-01
The framework of the Standard-Model Extension (SME) provides a relativistic quantum field theory for the study of Lorentz violation. The classical, nonrelativistic equations of motion can be extracted as a limit that is useful in various scenarios. In this work, we consider the effects of certain SME coefficients for Lorentz violation on the motion of macroscopic objects having net intrinsic spin in the classical, nonrelativistic limit.
Physics of quantum measurement and its interdisciplinary applications
Directory of Open Access Journals (Sweden)
Morikawa Masahiro
2014-04-01
Full Text Available Quantum dynamics of the collective mode and individual particles on a ring is studied as the simplest model of projective quantum measurement. In this model, the collective mode measures an individual single quantum system. The heart of the model is the wide separation of time scales which yields the distinction of classical and quantum degrees of freedom beyond the standard Gross-Pitaevskii equation. In some restricted cases we derive the Born probability rule. This model is the quantum mechanics version of the effective action method in quantum field theory, which describes the origin of the primordial density fluctuation as classical variables. It turns out that the classical version of this same model successfully describes the dynamics of geomagnetic variation including the polarity flips over 160 million years. The essence of this description is again the coexistence of the wide separated time scales.
Physical Meaning of the Optimum Measurement Process in Quantum Detection Theory
Osaki, Masao; Kozuka, Haruhisa; Hirota, Osamu
1996-01-01
The optimum measurement processes are represented as the optimum detection operators in the quantum detection theory. The error probability by the optimum detection operators goes beyond the standard quantum limit automatically. However the optimum detection operators are given by pure mathematical descriptions. In order to realize a communication system overcoming the standard quantum limit, we try to give the physical meaning of the optimum detection operators.
Many-Body Quantum Electrodynamics Networks: Non-Equilibrium Condensed Matter Physics with Light
Hur, Karyn Le; Henriet, Loïc; Petrescu, Alexandru; Plekhanov, Kirill; Roux, Guillaume; Schiró, Marco
2015-01-01
We review recent developments concerning non-equilibrium quantum dynamics and many-body physics with light, in superconducting circuits and Josephson analogues. We start with quantum impurity models summarizing the effect of dissipation and of driving the system. We mention theoretical and experimental efforts to characterize these non-equilibrium quantum systems. We show how Josephson junction systems can implement the equivalent of the Kondo effect with microwave photons. The Kondo effect i...
Problems and solutions in quantum chemistry and physics
Johnson, Charles S
1988-01-01
Unusually varied problems, with detailed solutions, cover quantum mechanics, wave mechanics, angular momentum, molecular spectroscopy, scattering theory, more. 280 problems, plus 139 supplementary exercises.
Visualization of the Invisible: The Qubit as Key to Quantum Physics
Dür, Wolfgang; Heusler, Stefan
2014-01-01
Quantum mechanics is one of the pillars of modern physics, however rather difficult to teach at the introductory level due to the conceptual difficulties and the required advanced mathematics. Nevertheless, attempts to identify relevant features of quantum mechanics and to put forward concepts of how to teach it have been proposed. Here we present…
Visualization of the Invisible: The Qubit as Key to Quantum Physics
Dür, Wolfgang; Heusler, Stefan
2014-01-01
Quantum mechanics is one of the pillars of modern physics, however rather difficult to teach at the introductory level due to the conceptual difficulties and the required advanced mathematics. Nevertheless, attempts to identify relevant features of quantum mechanics and to put forward concepts of how to teach it have been proposed. Here we present…
Körhasan, Nilüfer Didis
2015-01-01
Quantum theory is one of the most successful theories in physics. Because of its abstract, mathematical, and counter-intuitive nature, many students have problems learning the theory, just as teachers experience difficulty in teaching it. Pedagogical research on quantum theory has mainly focused on cognitive issues. However, affective issues about…
PREFACE: International Symposium "Nanoscience and Quantum Physics 2011" (nanoPHYS'11)
Saito, Susumu; Tanaka, Hidekazu; Nakamura, Takashi; Nakamura, Masaaki
2011-07-01
Quantum physics has developed modern views of nature for more than a century. In addition to this traditional role, quantum physics has acquired new significance in the 21st century as the field responsible for driving and supporting nanoscience research, which will have even greater importance in the future because nanoscience will be the academic foundation for new technologies. The Department of Physics, Tokyo Institute of Technology, are now conducting a "Nanoscience and Quantum Physics" project (Physics G-COE project) supported by the Global Center of Excellence Program of the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) in order to promote research and education in these important academic fields. The International Symposium on Nanoscience and Quantum Physics, held in Tokyo, Japan, 26-28 January 2011 (nanoPHYS'11) was organized by the Physics G-COE project of the Tokyo Institute of Technology to provide an international forum for the open exchange of topical information and for stimulating discussion on novel concepts and future prospects of nanoscience and quantum physics. There were a total of 118 papers including 34 invited papers. This nanoPHYS'11 is the fourth symposium of this kind organized by the Tokyo Institute of Technology. Topics focused on in the symposium included: Category 1: Novel nanostructure (Nanowires, Nanotubes, Spin-related structure, etc) Category 2: Novel transport and electronic properties (Graphene, Topological insulators, Coherent control, etc) Category 3: Electronic and optical properties of nanostructure Category 4: Fundamental physics and new concept in quantum physics Category 5: Quantum Physics - Quantum information Category 6: Quantum Physics - Nuclear and Hadron Physics Category 7: Quantum Physics - Astrophysics, etc All the papers submitted to this issue have been reviewed under a stringent refereeing process, according to the normal rules of this Journal. The editors are grateful to all the
Quantum Effects in Biological Systems
2016-01-01
Since the last decade the study of quantum mechanical phenomena in biological systems has become a vibrant field of research. Initially sparked by evidence of quantum effects in energy transport that is instrumental for photosynthesis, quantum biology asks the question of how methods and models from quantum theory can help us to understand fundamental mechanisms in living organisms. This approach entails a paradigm change challenging the related disciplines: The successful framework of quantum theory is taken out of its low-temperature, microscopic regimes and applied to hot and dense macroscopic environments, thereby extending the toolbox of biology and biochemistry at the same time. The Quantum Effects in Biological Systems conference is a platform for researchers from biology, chemistry and physics to present and discuss the latest developments in the field of quantum biology. After meetings in Lisbon (2009), Harvard (2010), Ulm (2011), Berkeley (2012), Vienna (2013), Singapore (2014) and Florence (2015),...
Quantum memories at finite temperature
Brown, Benjamin J.; Loss, Daniel; Pachos, Jiannis K.; Self, Chris N.; Wootton, James R.
2016-10-01
To use quantum systems for technological applications one first needs to preserve their coherence for macroscopic time scales, even at finite temperature. Quantum error correction has made it possible to actively correct errors that affect a quantum memory. An attractive scenario is the construction of passive storage of quantum information with minimal active support. Indeed, passive protection is the basis of robust and scalable classical technology, physically realized in the form of the transistor and the ferromagnetic hard disk. The discovery of an analogous quantum system is a challenging open problem, plagued with a variety of no-go theorems. Several approaches have been devised to overcome these theorems by taking advantage of their loopholes. The state-of-the-art developments in this field are reviewed in an informative and pedagogical way. The main principles of self-correcting quantum memories are given and several milestone examples from the literature of two-, three- and higher-dimensional quantum memories are analyzed.
Quantum physics in the nanoworld. Schroedinger's cat and the dwarfs
Energy Technology Data Exchange (ETDEWEB)
Lueth, Hans [Forschungszentrum Juelich GmbH (Germany). PGI-9 Semiconductor Nanoelectronics and Juelich Aachen Research Alliance (JARA)
2013-07-01
Gives a step-by-step derivation of the physical basis of quantum mechanics without using complex mathematics. Provides a close linking of experiment and theory. Describes most modern experiments related to nanoscience and to the foundation of quantum theory. Provides appendices describing the preparation of nanostructures and the importance of interface physics for nanoscience. Contains more than 40 problems to deepen the understanding. English language version of a successful German textbook. The book deals with all essential aspects of non-relativistic quantum physics up to the quantization of fields. In contrast to common textbooks of quantum mechanics, modern experiments are described both for the purpose of foundation of the theory and in relation to recent applications. In this respect applications to nano-electronics as well as the realization of quantum-bits are presented and discussed. Furthermore, links are made to other important research fields and applications, such as elementary particle physics, solid state physics and nuclear magnetic resonance tomography in medicine. Even though the representation of the topics is largely performed in terms of Dirac's bra-ket notation and by use of commutator algebra, the concrete description of the physical basis and the corresponding theoretical concepts are emphasized. Because of little requirement of complex mathematics, the book is suitable as an introduction into quantum physics, not only for physicists but also for chemists, biologists, engineers, computer scientists and even for philosophers as far as they are interested in natural philosophy and epistomology.
Understanding the physics of a possible non-Abelian fractional quantum hall effect state.
Energy Technology Data Exchange (ETDEWEB)
Pan, Wei; Crawford, Matthew; Tallakulam, Madhu; Ross, Anthony Joseph, III
2010-10-01
We wish to present in this report experimental results from a one-year Senior Council Tier-1 LDRD project that focused on understanding the physics of a possible non-Abelian fractional quantum Hall effect state. We first give a general introduction to the quantum Hall effect, and then present the experimental results on the edge-state transport in a special fractional quantum Hall effect state at Landau level filling {nu} = 5/2 - a possible non-Abelian quantum Hall state. This state has been at the center of current basic research due to its potential applications in fault-resistant topological quantum computation. We will also describe the semiconductor 'Hall-bar' devices we used in this project. Electron physics in low dimensional systems has been one of the most exciting fields in condensed matter physics for many years. This is especially true of quantum Hall effect (QHE) physics, which has seen its intellectual wealth applied in and has influenced many seemingly unrelated fields, such as the black hole physics, where a fractional QHE-like phase has been identified. Two Nobel prizes have been awarded for discoveries of quantum Hall effects: in 1985 to von Klitzing for the discovery of integer QHE, and in 1998 to Tsui, Stormer, and Laughlin for the discovery of fractional QHE. Today, QH physics remains one of the most vibrant research fields, and many unexpected novel quantum states continue to be discovered and to surprise us, such as utilizing an exotic, non-Abelian FQHE state at {nu} = 5/2 for fault resistant topological computation. Below we give a briefly introduction of the quantum Hall physics.
Pykacz, Jarosław
2015-01-01
This Brief presents steps towards elaborating a new interpretation of quantum mechanics based on a specific version of Łukasiewicz infinite-valued logic. It begins with a short survey of main interpretations of quantum mechanics already proposed, as well as various models of many-valued logics and previous attempts to apply them for the description of quantum phenomena. The prospective many-valued interpretation of quantum mechanics is soundly based on a theorem concerning the isomorphic representation of Birkhoff-von Neumann quantum logic in the form of a special Łukasiewicz infinite-valued logic endowed with partially defined conjunctions and disjunctions.
Tales of the quantum understanding physics' most fundamental theory
Hobson, Art
2016-01-01
This is a book about the quanta that make up our universe--the highly unified bundles of energy of which everything is made. It explains wave-particle duality, randomness, quantum states, non-locality, Schrodinger's cat, quantum jumps, and more, in everyday language for non-scientists and scientists who wish to fathom science's most fundamental theory.
The quantum physics bible the definitive guide to 200 years of subatomic science
Clegg, Brian
2017-01-01
An easy-to-understand guide to the complex subject of quantum physics. Quantum physics is how scientists describe the world of the very small. For other people, however, the rules of quantum physics seem to violate all logic: How can a particle be in more than one place at the same time? How can it tunnel through an impenetrable barrier? How can a cat in a box be both alive and dead? This book explains the complexities of quantum physics in bite-sized "lessons" that make it clear and accessible to all readers. The sections and chapters are: 1. Atoms -- quantum; quantum physics in everyday life; the periodic table; atoms and nuclei; isotopes; hydrogen atom (energy levels and spectra) 2. Photons -- photoelectric effect; thermal emission and the Planck distribution; wave particle duality (Young's slit experiment) 3. Quantum devices -- superconductors; transistor, diode; light-emitting diode; laser 4. Spin -- spin; fermions; exclusion principle; Fermi Dirac distribution; Bose-Einstein statistics 5. Wave Mechan...
Energy Technology Data Exchange (ETDEWEB)
Mueller, B.
1993-05-15
This report discusses research in the following topics: Hadron structure physics; relativistic heavy ion collisions; finite- temperature QCD; real-time lattice gauge theory; and studies in quantum field theory.
Exponential Sensitivity and its Cost in Quantum Physics.
Gilyén, András; Kiss, Tamás; Jex, Igor
2016-02-10
State selective protocols, like entanglement purification, lead to an essentially non-linear quantum evolution, unusual in naturally occurring quantum processes. Sensitivity to initial states in quantum systems, stemming from such non-linear dynamics, is a promising perspective for applications. Here we demonstrate that chaotic behaviour is a rather generic feature in state selective protocols: exponential sensitivity can exist for all initial states in an experimentally realisable optical scheme. Moreover, any complex rational polynomial map, including the example of the Mandelbrot set, can be directly realised. In state selective protocols, one needs an ensemble of initial states, the size of which decreases with each iteration. We prove that exponential sensitivity to initial states in any quantum system has to be related to downsizing the initial ensemble also exponentially. Our results show that magnifying initial differences of quantum states (a Schrödinger microscope) is possible; however, there is a strict bound on the number of copies needed.
Cognitive Issues in Learning Advanced Physics: An Example from Quantum Mechanics
Singh, Chandralekha
2016-01-01
We are investigating cognitive issues in learning quantum mechanics in order to develop effective teaching and learning tools. The analysis of cognitive issues is particularly important for bridging the gap between the quantitative and conceptual aspects of quantum mechanics and for ensuring that the learning tools help students build a robust knowledge structure. We discuss the cognitive aspects of quantum mechanics that are similar or different from those of introductory physics and their implications for developing strategies to help students develop a good grasp of quantum mechanics.
Margaritondo, G
2003-01-01
Quantum physics is the backbone of modern science: therefore, a correct first step is essential for students' success in many different disciplines. Unfortunately, many didactic approaches are still complicated, potentially confusing and often historically wrong. An alternate, simple, stimulating and historically correct approach is outlined here.
Energy Technology Data Exchange (ETDEWEB)
Margaritondo, G [Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)
2003-01-01
Quantum physics is the backbone of modern science: therefore, a correct first step is essential for students' success in many different disciplines. Unfortunately, many didactic approaches are still complicated, potentially confusing and often historically wrong. An alternate, simple, stimulating and historically correct approach is outlined here.
From quantum to classical: Schrödinger cats, entanglement, and decoherence
Davidovich, L.
2016-06-01
Since the beginning of quantum physics, the relation between the properties of the microscopic quantum and the macroscopic classical world has been an important source for the development of the theory, and has led to new insights on the role of the environment in the transition from quantum to classical physics. Decoherence affects both coherence and entanglement of open systems. Quantum optics and cavity quantum electrodynamics have allowed detailed investigations of this phenomenon, within the framework of microwaves and light waves. In this paper, I present a personal account of theoretical and experimental developments that have led to the probing of the subtle frontier between quantum and classical phenomena.
Marshman, Emily; Sayer, Ryan; Henderson, Charles; Singh, Chandralekha
2017-06-01
At large research universities, physics graduate teaching assistants (TAs) are often responsible for grading in courses at all levels. However, few studies have focused on TAs' grading practices in introductory and advanced physics courses. This study was designed to investigate whether physics graduate TAs grade students in introductory physics and quantum mechanics using different criteria and if so, why they may be inclined to do so. To investigate possible discrepancies in TAs' grading approaches in courses at different levels, we implemented a sequence of instructional activities in a TA professional development course that asked TAs to grade student solutions of introductory physics and upper-level quantum mechanics problems and explain why, if at all, their grading approaches were different or similar in the two contexts. We analyzed the differences in TAs' grading approaches in the two contexts and discuss the reasons they provided for the differences in their grading approaches in introductory physics and quantum mechanics in individual interviews, class discussions, and written responses. We find that a majority of the TAs graded solutions to quantum mechanics problems differently than solutions to introductory physics problems. In quantum mechanics, the TAs focused more on physics concepts and reasoning and penalized students for not showing evidence of understanding. The findings of the study have implications for TA professional development programs, e.g., the importance of helping TAs think about the difficulty of a problem from an introductory students' perspective and reflecting on the benefits of formative assessment.
Macroscopic Theory of Dark Sector
Directory of Open Access Journals (Sweden)
Boris E. Meierovich
2014-01-01
Full Text Available A simple Lagrangian with squared covariant divergence of a vector field as a kinetic term turned out to be an adequate tool for macroscopic description of the dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant. Massive fields describe two different forms of dark matter. The space-like massive vector field is attractive. It is responsible for the observed plateau in galaxy rotation curves. The time-like massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four-parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating nonsingular scenarios of evolution of the Universe. In particular, the singular big bang turns into a regular inflation-like transition from contraction to expansion with the accelerated expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution is a particular limiting case at the lower boundary of existence of regular oscillating solutions in the absence of vector fields. The simplicity of the general covariant expression for the energy-momentum tensor allows displaying the main properties of the dark sector analytically. Although the physical nature of dark sector is still unknown, the macroscopic theory can help analyze the role of dark matter in astrophysical phenomena without resorting to artificial model assumptions.
A short course in quantum information theory. An approach from theoretical physics
Energy Technology Data Exchange (ETDEWEB)
Diosi, L. [KFKI Research Institute for Partical and Nuclear Physics, Budapest (Hungary)
2007-07-01
This short and concise primer takes the vantage point of theoretical physics and the unity of physics. It sets out to strip the burgeoning field of quantum information science to its basics by linking it to universal concepts in physics. An extensive lecture rather than a comprehensive textbook, this volume is based on courses delivered over several years to advanced undergraduate and beginning graduate students, but essentially it addresses anyone with a working knowledge of basic quantum physics. Readers will find these lectures a most adequate entry point for theoretical studies in this field. (orig.)
Report and recommendations on multimedia materials for teaching and learning quantum physics
Mason, B.; Dębowska, E.; Arpornthip, T.; Girwidz, R.; Greczyło, T.; Kohnle, A.; Melder, T.; Michelini, M.; Santi, L.; Silva, J.
2016-05-01
An international collaboration of physicists, affiliated with Multimedia Physics for Teaching and Learning (MPTL) and MERLOT, performed a survey and review of multimedia-based learning materials for quantum physics and quantum mechanics. The review process was based on more than a decade of experience with similar topical learning material reviews. A total of approximately 250 items were considered for review and eight were recommended by the reviewers. These are described in this report. Observations about quantum learning resources and multimedia tools are included.
Héraud, Jean-Loup; Lautesse, Philippe; Ferlin, Fabrice; Chabot, Hugues
2017-01-01
Our work extends a previous study of epistemological presuppositions in teaching quantum physics in upper scientific secondary school in France. Here, the problematic reference of quantum theory's concepts is treated at the ontological level (the counterintuitive nature of quantum objects). We consider the approach of using narratives describing…
Quantum Mechanics at the Crossroads New Perspectives from History, Philosophy and Physics
Evans, James
2007-01-01
Quantum mechanics is a beautiful, strange and successful theory that originated in the 1920s. The theory, which Niels Bohr regarded as finished and complete, has in the last few decades rapidly developed in unexpected directions. An intense new focus on the stranger aspects of the theory, including entanglement and nonlocality, has resulted in new perceptions of the foundations of quantum mechanics, as well as surprising new exploitations of quantum phenomena. Historians and philosophers of science have also renewed their attention to quantum mechanics, opening up its human dimensions and asking searching questions about its meaning. This volume brings together new insights from different vantage points: Historians of physics, such as J. L. Heilbron; philosophers of science, such as Abner Shimony and Michel Bitbol; and quantum physicists, such as Wolfgang Ketterle and Roland Omnès, join forces to tackle essential questions in quantum mechanics and its interpretation. All the authors have written for a broad ...
Quantum simulations in phase-space: from quantum optics to ultra-cold physics
Drummond, Peter D.; Chaturvedi, Subhash
2016-07-01
As a contribution to the international year of light, we give a brief history of quantum optics in phase-space, with new directions including quantum simulations of multipartite Bell violations, opto-mechanics, ultra-cold atomic systems, matter-wave Bell violations, coherent transport and quantum fluctuations in the early Universe. We mostly focus on exact methods using the positive-P representation, and semiclassical truncated Wigner approximations.
Esfeld, Michael
2014-01-01
The paper has two aims: (1) it sets out to show that it is well motivated to seek for an account of quantum non-locality in the framework of ontic structural realism (OSR), which integrates the notions of holism and non-separability that have been employed since the 1980s to achieve such an account. However, recent research shows that OSR on its own cannot provide such an account. Against this background, the paper argues that by applying OSR to the primitive ontology theories of quantum physics, one can accomplish that task. In particular, Bohmian mechanics offers the best prospect for doing so. (2) In general, the paper seeks to bring OSR and the primitive ontology theories of quantum physics together: on the one hand, in order to be applicable to quantum mechanics, OSR has to consider what the quantum ontology of matter distributed in space-time is. On the other hand, as regards the primitive ontology theories, OSR provides the conceptual tools for these theories to answer the question of what the ontologi...
Quantum field theory, statistical physics, and information theory
Energy Technology Data Exchange (ETDEWEB)
Toyoda, Tadashi [Tokai Univ., Kanagawa (Japan)
2001-05-01
It is shown that the one-particle Matsubara temperature Green's function can be regarded as a Fisher information matrix on the basis of the quantum generalization of relative entropy due to Watanabe and Neumann.
Friedberg, R; Hohenberg, P C
2014-09-01
Formulations of quantum mechanics (QM) can be characterized as realistic, operationalist, or a combination of the two. In this paper a realistic theory is defined as describing a closed system entirely by means of entities and concepts pertaining to the system. An operationalist theory, on the other hand, requires in addition entities external to the system. A realistic formulation comprises an ontology, the set of (mathematical) entities that describe the system, and assertions, the set of correct statements (predictions) the theory makes about the objects in the ontology. Classical mechanics is the prime example of a realistic physical theory. A straightforward generalization of classical mechanics to QM is hampered by the inconsistency of quantum properties with classical logic, a circumstance that was noted many years ago by Birkhoff and von Neumann. The present realistic formulation of the histories approach originally introduced by Griffiths, which we call 'compatible quantum theory (CQT)', consists of a 'microscopic' part (MIQM), which applies to a closed quantum system of any size, and a 'macroscopic' part (MAQM), which requires the participation of a large (ideally, an infinite) system. The first (MIQM) can be fully formulated based solely on the assumption of a Hilbert space ontology and the noncontextuality of probability values, relying in an essential way on Gleason's theorem and on an application to dynamics due in large part to Nistico. Thus, the present formulation, in contrast to earlier ones, derives the Born probability formulas and the consistency (decoherence) conditions for frameworks. The microscopic theory does not, however, possess a unique corpus of assertions, but rather a multiplicity of contextual truths ('c-truths'), each one associated with a different framework. This circumstance leads us to consider the microscopic theory to be physically indeterminate and therefore incomplete, though logically coherent. The completion of the theory
Interpretations of quantum theory and conceptions of physics majors
Directory of Open Access Journals (Sweden)
Roberto Luiz Montenegro
2002-05-01
Full Text Available This paper investigates the “private” interpretations that students of quantum mechanics develop concerning this theory. By means of questionaires, we analyze their conceptions with respect to the double slit experiment, uncertainty principle, quantum state, retrodiction, and projection postulate. Correlating the students’ answers, we observe that different private interpretations are frequently employed for analyzing different problems. Other conclusions about the cognitive processes of the students are also obtained.
Fractional Quantum Hall Physics in Jaynes-Cummings-Hubbard Lattices
Hayward, Andrew L. C.; Martin, Andrew M.; Greentree, Andrew D.
2012-01-01
Jaynes-Cummings-Hubbard arrays provide unique opportunities for quantum emulation as they exhibit convenient state preparation and measurement, and in-situ tuning of parameters. We show how to realise strongly correlated states of light in Jaynes-Cummings-Hubbard arrays under the introduction of an effective magnetic field. The effective field is realised by dynamic tuning of the cavity resonances. We demonstrate the existence of Fractional Quantum Hall states by com- puting topological invar...
A quantum physical design flow using ILP and graph drawing
Yazdani, Maryam; Saheb Zamani, Morteza; Sedighi, Mehdi
2013-10-01
Implementing large-scale quantum circuits is one of the challenges of quantum computing. One of the central challenges of accurately modeling the architecture of these circuits is to schedule a quantum application and generate the layout while taking into account the cost of communications and classical resources as well as the maximum exploitable parallelism. In this paper, we present and evaluate a design flow for arbitrary quantum circuits in ion trap technology. Our design flow consists of two parts. First, a scheduler takes a description of a circuit and finds the best order for the execution of its quantum gates using integer linear programming regarding the classical resources (qubits) and instruction dependencies. Then a layout generator receives the schedule produced by the scheduler and generates a layout for this circuit using a graph-drawing algorithm. Our experimental results show that the proposed flow decreases the average latency of quantum circuits by about 11 % for a set of attempted benchmarks and by about 9 % for another set of benchmarks compared with the best in literature.
A short course in quantum information theory. An approach from theoretical physics. 2. ed.
Energy Technology Data Exchange (ETDEWEB)
Diosi, Lajos [KFKI Research Institute for Particle and Nuclear Physics (RMKI), Budapest (Hungary). MTA Budapest
2011-07-01
This short and concise primer takes the vantage point of theoretical physics and the unity of physics. It sets out to strip the burgeoning field of quantum information science to its basics by linking it to universal concepts in physics. An extensive lecture rather than a comprehensive textbook, this volume is based on courses delivered over several years to advanced undergraduate and beginning graduate students, but essentially it addresses anyone with a working knowledge of basic quantum physics. Readers will find these lectures a most adequate entry point for theoretical studies in this field. For the second edition, the authors has succeeded in adding many new topics while sticking to the conciseness of the overall approach. A new chapter on qubit thermodynamics has been added, while new sections and subsections have been incorporated in various chapter to deal with weak and time-continuous measurements, period-finding quantum algorithms and quantum error corrections. From the reviews of the first edition: ''The best things about this book are its brevity and clarity. In around 100 pages it provides a tutorial introduction to quantum information theory, including problems and solutions.. it's worth a look if you want to quickly get up to speed with the language and central concepts of quantum information theory, including the background classical information theory.'' (Craig Savage, Australian Physics, Vol. 44 (2), 2007). (orig.)
Babin, Anatoli
2016-01-01
In this monograph, the authors present their recently developed theory of electromagnetic interactions. This neoclassical approach extends the classical electromagnetic theory down to atomic scales and allows the explanation of various non-classical phenomena in the same framework. While the classical Maxwell–Lorentz electromagnetism theory succeeds in describing the physical reality at macroscopic scales, it struggles at atomic scales. Here, quantum mechanics traditionally takes over to describe non-classical phenomena such as the hydrogen spectrum and de Broglie waves. By means of modifying the classical theory, the approach presented here is able to consistently explain quantum-mechanical effects, and while similar to quantum mechanics in some respects, this neoclassical theory also differs markedly from it. In particular, the newly developed framework omits probabilistic interpretations of the wave function and features a new fundamental spatial scale which, at the size of the free electron, is much lar...
"Shut up and calculate": the available discursive positions in quantum physics courses
Johansson, Anders; Andersson, Staffan; Salminen-Karlsson, Minna; Elmgren, Maja
2016-08-01
Educating new generations of physicists is often seen as a matter of attracting good students, teaching them physics and making sure that they stay at the university. Sometimes, questions are also raised about what could be done to increase diversity in recruitment. Using a discursive perspective, in this study of three introductory quantum physics courses at two Swedish universities, we instead ask what it means to become a physicist, and whether certain ways of becoming a physicist and doing physics is privileged in this process. Asking the question of what discursive positions are made accessible to students, we use observations of lectures and problem solving sessions together with interviews with students to characterize the discourse in the courses. Many students seem to have high expectations for the quantum physics course and generally express that they appreciate the course more than other courses. Nevertheless, our analysis shows that the ways of being a "good quantum physics student" are limited by the dominating focus on calculating quantum physics in the courses. We argue that this could have negative consequences both for the education of future physicists and the discipline of physics itself, in that it may reproduce an instrumental "shut up and calculate"-culture of physics, as well as an elitist physics education. Additionally, many students who take the courses are not future physicists, and the limitation of discursive positions may also affect these students significantly.
Quantum manipulations based on macroscopic artificial atoms%宏观人工原子相关的量子相干操纵
Institute of Scientific and Technical Information of China (English)
孙昌璞; 王颖丹; 张鹏; 刘玉玺
2006-01-01
文章着重介绍作者及其合作者于2005年8月份发表在Physical Review Letters的2篇文章[1,2]及其相关的系列研究工作[3-5].其中包括:(1)利用超导电荷量子比特的"Bang-Bang"控制,去冷却与之相耦合的纳米机械谐振器件,使之接近基态,以展示其丰富的量子效应;(2)具有△型能级结构超导人工原子的物理实现及其绝热量子操纵的奇异特性.为了深入了解这些工作的物理和潜在的应用背景,文章同时也介绍子超导量子比特物理实现及其相关的"全固态系统腔量子电动力学"研究的新进展,强调了基于超导人工原子的强耦合量子光学结构形成的物理机制.
Localization and Pattern Formation in Quantum Physics. II. Waveletons in Quantum Ensembles
Fedorova, A N; Fedorova, Antonina N.; Zeitlin, Michael G.
2005-01-01
In this second part we present a set of methods, analytical and numerical, which can describe behaviour in (non) equilibrium ensembles, both classical and quantum, especially in the complex systems, where the standard approaches cannot be applied. The key points demonstrating advantages of this approach are: (i) effects of localization of possible quantum states; (ii) effects of non-perturbative multiscales which cannot be calculated by means of perturbation approaches; (iii) effects of formation of complex/collective quantum patterns from localized modes and classification and possible control of the full zoo of quantum states, including (meta) stable localized patterns (waveletons). We demonstrate the appearance of nontrivial localized (meta) stable states/patterns in a number of collective models covered by the (quantum)/(master) hierarchy of Wigner-von Neumann-Moyal-Lindblad equations, which are the result of ``wignerization'' procedure (Weyl-Wigner-Moyal quantization) of classical BBGKY kinetic hierarchy...
Experimental quantum simulations of many-body physics with trapped ions.
Schneider, Ch; Porras, Diego; Schaetz, Tobias
2012-02-01
Direct experimental access to some of the most intriguing quantum phenomena is not granted due to the lack of precise control of the relevant parameters in their naturally intricate environment. Their simulation on conventional computers is impossible, since quantum behaviour arising with superposition states or entanglement is not efficiently translatable into the classical language. However, one could gain deeper insight into complex quantum dynamics by experimentally simulating the quantum behaviour of interest in another quantum system, where the relevant parameters and interactions can be controlled and robust effects detected sufficiently well. Systems of trapped ions provide unique control of both the internal (electronic) and external (motional) degrees of freedom. The mutual Coulomb interaction between the ions allows for large interaction strengths at comparatively large mutual ion distances enabling individual control and readout. Systems of trapped ions therefore exhibit a prominent system in several physical disciplines, for example, quantum information processing or metrology. Here, we will give an overview of different trapping techniques of ions as well as implementations for coherent manipulation of their quantum states and discuss the related theoretical basics. We then report on the experimental and theoretical progress in simulating quantum many-body physics with trapped ions and present current approaches for scaling up to more ions and more-dimensional systems.
Fundamentals of quantum physics. Textbook for students of science and engineering
Energy Technology Data Exchange (ETDEWEB)
Pereyra Padilla, Pedro [Universidad Autonoma Metropolitana, Mexico City (Mexico). Fisica Teorica y Materia Condensada
2012-07-01
A clearly written basic textbook with a good balance between basic explanations and applications. Supplies new views on eigenvalues and eigenfunctions in quantum mechanics. Gives background needed to understand quantum cryptography, teleportation and computation. Provides a clear and consistent understanding of quantum concepts and quantum phenomenology. This book presents a comprehensive course of quantum mechanics for undergraduate and graduate students. After a brief outline of the innovative ideas that lead up to the quantum theory, the book reviews properties of the Schroedinger equation, the quantization phenomena and the physical meaning of wave functions. The book discusses, in a direct and intelligible style, topics of the standard quantum formalism like the dynamical operators and their expected values, the Heisenberg and matrix representation, the approximate methods, the Dirac notation, harmonic oscillator, angular momentum and hydrogen atom, the spin-field and spin-orbit interactions, identical particles and Bose-Einstein condensation etc. Special emphasis is devoted to study the tunneling phenomena, transmission coefficients, phase coherence, energy levels splitting and related phenomena, of interest for quantum devices and heterostructures. The discussion of these problems and the WKB approximation is done using the transfer matrix method, introduced at a tutorial level. This book is a textbook for upper undergraduate physics and electronic engineering students.
Bohmian mechanics. The physics and mathematics of quantum theory
Energy Technology Data Exchange (ETDEWEB)
Duerr, Detlef [Muenchen Univ. (Germany). Fakultaet Mathematik; Teufel, Stefan [Tuebingen Univ. (Germany). Mathematisches Inst.
2009-07-01
Bohmian Mechanics was formulated in 1952 by David Bohm as a complete theory of quantum phenomena based on a particle picture. It was promoted some decades later by John S. Bell, who, intrigued by the manifestly nonlocal structure of the theory, was led to his famous Bell's inequalities. Experimental tests of the inequalities verified that nature is indeed nonlocal. Bohmian mechanics has since then prospered as the straightforward completion of quantum mechanics. This book provides a systematic introduction to Bohmian mechanics and to the mathematical abstractions of quantum mechanics, which range from the self-adjointness of the Schroedinger operator to scattering theory. It explains how the quantum formalism emerges when Boltzmann's ideas about statistical mechanics are applied to Bohmian mechanics. The book is self-contained, mathematically rigorous and an ideal starting point for a fundamental approach to quantum mechanics. It will appeal to students and newcomers to the field, as well as to established scientists seeking a clear exposition of the theory. (orig.)
The experimental failure of macroscopic determinism: the case of an electrocardiogram
Lapiedra, Ramon
2010-01-01
Even if never elucidated, the question of determinism is a standing question along the history of human thinking. A physical system evolves in a deterministic way if its future is completely determined once we have fixed some present characteristics of it, i.e., its initial conditions. The problem addressed in the present paper is to test determinism in the macroscopic domain. By imposing a very plausible ``separability'' assumption, we prove that determinism enters in contradiction with the recorded outcomes of a given electrocardiogram. The interest of this result comes from the fact such a basic idea as determinism has never been experimentally tested up to now in the macroscopic domain, and as far as we know not even in the quantum domain.
Singh, Chandralekha
2015-01-01
Very little is known about how the nature of expertise in introductory and advanced courses compares in knowledge-rich domains such as physics. We develop a framework to compare the similarities and differences between learning and patterns of student difficulties in introductory physics and quantum mechanics. Based upon our framework, we argue that the qualitative patterns of student reasoning difficulties in introductory physics bear a striking resemblance to those found for upper-level quantum mechanics. The framework can guide the design of teaching and learning tools.
An Economic Research Inspired by the Fundamental Principles of the Quantum Physics
Directory of Open Access Journals (Sweden)
Iurie BADAR
2015-12-01
Full Text Available At the beginning of the XX-th century, after a glorious history of about two centuries, the Newton’s classical physics enters into a great conceptual crisis, marked by the famous findings, which have subsequently represented the fundamentals of the quantum theory. They have thrown out the visions of the classical physics on the main laws of Universe development, the role of the human being and of knowledge in its functioning. Therefore, the quantum theory, confusing the traditional picture of its origin and evolution, gave birth to multiple conceptual issues related not only to physics, but disposing of obvious philosophical, ontological, cognitive and, more recently, economic aspects...
Quantum-enhanced absorption refrigerators
Correa, Luis A; Alonso, Daniel; Adesso, Gerardo
2014-01-01
Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step t...
Looking into DNA breathing dynamics via quantum physics.
Wu, Lian-Ao; Wu, Stephen S; Segal, Dvira
2009-06-01
We study generic aspects of bubble dynamics in DNA under time-dependent perturbations, for example, temperature change, by mapping the associated Fokker-Planck equation to a quantum time-dependent Schrödinger equation with imaginary time. In the static case we show that the eigenequation is exactly the same as that of the beta-deformed nuclear liquid drop model, without the issue of noninteger angular momentum. A universal breathing dynamics is demonstrated by using an approximate method in quantum mechanics. The calculated bubble autocorrelation function qualitatively agrees with experimental data. Under time-dependent modulations, utilizing the adiabatic approximation, bubble properties reveal memory effects.
Lecture notes on "Quantum chromodynamics and statistical physics"
Munier, Stephane
2014-01-01
The concepts and methods used for the study of disordered systems have proven useful in the analysis of the evolution equations of quantum chromodynamics in the high-energy regime: Indeed, parton branching in the semi-classical approximation relevant at high energies is a peculiar branching-diffusion process, and parton branching supplemented by saturation effects (such as gluon recombination) is a reaction-diffusion process. In these lectures, we first introduce the basic concepts in the context of simple toy models, we study the properties of the latter, and show how the results obtained for the simple models may be taken over to quantum chromodynamics.
Energy Technology Data Exchange (ETDEWEB)
Vallet, V. [Munich Univ., Institute for Theoretical Chemistry, Technical (Germany)
2003-01-01
Molecular and nano-molecular systems containing rare earth and actinides elements have extraordinary chemical and physical properties. Computer simulations using quantum chemistry methods can play an important role in many investigative procedures and provide help in understanding the microscopic nature of the interactions governing these macroscopic properties. The recent theoretical efforts have been devoted to the development of accurate and efficient methods that take into account all important interactions influencing the electronic structures, such as electron correlation and relativity. In particular, we illustrate the importance of relativity on chemical and spectroscopic properties. We will then focus on the modelling aspects of solution chemistry. (author)
Energy Technology Data Exchange (ETDEWEB)
Grawert, G. (Marburg Univ. (Germany, F.R.). Fachbereich 13 - Physik)
1989-01-01
The aim of the textbook now present in fifth edition is the representation of the fundamental physical concepts of the theory of quantum mechanics. It is confined to the nonrelativistic quantum mechanics; however also themes are treated which are in an extended form important just for quantum field theory up to the modern development. (orig.) With 22 figs.
Rowe, D. J.; McCoy, A. E.; Caprio, M. A.
2016-03-01
The nuclear collective models introduced by Bohr, Mottelson and Rainwater, together with the Mayer-Jensen shell model, have provided the central framework for the development of nuclear physics. This paper reviews the microscopic evolution of the collective models and their underlying foundations. In particular, it is shown that the Bohr-Mottelson models have expressions as macroscopic limits of microscopic models that have precisely defined expressions in many-nucleon quantum mechanics. Understanding collective models in this way is especially useful because it enables the analysis of nuclear properties in terms of them to be revisited and reassessed in the light of their microscopic foundations.
Physics colloquium: Electron counting in quantum dots in and out of equilibrium
Geneva University
2011-01-01
GENEVA UNIVERSITY Ecole de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92olé Lundi 31 octobre 2011 17h00 - Ecole de Physique, Auditoire Stueckelberg PHYSICS COLLOQUIUM « Electron counting in quantum dots in and out of equilibrium » Prof. Klaus Ensslin Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland Electron transport through quantum dots is governed by Coulomb blockade. Using a nearby quantum point contact the time-dependent charge flow through quantum dots can be monitored on the basis of single electrons. This way electron transport has been investigated in equilibrium as well as out of equilibrium. Recently it has become possible to experimentally verify the fluctuation theorem. The talk will also address electron counting experiments in grapheme. Une verrée ...
Quantum chromodynamics effects in electroweak and Higgs physics
Indian Academy of Sciences (India)
Frank Petriello
2012-10-01
Several examples of the often intricate effects of higher-order quantum chromodynamics (QCD) corrections on predictions for hadron-collider observables, are discussed, using the production of electroweak gauge boson and the Standard Model Higgs boson as examples. Particular attention is given to the interplay of QCD effects and experimental cuts, and to the use of scale variations as estimates of theoretical uncertainties.
Geometric Langlands Program and Dualities in Quantum Physics
2009-04-30
systems, such as the KdV hier- archy, to an affine analogue of the Langlands duality. We have conjectured that common eigenvalues of the mutually...the spectra of the quantum KdV Hamiltonians. (5) In the joint papers [2, 3] with B. Feigin and L. Rybnikov, we have studied the spectra of the
Quantum Chromodynamics and Nuclear Physics at Extreme Energy Density
Energy Technology Data Exchange (ETDEWEB)
Mueller, B.; Bass, S.A.; Chandrasekharan, S.; Mehen, T.; Springer, R.P.
2005-11-07
The report describes research in theoretical quantum chromodynamics, including effective field theories of hadronic interactions, properties of strongly interacting matter at extreme energy density, phenomenology of relativistic heavy ion collisions, and algorithms and numerical simulations of lattice gauge theory and other many-body systems.
Does Quantum Physics Refute Realism, Materialism and Determinism?
Bunge, Mario
2012-01-01
It is argued that the correct answer to the three questions in the title is "no": that the theses being denied derive from traditional philosophy, not from the way the quantum theories are used. For example, the calculation of the energy spectrum of an atom assumes the autonomous existence of the atom, rather than its dependence upon the observer.…
Does Quantum Physics Refute Realism, Materialism and Determinism?
Bunge, Mario
2012-01-01
It is argued that the correct answer to the three questions in the title is "no": that the theses being denied derive from traditional philosophy, not from the way the quantum theories are used. For example, the calculation of the energy spectrum of an atom assumes the autonomous existence of the atom, rather than its dependence upon the observer.…
The macroscopic pancake bounce
Andersen Bro, Jonas; Sternberg Brogaard Jensen, Kasper; Nygaard Larsen, Alex; Yeomans, Julia M.; Hecksher, Tina
2017-01-01
We demonstrate that the so-called pancake bounce of millimetric water droplets on surfaces patterned with hydrophobic posts (Liu et al 2014 Nat. Phys. 10 515) can be reproduced on larger scales. In our experiment, a bed of nails plays the role of the structured surface and a water balloon models the water droplet. The macroscopic version largely reproduces the features of the microscopic experiment, including the Weber number dependence and the reduced contact time for pancake bouncing. The scalability of the experiment confirms the mechanisms of pancake bouncing, and allows us to measure the force exerted on the surface during the bounce. The experiment is simple and inexpensive and is an example where front-line research is accessible to student projects.