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quant-ph/9606024
null
Roberto Onofrio and Lorenza Viola
Quantum damping of position due to energy measurements
19 pages + 4 figures available upon request; Plain REVTeX; To be published in Phys. Rev. A
null
10.1103/PhysRevA.53.3773
null
quant-ph
null
Quantum theory for measurements of energy is introduced and its consequences for the average position of monitored dynamical systems are analyzed. It turns out that energy measurements lead to a localization of the expectation values of other observables. This is manifested, in the case of position, as a damping of the motion without classical analogue. Quantum damping of position for an atom bouncing on a reflecting surface in presence of a homogeneous gravitational field is dealt in detail and the connection with an experiment already performed in the classical regime is studied. We show that quantum damping is testable provided that the same measurement strength obtained in the experimental verification of the quantum Zeno effect in atomic spectroscopy [W. M. Itano et al., Phys. Rev. A {\bf 41}, 2295 (1990)] is made available.
[ { "version": "v1", "created": "Mon, 24 Jun 1996 10:01:56 GMT" } ]
2009-10-30T00:00:00
[ [ "Onofrio", "Roberto", "" ], [ "Viola", "Lorenza", "" ] ]
quant-ph/9606025
Todd A. Brun
Todd A. Brun (Physics, QMW, University of London)
Quantum jumps as decoherent histories
8 pages RevTeX 3.0, considerably revised and shortened. To appear in the 17 March issue of Phys. Rev. Letters
Phys.Rev.Lett. 78 (1997) 1833-1837
10.1103/PhysRevLett.78.1833
QMW-PH-96-11
quant-ph atom-ph gr-qc
null
Quantum open systems are described in the Markovian limit by master equations in Lindblad form. I argue that common ``quantum jumps'' techniques, which solve the master equation by unraveling its evolution into stochastic trajectories in Hilbert space, correspond closely to a particular set of decoherent histories. This is illustrated by a simple model of a photon counting experiment.
[ { "version": "v1", "created": "Mon, 24 Jun 1996 16:16:46 GMT" }, { "version": "v2", "created": "Sat, 22 Feb 1997 03:04:18 GMT" } ]
2009-10-30T00:00:00
[ [ "Brun", "Todd A.", "", "Physics, QMW, University of London" ] ]
quant-ph/9606026
Simon Gardiner
S. A. Gardiner (Innsbruck), J. I. Cirac (Castilla-La Mancha), and P. Zoller (Innsbruck)
Measurement of Arbitrary Observables of a Trapped Ion
4 pages RevTeX, 4 eps figures, packaged together with tar and gzip
null
null
null
quant-ph
null
We describe a method to perform a single quantum measurement of an arbitrary observable of a single ion moving in a harmonic potential. We illustrate the measurement procedure with explicit examples, namely the position and phase observables.
[ { "version": "v1", "created": "Mon, 24 Jun 1996 16:30:25 GMT" } ]
2007-05-23T00:00:00
[ [ "Gardiner", "S. A.", "", "Innsbruck" ], [ "Cirac", "J. I.", "", "Castilla-La Mancha" ], [ "Zoller", "P.", "", "Innsbruck" ] ]
quant-ph/9606027
Ryszard Horodecki
Ryszard Horodecki, Michal Horodecki and Pawel Horodecki
Teleportation, Bell's Inequalities and Inseparability
RevTeX, 4 pages
null
10.1016/0375-9601(96)00639-1
null
quant-ph
null
Relations between teleportation, Bell's inequalities and inseparability are investigated. It is shown that any mixed two spin-$1\over2$ state which violates the Bell-CHSH inequality is useful for teleportation. The result is extended to any Bell's inequalities constructed of the expectation values of products of spin operators. It is also shown that there exist inseparable states which are not useful for teleportation within the standard scheme.
[ { "version": "v1", "created": "Tue, 25 Jun 1996 15:59:46 GMT" } ]
2009-10-30T00:00:00
[ [ "Horodecki", "Ryszard", "" ], [ "Horodecki", "Michal", "" ], [ "Horodecki", "Pawel", "" ] ]
quant-ph/9606028
Paul M. Sheldon
Paul M. Sheldon (University of Texas at Dallas)
Correct interpretation of trace normalized density matrices as ensembles
Revision here adds two items : 1. an introduction attempting to illuminate debate by Penrose and Hawking on Schrodinger's cat in their book, "The nature of space and time", and 2. references extending my work inspired by Andreas Albrecht "Following a Collapsing Wavefunction" (hep-th/9309051). 6 pages, latex, refers to hep-th/9309051
null
null
null
quant-ph
null
A density operator, $\rho = {P}_{\alpha } |\alpha > <\alpha | + {P}_{\beta } |\beta > <\beta |$, with ${P}_{\alpha }$ and ${P}_{\beta }$ linearly independent normalized wave functions, must be traced normalized, so ${P}_{\beta } = 1 - {P}_{\alpha }$. However, unless $<\alpha |\beta > = 0$, ${P}_{\alpha }$ and ${P}_{\beta }$ cannot be interpreted as probabilities of finding $|\alpha >$ and $|\beta >$ respectively. We show that a density matrix comprised of two (${P}_{\alpha }$ and ${P}_{\beta }$ nonzero) non-orthogonal projectors have unique spectral decomposition into diagonal form with orthogonal projectors. Only then, according to axioms of Von Neumann and Fock, can we have probability interpretation of that density matrix, only then can the diagonal elements be interpreted as probabilities of an ensemble. Those probabilities on the diagonal are not ${P}_{\alpha }$ and ${P}_{\beta}$. Further, only in the case of orthogonal projectors can we have the degenerate situation in which multiple ensembles are permitted.
[ { "version": "v1", "created": "Tue, 25 Jun 1996 16:21:02 GMT" }, { "version": "v2", "created": "Wed, 31 Jul 1996 04:31:05 GMT" }, { "version": "v3", "created": "Fri, 2 Aug 1996 00:11:16 GMT" }, { "version": "v4", "created": "Sat, 3 May 1997 00:58:04 GMT" } ]
2008-02-03T00:00:00
[ [ "Sheldon", "Paul M.", "", "University of Texas at Dallas" ] ]
quant-ph/9606029
Marc Jaekel
Astrid Lambrecht (Max-Planck-Institut f\"ur Quantenoptik), Marc-Thierry Jaekel (Laboratoire de Physique Th\'eorique de l'Ecole Normale Sup\'erieure) and Serge Reynaud (Laboratoire Kastler-Brossel)
Motion Induced Radiation from a Vibrating Cavity
4 pages, to appear in Physical Review Letters
Phys. Rev. Lett. 77 (1996) 615
10.1103/PhysRevLett.77.615
LPTENS 96/03
quant-ph
null
We study the radiation emitted by a cavity moving in vacuum. We give a quantitative estimate of the photon production inside the cavity as well as of the photon flux radiated from the cavity. A resonance enhancement occurs not only when the cavity length is modulated but also for a global oscillation of the cavity. For a high finesse cavity the emitted radiation surpasses radiation from a single mirror by orders of magnitude.
[ { "version": "v1", "created": "Wed, 26 Jun 1996 14:05:18 GMT" } ]
2009-10-30T00:00:00
[ [ "Lambrecht", "Astrid", "", "Max-Planck-Institut für Quantenoptik" ], [ "Jaekel", "Marc-Thierry", "", "Laboratoire de Physique Théorique de l'Ecole Normale\n Supérieure" ], [ "Reynaud", "Serge", "", "Laboratoire Kastler-Brossel" ] ]
quant-ph/9606030
Marc Jaekel
Marc-Thierry Jaekel (Laboratoire de Physique Th\'eorique de l'Ecole Normale Sup\'erieure) and Serge Reynaud (Laboratoire Kastler-Brossel)
Space-Time Localisation with Quantum Fields
11 pages, to appear in Physics Letters A
Phys. Lett. A 220 (1996) 10
10.1016/0375-9601(96)00496-3
LPTENS 96/30
quant-ph gr-qc
null
We introduce observables associated with the space-time position of a quantum point defined by the intersection of two light pulses. The time observable is canonically conjugated to the energy. Conformal symmetry of massless quantum fields is used first to build the definition of these observables and then to describe their relativistic properties under frame transformations. The transformations to accelerated frames of the space-time observables depart from the laws of classical relativity. The Einstein laws for the shifts of clock rates and frequencies are recovered in the quantum description, and their formulation provides a conformal metric factor behaving as a quantum observable.
[ { "version": "v1", "created": "Wed, 26 Jun 1996 14:12:44 GMT" } ]
2009-10-30T00:00:00
[ [ "Jaekel", "Marc-Thierry", "", "Laboratoire de Physique Théorique de l'Ecole\n Normale Supérieure" ], [ "Reynaud", "Serge", "", "Laboratoire Kastler-Brossel" ] ]
quant-ph/9606031
Hans-Juergen Matschull
Hans-Juergen Matschull
Dirac's Canonical Quantization Programme
40 pages, LaTeX2e
null
null
null
quant-ph gr-qc hep-th
null
This is a collection of lectures given at the University of Heidelberg, especially but not exclusively for people who want to learn something about the canonical approach to quantum gravity, which is however not included in these lectures. They are about Dirac's general method to construct a quantum theory out of a classical theory, which has to be defined in terms of a Lagrangian. The classical Hamiltonian formalism is reviewed, with emphasis on the relation between constraints and gauge symmetries, and quantization is carried out without any kind of gauge fixing. The method is applied to three examples: the free electro-magnetic field, the relativistic point particle, and the very first steps of string theory are carried out.
[ { "version": "v1", "created": "Wed, 26 Jun 1996 19:28:09 GMT" } ]
2007-05-23T00:00:00
[ [ "Matschull", "Hans-Juergen", "" ] ]
quant-ph/9606032
Ali Mostafazadeh
Ali Mostafazadeh
Adiabatic Product Expansion
uuencoded LaTeX file, 8 pages
Phys.Lett. A228 (1997) 7-12
10.1016/S0375-9601(97)00100-X
Uni. of Alberta preprint, TPI June 1996
quant-ph hep-th
null
The time-evolution operator for an explicitly time-dependent Hamiltonian is expressed as the product of a sequence of unitary operators. These are obtained by successive time-dependent unitary transformations of the Hilbert space followed by the adiabatic approximation at each step. The resulting adiabatic product expansion yields a generalization of the quantum adiabatic approximation. Furthermore, it leads to an infinite class of exactly solvable models.
[ { "version": "v1", "created": "Fri, 28 Jun 1996 04:43:52 GMT" } ]
2009-10-30T00:00:00
[ [ "Mostafazadeh", "Ali", "" ] ]
quant-ph/9606033
Klaus Hasselmann
K. Hasselmann (Max Planck Institure for Meteorology, Hamburg, Germany)
The metron model: Elements of a unified deterministic theory of fields and particles
141 pages, LaTeX2e
Phys.Essays 9:311-325,1996
10.4006/1.3029238
MPI report no. 172, Hamburg, October 1995
quant-ph
null
Keywords (parts 1-4): metron / unified theory / wave particle duality / higher-dimensional gravity / solitons / Maxwell-Dirac-Einstein system / Standard Model / EPR paradox / Bell's theorem / arrow of time
[ { "version": "v1", "created": "Fri, 28 Jun 1996 11:21:07 GMT" }, { "version": "v2", "created": "Tue, 6 Aug 1996 13:15:56 GMT" } ]
2015-06-26T00:00:00
[ [ "Hasselmann", "K.", "", "Max Planck Institure for Meteorology, Hamburg, Germany" ] ]
quant-ph/9606034
null
G. M. D'Ariano, S. Mancini, V. I. Man'ko and P. Tombesi
Reconstructing the density operator by using generalized field quadratures
17 pages, Latex,accepted by Quantum and Semiclassical Optics
Quant.Semiclass.Opt. 8 (1996) 1017
10.1088/1355-5111/8/5/007
null
quant-ph
null
The Wigner function for one and two-mode quantum systems is explicitely expressed in terms of the marginal distribution for the generic linearly transformed quadratures. Then, also the density operator of those systems is written in terms of the marginal distribution of these quadratures. Some examples to apply this formalism, and a reduction to the usual optical homodyne tomography are considered.
[ { "version": "v1", "created": "Sat, 29 Jun 1996 11:54:31 GMT" } ]
2009-10-30T00:00:00
[ [ "D'Ariano", "G. M.", "" ], [ "Mancini", "S.", "" ], [ "Man'ko", "V. I.", "" ], [ "Tombesi", "P.", "" ] ]
quant-ph/9606035
Marek Szopa
Marek Szopa (University of Silesia, Katowice, Poland), Geert Mys and Arnout Ceulemans (University of Leuven, Leuven, Belgium)
The Canonical Form of the Rabi Hamiltonian
17 pages, LaTeX, no figures, to appear in J.Math.Phys
J.Math.Phys. 37 (1996) 5402-5411
10.1063/1.531711
null
quant-ph atom-ph hep-th
null
The Rabi Hamiltonian, describing the coupling of a two-level system to a single quantized boson mode, is studied in the Bargmann-Fock representation. The corresponding system of differential equations is transformed into a canonical form in which all regular singularities between zero and infinity have been removed. The canonical or Birkhoff-transformed equations give rise to a two-dimensional eigenvalue problem, involving the energy and a transformational parameter which affects the coupling strength. The known isolated exact solutions of the Rabi Hamiltonian are found to correspond to the uncoupled form of the canonical system.
[ { "version": "v1", "created": "Sat, 29 Jun 1996 18:14:45 GMT" } ]
2009-10-30T00:00:00
[ [ "Szopa", "Marek", "", "University of Silesia, Katowice, Poland" ], [ "Mys", "Geert", "", "University of Leuven, Leuven, Belgium" ], [ "Ceulemans", "Arnout", "", "University of Leuven, Leuven, Belgium" ] ]
quant-ph/9607001
Ludger Hannibal
Ludger Hannibal (University of Oldenburg, Germany)
Geometric Foundation of Spin and Isospin
9 pages Latex
null
null
null
quant-ph gr-qc
null
Various theories of spinning particles are interpreted as realizing elements of an underlying geometric theory. Classical particles are described by trajectories on the Poincare group. Upon quantization an eleven-dimensional Kaluza-Klein type theory is obtained which incorporates spin and isospin in a local SL(2,C) x U(1) x SU(2) theory with broken U(1)x SU(2) part.
[ { "version": "v1", "created": "Mon, 1 Jul 1996 08:11:32 GMT" } ]
2007-05-23T00:00:00
[ [ "Hannibal", "Ludger", "", "University of Oldenburg, Germany" ] ]
quant-ph/9607002
Olavo Leopoldino Da Silva Filho
L. S. F. Olavo
Quantum Mechanics as a Classical Theory XI: Thermodynamics and Equilibrium
11 pages, plain latex, no figures
null
null
UnB011
quant-ph
null
In this continuation paper the theory is further extended to reveal the connection between its formal aparatus, dealing with microscopic quantities, and the formal aparatus of thermodynamics, related to macroscopic properties of large systems. We will also derive the Born-Sommerfeld quantization rules from the formalism of the infinitesimal Wigner-Moyal transformations and, as a consequence of this result, we will also make a connection between the later and the path integral approach of Feynman. Some insights of the relation between quantum mechanics and equilibrium states will be given as a natural development of the interpretation of the above results.
[ { "version": "v1", "created": "Mon, 1 Jul 1996 20:33:06 GMT" } ]
2007-05-23T00:00:00
[ [ "Olavo", "L. S. F.", "" ] ]
quant-ph/9607003
Olavo Leopoldino Da Silva Filho
L.S.F. Olavo
Quantum Mechanics as a Classical Theory XII: Diffraction and Interference
9 pages of plain Latex
null
null
UnB-012
quant-ph
null
In this paper we will be concerned with the explanation of the interference and diffraction patterns observed as an outcome of the Young double slit experiment. We will show that such explanation may be given {\it only} in terms of a corpuscular theory, which has been our approach since the first paper of this series. This explanation will be accomplished with an extension we make here of the domain of applicability of the Born-Sommerfeld rules that we derived in paper XI of this series.
[ { "version": "v1", "created": "Mon, 1 Jul 1996 21:39:06 GMT" } ]
2016-09-08T00:00:00
[ [ "Olavo", "L. S. F.", "" ] ]
quant-ph/9607004
Alberto Rimini
Giulio Peruzzi and Alberto Rimini
Quantum measurement in a family of hidden-variable theories
16 pages, LaTeX; all special macros are included in the file; a figure is there, but it is processed by LaTeX
Found.Phys.Lett. 9 (1996) 505
10.1007/BF02190027
FNT/T-96/15
quant-ph
null
The measurement process for hidden-configuration formulations of quantum mechanics is analysed. It is shown how a satisfactory description of quantum measurement can be given in this framework. The unified treatment of hidden-configuration theories, including Bohmian mechanics and Nelson's stochastic mechanics, helps in understanding the true reasons why the problem of quantum measurement can succesfully be solved within such theories.
[ { "version": "v1", "created": "Thu, 4 Jul 1996 16:13:52 GMT" } ]
2009-10-30T00:00:00
[ [ "Peruzzi", "Giulio", "" ], [ "Rimini", "Alberto", "" ] ]
quant-ph/9607005
Victor Dodonov
V. V. Dodonov (1), A. B. Klimov (2), V.I. Man'ko (3) ( (1) Universidade Federal de Sao Carlos, Brasil, (2) Universidad de Guadalajara, Mexico, (3) Oservatorio Astronomico di Capodimonte, Napoli, Italy )
Low Energy Wave Packet Tunneling from a Parabolic Potential Well through a High Potential Barrier
14 pages, LaTex type, to appear in Physics Letters A
null
10.1016/0375-9601(96)00482-3
null
quant-ph
null
The problem of wave packet tunneling from a parabolic potential well through a barrier represented by a power potential is considered in the case when the barrier height is much greater than the oscillator ground state energy, and the difference between the average energy of the packet and the nearest oscillator eigenvalue is sufficiently small. The universal Poisson distribution of the partial tunneling rates from the oscillator energy levels is discovered. The explicit expressions for the tunneling rates of different types of packets (coherent, squeezed, even/odd, thermal, etc.) are given in terms of the exponential and modified Bessel functions. The tunneling rates turn out very sensitive to the energy distributions in the packets, and they may exceed significantly the tunneling rate from the energy state with the same average number of quanta.
[ { "version": "v1", "created": "Thu, 4 Jul 1996 20:35:23 GMT" } ]
2009-10-30T00:00:00
[ [ "Dodonov", "V. V.", "" ], [ "Klimov", "A. B.", "" ], [ "Man'ko", "V. I.", "" ] ]
quant-ph/9607006
Dirk Sondermann
Almut Beige, Gerhard C. Hegerfeldt, Dirk G. Sondermann
Laser Pulses as Measurements. Application to the Quantum Zeno Effect
18 pages, LaTeX; to appear in Quantum Semiclass. Opt
Quant.Semiclass.Opt. 8 (1996) 999
10.1088/1355-5111/8/5/006
null
quant-ph
null
Short pulses of a probe laser have been used in the past to measure whether a two-level atom is in its ground or excited state. The probe pulse couples the ground state to a third, auxiliary, level of the atom. Occurrence or absence of resonance fluorescence were taken to mean that the atom was found in its ground or excited state, respectively. In this paper we investigate to what extent this procedure results in an effective measurement to which the projection postulate can be applied, at least approximately. We discuss in detail the complications arising from an additional time development of the two-level system proper during a probe pulse. We extend our previous results for weak probe pulses to the general case and show that one can model an ideal (projection-postulate) measurement much better with a strong than a weak probe pulse. In an application to the quantum Zeno effect we calculate the slow-down of the atomic time development under n repeated probe pulse measurements and determine the corrections compared to the case of n ideal measurements.
[ { "version": "v1", "created": "Thu, 4 Jul 1996 22:32:53 GMT" } ]
2009-10-30T00:00:00
[ [ "Beige", "Almut", "" ], [ "Hegerfeldt", "Gerhard C.", "" ], [ "Sondermann", "Dirk G.", "" ] ]
quant-ph/9607007
Ryszard Horodecki
Ryszard Horodecki and Michal Horodecki
Information-theoretic aspects of quantum inseparability of mixed states
Revtex, 19 pages, to appear in Phys. Rev. A, vol. 54; one postscript figure available at request from [email protected]
null
10.1103/PhysRevA.54.1838
null
quant-ph
null
Information-theoretic aspects of quantum inseparability of mixed states are investigated in terms of the $\alpha$-entropy inequalities and teleportation fidelity. Inseparability of mixed states is defined and a complete characterization of the inseparable $2\times2$ systems with maximally disordered subsystems is presented within the Hilbert-Schmidt space formalism. A connection between teleportation and negative conditional $\alpha$-entropy is also emphasized.
[ { "version": "v1", "created": "Mon, 8 Jul 1996 11:46:14 GMT" } ]
2009-10-30T00:00:00
[ [ "Horodecki", "Ryszard", "" ], [ "Horodecki", "Michal", "" ] ]
quant-ph/9607008
Piotr Kochanski
Piotr Kochanski, Krzysztof Wodkiewicz
Intrinsic and Operational Observables in Quantum Mechanics
8 pages, LaTex type, 2 Encapsulated Postscript figures, uses a4wide.sty, to appear in acta physica slovaca vol. 46 No. 3 (1996)
null
null
IFT UW 96-06
quant-ph
null
The concept of intrinsic and operational observables in quantum mechanics is introduced. It is argued that, in any realistic description of a quantum measurement that includes a detecting device, it is possible to construct from the statistics of the recorded raw data a set of operational quantities that correspond to the intrinsic quantum mechanical observable. Using the concept of the propensity and the associated operational positive operator valued measure (POVM) a general description of the operational algebra of quantum mechanical observables is derived for a wide class of realistic detection schemes. This general approach is illustrated by the example of an operational Malus measurement of the spin phases and by an analysis of the operational homodyne detection of the phase of an optical field with a squeezed vacuum in the unused ports.
[ { "version": "v1", "created": "Wed, 10 Jul 1996 15:22:22 GMT" } ]
2007-05-23T00:00:00
[ [ "Kochanski", "Piotr", "" ], [ "Wodkiewicz", "Krzysztof", "" ] ]
quant-ph/9607009
Ryszard Horodecki
Michal Horodecki, Pawel Horodecki and Ryszard Horodecki
Distillability of Inseparable Quantum Systems
Revtex, 4 pages (in twocolumn format), introduction and conclusion are slightly modified; one postscript figure available at request from [email protected]
null
null
null
quant-ph
null
We apply the inseparability criterion for $2 \times 2$ systems, local filtering and Bennett et al. purification protocol [Phys. Rev. Lett. {\bf 76}, 722 (1996)] to show how to distill {\it any} inseparable $2\times 2$ system. The extended protocol is illustrated geometrically by means of the state parameters in the Hilbert-Schmidt space.
[ { "version": "v1", "created": "Thu, 11 Jul 1996 13:39:46 GMT" }, { "version": "v2", "created": "Wed, 2 Oct 1996 13:20:52 GMT" } ]
2008-02-03T00:00:00
[ [ "Horodecki", "Michal", "" ], [ "Horodecki", "Pawel", "" ], [ "Horodecki", "Ryszard", "" ] ]
quant-ph/9607010
K. Y. Szeto
K.Y. Szeto
Data Compression for Quantum Code
12 pages, Latex file double space
null
null
null
quant-ph
null
The general scheme of data compression using the quantum noiseless coding theorem of Schumacher is dicussed for general quantum sources. When the Hilbert space of the quantum source is decomposable into orthogonal subspaces, one can first perform classical data compression before performing the quantum data compression for individual subspaces. For minimizing the resource in quantum coding, a general parameterization of the dimensions in the Jozsa-Schumacher quantum data compression scheme is presented.
[ { "version": "v1", "created": "Fri, 12 Jul 1996 02:28:20 GMT" } ]
2007-05-23T00:00:00
[ [ "Szeto", "K. Y.", "" ] ]
quant-ph/9607011
Walter T. Strunz
Ian C. Percival and Walter T. Strunz
Detection of space-time fluctuations by a model matter interferometer
TeX, 23 pages, submitted to Proc. Roy. Soc. Lond
null
10.1098/rspa.1997.0025
QMW-PH-96-15
quant-ph
null
In papers on primary state diffusion (Percival 1994, 1995), numerical estimates suggested that fluctuations in the space-time metric on the scale of the Planck time (10^-44s) could be detected using atom interferometers. In this paper we first specify a stochastic metric obtained from fluctuations that propagate with the velocity of light, and then develop the non-Markovian quantum state diffusion theory required to estimate the resulting decoherence effects on a model matter interferometer. Both commuting and non-commuting fluctuations are considered. The effects of the latter are so large that if they applied to some real atom interferometry experiments they would have suppressed the observed interference. The model is too crude to conclude that such fluctuations do not exist, but it does demonstrate that the small numerical value of the Planck time does not alone prevent experimental access to Planck-scale phenomena in the laboratory.
[ { "version": "v1", "created": "Mon, 15 Jul 1996 17:03:18 GMT" } ]
2009-10-30T00:00:00
[ [ "Percival", "Ian C.", "" ], [ "Strunz", "Walter T.", "" ] ]
quant-ph/9607012
Hong-Chen FU
Hong-Chen Fu and Ryu Sasaki
Generalized Binomial States: Ladder Operator Approach
LaTeX-2e, 11 pages, no figure. Accepted for publication in J.Phys.A:math.Gen
J.Phys.A29:5637-5644,1996
10.1088/0305-4470/29/17/034
YITP-96-25
quant-ph
null
We show that the binomial states (BS) of Stoler {\it et al.} admit the ladder and displacement operator formalism. By generalizing the ladder operator formalism we propose an eigenvalue equation which possesses the number and the squeezed states as its limiting solutions. The explicit forms of the solutions, to be referred to as the {\it generalized binomial states} (GBS), are given. Corresponding to the wide range of the eigenvalue spectrum these GBS have as widely different properties. Their limits to number and {\it squeezed} states are investigated in detail. The time evolution of BS is obtained as a special case of the approach.
[ { "version": "v1", "created": "Mon, 15 Jul 1996 08:55:33 GMT" } ]
2008-11-26T00:00:00
[ [ "Fu", "Hong-Chen", "" ], [ "Sasaki", "Ryu", "" ] ]
quant-ph/9607013
Rafael Ferraro
Rafael Ferraro
The complete solution of the Hamilton-Jacobi equation in Quantum Mechanics
8 pages (TeX manuscript)
null
null
null
quant-ph gr-qc hep-th
null
An ordinary unambiguous integral representation for the finite propagator of a quantum system is found by starting of a privileged skeletonization of the functional action in phase space, provided by the complete solution of the Hamilton-Jacobi equation. This representation allows to regard the propagator as the sum of the contributions coming from paths where the momenta generated by the complete solution of the Hamilton-Jacobi equation are conserved -as it does happen on the classical trajectory-, but are not restricted to having the classical values associated with the boundary conditions for the original coordinates.
[ { "version": "v1", "created": "Wed, 17 Jul 1996 16:36:00 GMT" } ]
2007-05-23T00:00:00
[ [ "Ferraro", "Rafael", "" ] ]
quant-ph/9607014
Christophe Durr
Christoph Durr and Peter Hoyer
A Quantum Algorithm for Finding the Minimum
2 pages
null
null
null
quant-ph cs.DS
null
We give a quantum algorithm to find the index y in a table T of size N such that in time O(c sqrt N), T[y] is minimum with probability at least 1-1/2^c.
[ { "version": "v1", "created": "Thu, 18 Jul 1996 19:12:42 GMT" }, { "version": "v2", "created": "Thu, 7 Jan 1999 16:50:45 GMT" } ]
2008-02-03T00:00:00
[ [ "Durr", "Christoph", "" ], [ "Hoyer", "Peter", "" ] ]
quant-ph/9607015
Adonai S. Sant'Anna
Adonai S. Sant'Anna and Decio Krause (Departamento de Matematica, Universidade Federal do Parana)
Indistinguishable particles and hidden variables
17 pages, LaTeX format
null
10.1007/BF02764019
null
quant-ph
null
An axiomatics for indistinguishability of elementary particles in terms of hidden variables is presented in a manner which depart from the standard approaches usually given to hidden variables. Quantum distribution functions are also discussed and some related lines of work are suggested.
[ { "version": "v1", "created": "Thu, 18 Jul 1996 21:46:03 GMT" } ]
2009-10-30T00:00:00
[ [ "Sant'Anna", "Adonai S.", "", "Departamento de Matematica,\n Universidade Federal do Parana" ], [ "Krause", "Decio", "", "Departamento de Matematica,\n Universidade Federal do Parana" ] ]
quant-ph/9607016
Marc Jaekel
Astrid Lambrecht (Max-Planck-Institut f\"ur Quantenoptik), Marc-Thierry Jaekel (Laboratoire de Physique Th\'eorique de l'Ecole Normale Sup\'erieure) and Serge Reynaud (Laboratoire Kastler-Brossel)
Comment on ``Sonoluminescence as Quantum Vacuum Radiation''
1 page
Phys.Rev.Lett.78:2267,1997
10.1103/PhysRevLett.78.2267
LPTENS 96/40
quant-ph
null
We contest the recent claim by C. Eberlein (Physical Review Letters 76 (1996) 3842) that sonoluminescence may be explained in terms of quantum vacuum radiation. Due to fundamental physical limitations on bubble surface velocity, the predicted number of photons per flash is indeed much smaller than unity. Therefore, quantum vacuum radiation cannot be considered as an explanation of the observed sonoluminescence phenomenon.
[ { "version": "v1", "created": "Fri, 19 Jul 1996 13:42:12 GMT" } ]
2008-11-26T00:00:00
[ [ "Lambrecht", "Astrid", "", "Max-Planck-Institut für Quantenoptik" ], [ "Jaekel", "Marc-Thierry", "", "Laboratoire de Physique Théorique de l'Ecole Normale\n Supérieure" ], [ "Reynaud", "Serge", "", "Laboratoire Kastler-Brossel" ] ]
quant-ph/9607017
Preprints Libr/pam
Yuri Orlov
Peculiarities of Quantum Mechanics: Origins and Meaning
51 pages. LaTeX document with 4 EPS figures. A 5th figure(figure 2) can be obtained from http://w4.lns.cornell.edu/public/CLNS/1996/CLNS96-1399/1399-fig2.gif
null
null
CLNS 96/1399
quant-ph
null
The most peculiar, specifically quantum, features of quantum mechanics --- quantum nonlocality, indeterminism, interference of probabilities, quantization, wave function collapse during measurement --- are explained on a logical-geometrical basis. It is shown that truths of logical statements about numerical values of quantum observables are quantum observables themselves and are represented in quantum mechanics by density matrices of pure states. Structurally, quantum mechanics is a result of applying non-Abelian symmetries to truth operators and their eigenvectors --- wave functions. Wave functions contain information about conditional truths of all possible logical statements about physical observables and their correlations in a given physical system. These correlations are logical, hence nonlocal, and exist when the system is not observed. We analyze the physical conditions and logical and decision-making operations involved in the phenomena of wave function collapse and unpredictability of the results of measurements. Consistent explanations of the Stern-Gerlach and EPR-Bohm experiments are presented."
[ { "version": "v1", "created": "Fri, 19 Jul 1996 16:52:13 GMT" } ]
2016-09-08T00:00:00
[ [ "Orlov", "Yuri", "" ] ]
quant-ph/9607018
Mark Hillery
Vladimir Buzek and Mark Hillery
Quantum Copying: Beyond the No-Cloning Theorem
RevTex, 26 pages, to appear in Physical Review A
null
10.1103/PhysRevA.54.1844
null
quant-ph
null
We analyze to what extent it is possible to copy arbitrary states of a two-level quantum system. We show that there exists a "universal quantum copying machine", which approximately copies quantum mechanical states in such a way that the quality of its output does not depend on the input. We also examine a machine which combines a unitary transformation with a selective measurement to produce good copies of states in a neighborhood of a particular state. We discuss the problem of measurement of the output states.
[ { "version": "v1", "created": "Sat, 20 Jul 1996 14:15:01 GMT" } ]
2009-10-30T00:00:00
[ [ "Buzek", "Vladimir", "" ], [ "Hillery", "Mark", "" ] ]
quant-ph/9607019
John Klauder
John R. Klauder (University of Florida)
Coherent State Path Integrals for Systems with Constraints
Latex, 10 pages, no figures
null
null
null
quant-ph hep-th
null
We outline the principal results of a recent examination of the quantization of systems with first- and second-class constraints from the point of view of coherent-state phase-space path integration. Two examples serve to illustrate the procedures.
[ { "version": "v1", "created": "Mon, 22 Jul 1996 12:38:05 GMT" } ]
2007-05-23T00:00:00
[ [ "Klauder", "John R.", "", "University of Florida" ] ]
quant-ph/9607020
John Klauder
John R. Klauder (University of Florida)
New Measures for the Quantization of Systems with Constraints
Latex, 9 pages, no figures
null
null
null
quant-ph hep-th
null
Based on the results of a recent reexamination of the quantization of systems with first-class and second-class constraints from the point of view of coherent-state phase-space path integration, we give additional examples of the quantization procedure for reparameterization invariant Hamiltonians, for systems for which the original set of Lagrange multipliers are elevated to dynamical variables, as well as extend the formalism to include cases of first-class constraints the operator form of which have a spectral gap about the value zero that characterizes the quantum constraint subspace.
[ { "version": "v1", "created": "Mon, 22 Jul 1996 12:38:43 GMT" } ]
2007-05-23T00:00:00
[ [ "Klauder", "John R.", "", "University of Florida" ] ]
quant-ph/9607021
Max Tegmark
Max Tegmark
Measuring quantum states: an experimental setup for measuring the spatial density matrix
Final accepted version, with 2 figures included. Latest version at http://www.sns.ias.edu/~max/radon.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/radon.html (faster from Europe) or from [email protected]. To appear in Phys Rev A.
Phys Rev A, 54, 2703 (1996)
10.1103/PhysRevA.54.2703
null
quant-ph
null
To quantify the effect of decoherence in quantum measurements, it is desirable to measure not merely the square modulus of the spatial wavefunction, but the entire density matrix, whose phases carry information about momentum and how pure the state is. An experimental setup is presented which can measure the density matrix (or equivalently, the Wigner function) of a beam of identically prepared charged particles to an arbitrary accuracy, limited only by count statistics and detector resolution. The particles enter into an electric field causing simple harmonic oscillation in the transverse direction. This corresponds to rotating the Wigner function in phase space. With a slidable detector, the marginal distribution of the Wigner function can be measured from all angles. Thus the phase-space tomography formalism can be used to recover the Wigner function by the standard inversion of the Radon transform. By applying this technique to for instance double-slit experiments with various degrees of environment-induced decoherence, it should be possible to make our understanding of decoherence and apparent wave-function collapse less qualitative and more quantitative.
[ { "version": "v1", "created": "Thu, 25 Jul 1996 07:52:09 GMT" } ]
2009-10-30T00:00:00
[ [ "Tegmark", "Max", "" ] ]
quant-ph/9607022
Brif Constantin
C. Brif (1), A. Vourdas (2) and A. Mann (1) ((1) Technion, Haifa, (2) University of Liverpool)
Analytic representations based on SU(1,1) coherent states and their applications
LaTeX, 15 pages, no figures, to appear in J. Phys. A. More information on http://www.technion.ac.il/~brif/science.html
J.Phys.A29:5873-5886,1996
10.1088/0305-4470/29/18/017
null
quant-ph
null
We consider two analytic representations of the SU(1,1) Lie group: the representation in the unit disk based on the SU(1,1) Perelomov coherent states and the Barut-Girardello representation based on the eigenstates of the SU(1,1) lowering generator. We show that these representations are related through a Laplace transform. A ``weak'' resolution of the identity in terms of the Perelomov SU(1,1) coherent states is presented which is valid even when the Bargmann index $k$ is smaller than one half. Various applications of these results in the context of the two-photon realization of SU(1,1) in quantum optics are also discussed.
[ { "version": "v1", "created": "Fri, 26 Jul 1996 09:09:20 GMT" } ]
2008-11-26T00:00:00
[ [ "Brif", "C.", "" ], [ "Vourdas", "A.", "" ], [ "Mann", "A.", "" ] ]
quant-ph/9607023
Lev Vaidman
Lev Vaidman
Emergence of Weak Values
12 pages, LaTeX, to appear in "Quantum Interferometry" VCH Publishers (1996), edited by F. De Martini
null
null
null
quant-ph
null
Various quantum measurement procedures are analyzed and it is shown that under certain conditions they yield consistently {\em weak values} which might be very different from the eigenvalues, the allowed outcomes according to the standard quantum formalism. The weak value outcomes result from peculiar quantum interference of the pointer variable of the measuring device.
[ { "version": "v1", "created": "Fri, 26 Jul 1996 15:22:22 GMT" } ]
2007-05-23T00:00:00
[ [ "Vaidman", "Lev", "" ] ]
quant-ph/9607024
null
Lov K. Grover (Bell Labs, Murray Hill NJ)
A fast quantum mechanical algorithm for estimating the median
14 pages, single postscript file
null
null
Bell Labs Technical Memorandum No. ITD-96-30115J
quant-ph
null
Consider the problem of estimating the median of N items to a precision epsilon, i.e., the estimate should be such that, with a high probability, the number of items, with values both smaller than and larger than this estimate, is less than N*(1+epsilon)/2. Any classical algorithm to do this will need at least O(1/epsilon^2) samples. Quantum mechanical systems can simultaneously carry out multiple computations due to their wave like properties. This paper describes an O(1/epsilon) step algorithm for the above estimation.
[ { "version": "v1", "created": "Mon, 29 Jul 1996 19:30:14 GMT" } ]
2007-05-23T00:00:00
[ [ "Grover", "Lov K.", "", "Bell Labs, Murray Hill NJ" ] ]
quant-ph/9607025
null
Erasmo Recami and Giovanni Salesi
Kinematics and hydrodynamics of spinning particles
LaTeX file; needs kapproc.sty
Phys.Rev.A57:98-105,1998
10.1103/PhysRevA.57.98
null
quant-ph
null
In the first part (Sections 1 and 2) of this paper --starting from the Pauli current, in the ordinary tensorial language-- we obtain the decomposition of the non-relativistic field velocity into two orthogonal parts: (i) the "classical part, that is, the 3-velocity w = p/m OF the center-of-mass (CM), and (ii) the so-called "quantum" part, that is, the 3-velocity V of the motion IN the CM frame (namely, the internal "spin motion" or zitterbewegung). By inserting such a complete, composite expression of the velocity into the kinetic energy term of the non-relativistic classical (i.e., newtonian) lagrangian, we straightforwardly get the appearance of the so-called "quantum potential" associated, as it is known, with the Madelung fluid. This result carries further evidence that the quantum behaviour of micro-systems can be adirect consequence of the fundamental existence of spin. In the second part (Sections 3 and 4), we fix our attention on the total 3-velocity v = w + V, it being now necessary to pass to relativistic (classical) physics; and we show that the proper time entering the definition of the four-velocity v^mu for spinning particles has to be the proper time tau of the CM frame. Inserting the correct Lorentz factor into the definition of v^mu leads to completely new kinematical properties for v_mu v^mu. The important constraint p_mu v^mu = m, identically true for scalar particles, but just assumed a priori in all previous spinning particle theories, is herein derived in a self-consistent way.
[ { "version": "v1", "created": "Tue, 30 Jul 1996 04:43:38 GMT" } ]
2010-03-04T00:00:00
[ [ "Recami", "Erasmo", "" ], [ "Salesi", "Giovanni", "" ] ]
quant-ph/9607026
E. Schmidt
Eduard Schmidt, Ludwig Knoell and Dirk-Gunnar Welsch
Radiation field quantization in a nonlinear dielectric with dispersion and absorption
18 pages, uses revtex.sty
null
null
FSUJ TPI QO-09/96
quant-ph
null
The problem of quantizing the radiation field inside a nonlinear dielectric is studied. Based on the quantization of radiation in a linear dielectric which includes absorption and dispersion, we extend the theory in order to treat also nonlinear optical processes. We derive propagation equations in space and time for the quantized radiation field including the effects of linear absorption and dispersion as well as nonlinear optical effects. As a special case we derive the propagation equation of a narrow-frequency band light pulse in a Kerr medium.
[ { "version": "v1", "created": "Wed, 31 Jul 1996 15:15:01 GMT" } ]
2007-05-23T00:00:00
[ [ "Schmidt", "Eduard", "" ], [ "Knoell", "Ludwig", "" ], [ "Welsch", "Dirk-Gunnar", "" ] ]
quant-ph/9607027
Daniel Gottesman
Daniel Gottesman
Pasting Quantum Codes
7 pages, REVTeX, submitted to Phys. Rev. A
null
null
CALT-68-2066, QUIC-96-001
quant-ph
null
I describe a method for pasting together certain quantum error-correcting codes that correct one error to make a single larger one-error quantum code. I show how to construct codes encoding 7 qubits in 13 qubits using the method, as well as 15 qubits in 21 qubits and all the other "perfect" codes.
[ { "version": "v1", "created": "Wed, 31 Jul 1996 17:37:41 GMT" } ]
2007-05-23T00:00:00
[ [ "Gottesman", "Daniel", "" ] ]
quant-ph/9607028
Mauro Fortunato
Mauro Fortunato (Universitaet Ulm, Germany)
Comment on ``Creating Metastable Schroedinger Cat States''
1 page, RevTeX, 1 eps figure (fig_1.eps), accepted for publication in Physical Review Letters [Phys. Rev. Lett. 77 (9) (1996)]
Phys.Rev.Lett. 77 (1996) 2336
10.1103/PhysRevLett.77.2336
null
quant-ph
null
After a careful analysis of the feedback model recently proposed by Slosser and Milburn [Phys. Rev. Lett. 75, 418 (1995)], we are led to the conclusion that---under realistic conditions---their scheme is not significantly more effective in the production of linear superpositions of macroscopically distinguishable quantum states than the usual quantum-optical Kerr effect.
[ { "version": "v1", "created": "Wed, 31 Jul 1996 17:40:44 GMT" } ]
2009-10-30T00:00:00
[ [ "Fortunato", "Mauro", "", "Universitaet Ulm, Germany" ] ]
quant-ph/9607029
Shmuel Gurvitz
S.A. Gurvitz
Interaction-Free Measurement in mesoscopic systems and the reduction postulate
Experimental consequences of the collapse time and the relativistic requirement are discussed for mesoscopic and optical systems
null
null
null
quant-ph cond-mat
null
We show that a noninvasive,``negative-result measurement'' can be realized in quantum dot systems. The measurement process is studied by applying the Schr\"odinger equation to the whole system (including the detector). We demonstrate that the possibility of observing a particular state out of coherent superposition leads to collapse of the corresponding nondiagonal density-matrix elements of the measured system. No additional reduction postulate is needed. Experimental consequences of the collapse time and the relativistic requirement are discussed for mesoscopic and optical systems.
[ { "version": "v1", "created": "Wed, 31 Jul 1996 18:36:14 GMT" }, { "version": "v2", "created": "Sun, 27 Oct 1996 13:17:43 GMT" } ]
2008-02-03T00:00:00
[ [ "Gurvitz", "S. A.", "" ] ]
quant-ph/9607030
Richard Cleve
Richard Cleve, Daniel Gottesman
Efficient Computations of Encodings for Quantum Error Correction
16 pages, REVTeX, 3 figures within the text
null
10.1103/PhysRevA.56.76
CALT-68-2067, QUIC-96-002
quant-ph
null
We show how, given any set of generators of the stabilizer of a quantum code, an efficient gate array that computes the codewords can be constructed. For an n-qubit code whose stabilizer has d generators, the resulting gate array consists of O(n d) operations, and converts k-qubit data (where k = n - d) into n-qubit codewords.
[ { "version": "v1", "created": "Thu, 1 Aug 1996 03:39:51 GMT" } ]
2009-10-30T00:00:00
[ [ "Cleve", "Richard", "" ], [ "Gottesman", "Daniel", "" ] ]
quant-ph/9608001
Michael Nielsen
M. A. Nielsen, Carlton M. Caves (University of New Mexico)
Reversible quantum operations and their application to teleportation
10 pages, Revtex
null
10.1103/PhysRevA.55.2547
null
quant-ph
null
Quantum operations provide a general description of the state changes allowed by quantum mechanics. Simple necessary and sufficient conditions for an ideal quantum operation to be reversible by a unitary operation are derived in this paper. These results generalize recent work on reversible measurements by Mabuchi and Zoller [Phys. Rev. Lett. {\bf 76}, 3108 (1996)]. Quantum teleportation can be understood as a special case of the problem of reversing quantum operations. We characterize completely teleportation schemes of the type proposed by Bennett {\it et al.} [Phys. Rev. Lett. {\bf 70}, 1895 (1993)].
[ { "version": "v1", "created": "Thu, 1 Aug 1996 18:59:06 GMT" } ]
2009-10-30T00:00:00
[ [ "Nielsen", "M. A.", "", "University of New Mexico" ], [ "Caves", "Carlton M.", "", "University of New Mexico" ] ]
quant-ph/9608002
Olga Priyutova
V.P.Karassiov (Lebedev Physical Institute, Moscow), V.L.Derbov (Chernyshevsky State University, Saratov), S.I.Vinitsky (Joint Institute for Nuclear Research, Dubna), Olga M. Priyutova (Chernyshevsky State University, Saratov)
Polarization coherent states and geometric phases in quantum optics
17 pages, LATEX
null
null
null
quant-ph
null
Polarization coherent states (PCS) are considered as generalized coherent states of $SU(2)_p$ group of the polarization invariance of the light fields. The geometric phases of PCS are introduced in a way, analogous to that used in the classical polarization optics.
[ { "version": "v1", "created": "Fri, 2 Aug 1996 18:22:44 GMT" } ]
2007-05-23T00:00:00
[ [ "Karassiov", "V. P.", "", "Lebedev Physical Institute, Moscow" ], [ "Derbov", "V. L.", "", "Chernyshevsky State University, Saratov" ], [ "Vinitsky", "S. I.", "", "Joint Institute for\n Nuclear Research, Dubna" ], [ "Priyutova", "Olga M.", "", "Chernyshevsky State University,\n Saratov" ] ]
quant-ph/9608003
Kimball A. Milton
Kimball A. Milton
Comment on "Sonoluminescence as Quantum Vacuum Radiation"
1 page, no figures, REVTeX
null
null
OKHEP-96-05
quant-ph hep-ph
null
The insufficiency of the energy radiated in the model of Eberlein is discussed.
[ { "version": "v1", "created": "Fri, 2 Aug 1996 19:25:48 GMT" } ]
2007-05-23T00:00:00
[ [ "Milton", "Kimball A.", "" ] ]
quant-ph/9608004
Todd A. Brun
Ruediger Schack (Mathematics, Royal Holloway, London), Todd A. Brun (Physics, Queen Mary and Westfield, London)
A C++ library using quantum trajectories to solve quantum master equations
17 pages standard LaTeX + 3 figures (postscript). Submitted to Computer Physics Communications. Web site: http://galisteo.ma.rhbnc.ac.uk/applied/QSD.html
Comput.Phys.Commun. 102 (1997) 210-228
10.1016/S0010-4655(97)00019-2
QMW-PH-96-20
quant-ph
null
Quantum trajectory methods can be used for a wide range of open quantum systems to solve the master equation by unraveling the density operator evolution into individual stochastic trajectories in Hilbert space. This C++ class library offers a choice of integration algorithms for three important unravelings of the master equation. Different physical systems are modeled by different Hamiltonians and environment operators. The program achieves flexibility and user friendliness, without sacrificing execution speed, through the way it represents operators and states in Hilbert space. Primary operators, implemented in the form of simple routines acting on single degrees of freedom, can be used to build up arbitrarily complex operators in product Hilbert spaces with arbitrary numbers of components. Standard algebraic notation is used to build operators and to perform arithmetic operations on operators and states. States can be represented in a local moving basis, often leading to dramatic savings of computing resources. The state and operator classes are very general and can be used independently of the quantum trajectory algorithms. Only a rudimentary knowledge of C++ is required to use this package.
[ { "version": "v1", "created": "Mon, 5 Aug 1996 17:04:06 GMT" } ]
2009-10-30T00:00:00
[ [ "Schack", "Ruediger", "", "Mathematics, Royal Holloway, London" ], [ "Brun", "Todd A.", "", "Physics, Queen Mary and Westfield, London" ] ]
quant-ph/9608005
Tal Mor
T. Mor
TelePOVM -- New Faces of Teleportation
8 pages, Latex. To be presented in a workshop on FQT, A Golden Jubilee event of the TIFR, Sep. 1996, Bombay, India
null
null
null
quant-ph
null
We show two new aspects of teleportation based on generalized measurements: I. We present an alternative approach to teleportation based on ``generating $\rho$-ensembles at spacetime separation''; This approach provides a better understanding of teleportation. II. We define the concept of {\em conclusive teleportation} and we show how to teleport a quantum state using any pure entangled state; we show how to use the conclusive teleportation as a criterion for non-locality.
[ { "version": "v1", "created": "Mon, 5 Aug 1996 14:39:21 GMT" } ]
2007-05-23T00:00:00
[ [ "Mor", "T.", "" ] ]
quant-ph/9608006
Peter Shor
A. R. Calderbank (1), E. M Rains (2), P. W. Shor (1), and N. J. A. Sloane (1), ((1) AT&T Research, (2) Institute for Defense Analyses)
Quantum Error Correction via Codes over GF(4)
Latex, 46 pages. To appear in IEEE Transactions on Information Theory. Replaced Sept. 24, 1996, to correct a number of minor errors. Replaced Sept. 10, 1997. The second section has been completely rewritten, and should hopefully be much clearer. We have also added a new section discussing the developments of the past year. Finally, we again corrected a number of minor errors
null
null
null
quant-ph
null
The problem of finding quantum error-correcting codes is transformed into the problem of finding additive codes over the field GF(4) which are self-orthogonal with respect to a certain trace inner product. Many new codes and new bounds are presented, as well as a table of upper and lower bounds on such codes of length up to 30 qubits.
[ { "version": "v1", "created": "Tue, 6 Aug 1996 18:13:19 GMT" }, { "version": "v2", "created": "Wed, 7 Aug 1996 00:56:53 GMT" }, { "version": "v3", "created": "Tue, 24 Sep 1996 22:55:48 GMT" }, { "version": "v4", "created": "Wed, 25 Sep 1996 14:34:53 GMT" }, { "version": "v5", "created": "Wed, 10 Sep 1997 21:06:15 GMT" } ]
2008-02-03T00:00:00
[ [ "Calderbank", "A. R.", "", "AT&T Research" ], [ "Rains", "E. M", "", "Institute for Defense Analyses" ], [ "Shor", "P. W.", "", "AT&T Research" ], [ "Sloane", "N. J. A.", "", "AT&T Research" ] ]
quant-ph/9608007
null
J. Finkelstein
Consistent Histories may be strange, but so is standard Quantum Theory
5 pages, LaTeX, 1 figure drawn by LaTeX
null
null
SJSU/TP-96-14
quant-ph gr-qc
null
Interpretational questions that arise in the Consistent Histories formulation of quantum mechanics are illustrated by the familiar example of a beam passing through multiple slits.
[ { "version": "v1", "created": "Wed, 7 Aug 1996 17:33:02 GMT" } ]
2007-05-23T00:00:00
[ [ "Finkelstein", "J.", "" ] ]
quant-ph/9608008
Michael Martin Nieto
Michael Martin Nieto and D. Rodney Truax
Displacement-Operator Squeezed States. I. Time-Dependent Systems Having Isomorphic Symmetry Algebras
23 pages, LaTeX
J.Math.Phys. 38 (1997) 84-97
10.1063/1.531836
LA-UR-96-2755
quant-ph
null
In this paper we use the Lie algebra of space-time symmetries to construct states which are solutions to the time-dependent Schr\"odinger equation for systems with potentials $V(x,\tau)=g^{(2)}(\tau)x^2+g^{(1)}(\tau)x +g^{(0)}(\tau)$. We describe a set of number-operator eigenstates states, $\{\Psi_n(x,\tau)\}$, that form a complete set of states but which, however, are usually not energy eigenstates. From the extremal state, $\Psi_0$, and a displacement squeeze operator derived using the Lie symmetries, we construct squeezed states and compute expectation values for position and momentum as a function of time, $\tau$. We prove a general expression for the uncertainty relation for position and momentum in terms of the squeezing parameters. Specific examples, all corresponding to choices of $V(x,\tau)$ and having isomorphic Lie algebras, will be dealt with in the following paper (II).
[ { "version": "v1", "created": "Wed, 7 Aug 1996 20:07:34 GMT" } ]
2016-09-08T00:00:00
[ [ "Nieto", "Michael Martin", "" ], [ "Truax", "D. Rodney", "" ] ]
quant-ph/9608009
Michael Martin Nieto
Michael Martin Nieto and D. Rodney Truax
Displacement-Operator Squeezed States. II. Examples of Time-Dependent Systems Having Isomorphic Symmetry Algebras
24 pages, LaTeX
J.Math.Phys. 38 (1997) 98-114
10.1063/1.531837
LA-UR-96-2756
quant-ph
null
In this article, results from the previous paper (I) are applied to calculations of squeezed states for such well-known systems as the harmonic oscillator, free particle, linear potential, oscillator with a uniform driving force, and repulsive oscillator. For each example, expressions for the expectation values of position and momentum are derived in terms of the initial position and momentum, as well as in the $(\alpha,z)$- and in the $(z,\alpha)$-representations described in I. The dependence of the squeezed-state uncertainty products on the time and on the squeezing parameters are determined for each system.
[ { "version": "v1", "created": "Wed, 7 Aug 1996 20:08:09 GMT" } ]
2009-10-30T00:00:00
[ [ "Nieto", "Michael Martin", "" ], [ "Truax", "D. Rodney", "" ] ]
quant-ph/9608010
Cejnar Pavel
M. Biskup, P. Cejnar, R. Kotecky
Decoherence and Efficiency of Quantum Error Correction
13 pages, no figures, REVTeX style, resubmission to Phys.Rev.A, important changes
null
null
null
quant-ph
null
Certain physical aspects of quantum error correction are discussed for a quantum computer (n-qubit register) in contact with a decohering environment. Under rather plausible assumptions upon the form of the computer-environment interaction, the efficiency of a general correcting procedure is evaluated as a function of the spontaneous-decay duration and the rank of errors covered by the procedure. It is proved that the probability of errors can be made arbitrarily small by enhancing the correction method, provided the decohering interaction is represented by a bounded operator.
[ { "version": "v1", "created": "Thu, 8 Aug 1996 13:31:00 GMT" }, { "version": "v2", "created": "Mon, 7 Apr 1997 09:08:44 GMT" } ]
2008-02-03T00:00:00
[ [ "Biskup", "M.", "" ], [ "Cejnar", "P.", "" ], [ "Kotecky", "R.", "" ] ]
quant-ph/9608011
Andrew Steane
Andrew M. Steane (Department of Physics, University of Oxford)
The Ion Trap Quantum Information Processor
This is an invited contribution for Applied Physics B. It will be submitted at the end of September (1996), and I would greatly appreciate any constructive criticism or suggested additions before then (email [email protected]). 37 pages plus 8 figures. Replaced version corrects figure references
Appl.Phys. B64 (1997) 623
10.1007/s003400050225
null
quant-ph
null
An introductory review of the linear ion trap is given, with particular regard to its use for quantum information processing. The discussion aims to bring together ideas from information theory and experimental ion trapping, to provide a resource to workers unfamiliar with one or the other of these subjects. It is shown that information theory provides valuable concepts for the experimental use of ion traps, especially error correction, and conversely the ion trap provides a valuable link between information theory and physics, with attendant physical insights. Example parameters are given for the case of calcium ions. Passive stabilisation will allow about 200 computing operations on 10 ions; with error correction this can be greatly extended.
[ { "version": "v1", "created": "Thu, 8 Aug 1996 18:21:50 GMT" }, { "version": "v2", "created": "Fri, 9 Aug 1996 14:32:50 GMT" } ]
2009-10-30T00:00:00
[ [ "Steane", "Andrew M.", "", "Department of Physics, University of Oxford" ] ]
quant-ph/9608012
Raymond LaFlamme
Emanuel Knill and Raymond Laflamme
Concatenated Quantum Codes
16 pages in PostScirpt, the paper is also avalaible at http://qso.lanl.gov/qc/
null
null
null
quant-ph
null
One of the main problems for the future of practical quantum computing is to stabilize the computation against unwanted interactions with the environment and imperfections in the applied operations. Existing proposals for quantum memories and quantum channels require gates with asymptotically zero error to store or transmit an input quantum state for arbitrarily long times or distances with fixed error. In this report a method is given which has the property that to store or transmit a qubit with maximum error $\epsilon$ requires gates with error at most $c\epsilon$ and storage or channel elements with error at most $\epsilon$, independent of how long we wish to store the state or how far we wish to transmit it. The method relies on using concatenated quantum codes with hierarchically implemented recovery operations. The overhead of the method is polynomial in the time of storage or the distance of the transmission. Rigorous and heuristic lower bounds for the constant $c$ are given.
[ { "version": "v1", "created": "Thu, 8 Aug 1996 23:13:46 GMT" } ]
2007-05-23T00:00:00
[ [ "Knill", "Emanuel", "" ], [ "Laflamme", "Raymond", "" ] ]
quant-ph/9608013
Juan Leon
J. Leon (LAEFF and IMAFF, Madrid)
Time-of-arrival formalism for the relativistic particle
16 pages, no figures, uses LaTeX. The section "Interpretation" has been completely rewritten and some errors corrected
J.Phys.A30:4791-4802,1997
10.1088/0305-4470/30/13/027
LAEFF 96/17
quant-ph
null
A suitable operator for the time-of-arrival at a detector is defined for the free relativistic particle in 3+1 dimensions. For each detector position, there exists a subspace of detected states in the Hilbert space of solutions to the Klein Gordon equation. Orthogonality and completeness of the eigenfunctions of the time-of-arrival operator apply inside this subspace, opening up a standard probabilistic interpretation.
[ { "version": "v1", "created": "Fri, 9 Aug 1996 14:58:58 GMT" }, { "version": "v2", "created": "Tue, 26 Nov 1996 14:20:03 GMT" } ]
2008-11-26T00:00:00
[ [ "Leon", "J.", "", "LAEFF and IMAFF, Madrid" ] ]
quant-ph/9608014
Dmitriy Palatnik
Dmitriy Palatnik
Extra-symmetric Born--Infeld theory of electroweak and gravitational fields
preprint exists now as quant-ph/0202024
null
null
null
quant-ph gr-qc hep-th
null
This paper suggests a generalization of the Born--Infeld action (1932) for the case of electroweak and gravitational fields. Basic notions one deals with are Dirac matrices, $\gamma_{a}$, and dimensionless covariant derivatives, $\pi_{a} = - i\ell \nabla_{a}$, given in spinorial and scalar representations. The action contains a characteristic length $\ell$ (which is of order of magnitude of Planck's length), as a parameter and possesses an extra symmetry with respect to transformations of the Lorentz group imposed on pairs ($\gamma_{a}$, $\pi_{a}$). It's shown that parameter of the Lorentz group is associated with a constant value of the electroweak potential at spatial infinity.
[ { "version": "v1", "created": "Sun, 11 Aug 1996 21:40:00 GMT" }, { "version": "v2", "created": "Sat, 18 Jan 1997 16:07:47 GMT" }, { "version": "v3", "created": "Sun, 2 Feb 1997 18:51:11 GMT" }, { "version": "v4", "created": "Fri, 22 Jun 2001 01:04:52 GMT" }, { "version": "v5", "created": "Fri, 24 Aug 2001 21:19:09 GMT" }, { "version": "v6", "created": "Tue, 25 Dec 2001 01:30:36 GMT" }, { "version": "v7", "created": "Wed, 20 Feb 2002 04:29:51 GMT" }, { "version": "v8", "created": "Tue, 2 Mar 2004 23:24:15 GMT" } ]
2008-02-03T00:00:00
[ [ "Palatnik", "Dmitriy", "" ] ]
quant-ph/9608015
Park daegil
Soo-Young Lee, Jae-Rok Kahng, Sahng-Kyoon Yoo, D.K.Park, C.H.Lee, Chang Soo Park, Eui-Soon Yim
Instantonic approach to triple well potential
Revtex, 11 pages, Included one eps figure
Mod.Phys.Lett. A12 (1997) 1803-1813
10.1142/S0217732397001837
null
quant-ph hep-th
null
By using a usual instanton method we obtain the energy splitting due to quantum tunneling through the triple well barrier. It is shown that the term related to the midpoint of the energy splitting in propagator is quite different from that of double well case, in that it is proportional to the algebraic average of the frequencies of the left and central wells.
[ { "version": "v1", "created": "Mon, 12 Aug 1996 08:36:08 GMT" } ]
2009-10-30T00:00:00
[ [ "Lee", "Soo-Young", "" ], [ "Kahng", "Jae-Rok", "" ], [ "Yoo", "Sahng-Kyoon", "" ], [ "Park", "D. K.", "" ], [ "Lee", "C. H.", "" ], [ "Park", "Chang Soo", "" ], [ "Yim", "Eui-Soon", "" ] ]
quant-ph/9608016
V. P. Karasev
V.P. Karassiov
$sl(2)$ variational schemes for solving one class of quantum nonlinear models
9 pages, LATEX
null
null
LPI-OD-96-08
quant-ph
null
Hamiltonians of a wide-spread class of $G_{inv}$-invariant nonlinear quantum models, including multiboson and frequency conversion ones, are expressed as non-linear functions of $sl(2)$ generators. It enables us to use standard variational schemes, based on $sl(2)$ generalized coherent states as trial functions, for solving both spectral and evolution tasks. In such a manner a new analytical expression is found for energy spectra in a mean-field approximation which is beyond quasi-equidistant ones obtained earlier.
[ { "version": "v1", "created": "Mon, 12 Aug 1996 14:12:55 GMT" } ]
2007-05-23T00:00:00
[ [ "Karassiov", "V. P.", "" ] ]
quant-ph/9608017
Haret Rosu
H.C. Rosu
Comment on quant-ph/9509008 by Kumar and Khare
one revtex, doublecolumn page
null
null
IFUG-8-R2/1996
quant-ph
null
One can find some comments related to the isospectral issue
[ { "version": "v1", "created": "Mon, 12 Aug 1996 21:30:00 GMT" } ]
2007-05-23T00:00:00
[ [ "Rosu", "H. C.", "" ] ]
quant-ph/9608018
null
Sergei V. Shabanov (University of Valencia)
Path Integral in Holomorphic Representation without Gauge Fixation
Submitted to the Proceedings of the international conference Path Integrals 96, JINR, Dubna (Russia), May, 1996. Latex, 6 pages, no figures
null
null
E2-89-678
quant-ph
null
A method of path integral construction without gauge fixing in the holomorphic representation is proposed for finite-dimensional gauge models. This path integral determines a manifestly gauge-invariant kernel of the evolution operator.
[ { "version": "v1", "created": "Tue, 13 Aug 1996 08:56:48 GMT" } ]
2007-05-23T00:00:00
[ [ "Shabanov", "Sergei V.", "", "University of Valencia" ] ]
quant-ph/9608019
K. Berndl
Karin Berndl, Stefan Teufel
Comment on ``Hidden quantum nonlocality revealed by local filters''
3 pages, submitted to Physics Letters A
Phys.Lett. A224 (1997) 314-316
10.1016/S0375-9601(96)00819-5
null
quant-ph
null
In Section 3 of his paper (N. Gisin, Phys. Lett. A 210 (1996) 151), Gisin argues that a ``careless application of generalized quantum measurements can violate Bell's inequality even for mixtures of product states.'' However, the observed violation of the CHSH inequality is not in fact due to the application of generalized quantum measurements, but rather to a misapplication of the inequality itself -- to conditional expectations in which the conditioning depends upon the measurements under consideration.
[ { "version": "v1", "created": "Tue, 13 Aug 1996 10:39:08 GMT" } ]
2009-10-30T00:00:00
[ [ "Berndl", "Karin", "" ], [ "Teufel", "Stefan", "" ] ]
quant-ph/9608020
Hideo Mabuchi
Hideo Mabuchi
Dynamical identification of open quantum systems
Formatted with RevTex, 4 pages plus 4 EPS figures. To appear in Quantum and Semiclassical Optics (JEOS B)
null
null
null
quant-ph
null
I propose a quantum trajectories approach to parametric identification of the effective Hamiltonian for a Markovian open quantum system, and discuss an application motivated by recent experiments in cavity quantum electrodynamics. This example illustrates a strategy for quantum parameter estimation that efficiently utilizes the information carried by correlations between measurements distributed in time.
[ { "version": "v1", "created": "Tue, 13 Aug 1996 15:54:35 GMT" } ]
2007-05-23T00:00:00
[ [ "Mabuchi", "Hideo", "" ] ]
quant-ph/9608021
Brif Constantin
C. Brif, A. Mann (Technion, Haifa)
Nonclassical interferometry with intelligent light
to appear in Phys. Rev. A, REVTeX, 25 pages, 8 figures (compressed PostScript also available at http://www.technion.ac.il/~brif/abstracts/interferometers.html ). More information on http://www.technion.ac.il/~brif/science.html
Phys.Rev. A54 (1996) 4505
10.1103/PhysRevA.54.4505
null
quant-ph
null
We study the phase sensitivity of SU(2) and SU(1,1) interferometers fed by two-mode field states which are intelligent states for Hermitian generators of the SU(2) and SU(1,1) groups, respectively. Intelligent states minimize uncertainty relations and this makes possible an essential reduction of the quantum noise in interferometers. Exact closed expressions for the minimum detectable phase shift are obtained in terms of the Jacobi polynomials. These expressions are compared with results for some conventional input states, and some known results for the squeezed input states are reviewed. It is shown that the phase sensitivity for an interferometer that employs squeezing-producing active devices (such as four-wave mixers) should be analyzed in two regimes: (i) fixed input state and variable interferometer, and (ii) fixed interferometer and variable input state. The behavior of the phase sensitivity is essentially different in these two regimes. The use of the SU(2) intelligent states allows us to achieve a phase sensitivity of order $1/\bar{N}$ (where $\bar{N}$ is the total number of photons passing through the phase shifters of the interferometer) without adding four-wave mixers. This avoids the duality in the behavior of the phase sensitivity that occurs for the squeezed input. On the other hand, the SU(1,1) intelligent states have the property of achieving the phase sensitivity of order $1/\bar{N}$ in both regimes.
[ { "version": "v1", "created": "Wed, 14 Aug 1996 13:15:43 GMT" } ]
2009-10-30T00:00:00
[ [ "Brif", "C.", "", "Technion, Haifa" ], [ "Mann", "A.", "", "Technion, Haifa" ] ]
quant-ph/9608022
Brif Constantin
C. Brif (Technion, Haifa)
Coherent states for quantum systems with a trilinear boson Hamiltonian
to appear in Phys. Rev. A, REVTeX, 18 pages, 3 figures (compressed PostScript, available at http://www.technion.ac.il/~brif/abstracts/3lin_cs.html ). More information on this http://www.technion.ac.il/~brif/science.html
Phys.Rev. A54 (1996) 5253
10.1103/PhysRevA.54.5253
null
quant-ph
null
We introduce a set of coherent states which are associated with quantum systems governed by a trilinear boson Hamiltonian. These states are produced by the action of a nonunitary displacement operator on a reference state and can be equivalently defined by some eigenvalue equations. The system prepared initially in the reference state will evolve into the coherent state during the first instants of the interaction process. Some properties of the coherent states are discussed. In particular, the resolution of the identity is derived and the related analytic representation in the complex plane is developed. It is shown that this analytic representation coincides with a double representation based on the Glauber coherent states of the pump mode and on the SU(1,1) Perelomov coherent states of the signal-idler system. Entanglement between the field modes and photon statistics of the coherent states are studied. Connections between the coherent states and the long-time evolution induced by the trilinear Hamiltonian are considered.
[ { "version": "v1", "created": "Wed, 14 Aug 1996 13:21:04 GMT" } ]
2009-10-30T00:00:00
[ [ "Brif", "C.", "", "Technion, Haifa" ] ]
quant-ph/9608023
Zhong Tang
David Ritz Finkelstein, Heinrich Saller, and Zhong Tang
Beneath Gauge
Latex
Class.Quant.Grav.14:A127-A142,1997
10.1088/0264-9381/14/1A/011
null
quant-ph
null
Seeking a relativistic quantum infrastructure for gauge physics, we analyze spacetime into three levels of quantum aggregation analogous to atoms, bonds and crystals. Quantum spacetime points with no extension make up more complex link units with microscopic extension, which make up networks with macroscopic extension. Such a multilevel quantum theory implies parastatistics for the lowest level entities without additional physical assumptions. Any hypercubical vacuum mode with off-diagonal long-range order that is covariant under $\POINCARE$ also has bonus internal symmetries somewhat like those of the standard model. A vacuum made with the dipole link proposed earlier has too much symmetry. A quadrupole link solves this problem.
[ { "version": "v1", "created": "Thu, 15 Aug 1996 19:14:29 GMT" } ]
2010-04-06T00:00:00
[ [ "Finkelstein", "David Ritz", "" ], [ "Saller", "Heinrich", "" ], [ "Tang", "Zhong", "" ] ]
quant-ph/9608024
Zhong Tang
David Ritz Finkelstein, Heinrich Saller, and Zhong Tang
Hypercrystalline vacua
Latex
null
null
null
quant-ph
null
Let a quantum network be a Fermi-Dirac assembly of Fermi-Dirac assemblies of ...of quantum points, interpreted topologically. The simplest quantum-network vacuum modes with exact conservation of relativistic energy-momentum and angular momentum also support the local non-Abelian groups of the standard model, torsion and gravity. The spacetime points of these models naturally obey parastatistics. We construct a left-handed vacuum network among others.
[ { "version": "v1", "created": "Thu, 15 Aug 1996 19:50:12 GMT" } ]
2007-05-23T00:00:00
[ [ "Finkelstein", "David Ritz", "" ], [ "Saller", "Heinrich", "" ], [ "Tang", "Zhong", "" ] ]
quant-ph/9608025
Tal Mor
T. Mor
Reducing Quantum Errors and Improving Large Scale Quantum Cryptography
5 pages, RevTeX
null
null
null
quant-ph
null
Noise causes severe difficulties in implementing quantum computing and quantum cryptography. Several schemes have been suggested to reduce this problem, mainly focusing on quantum computation. Motivated by quantum cryptography, we suggest a coding which uses $N$ quantum bits ($N=n^2$) to encode one quantum bit, and reduces the error exponentially with $n$. Our result suggests the possibility of distributing a secure key over very long distances, and maintaining quantum states for very long times. It also provides a new quantum privacy amplification against a strong adversary.
[ { "version": "v1", "created": "Thu, 15 Aug 1996 19:07:55 GMT" } ]
2007-05-23T00:00:00
[ [ "Mor", "T.", "" ] ]
quant-ph/9608026
Andrew Steane
Andrew Steane (Department of Physics, University of Oxford)
Quantum Reed-Muller Codes
9 pages LaTeX. Replaced version corrects an important oversight. Further information at http://eve.physics.ox.ac.uk/ASGhome.html
null
null
null
quant-ph
null
A set of quantum error correcting codes based on classical Reed-Muller codes is described. The codes have parameters [[n,k,d]] = [[2^r, 2^r - C(r,t) - 2 sum_{i=0}^{t-1} C(r,i), 2^t + 2^{t-1} ]].
[ { "version": "v1", "created": "Fri, 16 Aug 1996 11:56:39 GMT" }, { "version": "v2", "created": "Thu, 22 Aug 1996 23:42:20 GMT" } ]
2008-02-03T00:00:00
[ [ "Steane", "Andrew", "", "Department of Physics, University of Oxford" ] ]
quant-ph/9608027
null
M. Kibler, L.G. Mardoyan and G.S. Pogosyan
On a Generalized Oscillator System: Interbasis Expansions
23 pages, Latex File, to be published in International Journal of Quantum Chemistry
null
null
null
quant-ph atom-ph chem-ph
null
This article deals with a nonrelativistic quantum mechanical study of a dynamical system which generalizes the isotropic harmonic oscillator system in three dimensions. The problem of interbasis expansions of the wavefunctions is completely solved. A connection between the generalized oscillator system (projected on the z-line) and the Morse system (in one dimension) is discussed.
[ { "version": "v1", "created": "Fri, 16 Aug 1996 15:39:06 GMT" } ]
2007-05-23T00:00:00
[ [ "Kibler", "M.", "" ], [ "Mardoyan", "L. G.", "" ], [ "Pogosyan", "G. S.", "" ] ]
quant-ph/9608028
Martin Plenio
M. B. Plenio, V. Vedral, and P. L. Knight (Imperial College London)
Conditional generation of error syndromes in fault-tolerant error correction
4 pages
Phys.Rev.A55:4593,1997
10.1103/PhysRevA.55.4593
null
quant-ph
null
In this paper we show how the fault--tolerant error correction scheme recently proposed by DiVincenzo and Shor may be improved. Our scheme, unlike the earlier one, can also deal with a single error that might occur {\em during} the gate operations that are required for the implementation of the error correction and not only in--between the gates and hence presents an improvement towards enabling error correction and with it the practical possibility of some more involved quantum computations, such as e.g. factorization of large numbers.
[ { "version": "v1", "created": "Sat, 17 Aug 1996 11:09:37 GMT" } ]
2008-12-18T00:00:00
[ [ "Plenio", "M. B.", "", "Imperial College London" ], [ "Vedral", "V.", "", "Imperial College London" ], [ "Knight", "P. L.", "", "Imperial College London" ] ]
quant-ph/9608029
Vladimir Privman
Dima Mozyrsky, Vladimir Privman, Steven P. Hotaling
Design of gates for quantum computation: the NOT gate
9 pages in LaTeX
Int.J.Mod.Phys.B11:2207-2215,1997
10.1142/S0217979297001143
null
quant-ph
null
We offer an alternative to the conventional network formulation of quantum computing. We advance the analog approach to quantum logic gate/circuit construction. As an illustration, we consider the spatially extended NOT gate as the first step in the development of this approach. We derive an explicit form of the interaction Hamiltonian corresponding to this gate and analyze its properties. We also discuss general extensions to the case of certain time-dependent interactions which may be useful for practical realization of quantum logic gates.
[ { "version": "v1", "created": "Sat, 17 Aug 1996 17:57:33 GMT" }, { "version": "v2", "created": "Tue, 16 Sep 1997 22:44:07 GMT" } ]
2014-11-18T00:00:00
[ [ "Mozyrsky", "Dima", "" ], [ "Privman", "Vladimir", "" ], [ "Hotaling", "Steven P.", "" ] ]
quant-ph/9608030
Vlatko Vedral
V. Vedral, M.A.Rippin, M.B.Plenio (Imperial College, London, UK)
Quantum Correlations, Local Interactions and Error Correction
submitted to The Physical Review A
null
10.1080/09500349708231878
null
quant-ph
null
We consider the effects of local interactions upon quantum mechanically entangled systems. In particular we demonstrate that non-local correlations cannot increase through local operations on any of the subsystems, but that through the use of quantum error correction methods, correlations can be maintained. We provide two mathematical proofs that local general measurements cannot increase correlations, and also derive general conditions for quantum error correcting codes. Using these we show that local quantum error correction can preserve nonlocal features of entangled quantum systems. We also demonstrate these results by use of specific examples employing correlated optical cavities interacting locally with resonant atoms. By way of counter example, we also describe a mechanism by which correlations can be increased, which demonstrates the need for it non-local interactions.
[ { "version": "v1", "created": "Tue, 20 Aug 1996 12:36:14 GMT" } ]
2015-06-26T00:00:00
[ [ "Vedral", "V.", "", "Imperial College, London, UK" ], [ "Rippin", "M. A.", "", "Imperial College, London, UK" ], [ "Plenio", "M. B.", "", "Imperial College, London, UK" ] ]
quant-ph/9608031
Ali Mostafazadeh
Ali Mostafazadeh
Non-Abelian Geometrical Phase for General Three-Dimensional Quantum Systems
Plain LaTeX, 17 pages
J.Phys.A30:7525-7535,1997
10.1088/0305-4470/30/21/023
University of Alberta preprint no: Thy 29-96
quant-ph hep-th
null
Adiabatic $U(2)$ geometric phases are studied for arbitrary quantum systems with a three-dimensional Hilbert space. Necessary and sufficient conditions for the occurrence of the non-Abelian geometrical phases are obtained without actually solving the full eigenvalue problem for the instantaneous Hamiltonian. The parameter space of such systems which has the structure of $\xC P^2$ is explicitly constructed. The results of this article are applicable for arbitrary multipole interaction Hamiltonians $H=Q^{i_1,\cdots i_n}J_{i_1}\cdots J_{i_n}$ and their linear combinations for spin $j=1$ systems. In particular it is shown that the nuclear quadrupole Hamiltonian $H=Q^{ij}J_iJ_j$ does actually lead to non-Abelian geometric phases for $j=1$. This system, being bosonic, is time-reversal-invariant. Therefore it cannot support Abelian adiabatic geometrical phases.
[ { "version": "v1", "created": "Tue, 20 Aug 1996 20:13:07 GMT" } ]
2008-11-26T00:00:00
[ [ "Mostafazadeh", "Ali", "" ] ]
quant-ph/9608032
Wytse van Dijk
K. A. Kiers (UBC) and W. van Dijk (McMaster)
Scattering in one dimension: The coupled Schroedinger equation, threshold behaviour and Levinson's theorem
to appear in Journal of Mathematic Physics, RevTex, 16 pages, 3 figures (PostScript)
J.Math.Phys.37:6033-6059,1996
10.1063/1.531762
null
quant-ph
null
We formulate scattering in one dimension due to the coupled Schr\"{o}dinger equation in terms of the $S$ matrix, the unitarity of which leads to constraints on the scattering amplitudes. Levinson's theorem is seen to have the form $\eta(0) = \pi (n_b + 1/2 n - 1/2 N)$, where $\eta(0)$ is the phase of the $S$ matrix at zero energy, $n_b$ the number of bound states with nonzero binding energy, $n$ the number of half-bound states, and $N$ the number of coupled equations. In view of the effects due to the half-bound states, the threshold behaviour of the scattering amplitudes is investigated in general, and is also illustrated by means of particular potential models.
[ { "version": "v1", "created": "Wed, 21 Aug 1996 20:59:17 GMT" } ]
2014-11-18T00:00:00
[ [ "Kiers", "K. A.", "", "UBC" ], [ "van Dijk", "W.", "", "McMaster" ] ]
quant-ph/9608033
Dr S. Chaturvedi
G.S.Agarwal and S. Chaturvedi
A non group theoretic proof of completeness of arbitrary coherent states $D(\alpha)\mid f>$
10 pages, latex, no figures
Mod.Phys.Lett.A11:2083-2090,1996
10.1142/S021773239600206X
null
quant-ph
null
A new proof for the completeness of the coherent states $D(\alpha )\mid f>$ for the Heisenberg Weyl group and the groups $SU(2)$ and $SU(1,1)$ is presented. Generalizations of these results and their consequences are disussed.
[ { "version": "v1", "created": "Thu, 22 Aug 1996 21:56:14 GMT" } ]
2008-11-26T00:00:00
[ [ "Agarwal", "G. S.", "" ], [ "Chaturvedi", "S.", "" ] ]
quant-ph/9608034
Dr S. Chaturvedi
P. Shanta, S. Chaturvedi and V.Srinivasan
Eigenstates of linear combinations of two boson creation and annihilation operators : An algebraic approach
17 pages, latex, no figures. Revised version. One additional reference
Mod.Phys.Lett. A11 (1996) 2381-2396
10.1142/S021773239600237X
null
quant-ph
null
Eigenstates of the linear combinations $a^2+\beta a^{\dagger2}$ and $ab+\beta a^\dagger b^\dagger$ of two boson creation and annihilation operators are presented. The algebraic procedure given here is based on the work of Shanta et al. [Phys. Rev. Lett. {\bf 72}, 1447, 1994] for constructing eigenstates of generalized annihilation operators.
[ { "version": "v1", "created": "Thu, 22 Aug 1996 21:58:20 GMT" }, { "version": "v2", "created": "Sat, 24 Aug 1996 21:25:24 GMT" } ]
2009-10-30T00:00:00
[ [ "Shanta", "P.", "" ], [ "Chaturvedi", "S.", "" ], [ "Srinivasan", "V.", "" ] ]
quant-ph/9608035
Ryszard Horodecki
Marek Zukowski, Ryszard Horodecki, Michal Horodecki and Pawel Horodecki
Generalized quantum measurements and local realism
Revtex, 12 pages; Some modifications of introduction has been made; a note stating that part of results had been obtained earlier by other authors, has been added; one postscript figure available at request from [email protected]
Phys.Rev. A58 (1998) 1694-1698
10.1103/PhysRevA.58.1694
null
quant-ph
null
The structure of a local hidden variable model for experiments involving sequences of measurements rigorously is analyzed. Constraints imposed by local realism on the conditional probabilities of the outcomes of such measurement schemes are explicitly derived. The violation of local realism in the case of ``hidden nonlocality'' is illustrated by an operational example.
[ { "version": "v1", "created": "Thu, 22 Aug 1996 11:48:05 GMT" }, { "version": "v2", "created": "Tue, 29 Oct 1996 16:11:40 GMT" } ]
2009-10-30T00:00:00
[ [ "Zukowski", "Marek", "" ], [ "Horodecki", "Ryszard", "" ], [ "Horodecki", "Michal", "" ], [ "Horodecki", "Pawel", "" ] ]
quant-ph/9608036
Dr S. Chaturvedi
S. Chaturvedi
A direct proof of completeness of squeezed odd-number states
6 pages, latex, no figures
Mod.Phys.Lett.A11:2805-2808,1996
10.1142/S0217732396002794
null
quant-ph
null
A direct proof of the resolution of the identity in the odd sector of the Fock space in terms of squeezed number states $D(\xi)|2m+1>; D(\xi) = \exp(({\xi}a^{\dagger2}-{\xi}^*{a^2})/2)$ is given. The proof entails evaluation of an integral involving Jacobi polynomials. This is achieved by the use of Racah identities.
[ { "version": "v1", "created": "Fri, 23 Aug 1996 20:24:11 GMT" } ]
2008-11-26T00:00:00
[ [ "Chaturvedi", "S.", "" ] ]
quant-ph/9608037
Hagen Kleinert
A. Pelster and H. Kleinert
Transformation Properties of Classical and Quantum Laws under Some Nonholonomic Spacetime Transformations
Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Paper also at http://www.physik.fu-berlin.de/~kleinert/kleiner_re249/preprint.html
null
null
null
quant-ph
null
Nonrelativistic Newton and Schroedinger equations remain correct not only under holonomic but also under nonholonomic transformations of the spacetime coordinates. Here we study the properties of transformations which are holonomic in the space coordinates while additionally tranforming the time in a path-dependent way. This makes them nonholonomic in spacetime. The resulting transformation formulas of physical quantities establish relations between different physical systems. Furthermore we point out certain differential-geometric features of these relations.
[ { "version": "v1", "created": "Mon, 26 Aug 1996 10:26:55 GMT" } ]
2007-05-23T00:00:00
[ [ "Pelster", "A.", "" ], [ "Kleinert", "H.", "" ] ]
quant-ph/9608038
Todd A. Brun
T.A. Brun (Physics, Queen Mary and Westfield, London), N. Gisin (GAP, University of Geneva), P.F. O'Mahony and M. Rigo (Mathematics, Royal Holloway, London)
From quantum trajectories to classical orbits
7 pages RevTeX 3.0 + 2 figures (postscript). Submitted to Physical Review Letters
null
10.1016/S0375-9601(97)00217-X
QMW-PH-96-22
quant-ph
null
Recently it has been shown that the evolution of open quantum systems may be ``unraveled'' into individual ``trajectories,'' providing powerful numerical and conceptual tools. In this letter we use quantum trajectories to study mesoscopic systems and their classical limit. We show that in this limit, Quantum Jump (QJ) trajectories approach a diffusive limit very similar to the Quantum State Diffusion (QSD) unraveling. The latter follows classical trajectories in the classical limit. Hence, both unravelings show the rise of classical orbits. This is true for both regular and chaotic systems (which exhibit strange attractors).
[ { "version": "v1", "created": "Mon, 26 Aug 1996 16:10:06 GMT" } ]
2009-10-30T00:00:00
[ [ "Brun", "T. A.", "", "Physics, Queen Mary and Westfield, London" ], [ "Gisin", "N.", "", "GAP,\n University of Geneva" ], [ "O'Mahony", "P. F.", "", "Mathematics, Royal\n Holloway, London" ], [ "Rigo", "M.", "", "Mathematics, Royal\n Holloway, London" ] ]
quant-ph/9608039
Ricardo Moritz Cavalcanti
R. M. Cavalcanti (PUC-Rio) and C. A. A. de Carvalho (UFRJ)
Subtleties in Quantum Mechanical Metastability
8 pages, revtex, a few minor changes, some references added
null
null
null
quant-ph cond-mat hep-th
null
We present a detailed discussion of some features of quantum mechanical metastability. We analyze the nature of decaying (quasistationary) states and the regime of validity of the exponencial law, as well as decays at finite temperature. We resort to very simple systems and elementary techniques to emphasize subtle aspects of the problem.
[ { "version": "v1", "created": "Mon, 26 Aug 1996 16:51:51 GMT" }, { "version": "v2", "created": "Tue, 27 May 1997 02:13:14 GMT" } ]
2008-02-03T00:00:00
[ [ "Cavalcanti", "R. M.", "", "PUC-Rio" ], [ "de Carvalho", "C. A. A.", "", "UFRJ" ] ]
quant-ph/9608040
Alan Kostelecky
Robert Bluhm, Alan Kostelecky, and Bogdan Tudose
Revival Structure of Stark Wave Packets
latex file, 11 pages
Phys.Rev.A55:819,1997
10.1103/PhysRevA.55.819
IUHET 327, January 1996
quant-ph
null
The revival structure of Stark wave packets is considered. These wave packets have energies depending on two quantum numbers and are characterized by two sets of classical periods and revival times. The additional time scales result in revival structures different from those of free Rydberg wave packets. We show that Stark wave packets can exhibit fractional revivals. We also show that these wave packets exhibit particular features unique to the Stark effect. For instance, the wave functions can be separated into distinct sums over even and odd values of the principal quantum number. These even and odd superpositions interfere in different ways, which results in unexpected periodicities in the interferograms of Stark wave packets.
[ { "version": "v1", "created": "Mon, 26 Aug 1996 21:48:50 GMT" } ]
2009-09-25T00:00:00
[ [ "Bluhm", "Robert", "" ], [ "Kostelecky", "Alan", "" ], [ "Tudose", "Bogdan", "" ] ]
quant-ph/9608041
Thorsten Koehler
Thorsten Koehler
Quantum jumps in hydrogen-like systems
7 pages RevTeX + 2 figures Phys. Rev A accepted
null
10.1103/PhysRevA.54.4553
null
quant-ph
null
In this paper it is shown that the Lyman-$\alpha$ transition of a single hydrogen-like system driven by a laser exhibits macroscopic dark periods, provided there exists an additional constant electric field. We describe the photon-counting process under the condition that the polarization of the laser coincides with the direction of the constant electric field. The theoretical results are given for the example of $^4{He}^+$. We show that the emission behavior depends sensitively on the Lamb shift (W.E. Lamb, R.C. Retherford, Phys. Rev. 72, 241 (1947)) between the $2s_{1/2}$ and $2p_{1/2}$ energy levels. A possibly realizable measurement of the mean duration of the dark periods should give quantitative information about the above energy difference by using the proposed photon-counting process.
[ { "version": "v1", "created": "Tue, 27 Aug 1996 08:49:04 GMT" } ]
2016-09-08T00:00:00
[ [ "Koehler", "Thorsten", "" ] ]
quant-ph/9608042
Frank Antonsen
Frank Antonsen (Niels Bohr Institute)
Wigner-Weyl-Moyal Formalism on Algebraic Structures
pure LaTeX
Int.J.Theor.Phys. 37 (1998) 697-758
null
null
quant-ph
null
We first introduce the Wigner-Weyl-Moyal formalism for a theory whose phase-space is an arbitrary Lie algebra. We also generalize to quantum Lie algebras and to supersymmetric theories. It turns out that the non-commutativity leads to a deformation of the classical phase-space: instead of being a vector space it becomes a manifold, the topology of which is given by the commutator relations. It is shown in fact that the classical phase-space, for a semi-simple Lie algebra, becomes a homogenous symplectic manifold. The symplectic product is also deformed. We finally make some comments on how to generalize to $C^*$-algebras and other operator algebras too.
[ { "version": "v1", "created": "Wed, 28 Aug 1996 15:16:45 GMT" } ]
2007-05-23T00:00:00
[ [ "Antonsen", "Frank", "", "Niels Bohr Institute" ] ]
quant-ph/9608043
Frank Antonsen
Frank Antonsen, Karsten Bormann
Wormholes and Time-Machines
LaTeX, appears in Proceedings Third International A. Friedmann Seminar, St. Petersburg 1995, Friedmann Laboratory Publishers 1996
null
null
null
quant-ph
null
It has been proposed that wormholes can be made to function as time-machines. This opens up the question of whether this can be accomodated within a self-consistent physics or not. In this contribution we present some quantum mechanical considerations in this respect.
[ { "version": "v1", "created": "Wed, 28 Aug 1996 15:40:01 GMT" } ]
2007-05-23T00:00:00
[ [ "Antonsen", "Frank", "" ], [ "Bormann", "Karsten", "" ] ]
quant-ph/9608044
David Politzer
H. David Politzer
Bose-stimulated scattering off a cold atom trap
18 pages (REVTeX), no figures
null
10.1103/PhysRevA.55.1140
CALT-68-2070
quant-ph
null
The angle and temperature dependence of the photon scattering rate for Bose-stimulated atom recoil transitions between occupied states is compared to diffraction and incoherent Rayleigh scattering near the Bose-Einstein transition for an optically thin trap in the limit of large particle number, N. Each of these processes has a range of angles and temperatures for which it dominates over the others by a divergent factor as N->oo.
[ { "version": "v1", "created": "Wed, 28 Aug 1996 22:31:07 GMT" } ]
2009-10-30T00:00:00
[ [ "Politzer", "H. David", "" ] ]
quant-ph/9608045
Hiromichi Nakazato
Raffaella Blasi (1), Hiromichi Nakazato (2), Mikio Namiki (2) Saverio Pascazio (1 and 3) ((1) Dipt. di Fisica, Univ. di Bari, Italy, (2) Dept. of Phys, Waseda Univ., Japan, (3) INFN, Bari, Italy)
Emergence of a Wiener process as a result of the quantum mechanical interaction with a macroscopic medium
20 pages, LaTeX, no figures
null
10.1016/S0378-4371(97)00043-5
BA-TH/96-246, WU-HEP-96-9
quant-ph hep-th
null
We analyze a modified version of the Coleman-Hepp model, that is able to take into account energy-exchange processes between the incoming particle and the linear array made up of $N$ spin-1/2 systems. We bring to light the presence of a Wiener dissipative process in the weak-coupling, macroscopic ($N \rightarrow \infty$) limit. In such a limit and in a restricted portion of the total Hilbert space, the particle undergoes a sort of Brownian motion, while the free Hamiltonian of the spin array serves as a Wiener process. No assumptions are made on the spectrum of the Hamiltonian of the spin system, and no partial trace is computed over its states. The mechanism of appearance of the stochastic process is discussed and contrasted to other noteworthy examples in the literature. The links with van Hove's ``$\lambda^2 T$ limits are emphasized.
[ { "version": "v1", "created": "Thu, 29 Aug 1996 09:30:48 GMT" } ]
2015-06-26T00:00:00
[ [ "Blasi", "Raffaella", "", "1 and 3" ], [ "Nakazato", "Hiromichi", "", "1 and 3" ], [ "Namiki", "Mikio", "", "1 and 3" ], [ "Pascazio", "Saverio", "", "1 and 3" ] ]
quant-ph/9608046
Jonathan Halliwell
Jonathan Halliwell, Andreas Zoupas (Imperial College)
The Post-Decoherence Density Matrix Propagator for Quantum Brownian Motion
17 pages, plain Tex, submitted to Physical Review D
Phys.Rev.D55:4697-4704,1997
10.1103/PhysRevD.55.4697
Imperial College preprint 95-96/67
quant-ph
null
Using the path integral representation of the density matrix propagator of quantum Brownian motion, we derive its asymptotic form for times greater than the localization time, $ (\hbar / \gamma k T )^{\half}$, where $\gamma$ is the dissipation and $T$ the temperature of the thermal environment. The localization time is typically greater than the decoherence time, but much shorter than the relaxation time, $\gamma^{-1}$. We use this result to show that the reduced density operator rapidly evolves into a state which is approximately diagonal in a set of generalized coherent states. We thus reproduce, using a completely different method, a result we previously obtained using the quantum state diffusion picture (Phys.Rev. D52, 7294 (1995)). We also go beyond this earlier result, in that we derive an explicit expression for the weighting of each phase space localized state in the approximately diagonal density matrix, as a function of the initial state. For sufficiently long times it is equal to the Wigner function, and we confirm that the Wigner function is positive for times greater than the localization time (multiplied by a number of order 1).
[ { "version": "v1", "created": "Thu, 29 Aug 1996 14:42:58 GMT" } ]
2008-12-18T00:00:00
[ [ "Halliwell", "Jonathan", "", "Imperial College" ], [ "Zoupas", "Andreas", "", "Imperial College" ] ]
quant-ph/9608047
Chris Adami
N. J. Cerf, C. Adami (California Institute of Technology)
Entropic Bell Inequalities
4 pages RevTeX, 2 figures. Minor revisions. To appear in Phys. Rev. A
Phys.Rev. A55 (1997) 3371
10.1103/PhysRevA.55.3371
KRL MAP-205
quant-ph
null
We derive entropic Bell inequalities from considering entropy Venn diagrams. These entropic inequalities, akin to the Braunstein-Caves inequalities, are violated for a quantum mechanical Einstein-Podolsky-Rosen pair, which implies that the conditional entropies of Bell variables must be negative in this case. This suggests that the satisfaction of entropic Bell inequalities is equivalent to the non-negativity of conditional entropies as a necessary condition for separability.
[ { "version": "v1", "created": "Thu, 29 Aug 1996 18:00:35 GMT" }, { "version": "v2", "created": "Wed, 12 Feb 1997 22:56:04 GMT" } ]
2009-10-30T00:00:00
[ [ "Cerf", "N. J.", "", "California Institute of Technology" ], [ "Adami", "C.", "", "California Institute of Technology" ] ]
quant-ph/9608048
Emanuel Knill
E. Knill
Non-binary Unitary Error Bases and Quantum Codes
10 pages, preliminary report
null
null
LANL report LAUR-96-2717
quant-ph
null
Error operator bases for systems of any dimension are defined and natural generalizations of the bit/sign flip error basis for qubits are given. These bases allow generalizing the construction of quantum codes based on eigenspaces of Abelian groups. As a consequence, quantum codes can be constructed from linear codes over $\ints_n$ for any $n$. The generalization of the punctured code construction leads to many codes which permit transversal (i.e. fault tolerant) implementations of certain operations compatible with the error basis.
[ { "version": "v1", "created": "Thu, 29 Aug 1996 19:17:10 GMT" }, { "version": "v2", "created": "Tue, 8 Oct 1996 21:43:52 GMT" } ]
2008-02-03T00:00:00
[ [ "Knill", "E.", "" ] ]
quant-ph/9608049
Emanuel Knill
E. Knill
Group Representations, Error Bases and Quantum Codes
11 pages, preliminary report
null
null
LANL report LAUR-96-2807
quant-ph
null
This report continues the discussion of unitary error bases and quantum codes begun in "Non-binary Unitary Error Bases and Quantum Codes". Nice error bases are characterized in terms of the existence of certain characters in a group. A general construction for error bases which are non-abelian over the center is given. The method for obtaining codes due to Calderbank et al. is generalized and expressed purely in representation theoretic terms. The significance of the inertia subgroup both for constructing codes and obtaining the set of transversally implementable operations is demonstrated.
[ { "version": "v1", "created": "Thu, 29 Aug 1996 19:32:40 GMT" } ]
2007-05-23T00:00:00
[ [ "Knill", "E.", "" ] ]
quant-ph/9609001
null
D.A. Trifonov
Algebraic Coherent States and Squeezing
15 pages, latex, 2 figures available upon request. In the replaced version 1 reference (the last one) is added
null
null
INRNE-TH-96/9
quant-ph hep-th
null
Eigenstates of general complex linear combination of SU(1,1) generators (su^c(1,1) algebraic coherent states (ACS)) are constructed and discussed. In case of quadratic boson representation ACS can exhibit strong both linear and quadratic amplitude squeezing. ACS for a given Lie group algebra contain the corresponding Perelomov CS with maximal symmetry.
[ { "version": "v1", "created": "Fri, 30 Aug 1996 15:44:54 GMT" }, { "version": "v2", "created": "Mon, 23 Sep 1996 15:50:20 GMT" } ]
2009-09-25T00:00:00
[ [ "Trifonov", "D. A.", "" ] ]
quant-ph/9609002
Carlo Rovelli
Carlo Rovelli
Relational Quantum Mechanics
Substantially revised version. LaTeX file
Int. J. of Theor. Phys. 35 (1996) 1637
10.1007/BF02302261
null
quant-ph gr-qc hep-th
null
I suggest that the common unease with taking quantum mechanics as a fundamental description of nature (the "measurement problem") could derive from the use of an incorrect notion, as the unease with the Lorentz transformations before Einstein derived from the notion of observer-independent time. I suggest that this incorrect notion is the notion of observer-independent state of a system (or observer-independent values of physical quantities). I reformulate the problem of the "interpretation of quantum mechanics" as the problem of deriving the formalism from a few simple physical postulates. I consider a reformulation of quantum mechanics in terms of information theory. All systems are assumed to be equivalent, there is no observer-observed distinction, and the theory describes only the information that systems have about each other; nevertheless, the theory is complete.
[ { "version": "v1", "created": "Sat, 31 Aug 1996 10:13:29 GMT" }, { "version": "v2", "created": "Mon, 24 Feb 1997 20:09:52 GMT" } ]
2009-10-30T00:00:00
[ [ "Rovelli", "Carlo", "" ] ]
quant-ph/9609003
Olavo Leopoldino Da Silva Filho
L.S.F. Olavo
Quantum Mechanics as a Classical Theory XIII: The Tunnel Effect
10 pages, plain latex
null
null
UnB-013
quant-ph
null
In this continuation paper we will address the problem of tunneling. We will show how to settle this phenomenon within our classical interpretation. It will be shown that, rigorously speaking, there is no tunnel effect at all.
[ { "version": "v1", "created": "Wed, 4 Sep 1996 19:25:30 GMT" } ]
2007-05-23T00:00:00
[ [ "Olavo", "L. S. F.", "" ] ]
quant-ph/9609004
Maraner
J.R. Klauder (Univ. of Florida, USA), P. Maraner (Univ. of Parma, Italy)
Dynamics as Shadow of Phase Space Geometry
LaTeX (epsfig macros), 30 pages, 1 figure
Annals Phys. 253 (1997) 356-375
10.1006/aphy.1996.5631
UPRF-96-462
quant-ph
null
Starting with the generally well accepted opinion that quantizing an arbitrary Hamiltonian system involves picking out some additional structure on the classical phase space (the {\sl shadow} of quantum mechanics in the classical theory), we describe classical as well as quantum dynamics as a purely geometrical effect by introducing a {\sl phase space metric structure}. This produces an ${\cal O}(\hbar)$ modification of the classical equations of motion reducing at the same time the quantization of an arbitrary Hamiltonian system to standard procedures. Our analysis is carried out in analogy with the adiabatic motion of a charged particle in a curved background (the additional metric structure) under the influence of a universal magnetic field (the classical symplectic structure). This allows one to picture dynamics in an unusual way, and reveals a dynamical mechanism that produces the selection of the right set of physical quantum states.
[ { "version": "v1", "created": "Thu, 5 Sep 1996 09:36:02 GMT" } ]
2009-10-30T00:00:00
[ [ "Klauder", "J. R.", "", "Univ. of Florida, USA" ], [ "Maraner", "P.", "", "Univ. of Parma,\n Italy" ] ]
quant-ph/9609005
K. Berndl
Stefan Teufel, Karin Berndl, Detlef D\"urr, Sheldon Goldstein, Nino Zangh\`{\i}
Locality and Causality in Hidden Variables Models of Quantum Theory
revised version, 21 pages, submitted to Physical Review A
Phys.Rev. A56 (1997) 1217
10.1103/PhysRevA.56.1217
null
quant-ph
null
Motivated by Popescu's example of hidden nonlocality, we elaborate on the conjecture that quantum states that are intuitively nonlocal, i.e., entangled, do not admit a local causal hidden variables model. We exhibit quantum states which either (i) are nontrivial counterexamples to this conjecture or (ii) possess a new kind of more deeply hidden irreducible nonlocality. Moreover, we propose a nonlocality complexity classification scheme suggested by the latter possibility. Furthermore, we show that Werner's (and similar) hidden variables models can be extended to an important class of generalized observables. Finally a result of Fine on the equivalence of stochastic and deterministic hidden variables is generalized to causal models.
[ { "version": "v1", "created": "Fri, 6 Sep 1996 12:40:31 GMT" }, { "version": "v2", "created": "Thu, 6 Feb 1997 11:09:58 GMT" }, { "version": "v3", "created": "Wed, 30 Apr 1997 13:20:17 GMT" } ]
2009-10-30T00:00:00
[ [ "Teufel", "Stefan", "" ], [ "Berndl", "Karin", "" ], [ "Dürr", "Detlef", "" ], [ "Goldstein", "Sheldon", "" ], [ "Zangh\\`ı", "Nino", "" ] ]
quant-ph/9609006
Lev Vaidman
Lev Vaidman
On Schizophrenic Experiences of the Neutron or Why We Should Believe in the Many-Worlds Interpretation of Quantum Theory
21 pages, 5 eps figures, LaTeX
null
null
TAUP 2058-93
quant-ph
null
This is a philosophical paper in favor of the Many-Worlds Interpretation (MWI) of quantum theory. The concept of the ``measure of existence of a world'' is introduced and some difficulties with the issue of probability in the framework of the MWI are resolved. Brief comparative analyses of the Bohm theory and the Many-Minds Interpretation are given.
[ { "version": "v1", "created": "Sat, 7 Sep 1996 18:39:23 GMT" } ]
2007-05-23T00:00:00
[ [ "Vaidman", "Lev", "" ] ]
quant-ph/9609007
Lev Vaidman
Lev Vaidman
Defending Time-Symmetrized Quantum Theory
19 pages, LaTeX
null
null
TAUP 2366-96
quant-ph
null
Recently, several authors have criticized time-symmetrized quantum theory originated by the work of Aharonov et al. (1964). The core of this criticism was the proof, which appeared in various forms, showing that counterfactual interpretation of time-symmetrized quantum theory cannot be reconciled with the standard quantum theory. I argue here that the apparent contradiction appears due to inappropriate usage of traditional time asymmetric approach to counterfactuals, and that the contradiction disappears when the problem is analyzed in terms of time-symmetric counterfactuals. I analyze various aspects of time-symmetry of quantum theory and defend the time-symmetrized formalism.
[ { "version": "v1", "created": "Sat, 7 Sep 1996 19:00:01 GMT" } ]
2007-05-23T00:00:00
[ [ "Vaidman", "Lev", "" ] ]
quant-ph/9609008
Park Dae Kil
Chang Soo Park, Soo-Young Lee, Jae-Rok Kahng, Sahng-Kyoon Yoo, D.K. Park, C.H. Lee, Eui-Soon Yim
Effect of Anharmonicity on the WKB Energy Splitting in a Double Well Potential
two eps figures are included
J.KoreanPhys.Soc.30:637-639,1997
null
GTP-96-02
quant-ph hep-th
null
We investigate the effect of anharmonicity on the WKB approximation in a double well potential. By incorporating the anharmonic perturbation into the WKB energy splitting formula we show that the WKB approximation can be greatly improved in the region over which the tunneling is appreciable. We also observe that the usual WKB results can be obtained from our formalism as a limiting case in which the two potential minima are far apart.
[ { "version": "v1", "created": "Mon, 9 Sep 1996 14:32:49 GMT" } ]
2008-11-26T00:00:00
[ [ "Park", "Chang Soo", "" ], [ "Lee", "Soo-Young", "" ], [ "Kahng", "Jae-Rok", "" ], [ "Yoo", "Sahng-Kyoon", "" ], [ "Park", "D. K.", "" ], [ "Lee", "C. H.", "" ], [ "Yim", "Eui-Soon", "" ] ]
quant-ph/9609009
David J. Fernandez C.
David J. Fernandez C. (Physics Department, CINVESTAV)
SUSUSY quantum mechanics
7 pages, 2 encapsulated postscript figures, uses epsf.sty talk given at the II International Workshop on Classical and Quantum Integrable Systems, Dubna (Russia), 8-12 July (1996) to be published in Int. J. Mod. Phys. A
Int.J.Mod.Phys.A12:171-176,1997
10.1142/S0217751X97000232
null
quant-ph hep-th
null
The exactly solvable eigenproblems in Schr\"odinger quantum mechanics typically involve the differential "shift operators". In the standard supersymmetric (SUSY) case, the shift operator turns out to be of first order. In this work, I discuss a technique to generate exactly solvable eigenproblems by using second order shift operators. The links between this method and SUSY are analysed. As an example, we show the existence of a two-parametric family of exactly solvable Hamiltonians, which contains the Abraham-Moses potentials as a particular case.
[ { "version": "v1", "created": "Sat, 14 Sep 1996 02:12:15 GMT" } ]
2011-04-15T00:00:00
[ [ "C.", "David J. Fernandez", "", "Physics Department, CINVESTAV" ] ]