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10,600 | Photon Statistics of a Two-Mode Squeezed Vacuum | quant-ph | We investigate the general case of the photon distribution of a two-mode
squeezed vacuum and show that the distribution of photons among the two modes
depends on four parameters: two squeezing parameters, the relative phase
between the two oscillators and their spatial orientation. The distribution of
the total number ... | physics |
10,601 | The Emergence of Classicality via Decoherence: Beyond the Caldeira-Legget Environment | quant-ph | Maximally predictive states, as defined in recent work by Zurek, Habib and
Paz, are studied for more elaborate environment models than a linear coupling.
An environment model which includes spatial correlations in the noise is
considered in the non-dissipative regime. The Caldeira-Leggett model is also
reconsidered in ... | physics |
10,602 | String Theory, Black Holes and Klein's Lemma | quant-ph | This is a writeup of a talk given at the Oskar Klein Centenery Symposium,
Stockholm, September 19-21, 1994. It is an essay on the black hole information
paradox and its connection with thermodynamics and the foundations of quantum
mechanics. | physics |
10,603 | On the Stronger Statement of Levinson's Theorem for the Dirac Equation | quant-ph | Recently a stronger statement of Levinson's theorem for the Dirac equation
was presented, where the limits of the phase shifts at $E=\pm M$ are related to
the numbers of nodes of radial functions at the same energies, respectively.
However, in this letter we show that this statement has to be modified because
the limit... | physics |
10,604 | Kochen-Specker theorem for 8-dimensional space | quant-ph | A Kochen-Specker contradiction is produced with 36 vectors in a real
8-dimensional Hilbert space. These vectors can be combined into 30 distinct
projection operators (14 of rank 2, and 16 of rank 1). A state-specific variant
of this contradiction requires only 13 vectors, a remarkably low number for 8
dimensions. | physics |
10,605 | Infinite matrices may violate the associative law | quant-ph | The momentum operator for a particle in a box is represented by an infinite
order Hermitian matrix $P$. Its square $P^2$ is well defined (and diagonal),
but its cube $P^3$ is ill defined, because $P P^2\neq P^2 P$. Truncating these
matrices to a finite order restores the associative law, but leads to other
curious resu... | physics |
10,606 | A general formulation of discrete-time quantum mechanics, restrictions on the action and the relation of unitarity to the existence theorem for initial-value problems | quant-ph | A general formlulation for discrete-time quantum mechanics, based on
Feynman's method in ordinary quantum mechanics, is presented. It is shown that
the ambiguities present in ordinary quantum mechanics (due to noncommutativity
of the operators), are no longer present here. Then the criteria for the
unitarity of the evo... | physics |
10,607 | Superconvergent Perturbation Method in Quantum Mechanics | quant-ph | An analogue of Kolmogorov's superconvergent perturbation theory in classical
mechanics is constructed for self adjoint operators. It is different from the
usual Rayleigh--Schr\"odinger perturbation theory and yields expansions for
eigenvalues and eigenvectors in terms of functions of the perturbation
parameter. | physics |
10,608 | Quantum Averaging I: Poincaré--von Zeipel is Rayleigh--Schrödinger | quant-ph | An exact analogue of the method of averaging in classical mechanics is
constructed for self--adjoint operators. It is shown to be completely
equivalent to the usual Rayleigh--Schr\"odinger perturbation theory but gives
the sums over intermediate states in closed form expressions. The anharmonic
oscillator and the Henon... | physics |
10,609 | Two Mode Quantum Systems: Invariant Classification of Squeezing Transformations and Squeezed States | quant-ph | A general analysis of squeezing transformations for two mode systems is given
based on the four dimensional real symplectic group $Sp(4,\Re)\/$. Within the
framework of the unitary metaplectic representation of this group, a
distinction between compact photon number conserving and noncompact photon
number nonconserving... | physics |
10,610 | Critique of proposed limit to space--time measurement, based on Wigner's clocks and mirrors | quant-ph | Based on a relation between inertial time intervals and the Riemannian
curvature, we show that space--time uncertainty derived by Ng and van Dam
implies absurd uncertainties of the Riemannian curvature. | physics |
10,611 | RESOLUTION OF A ``RETRODICTION PARADOX'' | quant-ph | It is shown that the ``retrodiction paradox'' recently introduced by Peres
arises not because of the fallacy of the time-symmetric approach as he claimed,
but due to an inappropriate usage of retrodiction. | physics |
10,612 | NONLOCALITY OF A SINGLE PHOTON REVISITED AGAIN | quant-ph | Comment on L. Hardy, Phys. Rev. Lett. {\bf 73}, 2279 (1994). It is argued
that the experiment proposed by Hardy should not be considered as a single
photon experiment. | physics |
10,613 | Reply to the comment of Y. Aharonov and L. Vaidman on ``Time asymmetry in quantum mechanics: a retrodiction paradox'' | quant-ph | In the standard physical interpretation of quantum theory, prediction and
retrodiction are not symmetric. The opposite assertion by some authors results
from their use of non-standard interpretations of the theory. | physics |
10,614 | CAUSALITY, MEMORY ERASING AND DELAYED CHOICE EXPERIMENTS | quant-ph | Comment on [R.L. Ingraham, Phys. Rev. A 50, 4502 (1994)]. Ingraham suggested
``a delayed-choice experiment with partial, controllable memory erasing''. It
is shown that he cannot be right since his predictions contradict relativistic
causality. A subtle quantum effect which was overlooked by Ingraham is
explained. | physics |
10,615 | Nonlinear Schroedinger equation and two-level atoms | quant-ph | General features of nonlinear quantum mechanics are discussed in the context
of applications to two-level atoms. | physics |
10,616 | Triple bracket generalization of quantum mechanics | quant-ph | An extension of the Liouville-von Neumann dynamics to a Nambu-type dynamics
is proposed. The resulting theory is the first version of nonlinear QM which is
free from internal inconsistencies. | physics |
10,617 | Selective continuous quantum measurements: Restricted path integrals and wave equations | quant-ph | We discuss both the restricted path integral (RPI) and the wave equation (WE)
techniques in the theory of continuous quantum measurements. We intend to make
Mensky's fresh review complete by transforming his "effective" WE with complex
Hamiltonian into Ito-differential equations. | physics |
10,618 | Sub-femtosecond determination of transmission delay times for a dielectric mirror (photonic bandgap) as a function of angle of incidence | quant-ph | Using a two-photon interference technique, we measure the delay for
single-photon wavepackets to be transmitted through a multilayer dielectric
mirror, which functions as a ``photonic bandgap'' medium. By varying the angle
of incidence, we are able to confirm the behavior predicted by the group delay
(stationary phase ... | physics |
10,619 | The Nine Lives of Schroedinger's Cat | quant-ph | This MSc dissertation surveys nine interpretations of non-relativistic
quantum mechanics. Extensive references are given. The interpretations covered
are: the orthodox interpretation, Bohr's interpretation, the idea that the mind
causes collapse, hidden variables, the many-worlds interpretation, the
many-minds interpre... | physics |
10,620 | How much time does a tunneling particle spend in the barrier region? | quant-ph | The question in the title may be answered by considering the outcome of a
``weak measurement'' in the sense of Aharonov et al. Various properties of the
resulting time are discussed, including its close relation to the Larmor times.
It is a universal description of a broad class of measurement interactions, and
its phy... | physics |
10,621 | Quantum Nonlocality in Two-Photon Experiments at Berkeley | quant-ph | We review some of our experiments performed over the past few years on
two-photon interference. These include a test of Bell's inequalities, a study
of the complementarity principle, an application of EPR correlations for
dispersion-free time-measurements, and an experiment to demonstrate the
superluminal nature of the... | physics |
10,622 | What happens to spin during the SO(3)->SE(2) contraction? (On spin and extended structures in quantum mechanics) | quant-ph | It is shown that the spin operator can be described by an algebra which is in
between so(3) and e(2). Relativistic version of the singlet state for two Dirac
electrons is discussed. It is shown that a measure of massless particle's
extension can be naturally constructed and that this measure corresponds at the
classica... | physics |
10,623 | Effective Quantum Observables | quant-ph | Thought experiments about the physical nature of set theoretical
counterexamples to the axiom of choice motivate the investigation of peculiar
constructions, e.g. an infinite dimensional Hilbert space with a modular
quantum logic. Applying a concept due to BENIOFF, we identify the intrinsically
effective Hamiltonians w... | physics |
10,624 | Nonlocal effects in Fock space | quant-ph | If a physical system contains a single particle, and if two distant detectors
test the presence of linear superpositions of one-particle and vacuum states, a
violation of classical locality can occur. It is due to the creation of a
two-particle component by the detecting process itself. | physics |
10,625 | An optical method for teleportation | quant-ph | A teleportation method using standard present day optical technology is
presented. | physics |
10,626 | Effect of Decoherence on Bell's Inequality for an EPR Pair | quant-ph | According to Bell's theorem, the degree of correlation between spatially
separated measurements on a quantum system is limited by certain inequalities
if one assumes the condition of locality. Quantum mechanics predicts that this
limit can be exceeded, making it nonlocal. We analyse the effect of an
environment modelle... | physics |
10,627 | Analysis of the Stern-Gerlach Measurement | quant-ph | A dynamical model for the collapse of the wave function in a quantum
measurement process is proposed by considering the interaction of a quantum
system (spin-1/2) with a macroscopic quantum apparatus interacting with an
environment in a dissipative manner. The dissipative interaction leads to
decoherence in the superpo... | physics |
10,628 | Optimal Measurements of Magnetic Flux in Superconducting Circuits and Macroscopic Quantum Mechanics | quant-ph | A model of repeated quantum measurements of magnetic flux in superconducting
circuits manifesting tunneling is discussed. The perturbation due to the
previous measurements of magnetic flux is always present unless quantum
nondemolition measurements are performed. By replacing the classical notion of
noninvasivity with ... | physics |
10,629 | Cannot Local Reality Exist in the EPR-Bohm Gedankenexperiment ? | quant-ph | We model measuring processes of a single spin-1/2 object and of a pair of
spin-1/2 objects in the EPR-Bohm state by systems of differential equations.
Our model is a local model with hidden-variables of the EPR-Bohm
Gedankenexperiment. Although there is no dynamical interaction between a pair
of spin-1/2 objects, the m... | physics |
10,630 | Conditional probabilities in quantum theory, and the tunneling time controversy | quant-ph | It is argued that there is a sensible way to define conditional probabilities
in quantum mechanics, assuming only Bayes's theorem and standard quantum
theory. These probabilities are equivalent to the ``weak measurement''
predictions due to Aharonov {\it et al.}, and hence describe the outcomes of
real measurements mad... | physics |
10,631 | IS THERE A CLASSICAL ANALOG OF A QUANTUM TIME-TRANSLATION MACHINE? | quant-ph | In a recent article [D. Suter, Phys. Rev. {\bf A 51}, 45 (1995)] Suter has
claimed to present an optical implementation of the quantum time-translation
machine which ``shows all the features that the general concept predicts and
also allows, besides the quantum mechanical, a classical description.'' It is
argued that t... | physics |
10,632 | Bell's inequalities and density matrices. Revealing hidden nonlocality. | quant-ph | As is well known, quantum mechanical behavior cannot, in general, be
simulated by a local hidden variables model. Most -if not all- the proofs of
this incompatibility refer to the correlations which arise when each of two (or
more) systems separated in space is subjected to a single ideal measurement.
This setting is g... | physics |
10,633 | Dissipation and memory capacity in the quantum brain model | quant-ph | The quantum model of the brain proposed by Ricciardi and Umezawa is extended
to dissipative dynamics in order to study the problem of memory capacity. It is
shown that infinitely many vacua are accessible to memory printing in a way
that in sequential information recording the storage of a new information does
not dest... | physics |
10,634 | Quantum Electrodynamics at Large Distances III: Verification of Pole Factorization and the Correspondence Principle | quant-ph | In two companion papers it was shown how to separate out from a scattering
function in quantum electrodynamics a distinguished part that meets the
correspondence-principle and pole-factorization requirements. The integrals
that define the terms of the remainder are here shown to have singularities on
the pertinent Land... | physics |
10,635 | Consistent use of paradoxes in deriving constraints on the dynamics of physical systems and of no-go-theorems | quant-ph | The classical methods used by recursion theory and formal logic to block
paradoxes do not work in quantum information theory. Since quantum information
can exist as a coherent superposition of the classical ``yes'' and ``no''
states, certain tasks which are not conceivable in the classical setting can be
performed in t... | physics |
10,636 | Roentgen term makes dipole approximation more divergent | quant-ph | The Roentgen correction to the dipole interaction term leads to an additional
divergency which can be eliminated for infinitely heavy atoms. For M < infinity
a probability of emission in a given direction is represented by a divergent
integral. | physics |
10,637 | INTRINSIC MECHANISM FOR ENTROPY CHANGE IN CLASSICAL AND QUANTUM EVOLUTION | quant-ph | It is shown that the existence of a time operator in the Liouville space
representation of both classical and quantum evolution provides a mechanism for
effective entropy change of physical states. In particular, an initially
effectively pure state can evolve under the usual unitary evolution to an
effectively mixed st... | physics |
10,638 | Is Mental Process Non-Computable? | quant-ph | It has recently been claimed that certain aspects of mental processing cannot
be simulated by computers, even in principle. The argument is examined and a
lacuna is identified. | physics |
10,639 | Why Classical Mechanics Cannot Naturally Accommodate Consciousness But Quantum Mechanics Can. | quant-ph | It is argued on the basis of certain mathematical characteristics that
classical mechanics is not constitutionally suited to accomodate consciousness,
whereas quantum mechanics is. These mathematical characteristics pertain to the
nature of the information represented in the state of the brain, and the way
this informa... | physics |
10,640 | Intrinsic and operational observables in quantum mechanics | quant-ph | The concept of intrinsic and operational observables in quantum mechanics is
introduced. In any realistic description of a quantum measurement that includes
a macroscopic detecting device, it is possible to construct from the statistics
of the recorded raw data a set of operational quantities that correspond to the
int... | physics |
10,641 | Interpretation of the evolution parameter of the Feynman parametrization of the Dirac equation | quant-ph | The Feynman parametrization of the Dirac equation is considered in order to
obtain an indefinite mass formulation of relativistic quantum mechanics. It is
shown that the parameter that labels the evolution is related to the proper
time. The Stueckelberg interpretation of antiparticles naturally arises from
the formalis... | physics |
10,642 | Nonlocal and local ghost fields in quantum correlations. | quant-ph | Einstein Podolsky Rosen quantum correlations are discussed from the
perspective of a ghost field introduced by Einstein. The concepts of ghost
field, hidden variables, local reality and the Bell inequality are reviewed. In
the framework of the correlated singlet state, it is shown that quantum
mechanics can be cast in ... | physics |
10,643 | Quantum Cryptography with Coherent States | quant-ph | The safety of a quantum key distribution system relies on the fact that any
eavesdropping attempt on the quantum channel creates errors in the
transmission. For a given error rate, the amount of information that may have
leaked to the eavesdropper depends on both the particular system and the
eavesdropping strategy. In... | physics |
10,644 | Quantum Cryptography Based on Orthogonal States | quant-ph | All existing quantum cryptosystems use non-orthogonal states as the carriers
of information. Non-orthogonal states cannot be cloned (duplicated) by an
eavesdropper. In result, any eavesdropping attempt must introduce errors in the
transmission, and therefore, can be detected by the legal users of the
communication chan... | physics |
10,645 | Quantum Oscillator with Kronig-Penney Excitation in Different Regimes of Damping | quant-ph | There are discussed the exact solution of the time--dependent Schr\"{o}dinger
equation for a damped quantum oscillator subject to a periodical frequency
delta--kicks describing squeezed states which are expressed in terms of
Chebyshev polynomials. The cases of strong and weak damping are investigated in
the frame of Ca... | physics |
10,646 | Deformation of Partical Distribution Functions due to Q-nonlinearity and Nonstationary Casimir Effect | quant-ph | The geometrical phase is shown to be integral of motion. Deformation of
particle distribution function corresponding to nonstationary Casimir effect is
expressed in terms of multivariable Hermite polynomials. Correction to Planck
distribution due to q--nonlinearity is discussed. | physics |
10,647 | Husimi Parametric Oscillator in Frame of Symplectic Group and Q-oscillators | quant-ph | Time--dependent integrals of motion which are linear forms in position and
momentum are discussed for Husimi parametric forced oscillator. Generalization
of these integrals of motion for q--oscillator is presented. Squeezing and
quadrature correlation phenomena are discussed on the base of Schr\"odinger
uncertainty rel... | physics |
10,648 | Photon Statistics for MUltimode Squeezed Schrödinger Cat States | quant-ph | Particle distributions in squeezed states, even and odd coherent states are
given in terms of multivariable Hermite polynomials. The Q--function and Wigner
function for nonclassical field states are discussed. | physics |
10,649 | Decay Rates of Metastable States in Cubic Potential by Variational Perturbation Theory | quant-ph | Variational perturbation theory is used to determine the decay rates of
metastable states across a cubic barrier of arbitrary height. For high
barriers, a variational resummation procedure is applied to the complex energy
eigenvalues obtained from a WKB expansion; for low barriers, the variational
resummation procedure... | physics |
10,650 | Quantum chaos: a decoherent definition. | quant-ph | We show that the rate of increase of von Neumann entropy computed from the
reduced density matrix of an open quantum system is an excellent indicator of
the dynamical behavior of its classical hamiltonian counterpart. In decohering
quantum analogs of systems which exhibit classical hamiltonian chaos entropy
production ... | physics |
10,651 | Detecting Casimir Forces through a Tunneling Electromechanical Transducer | quant-ph | We propose the use of a tunneling electromechanical transducer to dynamically
detect Casimir forces between two conducting surfaces. The maximum distance for
which Casimir forces should be detectable with our method is around $1 \mu$m,
while the lower limit is given by the ability to approach the surfaces. This
techniq... | physics |
10,652 | Quantum Electrodynamics at Large Distances I: Extracting the Correspondence-Principle Part. | quant-ph | The correspondence principle is important in quantum theory on both the
fundamental and practical levels: it is needed to connect theory to experiment,
and for calculations in the technologically important domain lying between the
atomic and classical regimes. Moreover, a correspondence-principle part of the
S-matrix i... | physics |
10,653 | Comment on 'Quantum Backreaction on "Classical" Variables' | quant-ph | It is argued that the bracket of Anderson's canonical theory should have been
antisymmetric otherwise serious controversies arise like violation of both
hermiticity and the Leibniz rule of differentiation. | physics |
10,654 | A pragmatic approach to the problem of the self-adjoint extension of Hamilton operators with the Aharonov-Bohm potential | quant-ph | We consider the problem of self-adjoint extension of Hamilton operators for
charged quantum particles in the pure Aharonov-Bohm potential (infinitely thin
solenoid). We present a pragmatic approach to the problem based on the
orthogonalization of the radial solutions for different quantum numbers. Then
we discuss a mod... | physics |
10,655 | Quantum Computers, Factoring, and Decoherence | quant-ph | In a quantum computer any superposition of inputs evolves unitarily into the
corresponding superposition of outputs. It has been recently demonstrated that
such computers can dramatically speed up the task of finding factors of large
numbers -- a problem of great practical significance because of its
cryptographic appl... | physics |
10,656 | Standard Model plus Gravity from Octonion Creators and Annihilators | quant-ph | Octonion creation and annihilation operators are used to construct the
Standard Model plus Gravity. The resulting phenomenological model is the
D4-D5-E6 model described in hep-ph/9501252 . | physics |
10,657 | Stronger-than-quantum correlations | quant-ph | After an elementary derivation of Bell's inequality, several forms of
expectation functions for two-valued observables are discussed. Special
emphasis is given to hypothetical stronger-than quantum expectation functions
which give rise to a maximal violation of Bell's inequality. | physics |
10,658 | Polarization Structure of Quantum Light Fields: A New Insight. 2: Generalized Coherent States, Squeezing and Geometric Phases | quant-ph | Within the new description of the polarization structure of quantum light
(given in Part I) some types of generalized coherent states related to the
polarization SU(2) group are examined. With their help we give a quasiclassical
description of polarization properties of light fields and discuss the concept
of squeezing... | physics |
10,659 | On the Global Existence of Bohmian Mechanics | quant-ph | We show that the particle motion in Bohmian mechanics, given by the solution
of an ordinary differential equation, exists globally: For a large class of
potentials the singularities of the velocity field and infinity will not be
reached in finite time for typical initial values. A substantial part of the
analysis is ba... | physics |
10,660 | Decoherence and the Quantum Zeno Effect | quant-ph | The experiment of Etano et al which demonstrated the quantum Zeno effect
(QZE) in an optical experiment was explained by Frerichs and Schenzle without
invoking the wave function collapse. In this report it is proposed that the
collapse does occur, and it can be explained by the `environment induced
decoherence' theory.... | physics |
10,661 | HyperDiamond Feynman Checkerboard in 4-dimensional Spacetime | quant-ph | A generalized Feynman Checkerboard model is constructed using a 4-dimensional
HyperDiamond lattice. The resulting phenomenological model is the D4-D5-E6
model described in hep-ph/9501252 and quant-ph/9503009. | physics |
10,662 | Conditional Quantum Dynamics and Logic Gates | quant-ph | Quantum logic gates provide fundamental examples of conditional quantum
dynamics. They could form the building blocks of general quantum information
processing systems which have recently been shown to have many interesting
non--classical properties. We describe a simple quantum logic gate, the quantum
controlled--NOT,... | physics |
10,663 | ON THE QUANTUM EVOLUTION OF CHAOTIC SYSTEMS AFFECTED BY REPEATED FREQUENT MEASUREMENT | quant-ph | We investigate the effect of repeated measurement for quantum dynamics of the
suppressed systems which classical counterparts exhibit chaos. The essential
feature of such systems is the quantum localization phenomena strongly limiting
motion in the energy space. Repeated frequent measurement of suppressed systems
resul... | physics |
10,664 | Gravity, energy conservation and parameter values in collapse models | quant-ph | We interpret the probability rule of the CSL collapse theory to mean that the
scalar field which causes collapse is the grvitational curvature scalar with
two sources, the expectation value of the mass density and a white noise
fluctuating source. We examine two models of the fluctuating source, monopole
fluctuations a... | physics |
10,665 | Quantum Mechanics as a Classical Theory I: Non-relativistic Theory | quant-ph | The objective of this series of three papers is to axiomatically derive
quantum mechanics from classical mechanics and two other basic axioms. In this
first paper, Schreodinger's equation for the density matrix is fist obtained
and from it Schroedinger's equation for the wave functions is derived. The
momentum and posi... | physics |
10,666 | Quantum Mechanics as a Classical Theory II: Relativistic Theory | quant-ph | In this article, the axioms presented in the first one are reformulated
according to the special theory of relativity. Using these axioms, quantum
mechanic's relativistic equations are obtained in the presence of
electromagnetic fields for both the density function and the probability
amplitude. It is shown that, withi... | physics |
10,667 | Quantum Mechanics as a Classical Theory III: Epistemology | quant-ph | The two previous papers developed quantum mechanical formalism from classical
mechanics and two additional postulates. In the first paper it was also shown
that the uncertainty relations possess no ontological validity and only reflect
the formalism's limitations. In this paper, a Realist Interpretation of quantum
mech... | physics |
10,668 | Quantum dynamics with two Planck constants and the semiclassical limit | quant-ph | The mathematical possibility of coupling two quantum dynamic systems having
two different Planck constants, respectively, is investigated. It turns out
that such canonical dynamics are always irreversible. Semiclassical dynamics is
obtained by letting one of the two Planck constants go to zero. This
semiclassical dynam... | physics |
10,669 | Quantum Mechanics as a Classical Theory IV: The Negative Mass Conjecture | quant-ph | The following two papers form a natural development of a previous series of
three articles on the foundations of quantum mechanics; they are intended to
take the theory there developed to its utmost logical and epistemological
consequences. We show in the first paper that relativistic quantum mechanics
might accommodat... | physics |
10,670 | Quantum Mechanics as a Classical Theory V: The Quantum Schwartzchild Problem | quant-ph | In this continuation paper, we apply the general relativistic quantum theory
for one particle systems, derived in paper II of this series, to a simple
problem: the quantum Schwartzchild problem, where one particle of mass {\it m%
} gravitates around a massive body. The results thus obtained reveal that, in
the realm of... | physics |
10,671 | Quantum mechanics of time-dependent systems. Construction of pure states | quant-ph | For time-dependent systems the wavefunction depends explicitly on time and it
is not a pure state of the Hamiltonian. We construct operators for which the
above wavefunction is a pure state. The method is based on the introduction of
conserved quantities $Q$ and the pure states are defined by ${\hat
Q}\psi=q\psi$. The ... | physics |
10,672 | Quantum Cryptography | quant-ph | Quantum cryptography is a new method for secret communications offering the
ultimate security assurance of the inviolability of a Law of Nature. In this
paper we shall describe the theory of quantum cryptography, its potential
relevance and the development of a prototype system at Los Alamos, which
utilises the phenome... | physics |
10,673 | Quantum Mechanical Coherence, Resonance, and Mind | quant-ph | Norbert Wiener and J.B.S. Haldane suggested during the early thirties that
the profound changes in our conception of matter entailed by quantum theory
opens the way for our thoughts, and other experiential or mind-like qualities,
to play a role in nature that is causally interactive and effective, rather
than purely ep... | physics |
10,674 | Higher order Schmidt decompositions | quant-ph | Necessary and sufficient conditions are given for the existence of extended
Schmidt decompositions, with more than two subspaces. | physics |
10,675 | Rydberg Atoms Ionisation by Microwave Field and Electromagnetic Pulses | quant-ph | A simple theory of the Rydberg atoms ionisation by electromagnetic pulses and
microwave field is presented. The analysis is based on the scale transformation
which reduces the number of parameters and reveals the functional dependencies
of the processes. It is shown that the observed ionisation of Rydberg atoms by
subp... | physics |
10,676 | Photon states associated with Holstein-Primakoff realization of SU(1,1) Lie algebra | quant-ph | Statistical and phase properties and number-phase uncertainty relations are
systematically investigated for photon states associated with the
Holstein-Primakoff realization of the SU(1,1) Lie algebra. Perelomov's SU(1,1)
coherent states and the eigenstates of the SU(1,1) lowering generator (the
Barut-Girardello states)... | physics |
10,677 | Discrete photodetection and Susskind-Glogower ladder operators | quant-ph | We assert that state reduction processes in different types of photodetection
experiments are described by using different kinds of ladder operators. A
special model of discrete photodetection is developed by the use of
superoperators which are based on the Susskind-Glogower raising and lowering
operators. | physics |
10,678 | A Survey on Bohmian Mechanics | quant-ph | Bohmian mechanics is the most naively obvious embedding imaginable of
Schr\"odinger's equation into a completely coherent physical theory. It
describes a world in which particles move in a highly non-Newtonian sort of
way, one which may at first appear to have little to do with the spectrum of
predictions of quantum me... | physics |
10,679 | COMBINATORIAL COMPUTATION OF CLEBSCH-GORDAN COEFFICIENTS | quant-ph | The addition of angular momenta can be reduced to elementary coupling
processes of spin-$\frac{1}{2}$-particles. In this way, a method is developed
which allows for a non-recursive, simultaneous computation of all
Clebsch-Gordan coefficients concerning the addition of two angular momenta. The
relevant equations can be ... | physics |
10,680 | Supersymmetry of Demkov-Ostrovsky effective potentials in the R_0=0 sector | quant-ph | We present a supersymmetric analysis of the wave problem with a
Demkov-Ostrovsky spherically symmetric class of focusing potentials at zero
energy. Following a suggestion of L\'evai, we work in the so-called R_0=0
sector in order to obtain the superpartner (fermionic) potentials within
Witten's supersymmetric procedure... | physics |
10,681 | Supersymmetric features of the Maxwell fish-eye lens | quant-ph | We provide a supersymmetric analysis of the Maxwell fisheye (MF) wave problem
at zero energy. Working in the so-called $R_{0}=0$ sector, we obtain the
corresponding superpartner (fermionic) MF effective potential within Witten's
one-dimensional (radial) supersymmetric procedure. | physics |
10,682 | Experimental limit on the blue shift of the frequency of light implied by a q-nonlinearity | quant-ph | We discuss the implications of an experiment in which the frequencies of two
laser beams are compared for different intensities in order to search for a
dependence of the frequency of light on its intensity. Since no such dependence
was found it is possible to place bounds on a description of the
electromagnetic field ... | physics |
10,683 | Quantization of electromagnetic field in inhomogeneous dispersive dielectrics | quant-ph | Canonical quantization of electromagnetic field inside the time--spatially
dispersive inhomogeneous dielectrics is presented. Interacting electromagnetic
and matter excitation fields create the closed system, Hamiltonian of which may
be diagonalized by generalized polariton transformation. Resulting dispersion
relation... | physics |
10,684 | The Rigged Hilbert Space Formulation of Quantum Mechanics and its Implications for Irreversibility | quant-ph | Quantum mechanics in the Rigged Hilbert Space formulation describes
quasistationary phenomena mathematically rigorously in terms of Gamow vectors.
We show that these vectors exhibit microphysical irreversibility, related to an
intrinsic quantum mechanical arrow of time, which states that preparation of a
state has to p... | physics |
10,685 | Second solution of Demkov-Ostrovsky superpotentials | quant-ph | We work out the second solution of the DO superpotentials in the $R_0=0$
sector. | physics |
10,686 | MARKOV DIFFUSIONS IN COMOVING COORDINATES AND STOCHASTIC QUANTIZATION OF THE FREE RELATIVISTIC SPINLESS PARTICLE | quant-ph | We revisit the classical approach of comoving coordinates in relativistic
hydrodynamics and we give a constructive proof for their global existence under
suitable conditions which is proper for stochastic quantization. We show that
it is possible to assign stochastic kinematics for the free relativistic
spinless partic... | physics |
10,687 | Review of R. Omnes, THE INTERPRETATION OF QUANTUM MECHANICS | quant-ph | Omnes' interpretation of quantum mechanics is summarized, and compared with
other consistent-history approaches by Gell-Mann and Hartle, and by Griffiths. | physics |
10,688 | Consistent Quantum Reasoning | quant-ph | Precise rules are developed in order to formalize the reasoning processes
involved in standard non-relativistic quantum mechanics, with the help of
analogies from classical physics. A classical or quantum description of a
mechanical system involves a {\it framework}, often chosen implicitly, and a
{\it statement} or as... | physics |
10,689 | A Simple Quantum Computer | quant-ph | We propose an implementation of a quantum computer to solve Deutsch's
problem, which requires exponential time on a classical computer but only
linear time with quantum parallelism. By using a dual-rail qubit representation
as a simple form of error correction, our machine can tolerate some amount of
decoherence and st... | physics |
10,690 | Wavelet basis for the Schrödinger equation | quant-ph | The self-similar representation for the Schr\"{o}dinger equation is derived. | physics |
10,691 | [p,q] does not equal (i h-bar) | quant-ph | In this short note, I point out that [p,q] does not equal (i h-bar), contrary
to the original claims of Born and Jordan, and Dirac. Rather, [p,q] is equal to
something that is *infinitesimally different* from (i h-bar). While this
difference is usually harmless, it does provide the solution of the Born-Jordan
"trace pa... | physics |
10,692 | Quantum oblivious transfer protocols based on EPR states | quant-ph | We describe efficient protocols for quantum oblivious transfer and for
one-out-of-two quantum oblivious transfer. These protocols, which can be
implemented with present technology, are secure against general attacks as long
as the cheater can not store the bit for an arbitrarily long period of time. | physics |
10,693 | A Universal Two--Bit Gate for Quantum Computation | quant-ph | We prove the existence of a class of two--input, two--output gates any one of
which is universal for quantum computation. This is done by explicitly
constructing the three--bit gate introduced by Deutsch [Proc.~R.~Soc.~London.~A
{\bf 425}, 73 (1989)] as a network consisting of replicas of a single two--bit
gate. | physics |
10,694 | Realism and Time Symmetry in Quantum Mechanics | quant-ph | We describe a gedanken experiment with an interferometer in the case of pre-
and postselection in two different time symmetric ways: We apply the ABL
formalism and the de Broglie--Bohm model. Interpreting these descriptions
ontologically, we get two very different concepts of reality. Finally, we
discuss some problems ... | physics |
10,695 | Universality in Quantum Computation | quant-ph | We show that in quantum computation almost every gate that operates on two or
more bits is a universal gate. We discuss various physical considerations
bearing on the proper definition of universality for computational components
such as logic gates. | physics |
10,696 | A Quantum Bit Commitment Protocol Based on EPR States | quant-ph | A protocol for quantum bit commitment is proposed. The protocol is feasible
with present technology and is secure against cheaters with unlimited computing
power as long as the sender does not have the technology to store an EPR
particle for an arbitrarily long period of time. The protocol is very
efficient, requiring ... | physics |
10,697 | Randomness, Nonlocality and information in entagled correlations | quant-ph | It is shown that the Einstein, Podolsky and Rosen (EPR) correlations for
arbitrary spin-s and the Greenberger, Horne and Zeilinger (GHZ) correlations
for three particles can be described by nonlocal joint and conditional quantum
probabilities. The nonlocality of these probabilities makes the Bell's
inequalities void. A... | physics |
10,698 | Spin-Orbit Pendulum: the Microscopic Stern-Gerlach Effect | quant-ph | The motion of a particle with a spin in spherical harmonic oscillator
potential with spin-orbit interaction is studied. We have focus our attention
on spatial motion of wave packets, giving a description complementary to motion
of spin discussed already in [1]. The particular initial conditions studied
here lead to the... | physics |
10,699 | Nonlinear Schroedinger Dynamics and Nonlinear Observables | quant-ph | It is is explained why physical consistency requires substituting linear
observables by nonlinear ones for quantum systems with nonlinear time evolution
of pure states. The exact meaning and the concrete physical interpretation are
described in full detail for a special case of the nonlinear Doebner-Goldin
equation. | physics |
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