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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
quant-ph/9809085 | Jerry Finkelstein | J. Finkelstein (LBNL and SJSU) | Ambiguities of arrival-time distributions in quantum theory | LaTex, 12 pages, no figures | Phys.Rev. A59 (1999) 3218-3222 | 10.1103/PhysRevA.59.3218 | SJSU/TP-98-18 | quant-ph | null | We consider the definition that might be given to the time at which a
particle arrives at a given place, both in standard quantum theory and also in
Bohmian mechanics. We discuss an ambiguity that arises in the standard theory
in three, but not in one, spatial dimension.
| [
{
"version": "v1",
"created": "Mon, 28 Sep 1998 21:07:30 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Finkelstein",
"J.",
"",
"LBNL and SJSU"
]
] |
quant-ph/9809086 | Andreas Mielke | Daniel Cremers and Andreas Mielke | Flow Equations for the Henon-Heiles Hamiltonian | latex, 14 pages, 6 figures, uses epsfig, accepted for publication in
Physica D | null | 10.1016/S0167-2789(98)00267-X | HD-TVP-98-4 | quant-ph chao-dyn nlin.CD | null | The Henon-Heiles Hamiltonian was introduced in 1964 as a mathematical model
to describe the chaotic motion of stars in a galaxy. By canonically
transforming the classical Hamiltonian to a Birkhoff-Gustavson normalform Delos
and Swimm obtained a discrete quantum mechanical energy spectrum. The aim of
the present work is to first quantize the classical Hamiltonian and to then
diagonalize it using different variants of flow equations, a method of
continuous unitary transformations introduced by Wegner in 1994. The results of
the diagonalization via flow equations are comparable to those obtained by the
classical transformation. In the case of commensurate frequencies the
transformation turns out to be less lengthy. In addition, the dynamics of the
quantum mechanical system are analyzed on the basis of the transformed
observables.
| [
{
"version": "v1",
"created": "Tue, 29 Sep 1998 14:18:19 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Cremers",
"Daniel",
""
],
[
"Mielke",
"Andreas",
""
]
] |
quant-ph/9809087 | S. F. Yelin | Michael Fleischhauer, Susanne F. Yelin | Radiative atom-atom interactions in optically dense media: Quantum
corrections to the Lorentz-Lorenz formula | 16 pages, 12 figures, subm. to PRA | null | 10.1103/PhysRevA.59.2427 | null | quant-ph | null | Generalized single-atom Maxwell-Bloch equations for optically dense media are
derived taking into account non-cooperative radiative atom-atom interactions.
Applying a Gaussian approximation and formally eliminating the degrees of
freedom of the quantized radiation field and of all but a probe atom leads to
an effective time-evolution operator for the probe atom. The mean coherent
amplitude of the local field seen by the atom is shown to be given by the
classical Lorentz-Lorenz relation. The second-order correlations of the field
lead to terms that describe relaxation or pump processes and level shifts due
to multiple scattering or reabsorption of spontaneously emitted photons. In the
Markov limit a nonlinear and nonlocal single-atom density matrix equation is
derived. To illustrate the effects of the quantum corrections we discuss
amplified spontaneous emission and radiation trapping in a dense ensemble of
initially inverted two-level atoms and the effects of radiative interactions on
intrinsic optical bistability in coherently driven systems.
| [
{
"version": "v1",
"created": "Tue, 29 Sep 1998 23:17:28 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Fleischhauer",
"Michael",
""
],
[
"Yelin",
"Susanne F.",
""
]
] |
quant-ph/9809088 | Sigmund Kohler | Sigmund Kohler, Thomas Dittrich, and Peter H\"anggi | Floquet-Markov description of the parametrically driven, dissipative
harmonic quantum oscillator | 29 pages, 7 figures | Phys.Rev. E55 (1997) 300-313 | 10.1103/PhysRevE.55.300 | null | quant-ph | null | Using the parametrically driven harmonic oscillator as a working example, we
study two different Markovian approaches to the quantum dynamics of a
periodically driven system with dissipation. In the simpler approach, the
driving enters the master equation for the reduced density operator only in the
Hamiltonian term. An improved master equation is achieved by treating the
entire driven system within the Floquet formalism and coupling it to the
reservoir as a whole. The different ensuing evolution equations are compared in
various representations, particularly as Fokker-Planck equations for the Wigner
function. On all levels of approximation, these evolution equations retain the
periodicity of the driving, so that their solutions have Floquet form and
represent eigenfunctions of a non-unitary propagator over a single period of
the driving. We discuss asymptotic states in the long-time limit as well as the
conservative and the high-temperature limits. Numerical results obtained within
the different Markov approximations are compared with the exact path-integral
solution. The application of the improved Floquet-Markov scheme becomes
increasingly important when considering stronger driving and lower
temperatures.
| [
{
"version": "v1",
"created": "Wed, 30 Sep 1998 12:09:46 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kohler",
"Sigmund",
""
],
[
"Dittrich",
"Thomas",
""
],
[
"Hänggi",
"Peter",
""
]
] |
quant-ph/9809089 | Michael Fleischhauer | Michael Fleischhauer and Oliver Veits | Long-time dynamics of spontaneous parametric down-conversion and quantum
limitations of conversion efficiency | 5 pages, 4 figures | null | 10.1515/zna-1999-0108 | null | quant-ph | null | We analyze the long-time quantum dynamics of degenerate parametric
down-conversion from an initial sub-harmonic vacuum (spontaenous
down-conversion). Standard linearization of the Heisenberg equations of motions
fails in this case, since it is based on an expansion around an unstable
classical solution and neglects pump depletion. Introducing a mean-field
approximation we find a periodic exchange of energy between the pump and
subharmonic mode goverened by an anharmonic pendulum equation. From this
equation the optimum interaction time or crystal length for maximum conversion
can be determined. A numerical integration of the 2-mode Schr"odinger equation
using a dynamically optimized basis of displaced and squeezed number states
verifies the characteristic times predicted by the mean-field approximation. In
contrast to semiclassical and mean-field predictions it is found that quantum
fluctuations of the pump mode lead to a substantial limitation of the
efficiency of parametric down-conversion.
| [
{
"version": "v1",
"created": "Wed, 30 Sep 1998 14:46:06 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Fleischhauer",
"Michael",
""
],
[
"Veits",
"Oliver",
""
]
] |
quant-ph/9810001 | Samuel L. Braunstein | Samuel L. Braunstein and H. J. Kimble | A posteriori teleportation | 1 page LaTeX including 1 figure. Scientific Correspondence about:
"Experimental quantum teleportation" Nature 390, 575 (1997) | Nature 394, 840-841 (1998) | 10.1038/29674 | null | quant-ph | null | The article by Bouwmeester et al. on experimental quantum teleportation
constitutes an important advance in the burgeoning field of quantum
information. The experiment was motivated by the proposal of Bennett et al. in
which an unknown quantum state is `teleported' by Alice to Bob. As illustrated
in Fig. 1, in the implementation of this procedure, by Bouwmeester et al., an
input quantum state is `disembodied' into quantum and classical components, as
in the original protocol. However, in contrast to the original scheme,
Bouwmeester et al.'s procedure necessarily destroys the state at Bob's
receiving terminal, so a `teleported' state can never emerge as a freely
propagating state for subsequent examination or exploitation. In fact,
teleportation is achieved only as a postdiction.
| [
{
"version": "v1",
"created": "Thu, 1 Oct 1998 11:03:55 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Braunstein",
"Samuel L.",
""
],
[
"Kimble",
"H. J.",
""
]
] |
quant-ph/9810002 | null | R. Gielerak (1 and 2), P. Lugiewicz (1) ((1) Inst. of T. Phys., Univ.
of Wroclaw, Poland (2) Inst. of T. Phys., Tech. Univ. of Zielona Gora,
Poland) | From Stochastic Differential Equations to Quantum Field Theory | 11 pages, Latex, to appear in: Reports On Mathematical Physics No.X
Vol.XX (199X) | Rept.Math.Phys. 44 (1999) 101-110 | 10.1016/S0034-4877(99)80150-5 | null | quant-ph | null | Covariant stochastic partial (pseudo-)differential equations are studied in
any dimension. In particular a large class of covariant interacting local
quantum fields obeying the Morchio-Strocchi system of axioms for indefinite
quantum field theory is constructed by solving the analysed equations. The
associated random cosurface models are discussed and some elementary properties
of them are outlined.
| [
{
"version": "v1",
"created": "Fri, 2 Oct 1998 10:21:16 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Gielerak",
"R.",
"",
"1 and 2"
],
[
"Lugiewicz",
"P.",
""
]
] |
quant-ph/9810003 | Andrew G. White | Paul G. Kwiat (1), Edo Waks (1 and 2), Andrew G. White (1), Ian
Appelbaum (1 and 3), Philippe H. Eberhard (4) ((1) Physics Division, P-23,
Los Alamos National Laboratory, (2) Ginzton Laboratory, Stanford University,
(3) Physics Dept., M.I.T., (4) Lawrence Berkeley Laboratory) | Ultra-bright source of polarization-entangled photons | 4 pages, 5 encapsulated Postscript figures. To appear in Physical
Review A (Rapid Communication) | Physical Review A 60, 773-776 (1999) | 10.1103/PhysRevA.60.R773 | null | quant-ph physics.optics | null | Using the process of spontaneous parametric down conversion in a novel
two-crystal geometry, one can generate a source of polarization-entangled
photon pairs which is orders of magnitude brighter than previous sources. We
have measured a high level of entanglement between photons emitted over a
relatively large collection angle, and over a 10-nm bandwidth. As a
demonstration of the source intensity, we obtained a 242-$\sigma$ violation of
Bell's inequalities in less than three minutes.
| [
{
"version": "v1",
"created": "Fri, 2 Oct 1998 16:26:56 GMT"
},
{
"version": "v2",
"created": "Fri, 21 May 1999 23:33:15 GMT"
},
{
"version": "v3",
"created": "Sat, 22 May 1999 00:17:31 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kwiat",
"Paul G.",
"",
"1 and 2"
],
[
"Waks",
"Edo",
"",
"1 and 2"
],
[
"White",
"Andrew G.",
"",
"1 and 3"
],
[
"Appelbaum",
"Ian",
"",
"1 and 3"
],
[
"Eberhard",
"Philippe H.",
""
]
] |
quant-ph/9810004 | Andrew G. White | A.G. White (1), P. K. Lam (1), M. S. Taubman (1), M. A. M. Marte (2),
S. Schiller (3), D. E. McClelland (1), and H.-A. Bachor (1) ((1) Physics
Department, Australian National University, (2) Institut fuer Physik,
Universitaet Innsbruck (3) Fakultaet fuer Physik, Universitaet Konstanz) | Classical and quantum signatures of competing chi(2) nonlinearities | 5 pages, 6 figures | Physical Review A 55, 4511-4515 (1997) | 10.1103/PhysRevA.55.4511 | null | quant-ph physics.optics | null | We report the first observation of the quantum effects of competing
$\chi^{(2)}$ nonlinearities. We also report new classical signatures of
competition, namely clamping of the second harmonic power and production of
nondegenerate frequencies in the visible. Theory is presented that describes
the observations as resulting from competition between various $\chi^{(2)}$
upconversion and downconversion processes. We show that competition imposes
hitherto unsuspected limits to both power generation and squeezing. The
observed signatures are expected to be significant effects in practical
systems.
| [
{
"version": "v1",
"created": "Fri, 2 Oct 1998 17:19:29 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"White",
"A. G.",
""
],
[
"Lam",
"P. K.",
""
],
[
"Taubman",
"M. S.",
""
],
[
"Marte",
"M. A. M.",
""
],
[
"Schiller",
"S.",
""
],
[
"McClelland",
"D. E.",
""
],
[
"Bachor",
"H. -A.",
""
]
] |
quant-ph/9810005 | Armen G. Grigoryan | A. V. Bogdanov, A. S. Gevorkyan, A. G. Grigoryan and S. A. Matveev | Internal Time Peculiarities as a Cause of Bifurcations Arising in
Classical Trajectory Problem and Quantum Chaos Creation in Three-Body System | 7 pages, 3 figures, accepted for publication in Int. J. of
Bifurcation & Chaos | null | 10.1142/S0218127499001590 | null | quant-ph | null | A new formulation of the theory of quantum mechanical multichannel scattering
for three-body collinear systems is proposed. It is shown, that in this simple
case the principle of quantum determinism in the general case breaks down and
we have a micro-irreversible quantum mechanics. The first principle
calculations of the quantum chaos (wave chaos) were pursued on the example of
an elementary chemical reaction Li+(FH)->(LiFH)*->(LiF)+H.
| [
{
"version": "v1",
"created": "Fri, 2 Oct 1998 21:17:53 GMT"
},
{
"version": "v2",
"created": "Tue, 6 Oct 1998 15:52:52 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Bogdanov",
"A. V.",
""
],
[
"Gevorkyan",
"A. S.",
""
],
[
"Grigoryan",
"A. G.",
""
],
[
"Matveev",
"S. A.",
""
]
] |
quant-ph/9810006 | null | M. Kibler, G.-H. Lamot and P. Winternitz | Classical Trajectories for two Ring-Shaped Potentials | 28 pages, Tex file | Int.J.Quant.Chem. 43 (1992) 625-645 | null | null | quant-ph physics.chem-ph physics.class-ph | null | This paper deals with the classical trajectories for two super-integrable
systems: a system known in quantum chemistry as the Hartmann system and a
system of potential use in quantum chemistry and nuclear physics. Both systems
correspond to ring-shaped potentials. They admit two maximally super-integrable
systems as limiting cases, viz, the isotropic harmonic oscillator system and
the Coulomb-Kepler system in three dimensions. The planarity of the
trajectories is studied in a systematic way. In general, the trajectories are
quasi-periodic rather than periodic. A constraint condition allows to pass from
quasi-periodic motions to periodic ones. When written in a quantum mechanical
context, this constraint condition leads to new accidental degeneracies for the
two systems studied.
| [
{
"version": "v1",
"created": "Sat, 3 Oct 1998 08:14:57 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kibler",
"M.",
""
],
[
"Lamot",
"G. -H.",
""
],
[
"Winternitz",
"P.",
""
]
] |
quant-ph/9810007 | Harald Weinfurter | Dik Bouwmeester, Jian-Wei Pan, Matthew Daniell, Harald Weinfurter,
Marek Zukowski, and Anton Zeilinger | A posteriori teleportation ? | 1 page LaTeX. Reply to a comment by S.L. Braunstein and H.J. Kimble,
Nature 394, 840-841 (1998) and quant-ph/9810001 | Nature 394 (1998) 841 | 10.1038/29678 | null | quant-ph | null | Braunstein and Kimble observe correctly that, in the Innsbruck experiment,
Nature 390, 575 (1997), one does not always observe a teleported photon
conditioned on a coincidence recording at the Bell-state analyser. However,
when a teleported photon appears, it has all the properties required by the
teleportation protocol.
| [
{
"version": "v1",
"created": "Sat, 3 Oct 1998 17:10:20 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bouwmeester",
"Dik",
""
],
[
"Pan",
"Jian-Wei",
""
],
[
"Daniell",
"Matthew",
""
],
[
"Weinfurter",
"Harald",
""
],
[
"Zukowski",
"Marek",
""
],
[
"Zeilinger",
"Anton",
""
]
] |
quant-ph/9810008 | Chi-Sheng Niu | Chi-Sheng Niu, Robert B. Griffiths (Department of Physics, Carnegie
Mellon University) | Two qubit copying machine for economical quantum eavesdropping | Minor changes. 26 pages RevTex including 7 PS figures | Phys.Rev. A60 (1999) 2764-2776 | 10.1103/PhysRevA.60.2764 | null | quant-ph | null | We study the mapping which occurs when a single qubit in an arbitrary state
interacts with another qubit in a given, fixed state resulting in some unitary
transformation on the two qubit system which, in effect, makes two copies of
the first qubit. The general problem of the quality of the resulting copies is
discussed using a special representation, a generalization of the usual Schmidt
decomposition, of an arbitrary two-dimensional subspace of a tensor product of
two 2-dimensional Hilbert spaces. We exhibit quantum circuits which can
reproduce the results of any two qubit copying machine of this type. A simple
stochastic generalization (using a ``classical'' random signal) of the copying
machine is also considered. These copying machines provide simple embodiments
of previously proposed optimal eavesdropping schemes for the BB84 and B92
quantum cryptography protocols.
| [
{
"version": "v1",
"created": "Sat, 3 Oct 1998 23:11:28 GMT"
},
{
"version": "v2",
"created": "Thu, 29 Apr 1999 23:42:51 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Niu",
"Chi-Sheng",
"",
"Department of Physics, Carnegie\n Mellon University"
],
[
"Griffiths",
"Robert B.",
"",
"Department of Physics, Carnegie\n Mellon University"
]
] |
quant-ph/9810009 | Aephraim M. Steinberg | A. M. Steinberg, S. Myrskog, Han Seb Moon, Hyun Ah Kim, Jalani Fox,
Jung Bog Kim | An atom optics experiment to investigate faster-than-light tunneling | 6 pages, 3 figures, submitted to Annalen der Physik as part of the
Proceedings of the Cologne Workshop on Superluminal Velocities | Annalen Phys. 7 (1998) 593-601 | 10.1002/(SICI)1521-3889(199812)7:7/8<593::AID-ANDP593>3.0.CO;2-H | null | quant-ph | null | We describe a series of atom optics experiments underway at Toronto for
investigating tunnelling interaction times of various sorts. We begin by
discussing some outstanding issues and confusions related to the question of
whether or not superluminal tunnelling can be construed as true
faster-than-light ``signal propagation,'' a question which we answer in the
negative. We then argue that atom optics is an arena ideally suited for
addressing a variety of remaining questions about how, where, and for how long
a particle interacts with a tunnel barrier. We present recent results on a
modified ``delta-kick cooling'' scheme which we have used to prepare Rubidium
atoms with one-dimensional de Broglie wavelengths on the order of an optical
wavelength, along with simulations showing that from these temperatures, we
will be able to use acousto-optically modulated dipole-force barriers to
velocity-select ultracold atom samples ideal for future tunnelling experiments.
| [
{
"version": "v1",
"created": "Sun, 4 Oct 1998 04:06:18 GMT"
}
] | 2016-04-20T00:00:00 | [
[
"Steinberg",
"A. M.",
""
],
[
"Myrskog",
"S.",
""
],
[
"Moon",
"Han Seb",
""
],
[
"Kim",
"Hyun Ah",
""
],
[
"Fox",
"Jalani",
""
],
[
"Kim",
"Jung Bog",
""
]
] |
quant-ph/9810010 | Mohammad Ardehali | M. Ardehali | Maximal violation of Bell's inequality in the case of real experiments | Latex file, 16 pages, no figures | null | null | null | quant-ph | null | Einstein's locality is invoked to derive a correlation inequality. In the
case of ideal experiments, this inequality is equivalent to Bell's original
inequality of 1965 which, as is well known, is violated by a maximum factor of
1.5. The crucial point is that even in the case of real experiments where
polarizers and detectors are non-ideal, the present inequality is violated by a
factor of 1.5, whereas previous inequalities such as Clauser-Horne-Shimony-Holt
inequality of 1969 and Clauser-Horne inequality of 1974 are violated by a
factor of $\sqrt 2$. The larger magnitude of violation can be of importance for
the experimental test of locality. Moreover, the supplementary assumption used
to derive this inequality is weaker than Garuccio-Rapisarda assumption. Thus an
experiment based on this inequality refutes a larger family of hidden variable
theories than an experiment based on Garuccio-Rapisarda inequality.
| [
{
"version": "v1",
"created": "Sun, 4 Oct 1998 07:38:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ardehali",
"M.",
""
]
] |
quant-ph/9810011 | Dr S. Chaturvedi | S. Chaturvedi, V. Srinivasan and G. S. Agarwal | Quantum phase space distributions in thermofield dynamics | 17 pages, revtex, no figures. number of pages were incorrectly stated
as 3 instead of 17. No other corrections | J.Phys.A32:1909-1918,1999 | 10.1088/0305-4470/32/10/009 | null | quant-ph | null | It is shown that the the quantum phase space distributions corresponding to a
density operator $\rho$ can be expressed, in thermofield dynamics, as overlaps
between the state $\mid \rho >$ and "thermal" coherent states. The usefulness
of this approach is brought out in the context of a master equation describing
a nonlinear oscillator for which exact expressions for the quantum phase
distributions for an arbitrary initial condition are derived.
| [
{
"version": "v1",
"created": "Mon, 5 Oct 1998 10:03:10 GMT"
},
{
"version": "v2",
"created": "Thu, 8 Oct 1998 05:54:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chaturvedi",
"S.",
""
],
[
"Srinivasan",
"V.",
""
],
[
"Agarwal",
"G. S.",
""
]
] |
quant-ph/9810012 | Jochen Dittmann | J. Dittmann | The Scalar Curvature of the Bures Metric on the Space of Density
Matrices | Latex, 9 pages | J.Geom.Phys. 31 (1999) 16-24 | 10.1016/S0393-0440(98)00068-0 | null | quant-ph math-ph math.DG math.MP | null | The Riemannian Bures metric on the space of (normalized) complex positive
matrices is used for parameter estimation of mixed quantum states based on
repeated measurements just as the Fisher information in classical statistics.
It appears also in the concept of purifications of mixed states in quantum
physics. Here we determine its scalar curvature and Ricci tensor and prove a
lower bound for the curvature on the submanifold of trace one matrices. This
bound is achieved for the maximally mixed state, a further hint for the quantum
statistical meaning of the scalar curvature.
| [
{
"version": "v1",
"created": "Mon, 5 Oct 1998 13:20:05 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Dittmann",
"J.",
""
]
] |
quant-ph/9810013 | Carlos Cabrillo | C. Cabrillo, J.I. Cirac, P. Garcia-Fernandez, P. Zoller | Creation of entangled states of distant atoms by interference | 10 pages, 2 figures | null | 10.1103/PhysRevA.59.1025 | null | quant-ph | null | We propose a scheme to create distant entangled atomic states. It is based on
driving two (or more) atoms with a weak laser pulse, so that the probability
that two atoms are excited is negligible. If the subsequent spontaneous
emission is detected, the entangled state is created. We have developed a model
to analyze the fidelity of the resulting state as a function of the dimensions
and location of the detector, and the motional properties of the atoms.
| [
{
"version": "v1",
"created": "Mon, 5 Oct 1998 18:41:16 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Cabrillo",
"C.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Garcia-Fernandez",
"P.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9810014 | Todd K. Timberlake | T. Timberlake and L. E. Reichl | Changes in Floquet state structure at avoided crossings: delocalization
and harmonic generation | 8 pages with 10 figures submitted to Physical Review A | Phys.Rev.A59:2886-2893,1999 | 10.1103/PhysRevA.59.2886 | null | quant-ph | null | Avoided crossings are common in the quasienergy spectra of strongly driven
nonlinear quantum wells. In this paper we examine the sinusoidally driven
particle in a square potential well to show that avoided crossings can alter
the structure of Floquet states in this system. Two types of avoided crossings
are identified: on type leads only to temporary changes (as a function of
driving field strength) in Floquet state structure while the second type can
lead to permanent delocalization of the Floquet states. Radiation spectra from
these latter states show significant increase in high harmonic generation as
the system passes through the avoided crossing.
| [
{
"version": "v1",
"created": "Mon, 5 Oct 1998 19:50:38 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Timberlake",
"T.",
""
],
[
"Reichl",
"L. E.",
""
]
] |
quant-ph/9810015 | Kurt Jacobs | K. Jacobs (Imperial College, London) | Topics in Quantum Measurement and Quantum Noise | PhD Thesis, 117 pages, 4 figures. Contains an elementary introduction
to quantum measurement theory, entanglement and non-locality, a simple
introduction to stochastic calculus, and a detailed introduction to the
input-output formulation of noise in optical cavities | null | null | null | quant-ph | null | In this thesis we consider primarily the dynamics of quantum systems
subjected to continuous observation. In the Schr\"{o}dinger picture the
evolution of a continuously monitored quantum system, referred to as a `quantum
trajectory', may be described by a stochastic equation for the state vector. We
present a method of deriving explicit evolution operators for linear quantum
trajectories, and apply this to a number of physical examples of varying
mathematical complexity.
In the Heisenberg picture evolution resulting from continuous observation may
be described by quantum Langevin equations. We use this method to examine the
noise spectrum that results from a continuous observation of the position of a
moving mirror, and examine the possibility of detecting the noise resulting
from the quantum back-action of the measurement.
In addition to the work on continuous measurement theory, we also consider
the problem of reconstructing the state of a quantum system from a set of
measurements. We present a scheme for determining the state of a single cavity
mode from the photon statistics measured both before and after an interaction
with one or two two-level atoms.
| [
{
"version": "v1",
"created": "Mon, 5 Oct 1998 23:50:04 GMT"
},
{
"version": "v2",
"created": "Tue, 6 Oct 1998 03:22:21 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Jacobs",
"K.",
"",
"Imperial College, London"
]
] |
quant-ph/9810016 | Robert B. Griffiths | Robert B. Griffiths | Consistent Histories and Quantum Delayed Choice | Latex 9 pages, 1 figure. Fundamental Problems in Quantum Theory,
University of Maryland Baltimore, 1997 | Fortsch.Phys.46:741,1998 | 10.1002/(SICI)1521-3978(199811)46:6/8<741::AID-PROP741>3.0.CO;2-D | null | quant-ph | null | John Wheeler devised a gedanken experiment in which a piece of apparatus can
be altered just before the arrival of particle, and this ``delayed choice''
can, seemingly, alter the quantum state of the particle at a much earlier time,
long before the choice is made.
A slightly different gedanken experiment, which exhibits the same conceptual
difficulty, is analyzed using the techniques of consistent history quantum
theory. The idea that the future influences the past disappears when proper
account is taken of the diversity of possible quantum descriptions of the
world, and their mutual compatibility or incompatibility.
| [
{
"version": "v1",
"created": "Tue, 6 Oct 1998 12:28:07 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Griffiths",
"Robert B.",
""
]
] |
quant-ph/9810017 | Castagnoli Giuseppe | Giuseppe Castagnoli (Information Technology Dept., Elsag Bailey,
Genova, Italy) | An Inherently Quantum Computation Paradigm: NP-complete=P Under the
Hypothetical Notion of Continuous Uncomplete von Neumann Measurement | 1 figure. From the Quantum Computation and Communication Pathfinder
Meeting in Helsinki (September 26-28, 1998) - extended version | null | null | null | quant-ph | null | The topical quantum computation paradigm is a transposition of the Turing
machine into the quantum framework. Implementations based on this paradigm have
limitations as to the number of: qubits, computation steps, efficient quantum
algorithms (found so far). A new exclusively quantum paradigm (with no
classical counterpart) is propounded, based on the speculative notion of
continuous uncomplete von Neumann measurement. Under such a notion, NP-complete
is equal to P. This can provide a mathematical framework for the search of
implementable paradigms, possibly exploiting particle statistics.
| [
{
"version": "v1",
"created": "Tue, 6 Oct 1998 13:35:57 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Castagnoli",
"Giuseppe",
"",
"Information Technology Dept., Elsag Bailey,\n Genova, Italy"
]
] |
quant-ph/9810018 | E. Schmidt | E. Schmidt, L. Knoell, D.-G. Welsch | Cumulant expansion for studying damped quantum solitons | 17 pages, 13 figures, revtex, psfig, multicols, published in
Phys.Rev.A | Phys. Rev. A 59, 2442 (1999) | 10.1103/PhysRevA.59.2442 | FSUJ TPI QO-12/98 | quant-ph | null | The quantum statistics of damped optical solitons is studied using
cumulant-expansion techniques. The effect of absorption is described in terms
of ordinary Markovian relaxation theory, by coupling the optical field to a
continuum of reservoir modes. After introduction of local bosonic field
operators and spatial discretization pseudo-Fokker-Planck equations for
multidimensional s-parameterized phase-space functions are derived. These
partial differential equations are equivalent to an infinite set of ordinary
differential equations for the cumulants of the phase-space functions.
Introducing an appropriate truncation condition, the resulting finite set of
cumulant evolution equations can be solved numerically. Solutions are presented
in Gaussian approximation and the quantum noise is calculated, with special
emphasis on squeezing and the recently measured spectral photon-number
correlations [Spaelter et al., Phys. Rev. Lett. 81, 786 (1998)].
| [
{
"version": "v1",
"created": "Tue, 6 Oct 1998 16:35:27 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Oct 1998 17:38:02 GMT"
},
{
"version": "v3",
"created": "Thu, 8 Apr 1999 17:16:09 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Schmidt",
"E.",
""
],
[
"Knoell",
"L.",
""
],
[
"Welsch",
"D. -G.",
""
]
] |
quant-ph/9810019 | L. F. Santos | L. F. Santos and C. O. Escobar | A Beable Interpretation of the Continuous Spontaneous Localization Model | 7 pages, \revtex \tightenlines, no figures, revised version | null | null | null | quant-ph | null | We extend the beable interpretation, due to Bell, to the continuous
spontaneous localization model (CSL). Results obtained by Vink are generalized
to the modified Schrodinger equation of Ghirardi, Pearle and Rimini (GPR),
which allows a beable interpretation for position and momentum.
| [
{
"version": "v1",
"created": "Tue, 6 Oct 1998 18:08:10 GMT"
},
{
"version": "v2",
"created": "Wed, 16 Dec 1998 00:33:36 GMT"
},
{
"version": "v3",
"created": "Wed, 24 Feb 1999 17:12:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Santos",
"L. F.",
""
],
[
"Escobar",
"C. O.",
""
]
] |
quant-ph/9810020 | Carlos Cabrillo | C. Cabrillo, J. L. Roldan, P. Garcia-Fernandez | Quantum noise reduction in singly resonant optical devices | 18 pages, 11 figures | null | null | null | quant-ph | null | Quantum noise in a model of singly resonant frequency doubling including
phase mismatch and driving in the harmonic mode is analyzed. The general
formulae about the fixed points and their stability as well as the squeezing
spectra calculated linearizing around such points are given. The use of a
nonlinear normalization allows to disentangle in the spectra the dynamic
response of the system from the contributions of the various noisy inputs. A
general ``reference'' model for one-mode systems is developed in which the
dynamic aspects of the problem are not contaminated by static contributions
from the noisy inputs. The physical insight gained permits the elaboration of
general criteria to optimize the noise suppression performance. With respect to
the squeezing in the fundamental mode the optimum working point is located near
the first turning point of the dispersive bistability induced by cascading of
the second order nonlinear response. The nonlinearities induced by conventional
crystals appear enough to reach it being the squeezing ultimately limited by
the escape efficiency of the cavity. In the case of the harmonic mode both,
finite phase mismatch and/or harmonic mode driving allow for an optimum dynamic
response of the system something not possible in the standard phase matched
Second Harmonic Generation. The squeezing is then limited by the losses in the
harmonic mode, allowing for very high degrees of squeezing because of the
non-resonant nature of the mode. This opens the possibility of very high
performances using artificial materials with resonantly enhanced
nonlinearities. It is also shown how it is possible to substantially increase
the noise reduction and at the same time to more than double the output power
for parameters corresponding to reported experiments.
| [
{
"version": "v1",
"created": "Wed, 7 Oct 1998 11:20:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Cabrillo",
"C.",
""
],
[
"Roldan",
"J. L.",
""
],
[
"Garcia-Fernandez",
"P.",
""
]
] |
quant-ph/9810021 | GuiHua Zeng | Guihua Zeng | Improvement of quantum key distribution protocols | 6 pages 3 figures | null | null | null | quant-ph | null | The security of the previous quantum key distribution protocols, which is
guaranteed by the nature of physics law, is based on the legitimate users.
However, the impersonation of Alice or Bob by eavesdropper, in practice. will
be existed in a large probability. In this paper an improvement scheme for the
security quantum key is proposed.
| [
{
"version": "v1",
"created": "Wed, 7 Oct 1998 11:34:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Zeng",
"Guihua",
""
]
] |
quant-ph/9810022 | David Vitali | Stefano Mancini, David Vitali, Paolo Tombesi | Stochastic Phase Space Localization for a Single Particle | 9 pages, 1 figure. Concluding section and figure revised. In press on
Phys. rev. A | Phys.Rev.A61:053404,2000 | 10.1103/PhysRevA.61.053404 | null | quant-ph | null | We propose a feedback scheme to control the vibrational motion of a single
trapped particle based on indirect measurements of its position. It results the
possibility of a motional phase space uncertainty contraction, correponding to
cool the particle close to the motional ground state.
| [
{
"version": "v1",
"created": "Wed, 7 Oct 1998 16:51:25 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Mar 1999 08:57:53 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Jul 1999 16:58:33 GMT"
},
{
"version": "v4",
"created": "Mon, 25 Oct 1999 13:34:26 GMT"
},
{
"version": "v5",
"created": "Mon, 14 Feb 2000 12:10:15 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Mancini",
"Stefano",
""
],
[
"Vitali",
"David",
""
],
[
"Tombesi",
"Paolo",
""
]
] |
quant-ph/9810023 | M. Czachor | Maciej Kuna, Marek Czachor, and Sergiej B. Leble (Politechnika
Gdanska) | Nonlinear von Neumann-type equations: Darboux invariance and spectra | Phys.Lett.A - in print | Phys.Lett. A255 (1999) 42-48 | 10.1016/S0375-9601(99)00157-7 | null | quant-ph nlin.SI solv-int | null | Generalized Euler-Arnold-von Neumann density matrix equations can be solved
by a binary Darboux transformation given here in a new form:
$\rho[1]=e^{P\ln(\mu/\nu)}\rho e^{-P\ln(\mu/\nu)}$ where $P=P^2$ is explicitly
constructed in terms of conjugated Lax pairs, and $\mu$, $\nu$ are complex. As
a result spectra of $\rho$ and $\rho[1]$ are identical. Transformations
allowing to shift and rescale spectrum of a solution are introduced, and a
class of stationary seed solutions is discussed.
| [
{
"version": "v1",
"created": "Wed, 7 Oct 1998 17:06:03 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Mar 1999 11:05:25 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Kuna",
"Maciej",
"",
"Politechnika\n Gdanska"
],
[
"Czachor",
"Marek",
"",
"Politechnika\n Gdanska"
],
[
"Leble",
"Sergiej B.",
"",
"Politechnika\n Gdanska"
]
] |
quant-ph/9810024 | Piotr Rozmej | R. Arvieu (1), P. Rozmej (2 and 3) ((1) ISN, Grenoble, France, (2)
University MCS, Lublin, Poland, (3) GSI, Darmstadt, Germany) | Geometrical properties of intelligent spin states and time evolution of
coherent states | 7 pages + 4 figures (11p), LaTeX2e, Paper accepted for publication in
J.Phys.A: Math.Gen | J.Phys.A32:2645-2652,1999 | 10.1088/0305-4470/32/14/005 | null | quant-ph math-ph math.MP physics.atom-ph | null | We remind the properties of the intelligent (and quasi-intelligent) spin
states introduced by Aragone et al. We use these states to construct families
of coherent wave packets on the sphere and we sketch the time evolution of
these wave packets for a rigid body molecule.
| [
{
"version": "v1",
"created": "Thu, 8 Oct 1998 16:42:50 GMT"
},
{
"version": "v2",
"created": "Fri, 12 Feb 1999 14:45:17 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Arvieu",
"R.",
"",
"2 and 3"
],
[
"Rozmej",
"P.",
"",
"2 and 3"
]
] |
quant-ph/9810025 | Martin Plenio | S. Bose, M. B. Plenio and V. Vedral | Mixed state dense coding and its relation to entanglement measures | extended version, 2 figures | null | null | null | quant-ph | null | Ideal dense coding protocols allow one to use prior maximal entanglement to
send two bits of classical information by the physical transfer of a single
encoded qubit. We investigate the case when the prior entanglement is not
maximal and the initial state of the entangled pair of qubits being used for
the dense coding is a mixed state. We find upper and lower bounds on the
capability to do dense coding in terms of the various measures of entanglement
and in terms of the average mutual distinguishability of the signal states.
| [
{
"version": "v1",
"created": "Thu, 8 Oct 1998 16:44:23 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Dec 1999 20:02:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bose",
"S.",
""
],
[
"Plenio",
"M. B.",
""
],
[
"Vedral",
"V.",
""
]
] |
quant-ph/9810026 | Paul Slater | Paul B. Slater (University of California) | A priori Probabilities of Separable Quantum States | 14 pages, 4 tables, 4 figures, to appear in J. Phys. A | J.Phys.A32:5261,1999 | 10.1088/0305-4470/32/28/306 | null | quant-ph physics.data-an | null | Zyczkowski, Horodecki, Sanpera, and Lewenstein (ZHSL) recently proposed a
``natural measure'' on the N-dimensional quantum systems (quant-ph/9804024),
but expressed surprise when it led them to conclude that for N = 2 x 2,
disentangled (separable) systems are more probable (0.632) in nature than
entangled ones. We contend, however, that ZHSL's (rejected) intuition has, in
fact, a sound theoretical basis, and that the a priori probability of
disentangled 2 x 2 systems should more properly be viewed as (considerably)
less than 0.5. We arrive at this conclusion in two quite distinct ways, the
first based on classical and the second, quantum considerations. Both
approaches, however, replace (in whole or part) the ZHSL (product) measure by
ones based on the volume elements of monotone metrics, which in the classical
case amounts to adopting the Jeffreys' prior of Bayesian theory. Only the
quantum-theoretic analysis (which yields the smallest probabilities of
disentanglement) uses the minimum number of parameters possible, N^2 - 1, as
opposed to N^2 + N - 1 (although this "over-parameterization", as recently
indicated by Byrd, should be avoidable). However, despite substantial
computation, we are not able to obtain precise estimates of these
probabilities, and the need for additional (possibly supercomputer) analyses is
indicated (particularly so, for higher-dimensional quantum systems, such as the
2 x 3 we also study here).
| [
{
"version": "v1",
"created": "Thu, 8 Oct 1998 21:53:51 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Nov 1998 18:27:24 GMT"
},
{
"version": "v3",
"created": "Thu, 18 Feb 1999 18:10:28 GMT"
},
{
"version": "v4",
"created": "Tue, 2 Mar 1999 19:57:35 GMT"
},
{
"version": "v5",
"created": "Tue, 1 Jun 1999 20:45:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Slater",
"Paul B.",
"",
"University of California"
]
] |
quant-ph/9810027 | Marc-Thierry Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique The'orique de l'Ecole
Normale Supe'rieure) and Serge Reynaud (Laboratoire Kastler Brossel) | Quantum Observables associated with Einstein Localisation | 18 pages, Frontier Tests of QED and Physics of the Vacuum (Sandansky,
June 1998) (abstract added) | Frontier Tests of QED and Physics of the Vacuum, Eds. E.Zavattini,
D.Bakalov and C.Rizzo, Heron Press, Sofia (1998) 389-404 | null | LPTENS 98/37 | quant-ph gr-qc | null | The description of relativistic effects requires a preliminary definition of
events localised in space-time while the clocks used for time definition and
the fields used in synchronisation or localisation procedures are necessarily
quantum systems.
We outline an algebraic framework where basic requirements of quantum theory
and relativity are consistently dealt with. This approach which may be termed
as a `quantum relativity' is built on the algebra of symmetries. It contains
the definition of quantum observables associated with Einstein localisation in
space-time as well as the evaluation of their commutation relations including
the energy-time relation. These commutators also describe the relativistic
shifts undergone under frame transformations, not only for inertial frames but
also for uniformly accelerated frames. The quantum redshift laws differ from
their classical counterparts while still obeying universal metric properties.
The paper presents this approach in terms closely connected to the seminal
Einstein conception of localisation in space-time and refers to already
published papers for more technical developments.
| [
{
"version": "v1",
"created": "Fri, 9 Oct 1998 10:38:18 GMT"
}
] | 2013-02-27T00:00:00 | [
[
"Jaekel",
"Marc-Thierry",
"",
"Laboratoire de Physique The'orique de l'Ecole\n Normale Supe'rieure"
],
[
"Reynaud",
"Serge",
"",
"Laboratoire Kastler Brossel"
]
] |
quant-ph/9810028 | Ghirardi Giancarlo, | GianCarlo Ghirardi | Quantum superpositions and definite perceptions:envisaging new feasible
experimental tests | 17 pages, Latex, one section added | Phys.Lett. A262 (1999) 1-14 | 10.1016/S0375-9601(99)00646-5 | null | quant-ph | null | We call attention on the fact that recent unprecedented technological
achievements, in particular in the field of quantum optics, seem to open the
way to new experimental tests which might be relevant both for the foundational
problems of quantum mechanics as well as for investigating the perceptual
processes.
| [
{
"version": "v1",
"created": "Fri, 9 Oct 1998 11:12:37 GMT"
},
{
"version": "v2",
"created": "Mon, 19 Oct 1998 15:48:28 GMT"
},
{
"version": "v3",
"created": "Wed, 1 Sep 1999 16:24:15 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Ghirardi",
"GianCarlo",
""
]
] |
quant-ph/9810029 | Miroljub Dugic | Miroljub Dugic (Faculty of Sci. Dept. Phys., Kragujevac, Yugoslavia) | Many Time Interpretation Of the Quantum Measurement Process | PlainTeX, 38 (double spaced) pages, no figures. Quick reading
instruction included | null | null | PMF KG-11 | quant-ph | null | Many Time Interpretation (MTI) proposes that each stochastic "quantum jump"
("reduction") concerning each single object (of an ensemble) represents a
consequence of a (stochastic) choice (change) of Time. Therefore, each single
object experiences its own (local), stochastically chosen Time, which is as
real for it, as the macroscopic Time is real in classical physics. Therefore,
instead of the "indeterminism" with regard to the macroscopic Time, MTI
proposes "determinism", but with regard to the set(s) of (stochastically
chosen) local Times. Within an axiomatization, which includes the composite
system "single object+apparatus+environment, MTI leads to : (i) Recognizing the
amplification process as the fundamental "part" of the measurement process,
(ii) Nonvalidity of the Schrodinger equation concerning the "whole", O+A+E,
which makes the "state reduction process" unnecessary and unphysical, (iii)
Natural deducibility of the macroscopic irreversibility, and (iv)
Nonequivalence of MTI with any existing measurement theory, or interpretation.
Thus, within MTI, the measurement problem reduces basically onto the search for
quantum effect, which would allow forthe local, stochastic change of Time.
| [
{
"version": "v1",
"created": "Sat, 10 Oct 1998 15:31:15 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Dugic",
"Miroljub",
"",
"Faculty of Sci. Dept. Phys., Kragujevac, Yugoslavia"
]
] |
quant-ph/9810030 | Rajendra Bhandari | Rajendra Bhandari | Comment on "Neutron Interferometric Observation of Noncyclic Phase" | 5 pages, 0 figures, submitted to Phys.Rev.Lett | Phys.Rev.Lett. 83 (1999) 2089 | 10.1103/PhysRevLett.83.2089 | null | quant-ph | null | A critique of a recent experiment [Wagh et.al., Phys.Rev.Lett.81, 1992 (7 Sep
1998)] to measure the noncyclic phase associated with a precessing neutron spin
in a neutron interferometer, as given by the Pancharatnam criterion, is
presented. It is pointed out that since the experiment measures, not the
noncyclic phase itself, but a quantity derived from it, it misses the most
interesting feature of such a phase, namely the different sign associated with
states lying in the upper and the lower hemispheres, a feature originating in
the existence of a phase singularity. Such effects have earlier been predicted
and seen in optical interference experiments using polarization of light as the
spinor [Bhandari, Phys.Rep.281, 1 (Mar 1997)].
| [
{
"version": "v1",
"created": "Mon, 12 Oct 1998 10:55:40 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bhandari",
"Rajendra",
""
]
] |
quant-ph/9810031 | Morgan W. Mitchell | J. C. Garrison, M. W. Mitchell, R. Y. Chiao and E. L. Bolda | Superluminal Signals: Causal Loop Paradoxes Revisited | 6 pages, 3 figures | Phys.Lett. A245 (1998) 19-25 | 10.1016/S0375-9601(98)00381-8 | null | quant-ph | null | Recent results demonstrating superluminal group velocities and tachyonic
dispersion relations reopen the question of superluminal signals and causal
loop paradoxes. The sense in which superluminal signals are permitted is
explained in terms of pulse reshaping, and the self-consistent behavior which
prevents causal loop paradoxes is illustrated by an explicit example.
| [
{
"version": "v1",
"created": "Mon, 12 Oct 1998 20:38:41 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Garrison",
"J. C.",
""
],
[
"Mitchell",
"M. W.",
""
],
[
"Chiao",
"R. Y.",
""
],
[
"Bolda",
"E. L.",
""
]
] |
quant-ph/9810032 | Christopher A. Fuchs | Christopher A. Fuchs | Just Two Nonorthogonal Quantum States | 7 pages, no figures, requires myplenumQPH.sty | null | null | null | quant-ph | null | From the perspective of quantum information theory, a system so simple as one
restricted to just two nonorthogonal states can be surprisingly rich in
physics. In this paper, we explore the extent of this statement through a
review of three topics: (1) ``nonlocality without entanglement'' as exhibited
in binary quantum communication channels, (2) the tradeoff between information
gain and state disturbance for two prescribed states, and (3) the quantitative
clonability of those states. Each topic in its own way quantifies the extent to
which two states are ``quantum'' with respect to each other, i.e., the extent
to which the two together violate some classical precept. It is suggested that
even toy examples such as these hold some promise for shedding light on the
foundations of quantum theory.
| [
{
"version": "v1",
"created": "Mon, 12 Oct 1998 21:53:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Fuchs",
"Christopher A.",
""
]
] |
quant-ph/9810033 | Georg Junker | F. Cannata (1), M. Ioffe (2), G. Junker (3) and D. Nishnianidze (2)
((1) Dipartimento di Fisica and INFN, Bologna, Ttaly, (2) Department of
Theoretical Physics, University of St. Petersburg, Russia, (3) Institut f\"ur
Theoretische Physik, Universit\"at Erlangen-N\"urnberg, Germany) | Intertwining relations of non-stationary Schr\"odinger operators | 18 pages, LaTeX209 | J.Phys.A32:3583-3598,1999 | 10.1088/0305-4470/32/19/309 | null | quant-ph hep-th math-ph math.MP | null | General first- and higher-order intertwining relations between non-stationary
one-dimensional Schr\"odinger operators are introduced. For the first-order
case it is shown that the intertwining relations imply some hidden symmetry
which in turn results in a $R$-separation of variables. The Fokker-Planck and
diffusion equation are briefly considered. Second-order intertwining operators
are also discussed within a general approach. However, due to its complicated
structure only particular solutions are given in some detail.
| [
{
"version": "v1",
"created": "Tue, 13 Oct 1998 08:39:52 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cannata",
"F.",
""
],
[
"Ioffe",
"M.",
""
],
[
"Junker",
"G.",
""
],
[
"Nishnianidze",
"D.",
""
]
] |
quant-ph/9810034 | Dae-Yup | Dae-Yup Song | Exact quantum states of a general time-dependent quadratic system from
classical action | Submitted to Phys. Rev. A | Phys.Rev. A59 (1999) 2616-2623 | 10.1103/PhysRevA.59.2616 | null | quant-ph | null | A generalization of driven harmonic oscillator with time-dependent mass and
frequency, by adding total time-derivative terms to the Lagrangian, is
considered. The generalization which gives a general quadratic Hamiltonian
system does not change the classical equation of motion. Based on the
observation by Feynman and Hibbs, the propagators (kernels) of the systems are
calculated from the classical action, in terms of solutions of the classical
equation of motion: two homogeneous and one particular solutions. The kernels
are then used to find wave functions which satisfy the Schr\"{o}dinger
equation. One of the wave functions is shown to be that of a Gaussian pure
state. In every case considered, we prove that the kernel does not depend on
the way of choosing the classical solutions, while the wave functions depend on
the choice. The generalization which gives a rather complicated quadratic
Hamiltonian is simply interpreted as acting an unitary transformation to the
driven harmonic oscillator system in the Hamiltonian formulation.
| [
{
"version": "v1",
"created": "Tue, 13 Oct 1998 09:55:12 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Nov 1998 06:44:42 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Song",
"Dae-Yup",
""
]
] |
quant-ph/9810035 | Harald Weinfurter | Dik Bouwmeester, Jian-Wei Pan, Matthew Daniell, Harald Weinfurter,
Anton Zeilinger | Observation of three-photon Greenberger-Horne-Zeilinger entanglement | Revtex, 4 pages, uses floats, epsfig | Phys.Rev.Lett. 82 (1999) 1345-1349 | 10.1103/PhysRevLett.82.1345 | null | quant-ph | null | We present the experimental observation of polarization entanglement for
three spatially separated photons. Such states of more than two entangled
particles, known as GHZ states, play a crucial role in fundamental tests of
quantum mechanics versus local realism and in many quantum information and
quantum computation schemes. Our experimental arrangement is such that we start
with two pairs of entangled photons and register one photon in a way that any
information as to which pair it belongs to is erased. The registered events at
the detectors for the remaining three photons then exhibit the desired GHZ
correlations.
| [
{
"version": "v1",
"created": "Tue, 13 Oct 1998 18:03:29 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bouwmeester",
"Dik",
""
],
[
"Pan",
"Jian-Wei",
""
],
[
"Daniell",
"Matthew",
""
],
[
"Weinfurter",
"Harald",
""
],
[
"Zeilinger",
"Anton",
""
]
] |
quant-ph/9810036 | Piotr Rozmej | W.Berej, P.Rozmej (University MCS, Lublin, Poland) | A Phase in a Coherent State Wave Function - Is It Always Irrelevant? | LaTeX, 4 pages, no figures, submitted to Am.J.Phys. Minor changes | Eur.J.Phys.20:L25-L27,1999 | 10.1088/0143-0807/20/3/007 | null | quant-ph | null | We point out that harmonic oscillator coherent states, in coordinate
representation, require particular phase factor, in order to represent
classical time evolution properly. The presence of such a phase is clearly
stated only in a minority of scientific sources discussing properties of
coherent states.
| [
{
"version": "v1",
"created": "Tue, 13 Oct 1998 19:32:04 GMT"
},
{
"version": "v2",
"created": "Thu, 15 Oct 1998 17:58:58 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Berej",
"W.",
"",
"University MCS, Lublin, Poland"
],
[
"Rozmej",
"P.",
"",
"University MCS, Lublin, Poland"
]
] |
quant-ph/9810037 | Lev Kaplan | L. Kaplan, N. T. Maitra, and E. J. Heller | Quantizing Constrained Systems: New Perspectives | 11 pages, 2 figures | Phys.Rev. A56 (1997) 2592 | 10.1103/PhysRevA.56.2592 | null | quant-ph chao-dyn nlin.CD | null | We consider quantum mechanics on constrained surfaces which have
non-Euclidean metrics and variable Gaussian curvature. The old controversy
about the ambiguities involving terms in the Hamiltonian of order hbar^2
multiplying the Gaussian curvature is addressed. We set out to clarify the
matter by considering constraints to be the limits of large restoring forces as
the constraint coordinates deviate from their constrained values. We find
additional ambiguous terms of order hbar^2 involving freedom in the
constraining potentials, demonstrating that the classical constrained
Hamiltonian or Lagrangian cannot uniquely specify the quantization: the
ambiguity of directly quantizing a constrained system is inherently
unresolvable. However, there is never any problem with a physical quantum
system, which cannot have infinite constraint forces and always fluctuates
around the mean constraint values. The issue is addressed from the perspectives
of adiabatic approximations in quantum mechanics, Feynman path integrals, and
semiclassically in terms of adiabatic actions.
| [
{
"version": "v1",
"created": "Tue, 13 Oct 1998 21:50:16 GMT"
}
] | 2009-08-14T00:00:00 | [
[
"Kaplan",
"L.",
""
],
[
"Maitra",
"N. T.",
""
],
[
"Heller",
"E. J.",
""
]
] |
quant-ph/9810038 | Holger Hofmann | Ortwin Hess and Holger F. Hofmann | Quantum Maxwell-Bloch equations for spontaneous emission in optical
semiconductor devices | 6 pages Latex and 4 figures, contribution to the proceedings of the
ISQM98 conference held August 24th to 27th in Tokyo | Quantum Coherence and Decoherence, edited by Y.A. Ono and K.
Fujikawa, Elsevier 1999 | null | null | quant-ph cond-mat physics.optics | null | We present quantum Maxwell-Bloch equations (QMBE) for spatially inhomogeneous
optical semiconductor devices taking into account the quantum noise effects
which cause spontaneous emission and amplified spontaneous emission. Analytical
expressions derived from the QMBE are presented for the spontaneous emission
factor beta and the far field pattern of amplified spontaneous emission in
broad area quantum well lasers.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 11:12:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hess",
"Ortwin",
""
],
[
"Hofmann",
"Holger F.",
""
]
] |
quant-ph/9810039 | Anders Sorensen | Anders Sorensen and Klaus Molmer (University of Aarhus) | Quantum computation with ions in thermal motion | 5 pages, including 5 figures. To appear in Phys. Rev. Lett. New
version demonstrates that our gate is insensitive to heating and shows how to
perform a control-not with our gate. Improved numerical simulations | Phys.Rev.Lett. 82 (1999) 1971-1974 | 10.1103/PhysRevLett.82.1971 | null | quant-ph | null | We propose an implementation of quantum logic gates via virtual vibrational
excitations in an ion trap quantum computer. Transition paths involving
unpopulated, vibrational states interfere destructively to eliminate the
dependence of rates and revolution frequencies on vibrational quantum numbers.
As a consequence quantum computation becomes feasible with ions whos vibrations
are strongly coupled to a thermal reservoir.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 13:33:22 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jan 1999 14:26:22 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Sorensen",
"Anders",
"",
"University of Aarhus"
],
[
"Molmer",
"Klaus",
"",
"University of Aarhus"
]
] |
quant-ph/9810040 | Anders Sorensen | Klaus Molmer and Anders Sorensen (University of Aarhus) | Multi-particle entanglement of hot trapped ions | 4 pages, including 3 figures. To appear in Phys. Rev. Lett. This
paper previously appeared under the name "Schrodingers cat in a hot trap".
The paper has been revised according to Phys. Rev. policy on Schrodinger
cats. No cats were harmed during the production of this manuscript | Phys.Rev.Lett. 82 (1999) 1835-1838 | 10.1103/PhysRevLett.82.1835 | null | quant-ph | null | We propose an efficient method to produce multi-particle entangled states of
ions in an ion trap for which a wide range of interesting effects and
applications have been suggested. Our preparation scheme exploits the
collective vibrational motion of the ions, but it works in such a way that this
motion need not be fully controlled in the experiment. The ions may, e.g., be
in thermal motion and exchange mechanical energy with a surrounding heat bath
without detrimental effects on the internal state preparation. Our scheme does
not require access to the individual ions in the trap.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 14:07:48 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jan 1999 14:59:10 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Molmer",
"Klaus",
"",
"University of Aarhus"
],
[
"Sorensen",
"Anders",
"",
"University of Aarhus"
]
] |
quant-ph/9810041 | Angelo Bassi | GianCarlo Ghirardi, Angelo Bassi | Do dynamical reduction models imply that arithmetic does not apply to
ordinary macroscopic objects? | 14 pages, LaTeX, To appear in the March Issue of Brit. Jou. Phil.
Sci. Typographical errors corrected | Brit. Journ. Phil. Sci. 50, 49 (1999) | null | null | quant-ph | null | We analyze a recent paper in which an alleged devastating criticism to the so
called GRW proposal to account for the objectification of the properties of
macroscopic systems has been presented and we show that the author has not
taken into account the precise implications of the GRW theory. This fact makes
his conclusions basically wrong. We also perform a survey of measurement theory
aimed to better focus the physical and the conceptual aspects of the so-called
macro-objectification problem.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 14:17:21 GMT"
},
{
"version": "v2",
"created": "Wed, 28 Oct 1998 16:03:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ghirardi",
"GianCarlo",
""
],
[
"Bassi",
"Angelo",
""
]
] |
quant-ph/9810042 | Anders Sorensen | Anders Soerensen and Klaus Moelmer (University of Aarhus) | Error free quantum communication through noisy channels | 6 pages, including 2 figures | Phys. Rev. A, vol 58, 2745 (1998) | 10.1103/PhysRevA.58.2745 | null | quant-ph | null | We suggest a method to perform a quantum logic gate between distant qubits by
off-resonant field-atom dispersive interactions. The scheme we present is shown
to work ideally even in the presence of errors in the photon channels used for
communication. The stability against errors arises from the paradoxical
situation that the transmitted photons carry no information about the state of
the qubits. In contrast to a previous proposal for ideal communication [Phys.
Rev. Lett. 78, 4293 (1997)] our proposal only involves single atoms in the
sending and receiving devices.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 14:58:57 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Soerensen",
"Anders",
"",
"University of Aarhus"
],
[
"Moelmer",
"Klaus",
"",
"University of Aarhus"
]
] |
quant-ph/9810043 | John Klauder | John R. Klauder | Coherent State Path Integrals at (Nearly) 40 | 6 pages, LaTeX, no figures, for the Florence Path Integral Conference
Proceedings | null | null | null | quant-ph hep-th math-ph math.MP | null | Coherent states can be used for diverse applications in quantum physics
including the construction of coherent state path integrals. Most definitions
make use of a lattice regularization; however, recent definitions employ a
continuous-time regularization that may involve a Wiener measure concentrated
on continuous phase space paths. The introduction of constraints is both
natural and economical in coherent state path integrals involving only the
dynamical and Lagrange multiplier variables. A preliminary indication of how
these procedures may possibly be applied to quantum gravity is briefly
discussed.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 15:22:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Klauder",
"John R.",
""
]
] |
quant-ph/9810044 | John Klauder | John R. Klauder | Coherent States for Discrete Spectrum Dynamics | 3 pages, LaTeX, no figures, for the Florence Path Integral Conference
Proceedings | null | null | null | quant-ph hep-th math-ph math.MP | null | Coherent states for general systems with discrete spectrum, such as the bound
states of the hydrogen atom, are discussed. The states in question satisfy: (1)
continuity of labeling, (2) resolution of unity, (3) temporal stability, and
(4) an action identity. This set of reasonable physical requirements uniquely
specify coherent states for the (bound state portion of the) hydrogen atom.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 18:18:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Klauder",
"John R.",
""
]
] |
quant-ph/9810045 | Ricardo Moritz Cavalcanti | C. A. A. de Carvalho, R. M. Cavalcanti, E. S. Fraga, S. E. Joras | Semiclassical Series at Finite Temperature | 25 pages + 5 figures | Annals Phys. 273 (1999) 146-170 | 10.1006/aphy.1998.5900 | null | quant-ph cond-mat.stat-mech hep-th | null | We derive the semiclassical series for the partition function of a
one-dimensional quantum-mechanical system consisting of a particle in a
single-well potential. We do this by applying the method of steepest descent to
the path-integral representation of the partition function, and we present a
systematic procedure to generate the terms of the series using the minima of
the Euclidean action as the only input. For the particular case of a quartic
anharmonic oscillator, we compute the first two terms of the series, and
investigate their high and low temperature limits. We also exhibit the
nonperturbative character of the terms, as each corresponds to sums over
infinite subsets of perturbative graphs. We illustrate the power of such
resummations by extracting from the first term an accurate nonperturbative
estimate of the ground-state energy of the system and a curve for the specific
heat. We conclude by pointing out possible extensions of our results which
include field theories with spherically symmetric classical solutions.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 19:37:57 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"de Carvalho",
"C. A. A.",
""
],
[
"Cavalcanti",
"R. M.",
""
],
[
"Fraga",
"E. S.",
""
],
[
"Joras",
"S. E.",
""
]
] |
quant-ph/9810046 | Li You | M. Marinescu and L. You (Georgia Institute of Technology) | Controlling atom-atom interaction at ultralow temperatures by dc
electric fields | 4 pages, 5 figures, accepted for a publication in Physical Review
Letters | Phys.Rev.Lett.81:4596-4599,1998 | 10.1103/PhysRevLett.81.4596 | null | quant-ph cond-mat | null | We propose a physical mechanism for tuning the atom-atom interaction strength
at ultra-low temperatures. In the presence of a dc electric field the
interatomic potential is changed due to the effective dipole-dipole interaction
between the polarized atoms. Detailed multi-channel scattering calculations
reveal features never before discussed for ultra-cold atomic collisions. We
demonstrate that optimal control of the effective atom-atom interactions can be
achieved under reasonable laboratory conditions. Implications of this research
on the physics of atomic Bose-Einstein condensation (BEC) and on the pursuit
for atomic degenerate fermion gases will be discussed.
| [
{
"version": "v1",
"created": "Wed, 14 Oct 1998 22:28:08 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Marinescu",
"M.",
"",
"Georgia Institute of Technology"
],
[
"You",
"L.",
"",
"Georgia Institute of Technology"
]
] |
quant-ph/9810047 | Karl Riedel | K. Riedel, P. Torma, V. Savichev, W.P. Schleich (University of Ulm,
Germany) | Control of dynamical localization by an additional quantum degree of
freedom | 6 pages, 4 figures, scheduled for Phys. Rev. A, Jan. 99 | null | 10.1103/PhysRevA.59.797 | null | quant-ph | null | We identify a new parameter that controls the localization length in a driven
quantum system. This parameter results from an additional quantum degree of
freedom. The center-of-mass motion of a two-level ion stored in a Paul trap and
interacting with a standing wave laser field exhibits this phenomenon. We also
discuss the influence of spontaneous emission.
| [
{
"version": "v1",
"created": "Thu, 15 Oct 1998 11:51:00 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Riedel",
"K.",
"",
"University of Ulm,\n Germany"
],
[
"Torma",
"P.",
"",
"University of Ulm,\n Germany"
],
[
"Savichev",
"V.",
"",
"University of Ulm,\n Germany"
],
[
"Schleich",
"W. P.",
"",
"University of Ulm,\n Germany"
]
] |
quant-ph/9810048 | Antonio Vidiella-Barranco | D.S. Freitas, A. Vidiella-Barranco, and J.A. Roversi (Universidade
Estadual de Campinas, SP, Brazil) | Field Purification in the intensity-dependent Jaynes-Cummings model | 14 pages, RevTex, 3 figures, accepted for publication in Physics
Letters A | Phys.Lett. A249 (1998) 275-280 | 10.1016/S0375-9601(98)00756-7 | null | quant-ph physics.atom-ph physics.optics | null | We have found that, in the intensity-dependent Jaynes-Cummings model, a field
initially prepared in a statistical mixture of two coherent states, $|\alpha>$
and $|-\alpha>$, evolves toward a pure state. We have also shown that an
even-coherent state turns periodically a into rotated odd-coherent state during
the evolution.
| [
{
"version": "v1",
"created": "Thu, 15 Oct 1998 14:31:17 GMT"
}
] | 2016-02-24T00:00:00 | [
[
"Freitas",
"D. S.",
"",
"Universidade\n Estadual de Campinas, SP, Brazil"
],
[
"Vidiella-Barranco",
"A.",
"",
"Universidade\n Estadual de Campinas, SP, Brazil"
],
[
"Roversi",
"J. A.",
"",
"Universidade\n Estadual de Campinas, SP, Brazil"
]
] |
quant-ph/9810049 | Siergiej Leble | S. B. Leble, N.V. Ustinov | On exact solutions of Maxwell-Bloch system for two-level medium with
degeneracy | LATEX, 11 pages | Chaos Solitons Fractals 11 (2000) 1763-1772 | null | null | quant-ph | null | Maxwell-Bloch system describing the resonant propagation of electromagnetic
pulses in both two-level media with degeneracy in angle moment projection and
three-level media with equal oscillator forces is considered. The inhomogeneous
broadening of energy levels is accounted. Binary Darboux Transformation
generating the solutions of the system is constructed. Pulses corresponding to
the transition between levels with largest population difference are shown to
be stable. The solution describing the propargation of pulses in the medium
exited by the periodic wave is obtained. The hierarchy of infinitesimal
symmetries is obtained by means of Darboux transformation.
| [
{
"version": "v1",
"created": "Thu, 15 Oct 1998 16:34:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Leble",
"S. B.",
""
],
[
"Ustinov",
"N. V.",
""
]
] |
quant-ph/9810050 | Ruediger Schack | R. Schack (Royal Holloway, University of London), C. M. Caves
(University of New Mexico) | Shifts on a finite qubit string: A class of quantum baker's maps | 6 pages, LaTeX, contribution to Dagstuhl seminar on quantum
algorithms | Appl.Algebra Engrg.Comm.Comput.10:305-310,2000 | null | null | quant-ph | null | We present two complementary ways in which Saraceno's symmetric version of
the quantum baker's map can be written as a shift map on a string of quantum
bits. One of these representations leads naturally to a family of quantizations
of the baker's map.
| [
{
"version": "v1",
"created": "Thu, 15 Oct 1998 20:46:40 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Jul 2000 12:06:51 GMT"
}
] | 2011-04-15T00:00:00 | [
[
"Schack",
"R.",
"",
"Royal Holloway, University of London"
],
[
"Caves",
"C. M.",
"",
"University of New Mexico"
]
] |
quant-ph/9810051 | Anil K. Patnaik | Anil K. Patnaik and G. S. Agarwal (Physical Research Laboratory,
Ahmedabad, India) | Cavity-induced coherence effects in spontaneous emission from
pre-Selection of polarization | 6 pages in REVTEX multicolumn format, 5 figures, new references
added, journal reference added | Physical Review A, Vol. 59, p. 3015 (1999) | 10.1103/PhysRevA.59.3015 | null | quant-ph | null | Spontaneous emission can create coherences in a multilevel atom having close
lying levels, subject to the condition that the atomic dipole matrix elements
are non-orthogonal. This condition is rarely met in atomic systems. We report
the possibility of bypassing this condition and thereby creating coherences by
letting the atom with orthogonal dipoles to interact with the vacuum of a
pre-selected polarized cavity mode rather than the free space vacuum. We derive
a master equation for the reduced density operator of a model four level atomic
system, and obtain its analytical solution to describe the interference
effects. We report the quantum beat structure in the populations.
| [
{
"version": "v1",
"created": "Fri, 16 Oct 1998 12:35:14 GMT"
},
{
"version": "v2",
"created": "Sun, 28 Mar 1999 07:20:32 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Patnaik",
"Anil K.",
"",
"Physical Research Laboratory,\n Ahmedabad, India"
],
[
"Agarwal",
"G. S.",
"",
"Physical Research Laboratory,\n Ahmedabad, India"
]
] |
quant-ph/9810052 | Sunish Menon | G. S. Agarwal | Mesoscopic superpositions of states - approach to classicality and
diagonalization in coherent state basis | 10 pages, two figure pages, RevTeX | null | 10.1103/PhysRevA.59.3071 | null | quant-ph | null | I consider the interaction of a superposition of mesoscopic coherent states
and its approach to a mixed state as a result of a suitably controlled
environment. I show how the presence of a gain medium in a cavity can lead to
diagonalization in coherent state basis in contrast to the standard model of
decoherence. I further show how the new model of decoherence can lead to the
generation of $s$ ordered quasi distributions.
| [
{
"version": "v1",
"created": "Fri, 16 Oct 1998 12:39:08 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Agarwal",
"G. S.",
""
]
] |
quant-ph/9810053 | Erasmo Recami | J. Jakiel, V.S. Olkhovsky and Erasmo Recami | On Superluminal motions in photon and particle tunnelings | standard LaTeX file; accepted for publication in Phys. Lett. A | Phys.Lett. A248 (1998) 156-160 | 10.1016/S0375-9601(98)00626-4 | null | quant-ph | null | It is shown that the Hartman-Fletcher effect is valid for all the known
expressions of the mean tunnelling time, in various nonrelativistic approaches,
for the case of finite width barriers without absorption. Then, we show that
the same effect is not valid for the tunnelling time mean-square fluctuations.
On the basis of the Hartman-Fletcher effect and the known analogy between
photon and nonrelativistic-particle tunnelling, one can explain the
Superluminal group-velocities observed in various photon tunnelling experiments
(without violation of the so-called "Einstein causality").
| [
{
"version": "v1",
"created": "Fri, 16 Oct 1998 15:33:35 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jakiel",
"J.",
""
],
[
"Olkhovsky",
"V. S.",
""
],
[
"Recami",
"Erasmo",
""
]
] |
quant-ph/9810054 | Adonai S. Sant'Anna | Adonai S. Sant'Anna and Daniel C. Freitas (Department of Mathematics,
Federal University at Parana) | The temperature of the quantum vacuum | 3 pages, revtex, no figures, 9 references. This work is a new version
of a paper submitted for publication in a major journal of physics | null | null | null | quant-ph | null | We propose that the quantum vacuum may be considered as a gas of virtual
photons which carry a non-vanishing linear momentum as well as a non-vanishing
energy. We study, in particular, the Casimir effect in order to show that these
virtual photons should satisfy a Fermi-Dirac statistics, which implies a
non-zero temperature of the vacuum state.
| [
{
"version": "v1",
"created": "Sat, 17 Oct 1998 19:03:15 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sant'Anna",
"Adonai S.",
"",
"Department of Mathematics,\n Federal University at Parana"
],
[
"Freitas",
"Daniel C.",
"",
"Department of Mathematics,\n Federal University at Parana"
]
] |
quant-ph/9810055 | David Meyer | Michael H. Freedman and David A. Meyer | Projective plane and planar quantum codes | 7 pages, plain TeX, 5 PostScript figures included with epsf.tex
(ignore the under/overfull \vbox error messages) | null | null | null | quant-ph | null | Cellulations of the projective plane RP^2 define single qubit topological
quantum error correcting codes since there is a unique essential cycle in
H_1(RP^2;Z_2). We construct three of the smallest such codes, show they are
inequivalent, and identify one of them as Shor's original 9 qubit repetition
code. We observe that Shor's code can be constructed in a planar domain and
generalize to planar constructions of higher genus codes for multiple qubits.
| [
{
"version": "v1",
"created": "Sun, 18 Oct 1998 04:30:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Freedman",
"Michael H.",
""
],
[
"Meyer",
"David A.",
""
]
] |
quant-ph/9810056 | null | Shi-Hai Dong and Zhong-Qi Ma | Exact Solutions to the Schr\"{o}dinger Equation for the potential
$V(r)=a r^2+b r^{-4}+c r^{-6}$ in 2D | Latex file, pages 9 and 2 eps figures, accepted by J. Phys. A | null | 10.1088/0305-4470/31/49/009 | null | quant-ph | null | Making use of an ${\it ansatz}$ for the eigenfunctions, we obtain an exact
closed form solution to the non-relativistic Schr\"{o}dinger equation with the
anharmonic potential, $V(r)=a r^2+b r^{-4}+c r^{-6}$ in two dimensions, where
the parameters of the potential $a, b, c$ satisfy some constraints.
| [
{
"version": "v1",
"created": "Mon, 19 Oct 1998 01:18:59 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Dong",
"Shi-Hai",
""
],
[
"Ma",
"Zhong-Qi",
""
]
] |
quant-ph/9810057 | Armen Allahverdyan | A.E. Allahverdyan, D.B. Saakian | About optimal measurements in quantum hypothesizes testing | 4 pages, revtex | null | null | null | quant-ph | null | We consider the problem of a state determination for a two-level quantum
system which can be in one of two nonorthogonal mixed states. It is proved that
for the two independent identical systems the optimal combined measurement
(which considers the pair as one system) cannot be less optimal than the
corresponding sequential one (local measurements, accompanying by transfer of
classical information). The case of equality is achieved only when the mixed
states have the same eigenvalues or the same eigenvectors. Further, we consider
a case then the two systems are entangled: measurement of one system induces a
reduction of the another one's state. The conclusion about optimal character of
combined measurement takes place again, and conditions where the
above-mentioned methods coincide are derived.
| [
{
"version": "v1",
"created": "Mon, 19 Oct 1998 06:52:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Allahverdyan",
"A. E.",
""
],
[
"Saakian",
"D. B.",
""
]
] |
quant-ph/9810058 | M. Ardehali | M. Ardehali | Bell's theorem, quantum mechanical non-locality and atomic cascade
photons | Latex file, 11 pages, no figures | null | null | null | quant-ph | null | Bell's theorem of 1965 is a proof that all realistic interpretations of
quantum mechanics must be non-local. Bell's theorem consists of two parts:
first a correlation inequality is derived that must be satisfied by all local
realistic theories; second it is demonstrated that quantum mechanical
probabilities violate this inequality in certain cases. In the case of ideal
experiments, Bell's theorem has been proven. However, in the case of real
experiments where polarizers and detectors are non-ideal, the theorem has not
yet been proven since the proof always requires some arbitrary and {\em ad hoc}
supplementary assumptions. In this paper, we state a new and rather weak
supplementary assumption for the ensemble of photons that emerge from the
polarizers, and we show that the conjunction of Einstein's locality with this
assumption leads to validity of an inequality that is violated by a factor as
large as 1.5 in the case of real experiments. Moreover, the present
supplementary assumption is considerably weaker and more general than Clauser,
Horne, Shimony, Holt supplementary assumption.
| [
{
"version": "v1",
"created": "Mon, 19 Oct 1998 08:55:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ardehali",
"M.",
""
]
] |
quant-ph/9810059 | Li You | K. G. Petrosyan and L. You | Topological phases and circulating states of Bose-Einstein condensates | 4 pages, 3 figures, accepted for publication in Phys. Rev. A | null | 10.1103/PhysRevA.59.639 | null | quant-ph cond-mat | null | We show that the quantum topological effect predicted by Aharonov and Casher
(AC effect) [Phys. Rev. Lett. 53, 319 (1984)] may be used to create circulating
states of magnetically trapped atomic Bose-Einstein condensates (BEC). A simple
experimental setup is suggested based on a multiply connected geometry such as
a toroidal trap or a magnetic trap pinched by a blue-detuned laser. We give
numerical estimates of such effects within the current atomic BEC experiments,
and point out some interesting properties of the associated quantized
circulating states.
| [
{
"version": "v1",
"created": "Tue, 20 Oct 1998 18:31:23 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Petrosyan",
"K. G.",
""
],
[
"You",
"L.",
""
]
] |
quant-ph/9810060 | William R. Wharton | William R. Wharton | Backward Causation and the EPR Paradox | 13 pages, submitted to American Journal of Physics | null | null | null | quant-ph | null | Backward causation in which future events affect the past is formalized in a
way consistent with Special Relativity and shown to restore locality to
nonrelativistic quantum mechanics. It can explain the correlations of the EPR
paradox without using hidden variables. It also restores time-symmetry to
microphysics. Quantum Mechanics has the right properties to allow for backward
causation. The new model is probably untestable experimentally but it has
profound philosophical implications concerning reality.
| [
{
"version": "v1",
"created": "Wed, 21 Oct 1998 15:39:49 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wharton",
"William R.",
""
]
] |
quant-ph/9810061 | Angel Ballesteros | Angel Ballesteros and Sergei M. Chumakov | On the spectrum of a Hamiltonian defined on su_q(2) and quantum optical
models | 11 pages, LaTeX, content changed | J.Phys.A 32:6261-6269,1999 | 10.1088/0305-4470/32/35/305 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Analytical expressions are given for the eigenvalues and eigenvectors of a
Hamiltonian with su_q(2) dynamical symmetry. The relevance of such an operator
in Quantum Optics is discussed. As an application, the ground state energy in
the Dicke model is studied through su_q(2) perturbation theory.
| [
{
"version": "v1",
"created": "Wed, 21 Oct 1998 16:34:02 GMT"
},
{
"version": "v2",
"created": "Thu, 18 Mar 2010 19:36:08 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Ballesteros",
"Angel",
""
],
[
"Chumakov",
"Sergei M.",
""
]
] |
quant-ph/9810062 | Gerald V. Dunne | G. N. Gibson, G. Dunne, and K. J. Bergquist | Tunneling Ionization Rates from Arbitrary Potential Wells | 13 pages, 7 figures, LaTeX | Phys.Rev.Lett. 81 (1998) 2663 | 10.1103/PhysRevLett.81.2663 | null | quant-ph hep-th physics.atom-ph | null | We present a practical numerical technique for calculating tunneling
ionization rates from arbitrary 1-D potential wells in the presence of a linear
external potential by determining the widths of the resonances in the spectral
density, rho(E), adiabatically connected to the field-free bound states. While
this technique applies to more general external potentials, we focus on the
ionization of electrons from atoms and molecules by DC electric fields, as this
has an important and immediate impact on the understanding of the multiphoton
ionization of molecules in strong laser fields.
| [
{
"version": "v1",
"created": "Wed, 21 Oct 1998 20:54:45 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Gibson",
"G. N.",
""
],
[
"Dunne",
"G.",
""
],
[
"Bergquist",
"K. J.",
""
]
] |
quant-ph/9810063 | Barbara M. Terhal | Barbara M. Terhal and David P. DiVincenzo | The problem of equilibration and the computation of correlation
functions on a quantum computer | 25 pages LaTex + 8 figures; various additional comments, results and
corrections | Phys.Rev. A61 (2000) 22301 | 10.1103/PhysRevA.61.022301 | null | quant-ph cond-mat | null | We address the question of how a quantum computer can be used to simulate
experiments on quantum systems in thermal equilibrium. We present two
approaches for the preparation of the equilibrium state on a quantum computer.
For both approaches, we show that the output state of the algorithm, after long
enough time, is the desired equilibrium. We present a numerical analysis of one
of these approaches for small systems. We show how equilibrium
(time)-correlation functions can be efficiently estimated on a quantum
computer, given a preparation of the equilibrium state. The quantum algorithms
that we present are hard to simulate on a classical computer. This indicates
that they could provide an exponential speedup over what can be achieved with a
classical device.
| [
{
"version": "v1",
"created": "Wed, 21 Oct 1998 23:16:12 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Nov 1998 22:15:31 GMT"
},
{
"version": "v3",
"created": "Tue, 4 May 1999 15:42:00 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Terhal",
"Barbara M.",
""
],
[
"DiVincenzo",
"David P.",
""
]
] |
quant-ph/9810064 | Ali Mostafazadeh | Ali Mostafazadeh | Non-Abelian Geometric Phase, Floquet Theory, and Periodic Dynamical
Invariants | Plain LaTeX, 13 pages, accepted for publication in J. Phys. A: Math.
Gen | J.Phys.A31:9975-9982,1998 | 10.1088/0305-4470/31/49/015 | Koc University preprint, September 1998 | quant-ph hep-th | null | For a periodic Hamiltonian, periodic dynamical invariants may be used to
obtain non-degenerate cyclic states. This observation is generalized to the
degenerate cyclic states, and the relation between the periodic dynamical
invariants and the Floquet decompositions of the time-evolution operator is
elucidated. In particular, a necessary condition for the occurrence of cyclic
non-adiabatic non-Abelian geometrical phase is derived. Degenerate cyclic
states are obtained for a magnetic dipole interacting with a precessing
magnetic field.
| [
{
"version": "v1",
"created": "Thu, 22 Oct 1998 14:37:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Mostafazadeh",
"Ali",
""
]
] |
quant-ph/9810065 | Rusins Freivalds | Arnolds Kikusts | A small 1-way quantum finite automaton | 7 pages, LATEX, uses article.sty | null | null | null | quant-ph | null | We study 1-way quantum finite automata (QFAs) and compare them with their
classical counterparts. We show that 1-way QFAs can be very space efficient. We
construct a 1-way QFAs that are quadratically smaller than any equivalent
deterministic finite automata and give the correct answer with a large
probability by recognizing the languages in a two letter alphabet "the number
of the letters a and the number of the letters b are divisible by n".
| [
{
"version": "v1",
"created": "Thu, 22 Oct 1998 15:54:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kikusts",
"Arnolds",
""
]
] |
quant-ph/9810066 | Michael John Butler | Michael Butler, Pieter Hartel (University of Southampton) | Reasoning about Grover's Quantum Search Algorithm using Probabilistic wp | 11 pages, 5 Postscript figures | null | null | University of Southampton DSSE-TR-98-10,
http://www.dsse.ecs.soton.ac.uk/techreports/ | quant-ph | null | Grover's search algorithm is designed to be executed on a quantum mechanical
computer. In this paper, the probabilistic wp-calculus is used to model and
reason about Grover's algorithm. It is demonstrated that the calculus provides
a rigorous programming notation for modelling this and other quantum algorithms
and that it also provides a systematic framework of analysing such algorithms.
| [
{
"version": "v1",
"created": "Thu, 22 Oct 1998 16:50:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Butler",
"Michael",
"",
"University of Southampton"
],
[
"Hartel",
"Pieter",
"",
"University of Southampton"
]
] |
quant-ph/9810067 | Adrian Kent | Adrian Kent | Coin Tossing is Strictly Weaker Than Bit Commitment | Final version; to appear in Phys. Rev. Lett | Phys.Rev.Lett. 83 (1999) 5382-5384 | 10.1103/PhysRevLett.83.5382 | DAMTP-1998-123 | quant-ph cs.CR | null | We define cryptographic assumptions applicable to two mistrustful parties who
each control two or more separate secure sites between which special relativity
guarantees a time lapse in communication. We show that, under these
assumptions, unconditionally secure coin tossing can be carried out by
exchanges of classical information. We show also, following Mayers, Lo and
Chau, that unconditionally secure bit commitment cannot be carried out by
finitely many exchanges of classical or quantum information. Finally we show
that, under standard cryptographic assumptions, coin tossing is strictly weaker
than bit commitment. That is, no secure classical or quantum bit commitment
protocol can be built from a finite number of invocations of a secure coin
tossing black box together with finitely many additional information exchanges.
| [
{
"version": "v1",
"created": "Thu, 22 Oct 1998 19:13:16 GMT"
},
{
"version": "v2",
"created": "Tue, 22 Jun 1999 13:29:08 GMT"
},
{
"version": "v3",
"created": "Fri, 29 Oct 1999 15:36:44 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kent",
"Adrian",
""
]
] |
quant-ph/9810068 | Adrian Kent | Adrian Kent | Unconditionally Secure Bit Commitment | Typos corrected. Reference details added. To appear in Phys. Rev.
Lett | Phys.Rev.Lett. 83 (1999) 1447-1450 | 10.1103/PhysRevLett.83.1447 | DAMTP-1997-135 | quant-ph cs.CR | null | We describe a new classical bit commitment protocol based on cryptographic
constraints imposed by special relativity. The protocol is unconditionally
secure against classical or quantum attacks. It evades the no-go results of
Mayers, Lo and Chau by requiring from Alice a sequence of communications,
including a post-revelation verification, each of which is guaranteed to be
independent of its predecessor.
| [
{
"version": "v1",
"created": "Thu, 22 Oct 1998 20:16:10 GMT"
},
{
"version": "v2",
"created": "Wed, 21 Apr 1999 15:54:05 GMT"
},
{
"version": "v3",
"created": "Tue, 22 Jun 1999 13:35:27 GMT"
},
{
"version": "v4",
"created": "Wed, 4 Aug 1999 12:40:29 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Kent",
"Adrian",
""
]
] |
quant-ph/9810069 | Simone Warzel | Bernhard Bodmann, Hajo Leschke and Simone Warzel | A rigorous path-integral formula for quantum-spin dynamics via planar
Brownian motion | 4 pages, contribution for the Florence path-integral conference
proceedings | pp. 173-176 in: Path Integrals from peV to TeV: 50 Years after
Feynman's Paper, Editors: R. Casalbuoni, R.Giachetti, V.Tognetti, R. Vaia,
P.Verrucchi, World Scientific, Singapore, 1999 | null | null | quant-ph | null | Adapting ideas of Daubechies and Klauder we derive a continuum path-integral
formula for the time evolution generated by a spin Hamiltonian. For this
purpose we identify the finite-dimensional spin Hilbert space with the
ground-state eigenspace of a suitable Sch\"odinger operator on
$L^2({\mathbb{R}}^2)$, the Hilbert space of square-integrable functions on the
Euclidean plane ${\mathbb{R}}^2$, and employ the Feynman-Kac-It\^o formula.
| [
{
"version": "v1",
"created": "Fri, 23 Oct 1998 12:12:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bodmann",
"Bernhard",
""
],
[
"Leschke",
"Hajo",
""
],
[
"Warzel",
"Simone",
""
]
] |
quant-ph/9810070 | Georg Junker | Georg Junker (Universit\"at Erlangen-Nu\"urnberg) | Quantum and classical stochastic dynamics: Exactly solvable models by
supersymmetric methods | 10 pages, 1 figure, LaTeX209, uses amsfonts and epsf, to appear in
the proceedings of "III. International Workshop on Classical and Quantum
Integrable Systems,Yerevan, Armenia, June 29 - July 04, 1998 | in "III. International Workshop on Classical and Quantum
Integrable Systems", L.G. Mardoyan, G.S. Pogosyan and A.N. Sissakian eds.,
(JINR Publishing, Dubna, 1998) 94-103 | null | null | quant-ph cond-mat.stat-mech math-ph math.MP nlin.SI solv-int | null | A supersymmetric method for the construction of so-called conditionally
exactly solvable quantum systems is reviewed and extended to classical
stochastic dynamical systems characterized by a Fokker-Planck equation with
drift. A class of drift-potentials on the real line as well as on the half line
is constructed for which the associated Fokker-Planck equation can be solved
exactly. Explicit drift potentials, which describe mono-, bi-, meta-or unstable
systems, are constructed and their decay rates and modes are given in closed
form.
| [
{
"version": "v1",
"created": "Fri, 23 Oct 1998 12:12:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Junker",
"Georg",
"",
"Universität Erlangen-Nuürnberg"
]
] |
quant-ph/9810071 | Apoorva D. Patel | Apoorva Patel (CTS, IISc, Bangalore, India) | On how to Produce Entangled States Violating Bell's Inequalities in
Quantum Theory | 8 pages, two column revtex, arguments elaborated and strengthened,
submitted to Physical Review A | null | null | IISc-CTS/11/98 | quant-ph hep-th | null | Feynman's path integrals provide a hidden variable description of quantum
mechanics (and quantum field theories). The time evolution kernel is unitary in
Minkowski time, but generically it becomes real and non-negative in Euclidean
time. It follows that the entangled state correlations, that violate Bell's
inequalities in Minkowski time, obey the inequalities in Euclidean time. This
observation emphasises the link between violation of Bell's inequalities in
quantum mechanics and unitarity of the theory. Search for an evolution kernel
that cannot be conveniently made non-negative leads to effective interactions
that violate time reversal invariance. Interactions giving rise to geometric
phases in the effective description of the theory, such as the anomalous
Wess-Zumino interactions, have this feature. I infer that they must be present
in any set-up that produces entangled states violating Bell's inequalities.
Such interactions would be a crucial ingredient in a quantum computer.
| [
{
"version": "v1",
"created": "Fri, 23 Oct 1998 14:40:36 GMT"
},
{
"version": "v2",
"created": "Thu, 24 Dec 1998 21:38:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Patel",
"Apoorva",
"",
"CTS, IISc, Bangalore, India"
]
] |
quant-ph/9810072 | Emmanuel Paspalakis | E. Paspalakis (Imperial College, London, UK), C. H. Keitel
(Universit\"at Freiburg, Germany) and P. L. Knight (Imperial College, London,
UK) | Fluorescence control through multiple interference mechanisms | 14 pages, 5 figures. To appear in Physical Review A | null | 10.1103/PhysRevA.58.4868 | null | quant-ph | null | We discuss the spontaneous emission from a coherently prepared and microwave
driven doublet of potentially closely spaced excited states to a common ground
level. Multiple interference mechanisms are identified which may lead to
fluorescence inhibition in well-separated regions of the spectrum or act
jointly in cancelling the spontaneous emission. In addition to phase
independent quantum interferences due to combined absorptions and emissions of
driving field photons, we distinguish two competing phase dependent
interference mechanisms as means of controlling the fluorescence. The
indistinguishable quantum paths may involve the spontaneous emission from the
same state of the doublet, originating from the two different components of the
initial coherent superposition. Alternatively the paths involve a different
spontaneous photon from each of two decaying states, necessarily with the same
polarization. This makes these photons indistinguishable in principle within
the uncertainty of the two decay rates. The phase dependence arises for both
mechanisms because the interfering paths differ by an unequal number of
stimulated absorptions and emissions of the microwave field photons.
| [
{
"version": "v1",
"created": "Fri, 23 Oct 1998 17:34:53 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Paspalakis",
"E.",
"",
"Imperial College, London, UK"
],
[
"Keitel",
"C. H.",
"",
"Universität Freiburg, Germany"
],
[
"Knight",
"P. L.",
"",
"Imperial College, London,\n UK"
]
] |
quant-ph/9810073 | Pavel Stovicek | P. Stovicek, O. Vana | Differential cross section for Aharonov--Bohm effect with non standard
boundary conditions | to appear in Europhys. Lett | Europhys.Lett. 44 (1998) 403-408 | 10.1209/epl/i1998-00486-2 | null | quant-ph | null | A basic analysis is provided for the differential cross section
characterizing Aharonov--Bohm effect with non standard (non regular) boundary
conditions imposed on a wave function at the potential barrier. If compared
with the standard case two new features can occur: a violation of rotational
symmetry and a more significant backward scattering.
| [
{
"version": "v1",
"created": "Fri, 23 Oct 1998 18:04:36 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Stovicek",
"P.",
""
],
[
"Vana",
"O.",
""
]
] |
quant-ph/9810074 | Ariel Caticha | Ariel Caticha | Insufficient reason and entropy in quantum theory | Minor changes that improve the clarity of the argument without
affecting its substance have been incorporated | Found.Phys.30:227-251,2000 | 10.1023/A:1003692916756 | null | quant-ph cond-mat.stat-mech gr-qc math-ph math.MP | null | The objective of the consistent-amplitude approach to quantum theory has been
to justify the mathematical formalism on the basis of three main assumptions:
the first defines the subject matter, the second introduces amplitudes as the
tools for quantitative reasoning, and the third is an interpretative rule that
provides the link to the prediction of experimental outcomes. In this work we
introduce a natural and compelling fourth assumption: if there is no reason to
prefer one region of the configuration space over another then they should be
`weighted' equally. This is the last ingredient necessary to introduce a unique
inner product in the linear space of wave functions. Thus, a form of the
principle of insufficient reason is implicit in the Hilbert inner product.
Armed with the inner product we obtain two results. First, we elaborate on an
earlier proof of the Born probability rule. The implicit appeal to insufficient
reason shows that quantum probabilities are not more objective than classical
probabilities. Previously we had argued that the consistent manipulation of
amplitudes leads to a linear time evolution; our second result is that time
evolution must also be unitary. The argument is straightforward and hinges on
the conservation of entropy. The only subtlety consists of defining the correct
entropy; it is the array entropy, not von Neumann's. After unitary evolution
has been established we proceed to introduce the useful notion of observables
and we explore how von Neumann's entropy can be linked to Shannon's information
theory. Finally, we discuss how various connections among the postulates of
quantum theory are made explicit within this approach.
| [
{
"version": "v1",
"created": "Sat, 24 Oct 1998 20:23:26 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Feb 1999 20:21:55 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Caticha",
"Ariel",
""
]
] |
quant-ph/9810075 | Bill Munro | W.J.Munro and G.J.Milburn | Characterizing GHZ Correlations in Nondegenerate Parametric Oscillation
via Phase Measurements | submitted to PRL, 4 pages, no figures | Phys.Rev.Lett.81:4285-4288,1998 | 10.1103/PhysRevLett.81.4285 | null | quant-ph | null | We present a potential realization of the Greenberger, Horne and Zeilinger
ALL or NOTHING contradiction of quantum mechanics with local realism using
phase measurement techniques in a simple photon number triplet. Such a triplet
could be generated using nondegenerate parametric oscillation.
| [
{
"version": "v1",
"created": "Mon, 26 Oct 1998 00:03:23 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Munro",
"W. J.",
""
],
[
"Milburn",
"G. J.",
""
]
] |
quant-ph/9810076 | Molotkov S. | S.N.Molotkov and S.S.Nazin (Institute of Solid State Physics, Russian
Academy of Sciences) | Photon Frequency Entanglement Swapping | 5 pages, 1 figure. Submitted to Phys.Lett. A | Phys.Lett. A252 (1999) 1-4 | 10.1016/S0375-9601(98)00890-1 | null | quant-ph | null | We propose a simple non-linear crystal based optical scheme for experimental
realization of the frequency entanglement swapping between the photons
belonging to two independent biphotons.
| [
{
"version": "v1",
"created": "Mon, 26 Oct 1998 11:17:41 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Nov 1998 11:10:19 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Molotkov",
"S. N.",
"",
"Institute of Solid State Physics, Russian\n Academy of Sciences"
],
[
"Nazin",
"S. S.",
"",
"Institute of Solid State Physics, Russian\n Academy of Sciences"
]
] |
quant-ph/9810077 | Viktor V. Dodonov | V. V. Dodonov (Univ. Federal de Sao Carlos, Brazil) | Resonance Photon Generation in a Vibrating Cavity | 23 pages, Latex2e with iopart.cls, no figures, to appear in J. Phys.
A | J.Phys.A31:9835-9854,1998 | 10.1088/0305-4470/31/49/008 | null | quant-ph hep-th | null | The problem of photon creation from vacuum due to the nonstationary Casimir
effect in an ideal one-dimensional Fabry--Perot cavity with vibrating walls is
solved in the resonance case, when the frequency of vibrations is close to the
frequency of some unperturbed electromagnetic mode: $\omega_w=p(\pi
c/L_0)(1+\delta)$, $|\delta|\ll 1$, (p=1,2,...). An explicit analytical
expression for the total energy in all the modes shows an exponential growth if
$|\delta|$ is less than the dimensionless amplitude of vibrations $\epsilon\ll
1$, the increment being proportional to $p\sqrt{\epsilon^2-\delta^2}$. The rate
of photon generation from vacuum in the (j+ps)th mode goes asymptotically to a
constant value $cp^2\sin^2(\pi j/p)\sqrt{\epsilon^2-\delta^2}/[\pi L_0
(j+ps)]$, the numbers of photons in the modes with indices p,2p,3p,... being
the integrals of motion. The total number of photons in all the modes is
proportional to $p^3(\epsilon^2-\delta^2) t^2$ in the short-time and in the
long-time limits. In the case of strong detuning $|\delta|>\epsilon$ the total
energy and the total number of photons generated from vacuum oscillate with the
amplitudes decreasing as $(\epsilon/\delta)^2$ for $\epsilon\ll|\delta|$. The
special cases of p=1 and p=2 are studied in detail.
| [
{
"version": "v1",
"created": "Mon, 26 Oct 1998 11:21:04 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Dodonov",
"V. V.",
"",
"Univ. Federal de Sao Carlos, Brazil"
]
] |
quant-ph/9810078 | David J. Fernandez C. | David J. Fernandez C | The manipulation problem in quantum mechanics | 15 pages, latex, 5 Postscript figures, uses epsf, to appear in the
proceedings of the workshop `Symmetries in quantum mechanics and quantum
optics', Burgos (Spain), september 21-24, 1998 | null | null | null | quant-ph hep-th | null | We explain the meaning of dynamical manipulation, and we illustrate its
mechanism by using a system composed of a charged particle in a Penning trap.
It is shown that by means of appropriate electric shocks (delta-like pulses)
applied to the trap walls one can induce the squeezing transformation. The
geometric phases associated to some cyclic evolutions, induced either by the
standard fields of the Penning trap or by the superposition of these plus a
rotating magnetic field, are analysed
| [
{
"version": "v1",
"created": "Mon, 26 Oct 1998 17:51:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"C",
"David J. Fernandez",
""
]
] |
quant-ph/9810079 | Armen G. Grigoryan | A. V. Bogdanov and A. S. Gevorkyan | Quantum chaos in the framework of complex probability processes.
Thermodynamics of nonrelativistic vaccum | LaTeX, 22 pages, 3 figures, presented on Int. Workshop "Trends in
Mathematical Physics", USA, October, 1998. Submitted to Phys. Rev. E | null | null | null | quant-ph chao-dyn nlin.CD | null | The problem of random motion of 1D quantum reactive harmonic oscillator
(QRHO) is formulated in terms of a wave functional regarded as a complex
probability process in an extended space. In the complex stochastic
differential equation (SDE) for this process the variables are separated with
the help of the Langevin-type model SDE introduced in the functional space. The
complete positive Fokker-Plank measure of the functional space is obtained. The
average wave function of roaming QRHO is obtained by means of functional
integration over the process with the complete Fokker-Plank measure in the
functional space. The local and averaged transition matrices of roaming QRHO
were constructed. The thermodynamics of nonrelativistic vacuum is investigated
in detail and expressions for the internal energy, Helmholtzian energy and
entropy are obtained. The oscillator's ground state energy, its shift and
broadening are calculated.
| [
{
"version": "v1",
"created": "Mon, 26 Oct 1998 19:20:25 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Oct 1998 05:44:05 GMT"
},
{
"version": "v3",
"created": "Mon, 9 Nov 1998 19:55:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bogdanov",
"A. V.",
""
],
[
"Gevorkyan",
"A. S.",
""
]
] |
quant-ph/9810080 | Gregor Weihs | Gregor Weihs, Thomas Jennewein, Christoph Simon, Harald Weinfurter,
and Anton Zeilinger (University of Innsbruck, Austria) | Violation of Bell's inequality under strict Einstein locality conditions | 5 pages, 3 figures, accepted for publication in Phys. Rev. Lett.;
find photographs and experimental data at http://www.quantum.at | Phys.Rev.Lett. 81 (1998) 5039-5043 | 10.1103/PhysRevLett.81.5039 | null | quant-ph | null | We observe strong violation of Bell's inequality in an Einstein, Podolsky and
Rosen type experiment with independent observers. Our experiment definitely
implements the ideas behind the well known work by Aspect et al. We for the
first time fully enforce the condition of locality, a central assumption in the
derivation of Bell's theorem. The necessary space-like separation of the
observations is achieved by sufficient physical distance between the
measurement stations, by ultra-fast and random setting of the analyzers, and by
completely independent data registration.
| [
{
"version": "v1",
"created": "Mon, 26 Oct 1998 20:23:17 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Weihs",
"Gregor",
"",
"University of Innsbruck, Austria"
],
[
"Jennewein",
"Thomas",
"",
"University of Innsbruck, Austria"
],
[
"Simon",
"Christoph",
"",
"University of Innsbruck, Austria"
],
[
"Weinfurter",
"Harald",
"",
"University of Innsbruck, Austria"
],
[
"Zeilinger",
"Anton",
"",
"University of Innsbruck, Austria"
]
] |
quant-ph/9810081 | A. F. Kracklauer | A. F. Kracklauer | The Error in Bell's Theorem | 2 pages RevTeX | null | null | null | quant-ph | null | An error in the proof of Bell's Theorem is identified and a semiclassical
model of the EPRB experiment is presented
| [
{
"version": "v1",
"created": "Tue, 27 Oct 1998 02:38:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kracklauer",
"A. F.",
""
]
] |
quant-ph/9810082 | Seth Lloyd | Seth Lloyd, Samuel L. Braunstein | Quantum computation over continuous variables | 9 pages, TeX | Phys.Rev.Lett. 82 (1999) 1784-1787 | 10.1103/PhysRevLett.82.1784 | null | quant-ph | null | This paper provides necessary and sufficient conditions for constructing a
universal quantum computer over continuous variables. As an example, it is
shown how a universal quantum computer for the amplitudes of the
electromagnetic field might be constructed using simple linear devices such as
beam-splitters and phase shifters, together with squeezers and nonlinear
devices such as Kerr-effect fibers and atoms in optical cavities. Such a device
could in principle perform `quantum floating point' computations. Problems of
noise, finite precision, and error correction are discussed.
| [
{
"version": "v1",
"created": "Tue, 27 Oct 1998 15:29:18 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lloyd",
"Seth",
""
],
[
"Braunstein",
"Samuel L.",
""
]
] |
quant-ph/9810083 | David Vitali | Luigi Palatella and Paolo Grigolini | The transition from a classical to a quantum world as a passage from
extensive to non-extensive thermodynamics | RevTex, 4 pages, 4 eps figures | null | null | null | quant-ph chao-dyn nlin.CD | null | We study the thermodynamical properties of the quantum kicked rotator,
coarsened by an external fluctuation with a weak intensity D, by means of the
Tsallis entropy with a changing entropic index q. The genuine entropic index,
corresponding to given values of D and $\hbar$ is that making the Tsallis
entropy increase linearly in time, and it is proved to become q <1 for suitably
large values of $\hbar $: This indicates a subdiffusional regime which, in
turn, signals the occurrence of quantum localization. Thus the process of
Anderson localization is shown to be compatible with a thermodynamical
representation provided that a non-extensive form of entropy is used.
| [
{
"version": "v1",
"created": "Tue, 27 Oct 1998 17:09:42 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Palatella",
"Luigi",
""
],
[
"Grigolini",
"Paolo",
""
]
] |
quant-ph/9810084 | Mark S. Byrd | Luis J. Boya, Mark Byrd, Mark Mims and E. C. G. Sudarshan | Density Matrices and Geometric Phases for n-state Systems | 10 pages LaTeX2e, UT article class, 1 figure | null | null | null | quant-ph | null | An explicit parameterization is given for the density matrices for $n$-state
systems. The geometry of the space of pure and mixed states and the entropy of
the $n$-state system is discussed. Geometric phases can arise in only specific
subspaces of the space of all density matrices. The possibility of obtaining
nontrivial abelian and nonabelian geometric phases in these subspaces is
discussed.
| [
{
"version": "v1",
"created": "Wed, 28 Oct 1998 01:13:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Boya",
"Luis J.",
""
],
[
"Byrd",
"Mark",
""
],
[
"Mims",
"Mark",
""
],
[
"Sudarshan",
"E. C. G.",
""
]
] |
quant-ph/9810085 | Viktor V. Dodonov | V. V. Dodonov, O. V. Man'ko, V. I. Man'ko, A. Wuensche | Energy-Sensitive and "Classical-like" Distances Between Quantum States | 23 pages, LaTex, 2 eps figures, to appear in Physica Scripta | Phys.Scripta 59 (1999) 81-89 | 10.1238/Physica.Regular.059a00081 | null | quant-ph | null | We introduce the concept of the ``polarized'' distance, which distinguishes
the orthogonal states with different energies. We also give new inequalities
for the known Hilbert-Schmidt distance between neighbouring states and express
this distance in terms of the quasiprobability distributions and the normally
ordered moments. Besides, we discuss the distance problem in the framework of
the recently proposed ``classical-like'' formulation of quantum mechanics,
based on the symplectic tomography scheme. The examples of the Fock, coherent,
``Schroedinger cats,'' squeezed, phase, and thermal states are considered.
| [
{
"version": "v1",
"created": "Wed, 28 Oct 1998 11:58:48 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Dodonov",
"V. V.",
""
],
[
"Man'ko",
"O. V.",
""
],
[
"Man'ko",
"V. I.",
""
],
[
"Wuensche",
"A.",
""
]
] |
quant-ph/9810086 | Marc-Thierry Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique The'orique de l'Ecole
Normale Supe'rieure) and Serge Reynaud (Laboratoire Kastler Brossel) | Observable Dirac Electron in Accelerated Frames | 7 pages, revised version | Phys.Lett. A256 (1999) 95 | 10.1016/S0375-9601(99)00228-5 | LPTENS 98/14 | quant-ph gr-qc | null | We present a new quantum algebraic description of an electron localized in
space-time. Positions in space and time, mass and Clifford generators are
defined as quantum operators. Commutation relations and relativistic shifts
under frame transformations are determined within a unique algebraic framework.
Redshifts, i.e. shifts under transformations to uniformly accelerated frames,
are evaluated and found to differ from the expressions of classical relativity.
| [
{
"version": "v1",
"created": "Wed, 28 Oct 1998 14:39:24 GMT"
},
{
"version": "v2",
"created": "Thu, 27 May 1999 13:11:17 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jaekel",
"Marc-Thierry",
"",
"Laboratoire de Physique The'orique de l'Ecole\n Normale Supe'rieure"
],
[
"Reynaud",
"Serge",
"",
"Laboratoire Kastler Brossel"
]
] |
quant-ph/9810087 | Dieter Jaksch | D. Jaksch, H.-J. Briegel, J.I. Cirac, C. W. Gardiner, and P. Zoller | Entanglement of atoms via cold controlled collisions | 4 pages 3 figures | Phys.Rev.Lett. 82 (1999) 1975-1978 | 10.1103/PhysRevLett.82.1975 | null | quant-ph cond-mat | null | We show that by using cold controlled collisions between two atoms one can
achieve conditional dynamics in moving trap potentials. We discuss implementing
two qubit quantum--gates and efficient creation of highly entangled states of
many atoms in optical lattices.
| [
{
"version": "v1",
"created": "Wed, 28 Oct 1998 17:08:23 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jaksch",
"D.",
""
],
[
"Briegel",
"H. -J.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Gardiner",
"C. W.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9810088 | A. Perez-Lorenzana | Merced Montesinos and Abdel P\'erez-Lorenzana | Minimal coupling and Feynman's proof | 11 pages, Latex file, no figures. Published version | Int.J.Theor.Phys. 38 (1999) 901-910 | null | null | quant-ph hep-th physics.class-ph | null | The non quantum relativistic version of the proof of Feynman for the Maxwell
equations is discussed in a framework with a minimum number of hypotheses
required. From the present point of view it is clear that the classical
equations of motion corresponding to the gauge field interactions can be
deduced from the minimal coupling rule, and we claim here resides the essence
of the proof of Feynman.
| [
{
"version": "v1",
"created": "Thu, 29 Oct 1998 03:51:54 GMT"
},
{
"version": "v2",
"created": "Fri, 17 Sep 1999 20:59:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Montesinos",
"Merced",
""
],
[
"Pérez-Lorenzana",
"Abdel",
""
]
] |
quant-ph/9810089 | Lev Vaidman | L. Vaidman | Teleportation: Dream or Reality? | Invited Talk in the Conference: Mysteries, Puzzles and Paradoxes in
Quantum Mechanics, 13 pages | null | 10.1063/1.57866 | null | quant-ph | null | Since its discovery in 1993, we witness an intensive theoretical and
experimental effort centered on teleportation. Very recently it was claimed in
the press that ``quantum teleportation has been achieved in the laboratory''
(T. Sudbery, Nature, 390, p. 551). Here, I briefly review this research
focusing on the connection to nonlocal measurements, and question Sudbery's
statement. A philosophical inquiry about the paradoxical meaning of
teleportation in the framework of the many-worlds interpretation is added.
| [
{
"version": "v1",
"created": "Thu, 29 Oct 1998 10:24:50 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Vaidman",
"L.",
""
]
] |
quant-ph/9810090 | Decio Krause | Decio Krause and Steven French | Opaque predicates, veiled sets and their logic | Latex2e, no fiugures | null | null | null | quant-ph | null | Motivated by considerations in the foundations of quantum mechanics and
inspired by the literature on vague predicates, we introduce the concept of an
opaque predicate. While in the case of vague predicates there is a kind of
indeterminacy with respect to the predicate, in the sense that the vagueness
concerns whether a well-determined object satisfies it or not, in the case of
opaque predicates the indeterminacy is with regard to the objects which should
satisfy them. In other words, their extensions are not well-defined, despite
the fact that the conditions for an object to satisfy the predicates are
well-known. We suggest that such opaque predicates (and more generally, what we
call opaque relations) can be characterized by a logic which encompasses a
semantics founded in quasi-set theory, and call their extensions veiled sets.
| [
{
"version": "v1",
"created": "Thu, 29 Oct 1998 11:34:55 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Krause",
"Decio",
""
],
[
"French",
"Steven",
""
]
] |
quant-ph/9810091 | Barbara M. Terhal | Barbara M. Terhal | A Family of Indecomposable Positive Linear Maps based on Entangled
Quantum States | 16 pages LaTex: updated and a derivation of a lower bound on epsilon
is added and calculated for one of the examples. Submitted to Lin. Alg. and
Its Appl | Linear Algebra Appl. 323 (2000) 61-73 | null | null | quant-ph math.FA | null | We introduce a new family of indecomposable positive linear maps based on
entangled quantum states. Central to our construction is the notion of an
unextendible product basis. The construction lets us create indecomposable
positive linear maps in matrix algebras of arbitrary high dimension.
| [
{
"version": "v1",
"created": "Thu, 29 Oct 1998 18:23:07 GMT"
},
{
"version": "v2",
"created": "Tue, 4 May 1999 09:54:37 GMT"
},
{
"version": "v3",
"created": "Wed, 3 May 2000 22:02:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Terhal",
"Barbara M.",
""
]
] |
quant-ph/9810092 | Diego A. R. Dalvit | Diego A. R. Dalvit and Francisco D. Mazzitelli | Creation of photons in an oscillating cavity with two moving mirrors | LaTex file, 17 pages, 3 figures, uses epsf.sty | Phys.Rev. A59 (1999) 3049-3059 | 10.1103/PhysRevA.59.3049 | null | quant-ph hep-th | null | We study the creation of photons in a one dimensional oscillating cavity with
two perfectly conducting moving walls. By means of a conformal transformation
we derive a set of generalized Moore's equations whose solution contains the
whole information of the radiation field within the cavity. For the case of
resonant oscillations we solve these equations using a renormalization group
procedure that appropriately deals with the secular behaviour present in a
naive perturbative approach. We study the time evolution of the energy density
profile and of the number of created photons inside the cavity.
| [
{
"version": "v1",
"created": "Thu, 29 Oct 1998 21:50:26 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Dalvit",
"Diego A. R.",
""
],
[
"Mazzitelli",
"Francisco D.",
""
]
] |
quant-ph/9810093 | Hiroo Azuma | Hiroo Azuma | Building partially entangled states with Grover's amplitude
amplification process | 22 pages, Latex2e, 8 epsf figures. The title is changed and
estimation of the number of quantum gates for our method is corrected. Many
parts of the article are rewritten and should hopefully be clear | Int.J.Mod.Phys. C11 (2000) 469-484 | 10.1142/S0129183100000407 | null | quant-ph | null | We discuss how to build some partially entangled states of $n$ two-state
quantum systems (qubits). The optimal partially entangled state with a high
degree of symmetry is considered to be useful for overcoming a shot noise limit
of Ramsey spectroscopy under some decoherence. This state is invariant under
permutation of any two qubits and inversion between the ground state $|0\ket$
and an excited state $|1\ket$ for each qubit. We show that using selective
phase shifts in certain basis vectors and Grover's inversion about average
operations, we can construct this high symmetric entangled state by
$({polynomial in $n$})\times 2^{n/2}$ successive unitary transformations that
are applied on two or three qubits. We can apply our method to build more
general entangled states.
| [
{
"version": "v1",
"created": "Fri, 30 Oct 1998 05:57:42 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Jan 2000 03:55:37 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Azuma",
"Hiroo",
""
]
] |
quant-ph/9810094 | Robert W. Spekkens | R. W. Spekkens and J. E. Sipe | Spatial fragmentation of a Bose-Einstein condensate in a double-well
potential | 10 pages, 2 figures, submitted to Phys. Rev. A | Phys. Rev. A 59, 3868 (1999) | 10.1103/PhysRevA.59.3868 | null | quant-ph | null | We present a theoretical study of the ground state of a Bose-Einstein
condensate with repulsive inter-particle interactions in a double-well
potential, using a restricted variational principle. Within such an approach,
there is a transition from a single condensate to a fragmented condensate as
the strength of the central barrier of the potential is increased. We determine
the nature of this transition through approximate analytic as well as numerical
solutions of our model in the regime where the inter-particle interactions can
be treated perturbatively. The degree of fragmentation of the condensate is
characterized by the degrees of first-order and second-order spatial coherence
across the barrier.
| [
{
"version": "v1",
"created": "Fri, 30 Oct 1998 18:31:55 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Spekkens",
"R. W.",
""
],
[
"Sipe",
"J. E.",
""
]
] |
quant-ph/9810095 | Allan Widom | Y.N. Srivastava, G. Vitiello, A. Widom | Quantum Measurements, Information and Entropy Production | RevTeX 7-Pages No Figures | Int.J.Mod.Phys. B13 (1999) 3369-3382 | 10.1142/S0217979299003076 | MQT 11-3121 | quant-ph hep-th | null | In order to understand the Landau-Lifshitz conjecture on the relationship
between quantum measurements and the thermodynamic second law, we discuss the
notion of ``diabatic'' and ``adiabatic'' forces exerted by the quantum object
on the classical measurement apparatus. The notion of heat and work in
measurements is made manifest in this approach, and the relationship between
information entropy and thermodynamic entropy is explored.
| [
{
"version": "v1",
"created": "Fri, 30 Oct 1998 22:23:30 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Srivastava",
"Y. N.",
""
],
[
"Vitiello",
"G.",
""
],
[
"Widom",
"A.",
""
]
] |
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