id
stringlengths 9
16
| submitter
stringlengths 1
64
⌀ | authors
stringlengths 3
62.8k
| title
stringlengths 1
382
| comments
stringlengths 1
1.15k
⌀ | journal-ref
stringlengths 1
557
⌀ | doi
stringlengths 7
153
⌀ | report-no
stringlengths 1
509
⌀ | categories
stringlengths 5
125
| license
stringclasses 9
values | abstract
stringlengths 6
6.09k
| versions
listlengths 1
187
| update_date
timestamp[s]date 2007-05-23 00:00:00
2025-04-04 00:00:00
| authors_parsed
sequencelengths 1
2.83k
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
quant-ph/9801041 | Daniel S. Abrams | Daniel S. Abrams (1), Seth Lloyd (2) ( (1) Dept. of Physics, MIT, (2)
Dept. of Mechanical Engineering, MIT) | Nonlinear quantum mechanics implies polynomial-time solution for
NP-complete and #P problems | 10 pages, no figures, submitted to Phys. Rev. Lett | Phys.Rev.Lett. 81 (1998) 3992-3995 | 10.1103/PhysRevLett.81.3992 | null | quant-ph | null | If quantum states exhibit small nonlinearities during time evolution, then
quantum computers can be used to solve NP-complete problems in polynomial time.
We provide algorithms that solve NP-complete and #P oracle problems by
exploiting nonlinear quantum logic gates. It is argued that virtually any
deterministic nonlinear quantum theory will include such gates, and the method
is explicitly demonstrated using the Weinberg model of nonlinear quantum
mechanics.
| [
{
"version": "v1",
"created": "Wed, 21 Jan 1998 00:34:54 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Abrams",
"Daniel S.",
""
],
[
"Lloyd",
"Seth",
""
]
] |
quant-ph/9801042 | Kurt Jacobs | K. Jacobs and P. L. Knight | Linear quantum trajectories: Applications to continuous projection
measurements | Revtex, 10 pages, 1 eps figure. v2: corrections to the operator
disentangling relation in appendix B | Phys.Rev. A 57, 2301 (1998) | 10.1103/PhysRevA.57.2301 | null | quant-ph | null | We present a method for obtaining evolution operators for linear quantum
trajectories. We apply this to a number of physical examples of varying
mathematical complexity, in which the quantum trajectories describe the
continuous projection measurement of physical observables. Using this method we
calculate the average conditional uncertainty for the measured observables,
being a central quantity of interest in these measurement processes.
| [
{
"version": "v1",
"created": "Wed, 21 Jan 1998 15:34:46 GMT"
},
{
"version": "v2",
"created": "Tue, 22 May 2007 16:57:02 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jacobs",
"K.",
""
],
[
"Knight",
"P. L.",
""
]
] |
quant-ph/9801043 | null | J. G. Muga, R. Sala and J. P. Palao | The time of arrival concept in quantum mechanics | 17 pages, to appear in Superlattices and Microstructures, Vol. 24,
No. 4, 1998 | Superlattices Microstruct. 23:833,1998 | 10.1006/spmi.1997.0544 | ULL-FIS-980102 | quant-ph | null | The concept and the formalization of the arrival time in quantum mechanics
are discussed. Different approaches based on trajectories, quantization rules,
time operators, phase space techniques, renewal equations or operational
procedures are reviewed or proposed. Open questions and loose ends are pointed
out.
| [
{
"version": "v1",
"created": "Wed, 21 Jan 1998 15:29:12 GMT"
}
] | 2011-08-17T00:00:00 | [
[
"Muga",
"J. G.",
""
],
[
"Sala",
"R.",
""
],
[
"Palao",
"J. P.",
""
]
] |
quant-ph/9801044 | W. A. Hofer | W. A. Hofer (TU-Wien) | A dynamic model of atoms: structure, internal interactions and photon
emissions of hydrogen | 12 pages (RevTeX) and 2 figures (eps). Paper updated and references
added. for related papers see http://cmmp.phys.ucl.ac.uk/~wah/qed/papers.html | null | null | null | quant-ph | null | The standard solution of the Schroedinger equation for the hydrogen atom is
analyzed. Comparing with the recently established internal properties of
electrons it is found, that these solutions cannot be seen as physically valid
states of the electron wave. The paper therefore proposes a new model of
hydrogen based on internal properties of electrons. The ground state of the
hydrogen system (T=0) is an inertial aggregation within the atomic shell, the
calculation yields an atomic radius of 0.330 nm. Electron proton interaction
within the atom are treated with a causal and deterministic model, the
resonance frequency of the hydrogen system of $ 6.57 \times 10^{15} Hz $ is
referred to elastic deformations of its nucleus, resonance levels are a result
of boundary conditions for radial electron waves and photon interactions due to
nuclear oscillations. Spectral emissions of excited atoms can be referred to a
decay of the state of motion of the coupled electron-proton system. The
framework developed is essentially deterministic, microphysical processes
analyzed are referred to material characteristics of particles involved.
Statistical effects are referred to interactions with the atomic environment,
the results derived are compatible with the second and third principle of
thermodynamics.
| [
{
"version": "v1",
"created": "Thu, 22 Jan 1998 12:31:54 GMT"
},
{
"version": "v2",
"created": "Thu, 8 Jun 2000 11:08:36 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Hofer",
"W. A.",
"",
"TU-Wien"
]
] |
quant-ph/9801045 | G. A. Koganov | Gennady A. Koganov and Reuben Shuker | Non-linear properties of strongly pumped lasers | 10 pages, 4 figures Submitted to Phys. Rev. A | null | null | BGU-qo-98/1 | quant-ph | null | Bloch equations for the atomic population and the polarization/coherence and
the equation of motion for the photon number in a laser are solved in steady
state as a function of the pump rate. Two level atom and two modes of three
levels atom are investigated. Close to threshold the usual linear dependence of
the intensity on the pump rate in found for all cases. However, far above
threshold strongly nonlinear dependence is encountered. In the cases for which
the pump connects the lower lasing state to one of the excited states the
character of the non-linearity differs crucially from the cases when the pump
in not related directly to the lower lasing state. Non-monotonic dependence of
laser intensity upon the pump rate is predicted. Detailed discussion of the
nonlinear behavior is presented, including saturation and depletion effects.
| [
{
"version": "v1",
"created": "Thu, 22 Jan 1998 14:14:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Koganov",
"Gennady A.",
""
],
[
"Shuker",
"Reuben",
""
]
] |
quant-ph/9801046 | Glenn Moy | G.M. Moy, J.J. Hope, C.M. Savage | The Born and Markov approximations for atom lasers | 10 pages, 3 figures. (2 new figues). Exact solutions have been
included in section II. Sections IV and V have been expanded. A new section
discussing the effects of gravity has been included | null | 10.1103/PhysRevA.59.667 | null | quant-ph | null | We discuss the use of the Born and Markov approximations in describing the
dynamics of an atom laser. In particular, we investigate the applicability of
the quantum optical Born-Markov master equation for describing output coupling.
We derive conditions based on the atomic reservoir, and atom dispersion
relations for when the Born-Markov approximations are valid and discuss
parameter regimes where these approximations fail in our atom laser model.
Differences between the standard optical laser model and the atom laser are due
to a combination of factors, including the parameter regimes in which a typical
atom laser would operate, the different reservoir state which is appropriate
for atoms, and the different dispersion relations between atoms and photons. We
present results based on an exact method in the regimes in which the
Born-Markov approximation fails. The exact solutions in some experimentally
relavent parameter regimes give non-exponential loss of atoms from a cavity.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 00:40:57 GMT"
},
{
"version": "v2",
"created": "Mon, 21 Sep 1998 04:29:40 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Moy",
"G. M.",
""
],
[
"Hope",
"J. J.",
""
],
[
"Savage",
"C. M.",
""
]
] |
quant-ph/9801047 | Andre Martin | Andre Martin | Stability of Three- and Four-Body Coulomb Systems | latex file, 15 pages, 8 figures | null | null | CERN-TH/98-23 | quant-ph | null | We discuss the stability of three- and four-particle system interacting by
pure Coulomb interactions, as a function of the masses and charges of the
particles. We present a certain number of general properties which allow to
answer a certain number of questions without or with less numerical
calculations.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 09:52:47 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Martin",
"Andre",
""
]
] |
quant-ph/9801048 | Tamas Kiss | U. Leonhardt, T. Kiss, and P. Piwnicki | Quantum back-action of optical observations on Bose condensates | 11 pages RevTex, 2 ps figures, revised. European Physical Journal D
(in press) | null | 10.1007/s100530050585 | null | quant-ph | null | Impressive pictures of moving Bose-Einstein condensates have been taken using
phase-contrast imaging M. R. Andrews et al., Science 273, 84 (1996). We
calculate the quantum backaction of this measurement technique. We find that
phase-contrast imaging is not a quantum nondemolition measurement of the atomic
density. Instead, the condensate gets gradually depleted at a rate that is
proportional to the light intensity and to the inverse cube of the optical wave
length. The fewer atoms are condensed the higher is the required intensity to
see a picture, and, consequently, the higher is the induced backaction. To
describe the quantum physics of phase-contrast imaging we put forward a new
approach to quantum-optical propagation. We develop an effective field theory
of paraxial optics in a fully quantized atomic medium.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 12:56:29 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Jul 1998 14:45:51 GMT"
},
{
"version": "v3",
"created": "Fri, 25 Sep 1998 10:04:27 GMT"
},
{
"version": "v4",
"created": "Tue, 25 May 1999 11:28:39 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Leonhardt",
"U.",
""
],
[
"Kiss",
"T.",
""
],
[
"Piwnicki",
"P.",
""
]
] |
quant-ph/9801049 | Astrid Lambrecht | A. Lambrecht, J.M. Courty, S. Reynaud, E. Giacobino | Cold atoms: A new medium for quantum optics | 6 pages, 6 figures, LaTeX | Appl.Phys. B60 (1995) 129-134 | 10.1007/BF01135854 | null | quant-ph | null | Laser-cooled and trapped cesium atoms have been used as a nonlinear medium in
a nearly resonant cavity. A study of the semiclassical dynamics of the system
was performed, showing bistability and instabilities. In the quantum domain,
squeezing in a probe beam having interacted with this system was demonstrated.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 16:26:09 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Lambrecht",
"A.",
""
],
[
"Courty",
"J. M.",
""
],
[
"Reynaud",
"S.",
""
],
[
"Giacobino",
"E.",
""
]
] |
quant-ph/9801050 | Astrid Lambrecht | A. Lambrecht, E. Giacobino and S. Reynaud | Atomic number fluctuations in a falling cold atom cloud | 21 pages, LaTeX | Quant.Semiclass.Opt. 8 (1996) 457-472 | 10.1088/1355-5111/8/3/009 | null | quant-ph | null | We evaluate the effective number of atoms in experiments where a probe laser
beam with a Gaussian profile passes through an atomic medium consisting of a
cold atom cloud released from a magneto-optical trap. Considering the case
where the initial distribution is a Gaussian function of position and velocity,
we give a quantitative description of the time variation of the effective atom
number while the cloud is exploding and falling. We discuss the two cases where
the effective number is defined from the linear and nonlinear phase shifts,
respectively. We also evaluate the fluctuations of the effective atom number by
calculating their correlation functions and the associated noise spectra.
Finally we estimate the effect of these fluctuations on experiments where the
probe beam passes through a cavity containing the atomic cloud.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 16:36:32 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lambrecht",
"A.",
""
],
[
"Giacobino",
"E.",
""
],
[
"Reynaud",
"S.",
""
]
] |
quant-ph/9801051 | Astrid Lambrecht | A. Lambrecht, T. Coudreau, A.M. Steinberg and E. Giacobino | Squeezing with cold atoms | 9 pages, 4 figures, LaTeX | Europhys.Lett. 36 (1996) 93-98 | 10.1209/epl/i1996-00192-1 | null | quant-ph | null | Cold atoms from a magneto-optic trap have been used as a nonlinear medium in
a nearly resonant cavity. Squeezing in a probe beam passing through the cavity
was demonstrated. The measured noise reduction is 40% for free atoms and 20%
for weakly trapped atoms.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 15:46:49 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lambrecht",
"A.",
""
],
[
"Coudreau",
"T.",
""
],
[
"Steinberg",
"A. M.",
""
],
[
"Giacobino",
"E.",
""
]
] |
quant-ph/9801052 | Astrid Lambrecht | A. Lambrecht, J.M. Courty and S. Reynaud | Transverse effects on squeezing with atoms | 25 pages, 1 figure, LaTeX | J.Phys.(France) 6 (1996) 1133-1151 | null | null | quant-ph | null | We evaluate the squeezing of a probe beam with a transverse Gaussian profile
interacting with an ensemble of two-level atoms in a cavity. We use the linear
input-output formalism where the effect of atoms is described by susceptibility
and noise functions. The transverse structure is accounted for by averaging
atomic functions over the intensity profile. The results of the plane-wave and
Gaussian-wave theories are compared. When large squeezing is predicted we find
the prediction of the plane-wave model not to be reliable outside the Kerr
domain. We give an estimate of the squeezing degradation due to the Gaussian
transverse structure.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 16:13:15 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lambrecht",
"A.",
""
],
[
"Courty",
"J. M.",
""
],
[
"Reynaud",
"S.",
""
]
] |
quant-ph/9801053 | Astrid Lambrecht | J.M. Courty and A. Lambrecht | Transverse-mode coupling in a Kerr medium | 11 pages, 6 figures, LaTeX | Phys.Rev. A54 (1996) 5243-5252 | 10.1103/PhysRevA.54.5243 | null | quant-ph | null | We analyze nonlinear transverse mode coupling in a Kerr medium placed in an
optical cavity and its influence on bistability and different kinds of quantum
noise reduction. Even for an input beam that is perfectly matched to a cavity
mode, the nonlinear coupling produces an excess noise in the fluctuations of
the output beam. Intensity squeezing seems to be particularly robust with
respect to mode coupling, while quadrature squeezing is more sensitive.
However, it is possible to find a mode the quadrature squeezing of which is not
affected by the coupling.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 17:03:38 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Courty",
"J. M.",
""
],
[
"Lambrecht",
"A.",
""
]
] |
quant-ph/9801054 | Astrid Lambrecht | A. Lambrecht, E. Giacobino, J.M. Courty | Optical nonlinear dynamics with cold atoms in a cavity | 6 pages, 7 figures, LaTeX | Opt.Commun. 115 (1995) 199-206 | 10.1016/0030-4018(94)00493-E | null | quant-ph | null | This paper presents the nonlinear dynamics of laser cooled and trapped cesium
atoms placed inside an optical cavity and interacting with a probe light beam
slightly detuned from the 6S1/2(F=4) to 6P3/2(F=5) transition. The system
exhibits very strong bistability and instabilities. The origin of the latter is
found to be a competition between optical pumping and non-linearities due to
saturation of the optical transition.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 17:46:23 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lambrecht",
"A.",
""
],
[
"Giacobino",
"E.",
""
],
[
"Courty",
"J. M.",
""
]
] |
quant-ph/9801055 | Astrid Lambrecht | A. Lambrecht, M.-T. Jaekel, S. Reynaud | The Casimir force for passive mirrors | 12 pages, 2 figures, LaTeX | Phys.Lett. A225 (1997) 188-194 | 10.1016/S0375-9601(96)00885-7 | null | quant-ph | null | We show that the Casimir force between mirrors with arbitrary frequency
dependent reflectivities obeys bounds due to causality and passivity
properties. The force is always smaller than the Casimir force between two
perfectly reflecting mirrors. For narrow-band mirrors in particular, the force
is found to decrease with the mirrors bandwidth.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 17:57:31 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lambrecht",
"A.",
""
],
[
"Jaekel",
"M. -T.",
""
],
[
"Reynaud",
"S.",
""
]
] |
quant-ph/9801056 | Henry Stapp | Henry P. Stapp (Lawrence Berkeley National Laboratory) | Comments on Unruh's Paper | Comments on quant-ph/9710032, 6 pages | null | null | LBNL- 41288 | quant-ph | null | Unruh has commented upon my recent proof that certain predictions of quantum
theory are incompatible with the assertion that no influence of any kind acts
backward in time in any Lorentz frame. Unruh fails to make a necessary
distinction between statements that assert the existence of values, and
statements that assert the existence merely of correlations between possible
values. Consequently his argument fails to show that my proof involves a tacit
or hidden reality assumption that is alien to quantum theory.
| [
{
"version": "v1",
"created": "Fri, 23 Jan 1998 23:44:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Stapp",
"Henry P.",
"",
"Lawrence Berkeley National Laboratory"
]
] |
quant-ph/9801057 | N. David Mermin | N. David Mermin | What is quantum mechanics trying to tell us? | 37 pages, no figures. This is the published version of the lecture
notes that expand on my earlier ``Ithaca interpretation of quantum
mechanics'', quant-ph/9609013. ``Wootters' theorem'' has become the SSC
theorem, an earlier citation has been added, and a joke about Talmudic
scholarship has been dropped at the request of a referee | American Journal of Physics 66, 753-767 (1998) | 10.1119/1.18955 | null | quant-ph | null | I explore whether it is possible to make sense of the quantum mechanical
description of physical reality by taking the proper subject of physics to be
correlation and only correlation, and by separating the problem of
understanding the nature of quantum mechanics from the hard problem of
understanding the nature of objective probability in individual systems, and
the even harder problem of understanding the nature of conscious awareness. The
resulting perspective on quantum mechanics is supported by some elementary but
insufficiently emphasized theorems. Whether or not it is adequate as a new
Weltanschauung, this point of view toward quantum mechanics provides a
different perspective from which to teach the subject or explain its peculiar
character to people in other fields.
| [
{
"version": "v1",
"created": "Sun, 25 Jan 1998 16:30:37 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Sep 1998 19:21:54 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Mermin",
"N. David",
""
]
] |
quant-ph/9801058 | Ron S. Rubin | Ron Rubin and Nathan Salwen | A Parity-Conserving Canonical Quantization for the Baker's Map | 23 pages | null | null | null | quant-ph | null | We present here a complete description of the quantization of the baker's
map. The method we use is quite different from that used in Balazs and Voros
[BV] and Saraceno [S]. We use as the quantum algebra of observables the
operators generated by {exp(2 Pi ix),exp (2 Pi ip)} and construct a unitary
propagator such that as Planck's constant tends to zero,the classical dynamics
is returned. For Planck's constant satisfying the integrality condition 1/N
with N even, and for periodic boundary conditions for the wave functions on the
torus, we show that the dynamics can be reduced to the dynamics on an
N-dimensional Hilbert space, and the unitary N by N matrix propagator is the
same as given in [BV] except for a small correction of order Planck's constant.
This correction is is shown to preserve the symmetry x->1-x and p->1-p of the
classical map for periodic boundary conditions.
| [
{
"version": "v1",
"created": "Sun, 25 Jan 1998 23:59:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rubin",
"Ron",
""
],
[
"Salwen",
"Nathan",
""
]
] |
quant-ph/9801059 | Konrad Banaszek | Konrad Banaszek (Uniwersytet Warszawski) | Statistical uncertainty in quantum optical photodetection measurements | 18 pages REVTeX, 7 figures included using epsf. Few minor corrections
made, clarified conclusions | J.Mod.Opt. 46 (1999) 675-692 | 10.1080/09500349908231294 | null | quant-ph physics.optics | null | We present a complete statistical analysis of quantum optical measurement
schemes based on photodetection. Statistical distributions of quantum
observables determined from a finite number of experimental runs are
characterized with the help of the generating function, which we derive using
the exact statistical description of raw experimental outcomes. We use the
developed formalism to point out that the statistical uncertainty results in
substantial limitations of the determined information on the quantum state:
though a family of observables characterizing the quantum state can be safely
evaluated from experimental data, its further use to obtain the expectation
value of some operators generates exploding statistical errors. These issues
are discussed using the example of phase-insensitive measurements of a single
light mode. We study reconstruction of the photon number distribution from
photon counting and random phase homodyne detection. We show that utilization
of the reconstructed distribution to evaluate a simple well-behaved observable,
namely the parity operator, encounters difficulties due to accumulation of
statistical errors. As the parity operator yields the Wigner function at the
phase space origin, this example also demonstrates that transformation between
various experimentally determined representations of the quantum state is a
quite delicate matter.
| [
{
"version": "v1",
"created": "Mon, 26 Jan 1998 07:59:35 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Mar 1998 20:31:26 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Banaszek",
"Konrad",
"",
"Uniwersytet Warszawski"
]
] |
quant-ph/9801060 | Svozil Karl | Karl Svozil | First International Conference on Unconventional Models of Computation
UMC'98. An Unconventional Review | latex, no figures, to be published in Bulletin of the European
Association of Theoretical Computer Sciences | null | null | null | quant-ph | null | Review of the First International Conference on Unconventional Models of
Computation UMC'98, Auckland, New Zealand, 5-9 January, 1998
| [
{
"version": "v1",
"created": "Mon, 26 Jan 1998 11:05:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Svozil",
"Karl",
""
]
] |
quant-ph/9801061 | Antoine Suarez | Antoine Suarez (Center for Quantum Philosophy, Zurich) | Does Quantum Mechanics imply influences acting backward in time in
impact series experiments? | 9 pages Latex, 1 eps figure | null | null | null | quant-ph | null | A real two-particle experiment is proposed in which one of the particles
undergoes two successive impacts on beam-splitters. It is shown that the
standard quantum mechanical superposition principle implies the possibility of
influences acting backward in time ("retrocausation"), in striking contrast
with the principle of causality. It is argued that nonlocality and
retrocausation are not necessarily entangled.
| [
{
"version": "v1",
"created": "Mon, 26 Jan 1998 17:13:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Suarez",
"Antoine",
"",
"Center for Quantum Philosophy, Zurich"
]
] |
quant-ph/9801062 | null | Vladimir S. Mashkevich (Institute of Physics, Kiev) | Comment on ``Quantum Entanglement and the Nonexistence of Superluminal
Signals'' | 3 pages, LATEX 2.09 | null | null | null | quant-ph | null | We argue that the claim given in quant-ph/9801014 is untenable. The fallacy
in the proof is a misinterpretation of the no-cloning theorem, which does not
allow quantum jumps, specifically measurements.
| [
{
"version": "v1",
"created": "Tue, 27 Jan 1998 09:36:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mashkevich",
"Vladimir S.",
"",
"Institute of Physics, Kiev"
]
] |
quant-ph/9801063 | Giacomo Mauro D'Ariano | Giacomo M. D'Ariano and Prem Kumar (Department of Electrical and
Computer Engineering Northwestern University, Evanston, IL, USA) | A quantum-mechanical study of optical regenerators based on
nonlinear-loop mirrors | 420KB tar file, including 5 eps figures. To appear on IEEE Photonics
Technology Letters | IEEE Photonics Tech.Lett. 10 (1998) 699-701 | 10.1109/68.669331 | null | quant-ph | null | We present a quantum-mechanical analysis of a nonlinear interferometer that
achieves optical switching via cross-phase modulation resulting from the Kerr
effect. We show how it performs as a very precise optical regenerator, highly
improving the transmitted bit-error rate in the presence of loss.
| [
{
"version": "v1",
"created": "Tue, 27 Jan 1998 10:23:14 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"D'Ariano",
"Giacomo M.",
"",
"Department of Electrical and\n Computer Engineering Northwestern University, Evanston, IL, USA"
],
[
"Kumar",
"Prem",
"",
"Department of Electrical and\n Computer Engineering Northwestern University, Evanston, IL, USA"
]
] |
quant-ph/9801064 | Stephen Choi | S. Choi, S. A. Morgan, and K. Burnett | Phenomenological damping in trapped atomic Bose-Einstein condensates | 5 pages including 2 figures. To appear in Phys. Rev. A as a Brief
Report | null | 10.1103/PhysRevA.57.4057 | null | quant-ph | null | The method of phenomenological damping developed by Pitaevskii for
superfluidity near the $\lambda$ point is simulated numerically for the case of
a dilute, alkali, inhomogeneous Bose-condensed gas near absolute zero. We study
several features of this method in describing the damping of excitations in a
Bose-Einstein condensate. In addition, we show that the method may be employed
to obtain numerically accurate ground states for a variety of trap potentials.
| [
{
"version": "v1",
"created": "Wed, 28 Jan 1998 11:31:26 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Choi",
"S.",
""
],
[
"Morgan",
"S. A.",
""
],
[
"Burnett",
"K.",
""
]
] |
quant-ph/9801065 | Giacomo Mauro D'Ariano | G. M. D'Ariano, C. Macchiavello, and L. Maccone (Dipartimento di
Fisica "A. Volta", Universita' di Pavia, Italy) | Noise, errors and information in quantum amplification | 20 pages, 4 eps figures, 41K gzipped tar file | Int.J.Mod.Phys. B11 (1997) 3385 | 10.1142/S0217979297001660 | null | quant-ph | null | We analyze and compare the characterization of a quantum device in terms of
noise, transmitted bit-error-rate (BER) and mutual information, showing how the
noise description is meaningful only for Gaussian channels. After reviewing the
description of a quantum communication channel, we study the insertion of an
amplifier. We focus attention on the case of direct detection, where the linear
amplifier has a 3 decibels noise figure, which is usually considered an
unsurpassable limit, referred to as the standard quantum limit (SQL). Both
noise and BER could be reduced using an ideal amplifier, which is feasible in
principle. However, just a reduction of noise beyond the SQL does not generally
correspond to an improvement of the BER or of the mutual information. This is
the case of a laser amplifier, where saturation can greatly reduce the noise
figure, although there is no corresponding improvement of the BER. Such
mechanism is illustrated on the basis of Monte Carlo simulations.
| [
{
"version": "v1",
"created": "Wed, 28 Jan 1998 18:21:33 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"D'Ariano",
"G. M.",
"",
"Dipartimento di\n Fisica \"A. Volta\", Universita' di Pavia, Italy"
],
[
"Macchiavello",
"C.",
"",
"Dipartimento di\n Fisica \"A. Volta\", Universita' di Pavia, Italy"
],
[
"Maccone",
"L.",
"",
"Dipartimento di\n Fisica \"A. Volta\", Universita' di Pavia, Italy"
]
] |
quant-ph/9801066 | Dr. Daniel A. Lidar | David Biron (1), Ofer Biham (1), Eli Biham (2), Markus Grassl (3) and
Daniel A. Lidar (4) ((1) Racah Institute of Physics, The Hebrew University,
Israel, (2) Computer Science Department, Technion, Israel, (3) Institut fur
Algorithmen und Kognitive Systeme, Universitat Karlsruhe, Germany, (4)
Department of Chemistry, University of California, Berkeley, USA) | Generalized Grover Search Algorithm for Arbitrary Initial Amplitude
Distribution | 8 pages, llncs style. To be published in the proceedings of the 1st
NASA International Conference on Quantum Computing and Quantum Communications | "Quantum Computing & Quantum Communications; First NASA
International Conference; selected papers, QCQC'98", C.P. Williams (ed.),
Lecture Notes in Computer Science vol. 1509, pp. 140-147 (Springer, 1998). | null | null | quant-ph | null | Grover's algorithm for quantum searching of a database is generalized to deal
with arbitrary initial amplitude distributions. First order linear difference
equations are found for the time evolution of the amplitudes of the r marked
and N-r unmarked states. These equations are solved exactly. An expression for
the optimal measurement time T \sim O(\sqrt{N/r}) is derived which is shown to
depend only on the initial average amplitudes of the marked and unmarked
states. A bound on the probability of measuring a marked state is derived,
which depends only on the standard deviation of the initial amplitude
distributions of the marked or unmarked states.
| [
{
"version": "v1",
"created": "Wed, 28 Jan 1998 19:22:47 GMT"
},
{
"version": "v2",
"created": "Mon, 11 May 1998 22:41:00 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Biron",
"David",
""
],
[
"Biham",
"Ofer",
""
],
[
"Biham",
"Eli",
""
],
[
"Grassl",
"Markus",
""
],
[
"Lidar",
"Daniel A.",
""
]
] |
quant-ph/9801067 | Matteo G. A. Paris | A. V. Chizhov, V. De Renzi and M. G. A. Paris | A two-step optimized measurement for the phase-shift | Latex 5 figs -- More info at http://enterprise.pv.infn.it/~paris | Phys.Lett. A237 (1998) 201 | 10.1016/S0375-9601(97)00852-9 | null | quant-ph | null | A two-step detection strategy is suggested for the precise measurement of the
optical phase-shift. In the first step an unsharp, however, unbiased joint
measurement of the phase and photon number is performed by heterodyning the
signal field. Information coming from this step is then used for suitable
squeezing of the probe mode to obtain a sharp phase distribution. Application
to squeezed states leads to a phase sensitivity scaling as $\Delta\phi\simeq
N^{-1}$ relative to the total number of photons impinged into the apparatus.
Numerical simulations of the whole detection strategy are also also presented.
| [
{
"version": "v1",
"created": "Thu, 29 Jan 1998 13:45:36 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Chizhov",
"A. V.",
""
],
[
"De Renzi",
"V.",
""
],
[
"Paris",
"M. G. A.",
""
]
] |
quant-ph/9801068 | Matteo G. A. Paris | Matteo G. A. Paris (Quantum Optics Group -- University of Pavia) | Quantum Binary Decision for Driven Harmonic Oscillator | Latex 5 figs -- More info at http://enterprise.pv.infn.it/~paris | Int.J.Mod.Phys. B11 (1997) 3419-3432 | 10.1142/S0217979297001684 | null | quant-ph | null | We address the problem of determining whether or not a harmonic oscillator
has been perturbed by an external force. Quantum detection and estimation
theory has been used in devising optimum measurement schemes. Detection
probability has been evaluated for different initial state preparations of
oscillator. The corresponding lower bounds on minimum detectable perturbation
intensity has been evaluated and a general bound for random phase perturbation
has been also induced.
| [
{
"version": "v1",
"created": "Thu, 29 Jan 1998 13:50:44 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Paris",
"Matteo G. A.",
"",
"Quantum Optics Group -- University of Pavia"
]
] |
quant-ph/9801069 | Michal Horodecki | Michal Horodecki, Pawel Horodecki and Ryszard Horodecki | Mixed-state entanglement and distillation: is there a ``bound''
entanglement in nature? | RevTeX, 4 pages | Phys.Rev.Lett. 80 (1998) 5239-5242 | 10.1103/PhysRevLett.80.5239 | null | quant-ph | null | It is shown that if a mixed state can be distilled to the singlet form, it
must violate partial transposition criterion [A. Peres, Phys. Rev. Lett. 76,
1413 (1996)]. It implies that there are two qualitatively different types of
entanglement: ``free'' entanglement which is distillable, and ``bound''
entanglement which cannot be brought to the singlet form useful for quantum
communication purposes. Possible physical meaning of the result is discussed.
| [
{
"version": "v1",
"created": "Thu, 29 Jan 1998 21:50:24 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Horodecki",
"Michal",
""
],
[
"Horodecki",
"Pawel",
""
],
[
"Horodecki",
"Ryszard",
""
]
] |
quant-ph/9801070 | Karin Muench-Berndl | D. Duerr, S. Goldstein, K. Muench-Berndl, N. Zanghi | Hypersurface Bohm-Dirac models | 17 pages, 3 figures, RevTex. Completely revised version | Phys.Rev. A60 (1999) 2729-2736 | 10.1103/PhysRevA.60.2729 | null | quant-ph | null | We define a class of Lorentz invariant Bohmian quantum models for N entangled
but noninteracting Dirac particles. Lorentz invariance is achieved for these
models through the incorporation of an additional dynamical space-time
structure provided by a foliation of space-time. These models can be regarded
as the extension of Bohm's model for N Dirac particles, corresponding to the
foliation into the equal-time hyperplanes for a distinguished Lorentz frame, to
more general foliations. As with Bohm's model, there exists for these models an
equivariant measure on the leaves of the foliation. This makes possible a
simple statistical analysis of position correlations analogous to the
equilibrium analysis for (the nonrelativistic) Bohmian mechanics.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 09:28:30 GMT"
},
{
"version": "v2",
"created": "Fri, 28 May 1999 14:27:49 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Duerr",
"D.",
""
],
[
"Goldstein",
"S.",
""
],
[
"Muench-Berndl",
"K.",
""
],
[
"Zanghi",
"N.",
""
]
] |
quant-ph/9801071 | Marc Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique The'orique de l'Ecole
Normale Supe'rieure), Astrid Lambrecht and Serge Reynaud (Laboratoire
Kastler-Brossel) | Relativity of Motion in Vacuum | 6 pages, Contribution for "Vacuum", eds E. Gunzig and S. Diner | null | null | LPTENS 97/61A | quant-ph gr-qc | null | The existence of vacuum fluctuations leads to reconsider the question of
relativity of motion. The present article is devoted to this aim with a main
line which can be formulated as follows: ``The principle of relativity of
motion is directly related to symmetries of quantum vacuum''. Keeping close to
this statement, we discuss the controversial relation between vacuum and
motion. We introduce the question of relativity of motion in its historical
development before coming to the results obtained more recently.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 10:17:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Jaekel",
"Marc-Thierry",
"",
"Laboratoire de Physique The'orique de l'Ecole\n Normale Supe'rieure"
],
[
"Lambrecht",
"Astrid",
"",
"Laboratoire\n Kastler-Brossel"
],
[
"Reynaud",
"Serge",
"",
"Laboratoire\n Kastler-Brossel"
]
] |
quant-ph/9801072 | Marc Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique The'orique de l'Ecole
Normale Supe'rieure) and Serge Reynaud (Laboratoire Kastler-Brossel) | Quantum Langevin Equations and Stability | 12 pages | J.Phys.I(France) 3 (1993) 339-352 | 10.1051/jp1:1993135 | LPTENS 92/12 | quant-ph | null | Different quantum Langevin equations obtained by coupling a particle to a
field are examined. Instabilities or violations of causality affect the motion
of a point charge linearly coupled to the electromagnetic field. In contrast,
coupling a scatterer with a reflection cut-off to radiation pressure leads to
stable and causal motions. The radiative reaction force exerted on a scatterer,
and hence its quasistatic mass, depend on the field state. Explicit expressions
for a particle scattering a thermal field in a two dimensional space-time are
given.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 10:18:33 GMT"
}
] | 2023-04-14T00:00:00 | [
[
"Jaekel",
"Marc-Thierry",
"",
"Laboratoire de Physique The'orique de l'Ecole\n Normale Supe'rieure"
],
[
"Reynaud",
"Serge",
"",
"Laboratoire Kastler-Brossel"
]
] |
quant-ph/9801073 | Marc Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique The'orique de l'Ecole
Normale Supe'rieure) and Serge Reynaud (Laboratoire Kastler-Brossel) | Quantum Fluctuations of Mass for a Mirror in Vacuum | 6 pages | Phys.Lett. A180 (1993) 9-14 | 10.1016/0375-9601(93)90486-J | LPTENS 93/21 | quant-ph | null | A mirror in vacuum is coupled to fluctuating quantum fields. As a result, its
energy-momentum and mass fluctuate. We compute the correlation spectra of force
and mass fluctuations for a mirror at rest in vacuum (of a scalar field in a
two-dimensional space-time). The obtained expressions agree with a mass
correction equal to a vacuum energy stored by the mirror. We introduce a
Lagrangian model which consistently describes a scalar field coupled to a
scatterer, with inertial mass being a quantum variable.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 10:19:42 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/9801074 | Marc Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique The'orique de l'Ecole
Normale Supe'rieure) and Serge Reynaud (Laboratoire Kastler-Brossel) | Gravitational Quantum Limit for Length Measurements | 6 pages | Phys.Lett. A185 (1994) 143-148 | 10.1016/0375-9601(94)90838-9 | LPTENS 93/44 | quant-ph gr-qc | null | We discuss a limit for sensitivity of length measurements which is due to the
effect of vacuum fluctuations of gravitational field. This limit is associated
with irreducible quantum fluctuations of geodesic distances and it is
characterized by a noise spectrum with an order of magnitude mainly determined
by Planck length. The gravitational vacuum fluctuations may (in an analysis
restricted to questions of principle and when the measurement strategy is
optimized) dominate fluctuations added by the measurement apparatus if
macroscopic masses, i.e. masses larger than Planck mass, are used.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 10:20:17 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/9801075 | Mayburov S. N. | S.Mayburov | Quantum Reference Frames and Relativistic Time Operator | 14 pages, Latex, Talk given at 'Uncertain Reality' Simposium, New
Delhi, January 1998. To appear in Proceedings. Version 2 - 04.02.98 : Some
Comments are added. Equation (21) corrected | null | null | null | quant-ph gr-qc | null | Aharonov-Kaufherr model of quantum space-time which accounts Reference Frames
(RF) quantum effects is considered in Relativistic Quantum Mechanics framework.
For RF connected with some macroscopic object its free quantum motion - wave
packet smearing results in additional uncertainty of test particle coordinate.
Due to the same effects the use of Galilean or Lorentz transformations for this
RFs becomes incorrect and the special quantum space-time transformations are
introduced.
In particular for any RF the proper time becomes the operator in other RF.
This time operator calculated solving relativistic Heisenberg equations for
some quantum clocks models.
Generalized Klein- Gordon equation proposed which depends on both the
particle and RF masses.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 14:32:23 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Feb 1998 13:41:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mayburov",
"S.",
""
]
] |
quant-ph/9801076 | S. Popescu | N. Linden, S. Popescu, A. Sudbery | Non-local properties of multi-particle density matrices | 13 pages RevTeX | Phys.Rev.Lett.83:243-247,1999 | 10.1103/PhysRevLett.83.243 | null | quant-ph | null | As far as entanglement is concerned, two density matrices of $n$ particles
are equivalent if they are on the same orbit of the group of local unitary
transformations, $U(d_1)\times...\times U(d_n)$ (where the Hilbert space of
particle $r$ has dimension $d_r$). We show that for $n$ greater than or equal
to two, the number of independent parameters needed to specify an $n$-particle
density matrix up to equivalence is $\Pi_r d_r^2 - \sum_r d_r^2 + n - 1$. For
$n$ spin-${1\over 2}$ particles we also show how to characterise generic
orbits, both by giving an explicit parametrisation of the orbits and by finding
a finite set of polynomial invariants which separate the orbits.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 15:03:49 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Linden",
"N.",
""
],
[
"Popescu",
"S.",
""
],
[
"Sudbery",
"A.",
""
]
] |
quant-ph/9801077 | Marek Ozana | M.Ozana, A.L.Shelankov | Squeezed States of a Particle in Magnetic Field | RevTex, 12 pages, 4 Postscript figures, submitted to Physics of the
Solid State; added references | Solid State Phys. 40 (1998) 1276 | 10.1134/1.1130543 | null | quant-ph | null | For a charged particle in a homogeneous magnetic field, we construct
stationary squeezed states which are eigenfunctions of the Hamiltonian and the
non-Hermitian operator $\hat{X}_{\Phi} = \hat{X} \cos \Phi + \hat{Y} \sin
\Phi$, $\hat{X}$ and $\hat{Y}$ being the coordinates of the Larmor circle
center and $\Phi$ is a complex parameter. In the family of the squeezed states,
the quantum uncertainty in the Larmor circle position is minimal. The wave
functions of the squeezed states in the coordinate representation are found and
their properties are discussed. Also, for arbitrary gauge of the vector
potential we derive the symmetry operators of translations and rotations.
| [
{
"version": "v1",
"created": "Fri, 30 Jan 1998 20:06:12 GMT"
},
{
"version": "v2",
"created": "Sat, 7 Feb 1998 18:27:47 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Ozana",
"M.",
""
],
[
"Shelankov",
"A. L.",
""
]
] |
quant-ph/9802001 | Waldemar Puszkarz | Waldemar Puszkarz | Energy Ambiguity in Nonlinear Quantum Mechanics | Slightly extended, new references added, Latex, 15 pages | null | null | null | quant-ph | null | We observe that in nonlinear quantum mechanics, unlike in the linear theory,
there exists, in general, a difference between the energy functional defined
within the Lagrangian formulation as an appropriate conserved component of the
canonical energy-momentum tensor and the energy functional defined as the
expectation value of the corresponding nonlinear Hamiltonian operator. Some
examples of such ambiguity are presented for a particularly simple model and
some known modifications. However, we point out that there exist a class of
nonlinear modifications of the Schr\"{o}dinger equation where this difference
does not occur, which makes them more consistent in a manner similar to that of
the linear Schr\"{o}dinger equation. It is found that necessary but not
sufficient a condition for such modifications is the homogeneity of the
modified Schr\"{o}dinger equation or its underlying Lagrangian density which is
assumed to be ``bilinear'' in the wave function in some rather general sense.
Yet, it is only for a particular form of this density that the ambiguity in
question does not arise. A salient feature of this form is the presence of
phase functionals. The present paper thus introduces a new class of
modifications characterized by this desirable and rare property.
| [
{
"version": "v1",
"created": "Tue, 3 Feb 1998 00:36:10 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Feb 1998 12:03:23 GMT"
},
{
"version": "v3",
"created": "Mon, 9 Feb 1998 04:09:47 GMT"
},
{
"version": "v4",
"created": "Wed, 3 Mar 1999 03:22:40 GMT"
},
{
"version": "v5",
"created": "Fri, 12 Mar 1999 11:14:48 GMT"
},
{
"version": "v6",
"created": "Mon, 17 May 1999 05:40:37 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Puszkarz",
"Waldemar",
""
]
] |
quant-ph/9802002 | Yurij N. Morokov | Yu. N. Morokov | Long beating wavelength in the Schwarz-Hora effect | 3 pages, RevTex | Phys.Rev.A56:5162,1997 | 10.1103/PhysRevA.56.5162 | null | quant-ph | null | Thirty years ago, H.Schwarz has attempted to modulate an electron beam with
optical frequency. When a 50-keV electron beam crossed a thin crystalline
dielectric film illuminated with laser light, electrons produced the
electron-diffraction pattern not only at a fluorescent target but also at a
nonfluorescent target. In the latter case the pattern was of the same color as
the laser light (the Schwarz-Hora effect). This effect was discussed
extensively in the early 1970s. However, since 1972 no reports on the results
of further attempts to repeat those experiments in other groups have appeared,
while the failures of the initial such attempts have been explained by Schwarz.
The analysis of the literature shows there are several unresolved up to now
contradictions between the theory and the Schwarz experiments. In this work we
consider the interpretation of the long-wavelength spatial beating of the
Schwarz-Hora radiation. A more accurate expression for the spatial period has
been obtained, taking into account the mode structure of the laser field within
the dielectric film. It is shown that the discrepancy of more than 10% between
the experimental and theoretical results for the spatial period cannot be
reduced by using the existing quantum models that consider a collimated
electron beam.
| [
{
"version": "v1",
"created": "Sun, 1 Feb 1998 07:23:23 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Morokov",
"Yu. N.",
""
]
] |
quant-ph/9802003 | Piotr Garbaczewski | P. Garbaczewski | Schroedinger's interpolation problem and its probabilistic solutions | Tex file, J. Tch. Phys. 38, 205-209, (1997) | J.Tech.Phys. 38 (1997) 205-209 | null | null | quant-ph cond-mat | null | Probablistic solutions of the so called Schr\"{o}dinger boundary data problem
provide for a unique Markovian interpolation between any two strictly positive
probability densities designed to form the input-output statistics data for a
certain dynamical process taking place in a finite-time interval. The key
problem is to select the jointly continuous in all variables positive semigroup
kernel, appropriate for the phenomenological (physical) situation.
| [
{
"version": "v1",
"created": "Mon, 2 Feb 1998 10:52:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Garbaczewski",
"P.",
""
]
] |
quant-ph/9802004 | Piotr Garbaczewski | P. Garbaczewski | Schroedinger's interpolation problem through Feynman-Kac kernels | Latex file, Acta Phys. Polon. B 27, 617-642, (1996) | Acta Phys.Polon. B27 (1996) 617-642 | null | null | quant-ph | null | We discuss the so-called Schr{\"o}dinger problem of deducing the microscopic
(basically stochastic) evolution that is consistent with given positive
boundary probability densities for a process covering a finite fixed time
interval. The sought for dynamics may preserve the probability measure or
induce its evolution, and is known to be uniquely reproducible, if the Markov
property is required. Feynman-Kac type kernels are the principal ingredients of
the solution and determine the transition probability density of the
corresponding stochastic process. The result applies to a large variety of
nonequilibrium statistical physics and quantum situations.
| [
{
"version": "v1",
"created": "Mon, 2 Feb 1998 10:52:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Garbaczewski",
"P.",
""
]
] |
quant-ph/9802005 | Piotr Garbaczewski | Ph. Blanchard, P. Garbaczewski | Natural boundaries for the Smoluchowski equation and affiliated
diffusion processes | Latex file, Phys. Rev. E 49, 3815-3824, (1994) | Phys.Rev.E49:3815-3824,1994 | 10.1103/PhysRevE.49.3815 | null | quant-ph cond-mat | null | The Schr\"{o}dinger problem of deducing the microscopic dynamics from the
input-output statistics data is known to admit a solution in terms of Markov
diffusions. The uniqueness of solution is found linked to the natural
boundaries respected by the underlying random motion. By choosing a reference
Smoluchowski diffusion process, we automatically fix the Feynman-Kac potential
and the field of local accelerations it induces. We generate the family of
affiliated diffusions with the same local dynamics, but different inaccessible
boundaries on finite, semi-infinite and infinite domains. For each diffusion
process a unique Feynman-Kac kernel is obtained by the constrained (Dirichlet
boundary data) Wiener path integration.As a by-product of the discussion, we
give an overview of the problem of inaccessible boundaries for the diffusion
and bring together (sometimes viewed from unexpected angles) results which are
little known, and dispersed in publications from scarcely communicating areas
of mathematics and physics.
| [
{
"version": "v1",
"created": "Mon, 2 Feb 1998 11:36:34 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Blanchard",
"Ph.",
""
],
[
"Garbaczewski",
"P.",
""
]
] |
quant-ph/9802006 | Paul Busch | P. Busch | Remarks on unsharp quantum observables, objectification, and modal
interpretations | 12 pages, LaTeX, Contribution to the Workshop "The Modal
Interpretation of Quantum Mechanics", Utrecht, 1996 | "The Modal Interpretation of Quantum Mechanics", eds. D.Dieks,
P.E. Vermaas, Kluwer, Dordrecht, 1998, pp. 279-288. | null | null | quant-ph | null | This paper addresses the question whether a variant of a modal interpretation
is conceivable that could accommodate property ascriptions associated with
nonorthogonal resolutions of the unity and nonorthogonal families of relative
states as they occur in imperfect or genuinely unsharp measurements. I will
review a recent formulation of the quantum measurement problem in the form of
an insolubility theorem that incorporates the case of unsharp object
observables as well as certain types of unsharp pointers. In addition to
demonstrating the necessity for some modification of quantum mechanics, this
allows me to specify the logical position of the modal interpretations as a
resolution to the measurement problem and to indicate why I think their current
versions are not yet capable of dealing adequately with unsharp quantum
observables. The technical tools that will have been explained along this line
of reasoning will finally serve to make precise the notion of (unsharp) value
ascription that I would find desirable for a modal interpretation to ascertain.
| [
{
"version": "v1",
"created": "Mon, 2 Feb 1998 16:32:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Busch",
"P.",
""
]
] |
quant-ph/9802007 | Daniel Gottesman | Daniel Gottesman | Fault-Tolerant Quantum Computation with Higher-Dimensional Systems | 12 pages, LaTeX w/ llncs style, to be presented at the 1st NASA
International Conference on Quantum Computing and Quantum Communications | Chaos Solitons Fractals 10:1749-1758,1999 | 10.1016/S0960-0779(98)00218-5 | LA-UR 98-270 | quant-ph | null | Instead of a quantum computer where the fundamental units are 2-dimensional
qubits, we can consider a quantum computer made up of d-dimensional systems.
There is a straightforward generalization of the class of stabilizer codes to
d-dimensional systems, and I will discuss the theory of fault-tolerant
computation using such codes. I prove that universal fault-tolerant computation
is possible with any higher-dimensional stabilizer code for prime d.
| [
{
"version": "v1",
"created": "Mon, 2 Feb 1998 23:02:38 GMT"
}
] | 2010-05-27T00:00:00 | [
[
"Gottesman",
"Daniel",
""
]
] |
quant-ph/9802008 | Taksu Cheon de Caracorum | Takaomi Shigehara (Saitama U), Hiroshi Mizoguchi (Saitama U),
Taketoshi Mishima (Saitama U), Taksu Cheon (Kochi Tech) | Chaos Induced by Quantization | ReVTeX 7pg with inlet figures | IEICE Trans.Fund.Elec.Comm.Comp.Sci. E81-A (1998) 1762-1768 | null | null | quant-ph chao-dyn cond-mat nlin.CD | null | In this paper, we show that two-dimensional billiards with point interactions
inside exhibit a chaotic nature in the microscopic world, although their
classical counterpart is non-chaotic. After deriving the transition matrix of
the system by using the self-adjoint extension theory of functional analysis,
we deduce the general condition for the appearance of chaos. The prediction is
confirmed by numerically examining the statistical properties of energy
spectrum of rectangular billiards with multiple point interactions inside. The
dependence of the level statistics on the strength as well as the number of the
scatterers is displayed.
KEYWORDS: wave chaos, quantum mechanics, pseudointegrable billiard, point
interaction, functional analysis
| [
{
"version": "v1",
"created": "Tue, 3 Feb 1998 06:45:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Shigehara",
"Takaomi",
"",
"Saitama U"
],
[
"Mizoguchi",
"Hiroshi",
"",
"Saitama U"
],
[
"Mishima",
"Taketoshi",
"",
"Saitama U"
],
[
"Cheon",
"Taksu",
"",
"Kochi Tech"
]
] |
quant-ph/9802009 | Chau Hoi Fung | H. F. Chau | Quantum Convolutional Error Correction Codes | To be reported in the 1st NASA Conf. on Quantum Comp., uses
llncs.sty, 12 pages | null | null | HKUPHYS-HFC-013 | quant-ph | null | I report two general methods to construct quantum convolutional codes for
quantum registers with internal $N$ states. Using one of these methods, I
construct a quantum convolutional code of rate 1/4 which is able to correct one
general quantum error for every eight consecutive quantum registers.
| [
{
"version": "v1",
"created": "Tue, 3 Feb 1998 10:11:06 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Chau",
"H. F.",
""
]
] |
quant-ph/9802010 | Fabian Wagner | Michael L.G. Redhead, Fabian Wagner | Unified Treatment of EPR and Bell Arguments in Algebraic Quantum Field
Theory | 12 Pages, LaTex, to appear in Found.Phys.Letters | Found.Phys.Lett. 11 (1998) 111-125 | null | DAMTP-98-8 | quant-ph | null | A conjecture concerning vacuum correlations in axiomatic quantum field theory
is proved. It is shown that this result can be applied both in the context of
EPR-type experiments and Bell-type experiments.
| [
{
"version": "v1",
"created": "Tue, 3 Feb 1998 11:08:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Redhead",
"Michael L. G.",
""
],
[
"Wagner",
"Fabian",
""
]
] |
quant-ph/9802011 | Paul Busch | P. Busch | Can `unsharp objectification' solve the quantum measurement problem? | 8 pages, LaTeX, Contribution to the Quantum Structures Conference,
Berlin, 1996 | Int.J.Theor.Phys. 37 (1998) 241-247 | null | null | quant-ph | null | The quantum measurement problem is formulated in the form of an insolubility
theorem that states the impossibility of obtaining, for all available object
preparations, a mixture of states of the compound object and apparatus system
that would represent definite pointer positions. A proof is given that
comprises arbitrary object observables, whether sharp or unsharp, and besides
sharp pointer observables a certain class of unsharp pointers, namely, those
allowing for the property of pointer value definiteness. A recent result of H.
Stein is applied to allow for the possibility that a given measurement may not
be applicable to all possible object states but only to a subset of them. The
question is raised whether the statement of the insolubility theorem remains
true for genuinely unsharp observables. This gives rise to a precise notion of
unsharp objectification.
| [
{
"version": "v1",
"created": "Tue, 3 Feb 1998 12:07:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Busch",
"P.",
""
]
] |
quant-ph/9802012 | Papp Zoltan | G. L\'evai, B. K\'onya and Z. Papp | Unified treatment of the Coulomb and harmonic oscillator potentials in
$D$ dimensions | 18 pages, 3 ps figures, revtex | J.Math.Phys. 39 (1998) 5811-5823 | 10.1063/1.532595 | null | quant-ph | null | Quantum mechanical models and practical calculations often rely on some
exactly solvable models like the Coulomb and the harmonic oscillator
potentials. The $D$ dimensional generalized Coulomb potential contains these
potentials as limiting cases, thus it establishes a continuous link between the
Coulomb and harmonic oscillator potentials in various dimensions. We present
results which are necessary for the utilization of this potential as a model
and practical reference problem for quantum mechanical calculations. We define
a Hilbert space basis, the generalized Coulomb-Sturmian basis, and calculate
the Green's operator on this basis and also present an SU(1,1) algebra
associated with it. We formulate the problem for the one-dimensional case too,
and point out that the complications arising due to the singularity of the
one-dimensional Coulomb problem can be avoided with the use of the generalized
Coulomb potential.
| [
{
"version": "v1",
"created": "Tue, 3 Feb 1998 13:45:35 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Lévai",
"G.",
""
],
[
"Kónya",
"B.",
""
],
[
"Papp",
"Z.",
""
]
] |
quant-ph/9802013 | Gennady Berman | Gennady P. Berman, Gary D. Doolen, Gustavo V. L\'opez, V.I.
Tsifrinovich | Generalized Quantum Control-Not Gate in Two-Spin Ising System | 8 pages, 4 figures | null | null | null | quant-ph | null | The physical implementation of the quantum Control-Not gate for a two-spin
system is investigated numerically. The concept of a generalized quantum
Control-Not gate, with arbitrary phase shift, is introduced. It is shown that a
resonant $\pi$-pulse provides a simple example of a generalized quantum
Control-Not gate.
| [
{
"version": "v1",
"created": "Tue, 3 Feb 1998 22:10:51 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Berman",
"Gennady P.",
""
],
[
"Doolen",
"Gary D.",
""
],
[
"López",
"Gustavo V.",
""
],
[
"Tsifrinovich",
"V. I.",
""
]
] |
quant-ph/9802014 | S. E. Massen | S.E. Massen and C.P. Panos | Universal property of the information entropy in atoms, nuclei and
atomic clusters | 3 pages, REVTEX, one figure | Phys.Lett. A246 (1998) 530-533 | 10.1016/S0375-9601(98)00524-6 | THES-TP 98/01 | quant-ph | null | The position- and momentum-space information entropies of the electron
distributions of atomic clusters are calculated using a Woods-Saxon single
particle potential. The same entropies are also calculated for nuclear
distributions according to the Skyrme parametrization of the nuclear mean
field. It turns out that a similar functional form S=a+b ln N for the entropy
as function of the number of particles N holds approximately for atoms, nuclei
and atomic clusters. It is conjectured that this is a universal property of a
many-fermion system in a mean field. It is also seen that there is an analogy
of our expression for S to Boltzmann's thermodynamic entropy S=k ln W.
| [
{
"version": "v1",
"created": "Wed, 4 Feb 1998 13:01:37 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Massen",
"S. E.",
""
],
[
"Panos",
"C. P.",
""
]
] |
quant-ph/9802015 | Gennady Berman | Gennady P. Berman, Gary D. Doolen, Gustavo V. Lopez, and Vladimir I.
Tsifrinovich | Quantum Entangled States and Quasiclassical Dynamics in Macroscopic Spin
Systems | 6 pages 2 figures | null | null | null | quant-ph | null | When dealing with macroscopic objects one usually observes quasiclassical
phenomena, which can be described in terms of quasiclassical (or classical)
equations of motion. Recent development of the theory of quantum computation is
based on implementation of the entangled states which do not have a classical
analogy. Using a simple example of a paramagnetic spin system we show that the
entangled states can be detected in standard macroscopic experiments as a sharp
deviation from quasiclassical motion.
| [
{
"version": "v1",
"created": "Thu, 5 Feb 1998 04:09:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Berman",
"Gennady P.",
""
],
[
"Doolen",
"Gary D.",
""
],
[
"Lopez",
"Gustavo V.",
""
],
[
"Tsifrinovich",
"Vladimir I.",
""
]
] |
quant-ph/9802016 | Gennady Berman | Gennady P. Berman, Gary D. Doolen, Gustavo V. Lopez, and Vladimir I.
Tsifrinovich | Dynamics of a Quantum Control-Not Gate for an Ensemble of Four-Spin
Molecules at Room Temperature | 7 pages 3 figures | null | 10.1103/PhysRevB.58.11570 | null | quant-ph | null | We investigate numerically a single-pulse implementation of a quantum
Control-Not (CN) gate for an ensemble of Ising spin systems at room
temperature. For an ensemble of four-spin ``molecules'' we simulate the
time-evolution of the density matrix, for both digital and superpositional
initial conditions. Our numerical calculations confirm the feasibility of
implementation of quantum CN gate in this system at finite temperature, using
electromagnetic $\pi$-pulse.
| [
{
"version": "v1",
"created": "Thu, 5 Feb 1998 04:53:49 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Berman",
"Gennady P.",
""
],
[
"Doolen",
"Gary D.",
""
],
[
"Lopez",
"Gustavo V.",
""
],
[
"Tsifrinovich",
"Vladimir I.",
""
]
] |
quant-ph/9802017 | Ramin Golestanian | Ramin Golestanian, and Mehran Kardar | Path Integral Approach to the Dynamic Casimir Effect with Fluctuating
Boundaries | RevTeX with 1 ps figure using epsf | Phys.Rev.A58:1713-1722,1998 | 10.1103/PhysRevA.58.1713 | null | quant-ph cond-mat | null | A path integral formulation is developed for the dynamic Casimir effect. It
allows us to study arbitrary deformations in space and time of the perfectly
reflecting (conducting) boundaries of a cavity. The mechanical response of the
intervening vacuum is calculated to linear order in the frequency-wavevector
plane, using which a plethora of interesting phenomena can be studied. For a
single corrugated plate we find a correction to mass at low frequencies, and an
effective shear viscosity at high frequencies that are both anisotropic. The
anisotropy is set by the wavevector of the corrugation. For two plates, the
mass renormalization is modified by a function of the ratio between the
separation of the plates and the wave-length of corrugations. The dissipation
rate is not modified for frequencies below the lowest optical mode of the
cavity, and there is a resonant dissipation for all frequencies greater than
that. In this regime, a divergence in the response function implies that such
high frequency deformation modes of the cavity can not be excited by any
macroscopic external forces. This phenomenon is intimately related to resonant
particle creation. For particular examples of two corrugated plates that are
stationary, or moving uniformly in the lateral directions, Josephson-like
effects are observed. For capillary waves on the surface of mercury a
renormalization to surface tension, and sound velocity is obtained.
| [
{
"version": "v1",
"created": "Thu, 5 Feb 1998 18:31:14 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Dec 1998 23:17:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Golestanian",
"Ramin",
""
],
[
"Kardar",
"Mehran",
""
]
] |
quant-ph/9802018 | Emanuel Knill | D. G. Cory, W. Mass, M. Price, E. Knill, R. Laflamme, W. H. Zurek, T.
F. Havel, S. S. Somaroo | Experimental Quantum Error Correction | 5 pages, three figures | Phys.Rev.Lett. 81 (1998) 2152-2155 | 10.1103/PhysRevLett.81.2152 | null | quant-ph | null | Quantum error correction is required to compensate for the fragility of the
state of a quantum computer. We report the first experimental implementations
of quantum error correction and confirm the expected state stabilization. In
NMR computing, however, a net improvement in the signal-to-noise would require
very high polarization. The experiment implemented the 3-bit code for phase
errors in liquid state state NMR.
| [
{
"version": "v1",
"created": "Fri, 6 Feb 1998 01:00:26 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Cory",
"D. G.",
""
],
[
"Mass",
"W.",
""
],
[
"Price",
"M.",
""
],
[
"Knill",
"E.",
""
],
[
"Laflamme",
"R.",
""
],
[
"Zurek",
"W. H.",
""
],
[
"Havel",
"T. F.",
""
],
[
"Somaroo",
"S. S.",
""
]
] |
quant-ph/9802019 | Paul Slater | Paul B. Slater (University of California) | Volume Elements of Monotone Metrics on the n x n Density Matrices as
Densities-of-States for Thermodynamic Purposes. II | 15 pages, LaTeX, 7 postscript figures. We retitle and slightly modify
the paper. For Part I (the case of partially entangled spin-1/2 particles),
see quant-ph/9711010 | null | null | null | quant-ph cond-mat | null | We derive explicit expressions for the volume elements of both the minimal
and maximal monotone metrics over the (n^{2} - 1)-dimensional convex set of n x
n density matrices for the cases n = 3 and 4. We make further progress for the
specific n = 3 maximal-monotone case, by taking the limit of a certain ratio of
integration results, obtained using an orthogonal set of eight coordinates. By
doing so, we find remarkably simple marginal probability distributions based on
the corresponding volume element, which we then use for thermodynamic purposes.
We, thus, find a spin-1 analogue of the Langevin function. In the fully general
n = 4 situation, however, we are impeded in making similar progress by the
inability to diagonalize a 3 x 3 Hermitian matrix and thereby obtain an
orthogonal set of coordinates to use in the requisite integrations.
| [
{
"version": "v1",
"created": "Fri, 6 Feb 1998 20:19:47 GMT"
},
{
"version": "v10",
"created": "Wed, 5 Aug 1998 21:06:00 GMT"
},
{
"version": "v11",
"created": "Wed, 2 Sep 1998 18:17:22 GMT"
},
{
"version": "v12",
"created": "Thu, 3 Sep 1998 16:06:59 GMT"
},
{
"version": "v13",
"created": "Mon, 7 Dec 1998 21:44:40 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Feb 1998 17:41:30 GMT"
},
{
"version": "v3",
"created": "Tue, 10 Mar 1998 17:53:34 GMT"
},
{
"version": "v4",
"created": "Thu, 26 Mar 1998 22:06:30 GMT"
},
{
"version": "v5",
"created": "Fri, 27 Mar 1998 23:48:04 GMT"
},
{
"version": "v6",
"created": "Mon, 11 May 1998 16:25:17 GMT"
},
{
"version": "v7",
"created": "Thu, 21 May 1998 22:15:02 GMT"
},
{
"version": "v8",
"created": "Fri, 26 Jun 1998 23:19:04 GMT"
},
{
"version": "v9",
"created": "Thu, 2 Jul 1998 15:50:34 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Slater",
"Paul B.",
"",
"University of California"
]
] |
quant-ph/9802020 | Carlo Rovelli | Carlo Rovelli | ``Incerto tempore, incertisque loci'': Can we compute the exact time at
which a quantum measurement happens? | 6 pages, revtex | Found.Phys. 28 (1998) 1031-1043 | null | null | quant-ph gr-qc | null | Without addressing the measurement problem (i.e. what causes the wave
function to ``collapse'', or to ``branch'', or a history to become realized, or
a property to actualize), I discuss the problem of the timing of the quantum
measurement: assuming that in an appropriate sense a measurement happens, when
precisely does it happen? This question can be posed within most
interpretations of quantum mechanics. By introducing the operator M, which
measures whether or not the quantum measurement has happened, I suggest that,
contrary to what is often claimed, quantum mechanics does provide a precise
answer to this question, although a somewhat surprising one.
| [
{
"version": "v1",
"created": "Sat, 7 Feb 1998 20:23:06 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Feb 1998 14:42:35 GMT"
},
{
"version": "v3",
"created": "Fri, 13 Mar 1998 20:59:46 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rovelli",
"Carlo",
""
]
] |
quant-ph/9802021 | Asher Peres | Asher Peres | Comparing the strengths of various Bell inequalities | This paper has been withdrawn | null | null | null | quant-ph | null | This paper has been withdrawn because it is superseded by quant-ph/9905084
"Bayesian analysis of Bell inequalities.
| [
{
"version": "v1",
"created": "Mon, 9 Feb 1998 08:09:08 GMT"
},
{
"version": "v2",
"created": "Fri, 11 Jun 1999 07:58:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Peres",
"Asher",
""
]
] |
quant-ph/9802022 | Masanao Ozawa | Masanao Ozawa (Nagoya University) | On the Concept of Quantum State Reduction: Inconsistency of the Orthodox
View | 15 pages, LaTeX, 1 Postscript figure | Annals of the Japan Association for Philosophy of Science 11 (2),
107-121 (2003) | 10.4288/jafpos1956.11.107 | null | quant-ph | null | The argument is re-examined that the program of deriving the rule of state
reduction from the Schroedinger equation holding for the object-apparatus
composite system falls into a vicious circle or an infinite regress called the
von Neumann chain. It is shown that this argument suffers from a serious
physical inconsistency concerning the causality between the reading of the
outcome and the state reduction. A consistent argument which accomplishes the
above program without falling into the circular argument is presented.
| [
{
"version": "v1",
"created": "Mon, 9 Feb 1998 10:05:54 GMT"
}
] | 2020-06-26T00:00:00 | [
[
"Ozawa",
"Masanao",
"",
"Nagoya University"
]
] |
quant-ph/9802023 | M. Dakna | M. Dakna, G. Breitenbach, J. Mlynek, T. Opatrny, S. Schiller and D.-G.
Welsch | Homodyne measurement of exponential phase moments for quantum-phase
reconstruction | 1 Table and 4 Postscript figures, using Latex | null | null | null | quant-ph | null | We directly sample the exponential moments of the canonical phase for various
quantum states from the homodyne output. The method enables us to study the
phase properties experimentally, without making the detour via reconstructing
the density matrix or the Wigner function and calculating the phase statistics
from them. In particular, combing the measurement with a measurement of the
photon-number variance, we verify fundamental number-phase uncertainty.
| [
{
"version": "v1",
"created": "Mon, 9 Feb 1998 10:53:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dakna",
"M.",
""
],
[
"Breitenbach",
"G.",
""
],
[
"Mlynek",
"J.",
""
],
[
"Opatrny",
"T.",
""
],
[
"Schiller",
"S.",
""
],
[
"Welsch",
"D. -G.",
""
]
] |
quant-ph/9802024 | Paivi Torma | Paivi Torma | Transitions in quantum networks | Revised version: Eq.(7) of the previous version changed, references
added; 4 pages, 1 figure | Phys.Rev.Lett. 81 (1998) 2185-2189 | 10.1103/PhysRevLett.81.2185 | null | quant-ph | null | We consider transitions in quantum networks analogous to those in the
two-dimensional Ising model. We show that for a network of active components
the transition is between the quantum and the classical behaviour of the
network, and the critical amplification coincides with the fundamental quantum
cloning limit.
| [
{
"version": "v1",
"created": "Mon, 9 Feb 1998 14:23:42 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Feb 1998 15:14:46 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Torma",
"Paivi",
""
]
] |
quant-ph/9802025 | Dominic Mayers | Dominic Mayers | Unconditional security in Quantum Cryptography | Version 5: This is an improved version of the paper that was
published in JACM. Previous version: Revtex 18 pages. An appendix which
summarizes the notations was added. As in the previous version, the proof
uses the POVM model to prove the security of quantum key distribution against
all attacks. The proof assumes a noisy channel and an imperfect measuring
apparatus | JACM, vol 48, no 3, May 2001, p 351-406 | null | null | quant-ph | null | Basic techniques to prove the unconditional security of quantum cryptography
are described. They are applied to a quantum key distribution protocol proposed
by Bennett and Brassard in 1984. The proof considers a practical variation on
the protocol in which the channel is noisy and photons may be lost during the
transmission. The initial coding into the channel must be perfect (i.e.,
exactly as described in the protocol). No restriction is imposed on the
detector used at the receiving side of the channel, except that whether or not
the received system is detected must be independent of the basis used to
measure this system.
| [
{
"version": "v1",
"created": "Tue, 10 Feb 1998 22:11:06 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Feb 1998 02:05:47 GMT"
},
{
"version": "v3",
"created": "Thu, 9 Apr 1998 22:35:25 GMT"
},
{
"version": "v4",
"created": "Tue, 15 Sep 1998 02:59:15 GMT"
},
{
"version": "v5",
"created": "Wed, 29 Sep 2004 01:44:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mayers",
"Dominic",
""
]
] |
quant-ph/9802026 | Comman area for Thpd | Arun Kumar Pati | Uncertainty, non-locality and Bell's inequality | 12 pages, Latex, no figures, Talk presented in International
Symposium on ``Uncertain Reality''held at New Delhi, 5-9th Jan. 1998 | null | null | null | quant-ph | null | We derive a Bell-like inequality involving all correlations in local
observables with uncertainty free states and show that the inequality is
violated in quantum mechanics for EPR and GHZ states. If the uncertainties are
allowed in local observables then the statistical predictions of hidden
variable theory is well respected in quantum world. We argue that the
uncertainties play a key role in understanding the non-locality issues in
quantum world. Thus we can not rule out the possibility that a local, realistic
hidden variable theory with statistical uncertainties in the observables might
reproduce all the results of quantum theory.
| [
{
"version": "v1",
"created": "Wed, 11 Feb 1998 04:24:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pati",
"Arun Kumar",
""
]
] |
quant-ph/9802027 | Dominique Delande | Dominique Delande and Jakub Zakrzewski | Spontaneous emission of non-dispersive Rydberg wave packets | 14 pages, 4 figures | null | 10.1103/PhysRevA.58.466 | null | quant-ph | null | Non dispersive electronic Rydberg wave packets may be created in atoms
illuminated by a microwave field of circular polarization. We discuss the
spontaneous emission from such states and show that the elastic incoherent
component (occuring at the frequency of the driving field) dominates the
spectrum in the semiclassical limit, contrary to earlier predictions. We
calculate the frequencies of single photon emissions and the associated rates
in the "harmonic approximation", i.e. when the wave packet has approximately a
Gaussian shape. The results agree well with exact quantum mechanical
calculations, which validates the analytical approach.
| [
{
"version": "v1",
"created": "Wed, 11 Feb 1998 15:51:10 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Delande",
"Dominique",
""
],
[
"Zakrzewski",
"Jakub",
""
]
] |
quant-ph/9802028 | Alexander Y. Vlasov | Alexander Yu. Vlasov (FCR/IRH, St.-Petersburg, Russia) | Analogue Quantum Computers for Data Analysis | 7 pages, standard article LaTeX2e document class | null | null | QCY-VAY12-291297 | quant-ph cs.CV | null | Analogue computers use continuous properties of physical system for modeling.
In the paper is described possibility of modeling by analogue quantum computers
for some model of data analysis. It is analogue associative memory and a formal
neural network. A particularity of the models is combination of continuous
internal processes with discrete set of output states. The modeling of the
system by classical analogue computers was offered long times ago, but now it
is not very effectively in comparison with modern digital computers. The
application of quantum analogue modelling looks quite possible for modern level
of technology and it may be more effective than digital one, because number of
element may be about Avogadro number (N=6.0E23).
| [
{
"version": "v1",
"created": "Wed, 11 Feb 1998 16:25:41 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vlasov",
"Alexander Yu.",
"",
"FCR/IRH, St.-Petersburg, Russia"
]
] |
quant-ph/9802029 | Suncp | C.P Sun, H.Zhan, X.F, Liu | On decoherence in quantum algorithm via dynamic models for quantum
measurement | 12 pages, Revtex | null | null | AMO98-2, ITP-AC | quant-ph | null | The possible effect of environment on the efficiency of a quantum algorithm
is considered explicitely. It is illustrated through the example of Shor's
prime factorization algorithm that this effect may be disastrous. The influence
of environment on quantum computation is probed on the basis of its analogy to
the problem of wave function collapse in quantum measurement.Techniques from
the Hepp-Colemen approach and its generalization are used to deal with
decoherence problems in quantum computation including dynamic mechanism of
decoherence, quantum error avoiding tricks and calculation of decoherence time.
| [
{
"version": "v1",
"created": "Wed, 11 Feb 1998 16:34:05 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Feb 1998 11:38:33 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sun",
"C. P",
""
],
[
"Zhan",
"H.",
""
],
[
"F",
"X.",
""
],
[
"Liu",
"",
""
]
] |
quant-ph/9802030 | Grosa | V. I. Man'ko, L. Rosa, and P. Vitale | Time-Dependent Invariants and Green's Functions in the Probability
Representation of Quantum Mechanics | 29 pages, RevTex, 6 eps-figures, to appear on Phys. Rev. A | Phys.Rev. A57 (1998) 3291 | 10.1103/PhysRevA.57.3291 | Napoli Preprint DSF-57/97 | quant-ph hep-th | null | In the probability representation of quantum mechanics, quantum states are
represented by a classical probability distribution, the marginal distribution
function (MDF), whose time dependence is governed by a classical evolution
equation. We find and explicitly solve, for a wide class of Hamiltonians, new
equations for the Green's function of such an equation, the so-called classical
propagator. We elucidate the connection of the classical propagator to the
quantum propagator for the density matrix and to the Green's function of the
Schr\"odinger equation. Within the new description of quantum mechanics we give
a definition of coherence solely in terms of properties of the MDF and we test
the new definition recovering well known results. As an application, the forced
parametric oscillator is considered . Its classical and quantum propagator are
found, together with the MDF for coherent and Fock states.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 09:31:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Man'ko",
"V. I.",
""
],
[
"Rosa",
"L.",
""
],
[
"Vitale",
"P.",
""
]
] |
quant-ph/9802031 | Frank Antonsen | Frank Antonsen | Zeta-Functions and Star-Products | LaTeX2e with 2 Postscript figures | null | null | null | quant-ph hep-th math-ph math.MP | null | We use the definition of a star (or Moyal or twisted) product to give a
phasespace definition of the $\zeta$-function. This allows us to derive new
closed expressions for the coefficients of the heat kernel in an asymptotic
expansion for operators of the form $\alpha p^2+v(q)$. For the particular case
of the harmonic oscillator we furthermore find a closed form for the Green's
function. We also find a relationship between star exponentials, path integrals
and Wigner functions, which in a simple example gives a relation between the
star exponential of the Chern-Simons action and knot invariants.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 10:03:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Antonsen",
"Frank",
""
]
] |
quant-ph/9802032 | Antoine Suarez | Antoine Suarez (Center for Quantum Philosophy, Zurich) | Quantum mechanical retrocausation? Call for nonlocal causal models! | 6 pages Latex, 1 eps figure | null | null | null | quant-ph | null | A new possible version of multisimultaneous causality is proposed, and real
experiments allowing us to decide between this view and quantum mechanical
retrocausation are further discussed. The interest of testing quantum mechanics
against as many nonlocal causal models as possible is stressed.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 10:46:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Suarez",
"Antoine",
"",
"Center for Quantum Philosophy, Zurich"
]
] |
quant-ph/9802033 | David Vitali | David Vitali and Paolo Tombesi | Decoherence Control for Optical Qubits | To be presented at 1st NASA Conf. on Quantum Computation. 12 pages,
uses llncs.sty, 2 figures | Lect.Notes Comput.Sci. 1509 (1999) 402-412 | null | DMF-08 | quant-ph | null | Photons in cavities have been already used for the realization of simple
quantum gates [Q.A. Turchette, Phys. Rev. Lett. 75,4710 (1995)]. We present a
method for combatting decoherence in this case.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 13:43:56 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vitali",
"David",
""
],
[
"Tombesi",
"Paolo",
""
]
] |
quant-ph/9802034 | null | Stefano Mancini, David Vitali and Paolo Tombesi (Dip. Matematica e
Fisica, Univ. Camerino, Italy) | Optomechanical Cooling of a Macroscopic Oscillator by Homodyne Feedback | 9 pages, RevTeX, Figures available from authors, to appear in Phys.
Rev. Lett | Phys.Rev.Lett. 80 (1998) 688 | 10.1103/PhysRevLett.80.688 | null | quant-ph | null | We propose a simple optomechanical model in which a mechanical oscillator
quadrature could be "cooled" well below its equilibrium temperature by applying
a suitable feedback to drive the orthogonal quadrature by means of the homodyne
current of the radiation field used to probe its position.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 16:33:03 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Mancini",
"Stefano",
"",
"Dip. Matematica e\n Fisica, Univ. Camerino, Italy"
],
[
"Vitali",
"David",
"",
"Dip. Matematica e\n Fisica, Univ. Camerino, Italy"
],
[
"Tombesi",
"Paolo",
"",
"Dip. Matematica e\n Fisica, Univ. Camerino, Italy"
]
] |
quant-ph/9802035 | Lov K. Grover | Lov K. Grover (Bell Labs, Murray Hill, NJ) | Quantum search on structured problems | To be presented at the 1st NASA QCQC conference in Palm Springs,
California, Feb. 17-20, '98. 12 pages, postscript | null | 10.1016/S0960-0779(98)00217-3 | null | quant-ph | null | This paper shows how a basic property of unitary transformations can be used
for meaningful computations. This approach immediately leads to search-type
applications, where it improves the number of steps by a square-root - a simple
minded search that takes N steps, can be improved to O(sqrt(N)) steps. The
quantum search algorithm is one of several immediate consequences of this
framework. Several novel search-related applications are presented.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 17:04:28 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Grover",
"Lov K.",
"",
"Bell Labs, Murray Hill, NJ"
]
] |
quant-ph/9802036 | Tal Mor | Tal Mor | No-cloning of Orthogonal States in Composite Systems | 4 pages, RevTeX, to be published in PRL | Phys.Rev.Lett.80:3137-3140,1998 | 10.1103/PhysRevLett.80.3137 | null | quant-ph | null | The no-cloning principle tells us that non-orthogonal quantum states cannot
be cloned, but it does not tell us that orthogonal states can always be cloned.
We suggest a situation where the cloning transformations are restricted,
leading to a novel type of no-cloning principle. In the case of a composite
system made of two subsystems: if the subsystems are only available one after
the other then there are various cases when orthogonal states cannot be cloned.
Surprising examples are given, which give a radically better insight regarding
the basic concepts of quantum cryptography.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 19:30:19 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Mor",
"Tal",
""
]
] |
quant-ph/9802037 | Emanuel Knill | E. Knill, R. Laflamme | On the Power of One Bit of Quantum Information | 5 pages | Phys.Rev.Lett.81:5672-5675,1998 | 10.1103/PhysRevLett.81.5672 | null | quant-ph | null | In standard quantum computation, the initial state is pure and the answer is
determined by making a measurement of some of the bits in the computational
basis. What can be accomplished if the initial state is a highly mixed state
and the answer is determined by measuring the expectation of $\sigma_z$ on the
first bit with bounded sensitivity? This is the situation in high temperature
ensemble quantum computation. We show that in this model it is possible to
perform interesting physics simulations which have no known efficient classical
algorithms, even though the model is less powerful then standard quantum
computing in the presence of oracles.
| [
{
"version": "v1",
"created": "Thu, 12 Feb 1998 21:25:08 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Knill",
"E.",
""
],
[
"Laflamme",
"R.",
""
]
] |
quant-ph/9802038 | Robert Clifton | Jason Zimba (Dept. of Physics, UC Berkeley) and Rob Clifton (Dept. of
Philosophy, Univ. of Pittsburgh) | Valuations on Functionally Closed Sets of Quantum Mechanical Observables
and Von Neumann's 'No-Hidden-Variables' Theorem | 39 Pages, AMS-LaTeX, To Appear in Dennis Dieks and Pieter Vermaas
(eds.), The Modal Interpretation of Quantum Mechanics, University of Western
Ontario Series in Philosophy of Science, Kluwer Academic Publishers, 1998 | null | null | null | quant-ph | null | We apply the machinery of projection lattices and von Neumann algebras to
analyze the question of how modal interpretations can (and do) circumvent von
Neumann's infamous 'no-hidden-variables' theorem.
| [
{
"version": "v1",
"created": "Fri, 13 Feb 1998 05:21:20 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Zimba",
"Jason",
"",
"Dept. of Physics, UC Berkeley"
],
[
"Clifton",
"Rob",
"",
"Dept. of\n Philosophy, Univ. of Pittsburgh"
]
] |
quant-ph/9802039 | Masanao Ozawa | Masanao Ozawa (Nagoya University) | Operational Characterization of Simultaneous Measurements in Quantum
Mechanics | 9 pages, REVTeX | Phys.Lett. A275 (2000) 5-11 | 10.1016/S0375-9601(00)00489-8 | null | quant-ph | null | Quantum mechanics predicts the joint probability distribution of the outcomes
of simultaneous measurements of commuting observables, but, in the state of the
art, has lacked the operational definition of simultaneous measurements. The
question is answered as to when the consecutive applications of measuring
apparatuses give a simultaneous measurement of their observables. For this
purpose, all the possible state reductions caused by measurements of an
observable is also characterized by their operations.
| [
{
"version": "v1",
"created": "Fri, 13 Feb 1998 08:59:21 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Ozawa",
"Masanao",
"",
"Nagoya University"
]
] |
quant-ph/9802040 | Richard Cleve | Harry Buhrman (CWI, Amsterdam), Richard Cleve (U of Calgary), Avi
Wigderson (Hebrew U) | Quantum vs. Classical Communication and Computation | 6 pages, LaTeX w/ ACMconf style, no figures, made changes in notation
in order to be consistent with other papers. To appear in Proceedings of the
30th Annual ACM Symposium on Theory of Computing (ACM Press) | null | null | null | quant-ph | null | We present a simple and general simulation technique that transforms any
black-box quantum algorithm (a la Grover's database search algorithm) to a
quantum communication protocol for a related problem, in a way that fully
exploits the quantum parallelism. This allows us to obtain new positive and
negative results. The positive results are novel quantum communication
protocols that are built from nontrivial quantum algorithms via this
simulation. These protocols, combined with (old and new) classical lower
bounds, are shown to provide the first asymptotic separation results between
the quantum and classical (probabilistic) two-party communication complexity
models. In particular, we obtain a quadratic separation for the bounded-error
model, and an exponential separation for the zero-error model. The negative
results transform known quantum communication lower bounds to computational
lower bounds in the black-box model. In particular, we show that the quadratic
speed-up achieved by Grover for the OR function is impossible for the PARITY
function or the MAJORITY function in the bounded-error model, nor is it
possible for the OR function itself in the exact case. This dichotomy naturally
suggests a study of bounded-depth predicates (i.e. those in the polynomial
hierarchy) between OR and MAJORITY. We present black-box algorithms that
achieve near quadratic speed up for all such predicates.
| [
{
"version": "v1",
"created": "Sat, 14 Feb 1998 20:05:21 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Mar 1998 02:42:23 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Buhrman",
"Harry",
"",
"CWI, Amsterdam"
],
[
"Cleve",
"Richard",
"",
"U of Calgary"
],
[
"Wigderson",
"Avi",
"",
"Hebrew U"
]
] |
quant-ph/9802041 | Miroljub Dugic | M. Dugic | On the necessary conditions for the occurrence of the
"environment-induced superselection rules" | Plain TeX, 5 pages | null | null | PMF KG-7 | quant-ph | null | We briefly summarize the main recently obtained results concerning existence
of the (effective) necessary conditions for the occurrence of the
"environment-induced superselection rules" (decoherence).
| [
{
"version": "v1",
"created": "Sun, 15 Feb 1998 10:57:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dugic",
"M.",
""
]
] |
quant-ph/9802042 | Lev Vaidman | L. Vaidman | Time-Symmetrized Counterfactuals in Quantum Theory | Submitted to PSA98 | null | null | null | quant-ph | null | Counterfactuals in quantum theory are briefly reviewed and it is argued that
they are very different from counterfactuals considered in the general
philosophical literature. The issue of time symmetry of quantum counterfactuals
is considered and a novel time-symmetric definition of quantum counterfactuals
is proposed. This definition is applied for analyzing several controversies
related to quantum counterfactuals.
| [
{
"version": "v1",
"created": "Sun, 15 Feb 1998 17:48:05 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Feb 1998 13:45:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vaidman",
"L.",
""
]
] |
quant-ph/9802043 | Tad Hogg | Tad Hogg and Mehmet Yanik | Local Search Methods for Quantum Computers | 28 pages, 6 figures, for related papers see
http://www.parc.xerox.com/dynamics/www/quantum.html | null | null | null | quant-ph | null | Local search algorithms use the neighborhood relations among search states
and often perform well for a variety of NP-hard combinatorial search problems.
This paper shows how quantum computers can also use these neighborhood
relations. An example of such a local quantum search is evaluated empirically
for the satisfiability (SAT) problem and shown to be particularly effective for
highly constrained instances. For problems with an intermediate number of
constraints, it is somewhat less effective at exploiting problem structure than
incremental quantum methods, in spite of the much smaller search space used by
the local method.
| [
{
"version": "v1",
"created": "Mon, 16 Feb 1998 18:34:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hogg",
"Tad",
""
],
[
"Yanik",
"Mehmet",
""
]
] |
quant-ph/9802044 | Gh.-S. Paraoanu | Gh.-S. Paraoanu, H. Scutaru | Classical states via decoherence | 6 pages, LaTeX | Phys.Lett. A238 (1998) 219 | 10.1016/S0375-9601(97)00925-0 | null | quant-ph | null | The initial states which minimize the predictability loss for a damped
harmonic oscillator are identified as quasi-free states with a symmetry
dictated by the environment's diffusion coefficients. For an isotropic
diffusion in phase space, coherent states (or mixtures of coherent states) are
selected as the most stable ones.
| [
{
"version": "v1",
"created": "Mon, 16 Feb 1998 21:36:02 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Paraoanu",
"Gh. -S.",
""
],
[
"Scutaru",
"H.",
""
]
] |
quant-ph/9802045 | Michael Sipser | E. Farhi (MIT), J. Goldstone (MIT), S. Gutmann (Northeastern), M.
Sipser (MIT) | A Limit on the Speed of Quantum Computation in Determining Parity | 9 pages, latex | Phys.Rev.Lett.81:5442-5444,1998 | 10.1103/PhysRevLett.81.5442 | MIT-CTP-2716 | quant-ph | null | Consider a function f which is defined on the integers from 1 to N and takes
the values -1 and +1. The parity of f is the product over all x from 1 to N of
f(x). With no further information about f, to classically determine the parity
of f requires N calls of the function f. We show that any quantum algorithm
capable of determining the parity of f contains at least N/2 applications of
the unitary operator which evaluates f. Thus for this problem, quantum
computers cannot outperform classical computers.
| [
{
"version": "v1",
"created": "Mon, 16 Feb 1998 23:25:19 GMT"
},
{
"version": "v2",
"created": "Thu, 8 Oct 1998 21:20:54 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Farhi",
"E.",
"",
"MIT"
],
[
"Goldstone",
"J.",
"",
"MIT"
],
[
"Gutmann",
"S.",
"",
"Northeastern"
],
[
"Sipser",
"M.",
"",
"MIT"
]
] |
quant-ph/9802046 | Suarez | Bernard d'Espagnat (Laboratory of Theoretical Physics and High
Energies, Paris) | Quantum Theory : A Pointer To An Independent Reality | 17 pages Latex, minor changes in Version 2. This article presents
d'Espagnat's conception of "Veiled Reality". It incorporates also a comment
to a contribution in the book edited by A. Driessen and A. Suarez:
"Mathematical Undecidability, Quantum Nonlocality, and the Question of the
Existence of God", Kluwer Academic Publishers, Dordrecht, The Netherlands,
1997. The submission is made in agreement with Bernard d'Espagnat | null | null | null | quant-ph | null | While philosophy of science is the study of problems of knowledge concerning
science in general, there also exists - or should exist - a '' philosophy in
science'' directed at finding out in what ways our actual scientific knowledge
may validly contribute to the basic philosophical quest. Contrary to philosophy
of science, which is a subject for philosophers, philosophy in science calls on
the services of physicists. When, in its spirit, quantum theory and Bell's
theorem are used as touchstones, the two main traditional philosophical
approaches, realism and idealism, are found wanting. A more suitable conception
seems to be an intermediate one, in which the mere postulated existence of a
holistic and hardly knowable Mind-Independent Reality is found to have an
explaining power. Some corrections to comments by Schins of a previous work on
the same subject are incorporated.
| [
{
"version": "v1",
"created": "Tue, 17 Feb 1998 06:56:59 GMT"
},
{
"version": "v2",
"created": "Sun, 10 May 1998 14:28:20 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"d'Espagnat",
"Bernard",
"",
"Laboratory of Theoretical Physics and High\n Energies, Paris"
]
] |
quant-ph/9802047 | Gonzalo Garcia de Polavieja | Gonzalo Garcia de Polavieja | Quantum state sensitivity to initial conditions | 1 .tex file and 2 .ps figures. Physical Review A (to appear 1 May) | null | null | null | quant-ph | null | The different time-dependent distances of two arbitrarily close quantum or
classical-statistical states to a third fixed state are shown to imply an
experimentally relevant notion of state sensitivity to initial conditions. A
quantitative classification scheme of quantum states by their sensitivity and
instability in state space is given that reduces to the one performed by
classical-mechanical Lyapunov exponents in the classical limit
| [
{
"version": "v1",
"created": "Tue, 17 Feb 1998 09:51:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"de Polavieja",
"Gonzalo Garcia",
""
]
] |
quant-ph/9802048 | C. H. Oh | Xiang-Bin Wang, C.H. Oh and L.C. Kwek | General Approach to Functional Forms for the Exponential Quadratic
Operators in Coordinate-Momentum Space | To appear in J. Phys. A: Mathematics and General | J.Phys.A31:4329-4336,1998 | 10.1088/0305-4470/31/18/020 | null | quant-ph physics.comp-ph physics.optics | null | In a recent paper [Nieto M M 1996 Quantum and Semiclassical Optics, 8 1061;
quant-ph/9605032], the one dimensional squeezed and harmonic oscillator
time-displacement operators were reordered in coordinate-momentum space. In
this paper, we give a general approach for reordering multi-dimensional
exponential quadratic operator(EQO) in coordinate-momentum space. An explicit
computational formula is provided and applied to the single mode and
double-mode EQO through the squeezed operator and the time displacement
operator of the harmonic oscillator.
| [
{
"version": "v1",
"created": "Wed, 18 Feb 1998 03:05:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wang",
"Xiang-Bin",
""
],
[
"Oh",
"C. H.",
""
],
[
"Kwek",
"L. C.",
""
]
] |
quant-ph/9802049 | Ronald de Wolf | Robert Beals (U of Arizona), Harry Buhrman (CWI), Richard Cleve (U of
Calgary), Michele Mosca (U of Oxford), Ronald de Wolf (CWI and U of
Amsterdam) | Quantum Lower Bounds by Polynomials | 10 pages, LaTeX, no figures, final version to appear in FOCS'98 | null | null | null | quant-ph cs.CC | null | We examine the number T of queries that a quantum network requires to compute
several Boolean functions on {0,1}^N in the black-box model. We show that, in
the black-box model, the exponential quantum speed-up obtained for partial
functions (i.e. problems involving a promise on the input) by Deutsch and Jozsa
and by Simon cannot be obtained for any total function: if a quantum algorithm
computes some total Boolean function f with bounded-error using T black-box
queries then there is a classical deterministic algorithm that computes f
exactly with O(T^6) queries.
We also give asymptotically tight characterizations of T for all symmetric f
in the exact, zero-error, and bounded-error settings. Finally, we give new
precise bounds for AND, OR, and PARITY. Our results are a quantum extension of
the so-called polynomial method, which has been successfully applied in
classical complexity theory, and also a quantum extension of results by Nisan
about a polynomial relationship between randomized and deterministic decision
tree complexity.
| [
{
"version": "v1",
"created": "Wed, 18 Feb 1998 17:41:12 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Feb 1998 16:02:23 GMT"
},
{
"version": "v3",
"created": "Wed, 30 Sep 1998 08:07:23 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Beals",
"Robert",
"",
"U of Arizona"
],
[
"Buhrman",
"Harry",
"",
"CWI"
],
[
"Cleve",
"Richard",
"",
"U of\n Calgary"
],
[
"Mosca",
"Michele",
"",
"U of Oxford"
],
[
"de Wolf",
"Ronald",
"",
"CWI and U of\n Amsterdam"
]
] |
quant-ph/9802050 | A. Khare | Avinash Khare and Uday P. Sukhatme | Exact Solution of a Class of Three-Body Scattering Problems in One
dimension | Latex file, no figures, To be Published in Phys. Lett. A | Phys.Lett. A241 (1998) 14-18 | 10.1016/S0375-9601(98)00090-5 | UICHEP-TH/97-11; IOP-BBSR/97-38 | quant-ph | null | We present an exact solution of the three-body scattering problem for a one
parameter family of one dimensional potentials containing the Calogero and
Wolfes potentials as special limiting cases. The result is an interesting
nontrivial relationship between the final momenta $p'_i$ and the initial
momenta $p_i$ of the three particles. We also discuss another one parameter
family of potentials for all of which $p'_i=-p_i~(i=1,2,3)$.
| [
{
"version": "v1",
"created": "Thu, 19 Feb 1998 04:41:13 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Khare",
"Avinash",
""
],
[
"Sukhatme",
"Uday P.",
""
]
] |
quant-ph/9802051 | M. Czachor | Marek Czachor | Notes on nonlinear quantum algorithms | one 1/4 changed to 1/2, conclusions unchanged | Acta Phys.Slov. 48 (1998) 157 | null | null | quant-ph | null | Recenty Abrams and Lloyd have proposed a fast algorithm that is based on a
nonlinear evolution of a state of a quantum computer. They have explicitly used
the fact that nonlinear evolutions in Hilbert spaces do not conserve scalar
products of states, and applied a description of separated systems taken from
Weinberg's nonlinear quantum mechanics. On the other hand it is known that
violation of orthogonality combined with the Weinberg-type description
generates unphysical, arbitrarily fast influences between noninteracting
systems. It was not therefore clear whether the algorithm is fast because
arbitrarily fast unphysical effects are involved. In these notes I show that
this is not the case. I analyze both algorithms proposed by Abrams and Lloyd on
concrete, simple models of nonlinear evolution. The description I choose is
known to be free of the unphysical influences (therefore it is not the Weinberg
one). I show, in particular, that the correct local formalism allows even to
simplify the algorithm.
| [
{
"version": "v1",
"created": "Thu, 19 Feb 1998 19:40:10 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Feb 1998 17:49:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Czachor",
"Marek",
""
]
] |
quant-ph/9802052 | Michael J. W. Hall | Michael J. W. Hall | Random quantum correlations and density operator distributions | 13 pages, no figures; a new page of additional notes at end draws
attention to 3 new references and their relevance | Phys.Lett. A242 (1998) 123-129 | 10.1016/S0375-9601(98)00190-X | ANU-97-21.10 | quant-ph | null | Consider the question: what statistical ensemble corresponds to minimal prior
knowledge about a quantum system ? For the case where the system is in fact
known to be in a pure state there is an obvious answer, corresponding to the
unique unitarily-invariant measure on the Hilbert sphere. However, the problem
is open for the general case where states are described by density operators.
Here two approaches to the problem are investigated.
The first approach assumes that the system is randomly correlated with a
second system, where the ensemble of composite systems is described by a random
pure state. Results for qubits randomly correlated with other systems are
presented, including average entanglement entropies. It is shown that maximum
correlation is guaranteed in the limit as one system becomes
infinite-dimensional.
The second approach relies on choosing a metric on the space of density
operators, and generating a corresponding ensemble from the induced volume
element. Comparisons between the approaches are made for qubits, for which the
second approach (based on the Bures metric) yields the most symmetric, and
hence the least informative, ensemble of density operators.
| [
{
"version": "v1",
"created": "Thu, 19 Feb 1998 15:28:59 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Jul 1998 10:51:50 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Hall",
"Michael J. W.",
""
]
] |
quant-ph/9802053 | Robert W. Spekkens | R. W. Spekkens and J. E. Sipe | Some remarks on the fragmentation of Bose condensates | 4 pages, REVTEX, to be published in the proceedings of the
Fundamental Problems in Quantum Theory Workshop, University of Maryland
Baltimore County, August 4-7, 1997 | Prog. Phys. 46, 873 (1998) | 10.1002/(SICI)1521-3978(199811)46:6/8<873::AID-PROP873>3.0.CO;2-Q | null | quant-ph | null | We show how fragmentation of a Bose-Einstein condensate can occur given
repulsive inter-particle interactions and a non-uniform external potential.
| [
{
"version": "v1",
"created": "Thu, 19 Feb 1998 19:53:26 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Spekkens",
"R. W.",
""
],
[
"Sipe",
"J. E.",
""
]
] |
quant-ph/9802054 | Raymond Laflamme | Wojciech H. Zurek | Decoherence, chaos, quantum-classical correspondence, and the
algorithmic arrow of time | 26 pages in Tex, 3 figures | Phys.Scripta T76:186-198,1998 | 10.1238/Physica.Topical.076a00186 | null | quant-ph | null | The environment -- external or internal degrees of freedom coupled to the
system -- can, in effect, monitor some of its observables. As a result, the
eigenstates of these observables decohere and behave like classical states:
Continuous destruction of superpositions leads to environment-induced
superselection (einselection). Here I investigate it in the context of quantum
chaos (i. e., quantum dynamics of systems which are classically chaotic).
| [
{
"version": "v1",
"created": "Fri, 20 Feb 1998 00:46:03 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Zurek",
"Wojciech H.",
""
]
] |
quant-ph/9802055 | G. A. Koganov | Gennady A. Koganov and Reuben Shuker | Threshold and non-linear behavior of lasers of $\Lambda$ and V -
configurations | 9 pages, 5 figures | null | 10.1103/PhysRevA.58.1559 | BGU-qo-98/2 | quant-ph | null | Dynamic properties of closed three level laser systems are investigated. Two
schemes of pumping - $\Lambda$ and V - are considered. It is shown that the
non-linear behavior of the photon number as a function of pump both near and
far above threshold is crucially different for these two configurations. In
particular, it is found that in the high pump regime laser can turn off in a
phase-transition-like manner in both $\Lambda$ and V schemes.
| [
{
"version": "v1",
"created": "Fri, 20 Feb 1998 13:25:14 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Mar 1998 17:43:13 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Koganov",
"Gennady A.",
""
],
[
"Shuker",
"Reuben",
""
]
] |
quant-ph/9802056 | Allan Widom | A. Widom, Y. N. Srivastava, E. Sassaroli | Acuasal Behavior in Quantum Electrodynamics | LaTeX 13 Pages, Presented at the International Conference on
Macroscopic Quantum Coherence, July 1997, Northeastern University, Boston | null | null | MQC-0030 | quant-ph | null | Acausal features of quantum electrodynamic processes are discussed. While
these processes are not present for the classical electrodynamic theory, in the
quantum electrodynamic theory, acausal processes are well known to exist. For
example, any Feynman diagram with a ``loop'' in space-time describes a
``particle'' which may move forward in time or backward in time or in
space-like directions. The engineering problems involved in experimentally
testing such causality violations on a macroscopic scale are explored.
| [
{
"version": "v1",
"created": "Sun, 22 Feb 1998 21:57:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Widom",
"A.",
""
],
[
"Srivastava",
"Y. N.",
""
],
[
"Sassaroli",
"E.",
""
]
] |
quant-ph/9802057 | Safonov S. S. | S. S. Safonov (Moscow Institute of Physics and Technology) | Caldirola-Kanai Oscillator in Classical Formulation of Quantum Mechanics | LaTeX, 5 pages, 1 Postscript figure, Contribution to the VIII
International Conference on Symmetry Methods in Physics, Dubna 1997, to be
published in the Proceedings of the Conference | Phys.Atom.Nucl.63:692-694,2000; Yad.Fiz.63:757-759,2000 | 10.1134/1.855692 | null | quant-ph | null | The quadrature distribution for the quantum damped oscillator is introduced
in the framework of the formulation of quantum mechanics based on the
tomography scheme. The probability distribution for the coherent and Fock
states of the damped oscillator is expressed explicitly in terms of Gaussian
and Hermite polynomials, correspondingly.
| [
{
"version": "v1",
"created": "Mon, 23 Feb 1998 08:00:31 GMT"
}
] | 2011-04-15T00:00:00 | [
[
"Safonov",
"S. S.",
"",
"Moscow Institute of Physics and Technology"
]
] |
quant-ph/9802058 | Andrew Steane | D. Stevens, J. Brochard and A. M. Steane (Clarendon Laboratory, Oxford
University) | Simple experimental methods for trapped ion quantum processors | 13 pages LaTeX plus 6 PostScript figures. Submitted to Physical
Review A | null | 10.1103/PhysRevA.58.2750 | null | quant-ph | null | Two techniques are described that simplify the experimental requirements for
measuring and manipulating quantum information stored in trapped ions. The
first is a new technique using electron shelving to measure the populations of
the Zeeman sublevels of the ground state, in an ion for which no cycling
transition exists from any of these sublevels. The second technique is laser
cooling to the vibrational ground state, without the need for a trap operating
in the Lamb-Dicke limit. This requires sideband cooling in a sub-recoil regime.
We present a thorough analysis of sideband cooling on one or a pair of
sidebands simultaneously.
| [
{
"version": "v1",
"created": "Mon, 23 Feb 1998 15:27:27 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Stevens",
"D.",
"",
"Clarendon Laboratory, Oxford\n University"
],
[
"Brochard",
"J.",
"",
"Clarendon Laboratory, Oxford\n University"
],
[
"Steane",
"A. M.",
"",
"Clarendon Laboratory, Oxford\n University"
]
] |
quant-ph/9802059 | M. Czachor | Marek Czachor and Li You | Spatially sequential turn-on of spontaneous emission from an atomic wave
packet | to be published in Int.J.Theor.Phys.; revtex, 3 ps figures | Int.J.Theor.Phys. 38 (1999) 277-288 | null | null | quant-ph | null | We discuss a simple example demonstrating that spontaneous emission from
"space-time-superposed" atomic center-of-mass wave packets is nontrivially and
time-dependent modified with respect to the standard dipole-pattern typical of
"space-superposed" wave packets. Our approach provides an approximate
description of a nonsimultaneous interaction of electromagnetic field with
different parts of a wave packet.
| [
{
"version": "v1",
"created": "Mon, 23 Feb 1998 18:28:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Czachor",
"Marek",
""
],
[
"You",
"Li",
""
]
] |
quant-ph/9802060 | Klaus Gheri | K.M. Gheri, C. Saavedra, P. Toermae, J. I. Cirac, and P. Zoller | Entanglement engineering of one-photon wavepackets using a single-atom
source | 4 pages, 2 figures | null | 10.1103/PhysRevA.58.R2627 | null | quant-ph | null | We propose a cavity-QED scheme for the controlled generation of sequences of
entangled single-photon wavepackets. A photon is created inside a cavity via an
active medium, such as an atom, and decays into the continuum of radiation
modes outside the cavity(coupled, for example to an optical fiber). Subsequent
wavepackets generated in this way behave as independent logical qubits. This
and the possibility of producing maximally entangled multi-qubit states suggest
many applications in quantum communication.
| [
{
"version": "v1",
"created": "Tue, 24 Feb 1998 09:42:43 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Feb 1998 08:27:10 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Gheri",
"K. M.",
""
],
[
"Saavedra",
"C.",
""
],
[
"Toermae",
"P.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9802061 | Andrew Steane | Andrew M. Steane (Clarendon Laboratory, Oxford University) | Enlargement of Calderbank Shor Steane quantum codes | 12 pages. Submitted to IEEE Trans. Inf. Theory. Mistake in proof
corrected | IEEE Trans.Info.Theor. 45 (1999) 2492-2495 | null | null | quant-ph | null | It is shown that a classical error correcting code C = [n,k,d] which contains
its dual, C^{\perp} \subseteq C, and which can be enlarged to C' = [n,k' > k+1,
d'], can be converted into a quantum code of parameters [[ n, k+k' - n, min(d,
3d'/2) ]]. This is a generalisation of a previous construction, it enables many
new codes of good efficiency to be discovered. Examples based on classical Bose
Chaudhuri Hocquenghem (BCH) codes are discussed.
| [
{
"version": "v1",
"created": "Tue, 24 Feb 1998 15:44:11 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Mar 1998 15:01:23 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Steane",
"Andrew M.",
"",
"Clarendon Laboratory, Oxford University"
]
] |
quant-ph/9802062 | Andris Ambainis | A. Ambainis, R. Freivalds | 1-way quantum finite automata: strengths, weaknesses and generalizations | 23 pages LaTeX, 1 figure, to appear at FOCS'98 | null | null | null | quant-ph cs.CC | null | We study 1-way quantum finite automata (QFAs). First, we compare them with
their classical counterparts. We show that, if an automaton is required to give
the correct answer with a large probability (over 0.98), then the power of
1-way QFAs is equal to the power of 1-way reversible automata. However, quantum
automata giving the correct answer with smaller probabilities are more powerful
than reversible automata.
Second, we show that 1-way QFAs can be very space-efficient. Namely, we
construct a 1-way QFA which is exponentially smaller than any equivalent
classical (even randomized) finite automaton. This construction may be useful
for design of other space-efficient quantum algorithms.
Third, we consider several generalizations of 1-way QFAs. Here, our goal is
to find a model which is more powerful than 1-way QFAs keeping the quantum part
as simple as possible.
| [
{
"version": "v1",
"created": "Wed, 25 Feb 1998 00:34:35 GMT"
},
{
"version": "v2",
"created": "Thu, 7 May 1998 02:03:38 GMT"
},
{
"version": "v3",
"created": "Wed, 30 Sep 1998 00:46:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ambainis",
"A.",
""
],
[
"Freivalds",
"R.",
""
]
] |
quant-ph/9802063 | Dr N. Mavromatos | N.E. Mavromatos and D.V. Nanopoulos | Quantum Mechanics in Cell Microtubules: Wild Imagination or Realistic
Possibility? | 33 pages revtex, axodraw.style. Based on a talk given by N.E.M. at
the Workshop `Biophysics of the Cytoskeleton', Banff Conference Center,
Canada, August 18-22 1997, to appear in `Advances in Structural Biology' | null | null | OUTP-98-15P, ACT-1/98, CTP-7/98 | quant-ph cond-mat | null | We focus on potential mechanisms for `energy-loss-free' transport along the
cell microtubules, which could be considered as realizations of Fr\"ohlich's
ideas on the role of solitons for superconductivity and/or biological matter.
In particular, by representing the MT arrangements as `cavities',we present a
novel scenario on the formation of macroscopic (or mesoscopic) quantum-coherent
states, as a result of the (quantum-electromagnetic) interactions of the MT
dimers with the surrounding molecules of the ordered water in the interior of
the MT cylinders. We present some generic order of magnitude estimates of the
decoherence time in a typical model for MT dynamics. The role of (conjectured)
ferroelectric properties of MT arrangements on the above quantum phenomena is
emphasized. Based on these considerations, we also present a conjecture on the
role of the MT in `holographic' information processing, which resembles the
situation encountered in internal source X-ray holography in atomic physics.
| [
{
"version": "v1",
"created": "Wed, 25 Feb 1998 15:01:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mavromatos",
"N. E.",
""
],
[
"Nanopoulos",
"D. V.",
""
]
] |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.