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/9805030 | Marco Toller | Marco Toller (Department of Physics of the University, I. N. F. N.,
Trento, Italy) | Localization of Events in Space-Time | 31 pages, latex, no figures | Phys.Rev.A59:960,1999 | 10.1103/PhysRevA.59.960 | null | quant-ph | null | The present paper deals with the quantum coordinates of an event in
space-time, individuated by a quantum object. It is known that these
observables cannot be described by self-adjoint operators or by the
corresponding spectral projection-valued measure. We describe them by means of
a positive-operator-valued (POV) measure in the Minkowski space-time,
satisfying a suitable covariance condition with respect to the Poincare' group.
This POV measure determines the probability that a measurement of the
coordinates of the event gives results belonging to a given set in space-time.
We show that this measure must vanish on the vacuum and the one-particle
states, which cannot define any event. We give a general expression for the
Poincare' covariant POV measures. We define the baricentric events, which lie
on the world-line of the centre-of-mass, and we find a simple expression for
the average values of their coordinates. Finally, we discuss the conditions
which permit the determination of the coordinates with an arbitrary accuracy.
| [
{
"version": "v1",
"created": "Mon, 11 May 1998 10:21:39 GMT"
}
] | 2011-08-17T00:00:00 | [
[
"Toller",
"Marco",
"",
"Department of Physics of the University, I. N. F. N.,\n Trento, Italy"
]
] |
quant-ph/9805031 | Stefano Liberati | S. Liberati, F. Belgiorno, Matt Visser, D.W. Sciama | Sonoluminescence as a QED vacuum effect: Probing Schwinger's proposal | 18 pages, ReV_TeX 3.2, 9 figures. Major revisions: This document is
now limited to providing a probe of Schwinger's original suggestion for
sonoluminescence. For details on our own variant of Schwinger's ideas see
quant-ph/9805023, quant-ph/9904013, quant-ph/9904018, quant-ph/9905034 | J.Phys.A33:2251-2272,2000 | 10.1088/0305-4470/33/11/307 | SISSA 44/98/A | quant-ph cond-mat hep-ph hep-th | null | Several years ago Schwinger proposed a physical mechanism for
sonoluminescence in terms of photon production due to changes in the properties
of the quantum-electrodynamic (QED) vacuum arising from a collapsing dielectric
bubble. This mechanism can be re-phrased in terms of the Casimir effect and has
recently been the subject of considerable controversy. The present paper probes
Schwinger's suggestion in detail: Using the sudden approximation we calculate
Bogolubov coefficients relating the QED vacuum in the presence of the expanded
bubble to that in the presence of the collapsed bubble. In this way we derive
an estimate for the spectrum and total energy emitted. We verify that in the
sudden approximation there is an efficient production of photons, and further
that the main contribution to this dynamic Casimir effect comes from a volume
term, as per Schwinger's original calculation. However, we also demonstrate
that the timescales required to implement Schwinger's original suggestion are
not physically relevant to sonoluminescence. Although Schwinger was correct in
his assertion that changes in the zero-point energy lead to photon production,
nevertheless his original model is not appropriate for sonoluminescence. In
other works (see quant-ph/9805023, quant-ph/9904013, quant-ph/9904018,
quant-ph/9905034) we have developed a variant of Schwinger's model that is
compatible with the physically required timescales.
| [
{
"version": "v1",
"created": "Mon, 11 May 1998 14:19:43 GMT"
},
{
"version": "v2",
"created": "Tue, 29 Jun 1999 10:16:18 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Liberati",
"S.",
""
],
[
"Belgiorno",
"F.",
""
],
[
"Visser",
"Matt",
""
],
[
"Sciama",
"D. W.",
""
]
] |
quant-ph/9805032 | Giacomo Mauro D'Ariano | G. M. D'Ariano and L. Maccone (Dipartimento di Fisica ``A. Volta'',
Pavia, Italy) | Measuring quantum optical Hamiltonians | Accepted for publication on Phys. Rev. Lett. 8 eps figures, 4
two-column pages in REVTEX | Phys.Rev.Lett. 80 (1998) 5465-5468 | 10.1103/PhysRevLett.80.5465 | null | quant-ph | null | We show how recent state-reconstruction techniques can be used to determine
the Hamiltonian of an optical device that evolves the quantum state of
radiation. A simple experimental setup is proposed for measuring the
Liouvillian of phase-insensitive devices. The feasibility of the method with
current technology is demonstrated on the basis of Monte Carlo simulated
experiments.
| [
{
"version": "v1",
"created": "Mon, 11 May 1998 14:25:50 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"D'Ariano",
"G. M.",
"",
"Dipartimento di Fisica ``A. Volta'',\n Pavia, Italy"
],
[
"Maccone",
"L.",
"",
"Dipartimento di Fisica ``A. Volta'',\n Pavia, Italy"
]
] |
quant-ph/9805033 | Masanao Ozawa | Masanao Ozawa (Nagoya University) | Controlling Quantum State Reduction | 9 pages, REVTeX | Phys.Lett. A282 (2001) 336-342 | 10.1016/S0375-9601(01)00174-8 | null | quant-ph | null | Every measurement leaves the object in a family of states indexed by the
possible outcomes. This family, called the posterior states, is usually a
family of the eigenstates of the measured observable, but it can be an
arbitrary family of states by controlling the object-apparatus interaction. A
potentially realizable object-apparatus interaction measures position in such a
way that the posterior states are the translations of an arbitrary wave
function. In particular, position can be measured without perturbing the object
in a momentum eigenstate.
| [
{
"version": "v1",
"created": "Tue, 12 May 1998 08:12:57 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Ozawa",
"Masanao",
"",
"Nagoya University"
]
] |
quant-ph/9805034 | Mohammad Ardehali | M. Ardehali | Maximal violation of Bell's inequality and atomic cascade photons | LaTeX file, 18 pages, no figures. The paper has been significantly
modified. It is shown that the in the case of ideal experiments, the
inequality derived in this paper is equivalent to Bell's original inequality
of 1965 which, as is well known, is violated by a factor of 1.5. The crucial
point is that even in the case of real experiments where polarizers and
detectors are non-ideal, the present inequality is violated by a factor of
1.5, whereas previous inequalities such as CHSH inequality of 1969 and CH
inequality of 1974 are violated by a factor of $\sqrt 2$ | null | null | null | quant-ph | null | A correlation inequality is derived from local realism and a supplementary
assumption. This inequality is violated by a factor of 1.5 in the case of real
experiments, whereas previous inequalities such as Clauser-Horne-Shimony-Holt
inequality of 1969 and Clauser-Horne inequality of 1974 are violated by a
factor of $\sqrt 2$. Thus the magnitude of violation of this inequality is
approximately 20.7% larger than the magnitude of violation of previous
inequalities. Moreover, the present inequality can be used to test locality
very simply because it requires the measurements of only two detection
probabilities. In contrast, Clauser-Horne inequality requires the measurements
of five detection probabilities.
| [
{
"version": "v1",
"created": "Tue, 12 May 1998 08:17:03 GMT"
},
{
"version": "v2",
"created": "Sat, 19 Sep 1998 07:56:56 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ardehali",
"M.",
""
]
] |
quant-ph/9805035 | null | J. P. Palao, J. G. Muga, and R. Sala | Composite absorbing potentials | 9 pages, Revtex, 2 postscript figures. Accepted in Phys. Rev. Lett | Phys.Rev.Lett. 80 (1998) 5469-5472 | 10.1103/PhysRevLett.80.5469 | ULL 9805001 | quant-ph | null | The multiple scattering interferences due to the addition of several
contiguous potential units are used to construct composite absorbing potentials
that absorb at an arbitrary set of incident momenta or for a broad momentum
interval.
| [
{
"version": "v1",
"created": "Tue, 12 May 1998 12:40:41 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Palao",
"J. P.",
""
],
[
"Muga",
"J. G.",
""
],
[
"Sala",
"R.",
""
]
] |
quant-ph/9805036 | Siergiej Leble | S B Leble, A V Yurov (Technical University of Gdansk, Kaliningrad
State University) | The addition of the lower level to spectrums of matrix and scalar
components of d=2 SUSY Hamiltonian | amstex | null | null | null | quant-ph | null | Supersymmetrical quantum--mechanical system is consider in the case of d=2.
The problem of addition of the lower level to spectrums of matrix and scalar
components of d=2 SUSY Hamiltonian is investigated. It is shown that in the
case, the level E=0 may be degenerate. The multi--dimensional scalar
Hamiltonians with energy spectra coinciding up to finite number of discrete
levels are constructed.
| [
{
"version": "v1",
"created": "Tue, 12 May 1998 16:52:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Leble",
"S B",
"",
"Technical University of Gdansk, Kaliningrad\n State University"
],
[
"Yurov",
"A V",
"",
"Technical University of Gdansk, Kaliningrad\n State University"
]
] |
quant-ph/9805037 | Wim van Dam | Lucien Hardy (U of Oxford) and Wim van Dam (U of Oxford, CWI) | Quantum Whispers | LaTeX2e document, 16 pages, 5 figures, all 6 files should be in the
same directory before processing the LaTeX file | Phys.Rev. A59 (1999) 2635-2640 | 10.1103/PhysRevA.59.2635 | CQC-130598 | quant-ph | null | It is shown that with the use of entanglement a specific two party
communication task can be done with a systematically smaller expected error
than any possible classical protocol could do. The example utilises the very
tight correlation between separate spin measurements on a singlet state for
small differences in the angles of these two measurements. An extension of this
example to many parties arranged in a row with only local, one-to-one
communication (whispering) is then considered. It is argued that in this
scenario there exists no reliable classical protocol, whereas in the quantum
case there does.
| [
{
"version": "v1",
"created": "Wed, 13 May 1998 01:48:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hardy",
"Lucien",
"",
"U of Oxford"
],
[
"van Dam",
"Wim",
"",
"U of Oxford, CWI"
]
] |
quant-ph/9805038 | I. Rotter | W.D. Heiss, M. Mueller and I. Rotter | Collectivity, Phase Transitions and Exceptional Points in Open Quantum
Systems | 22 pages, 4 figures | Phys.Rev. E58 (1998) 2894-2901 | 10.1103/PhysRevE.58.2894 | null | quant-ph | null | Phase transitions in open quantum systems, which are associated with the
formation of collective states of a large width and of trapped states with
rather small widths, are related to exceptional points of the Hamiltonian.
Exceptional points are the singularities of the spectrum and eigenfunctions,
when they are considered as functions of a coupling parameter. In the present
paper this parameter is the coupling strength to the continuum. It is shown
that the positions of the exceptional points (their accumulation point in the
thermodynamical limit) depend on the particular type and energy dependence of
the coupling to the continuum in the same way as the transition point of the
corresponding phase transition.
| [
{
"version": "v1",
"created": "Wed, 13 May 1998 11:07:10 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Heiss",
"W. D.",
""
],
[
"Mueller",
"M.",
""
],
[
"Rotter",
"I.",
""
]
] |
quant-ph/9805039 | David Meyer | David A. Meyer (University of California/San Diego) | Scale decoherence in inhomogeneous potentials | 10 pages, plain TeX, 4 PostScript figures included with epsf.tex
(ignore the under/overfull \vbox error messages) | null | null | null | quant-ph | null | Finite precision measurement factors the Hilbert space of a quantum system
into a tensor product $H_{coarse} \otimes H_{fine}$. This is mathematically
equivalent to the partition into system and environment which forms the arena
for decoherence, so we describe the consequences of the inaccessibility of
$H_{fine}$ as scale decoherence. Considering the experimentally important case
of a harmonic oscillator potential as well as a periodic piecewise constant
potential, we show that scale decoherence occurs for inhomogeneous potentials
and may explain part of the decoherence observed in recent and proposed
experiments on mesoscopic superpositions of quantum states.
| [
{
"version": "v1",
"created": "Thu, 14 May 1998 01:46:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Meyer",
"David A.",
"",
"University of California/San Diego"
]
] |
quant-ph/9805040 | Alexander Kozhekin | G. Kurizki, A. E. Kozhekin, A. G. Kofman (Weizmann Inst. of Science,
Israel) and M. Blaauboer (Vrije Universiteit, The Netherlands) | Optical Tachyons in Parametric Amplifiers: How Fast Can Quantum
Information Travel? | Contribution to the Internet session, VII Seminar on Quantum Optics
(Raubichi, BELARUS, May 18-20, 1998), see http://194.158.195.199/ (10 pages,
RevTeX, 8 figures) | Opt.Spectrosc.87:505-512,1999 | null | null | quant-ph physics.optics | null | We show that optical tachyonic dispersion corresponding to superluminal
(faster than-light) group velocities characterizes parametrically amplifying
media. The turn-on of parametric amplification in finite media, followed by
illumination by spectrally narrow probe wavepackets, can give rise to transient
tachyonic wavepackets. In the stable (sub-threshold) operating regime of an
optical phase conjugator it is possible to transmit probe pulses with a
superluminally advanced peak, whereas conjugate reflection is always
subluminal. In the unstable (above-threshold) regime, superluminal response
occurs both in reflection and in transmission, at times preceding the onset of
exponential growth due to the instability. Remarkably, the quantum information
transmitted by probe or conjugate pulses, albeit causal, is confined to times
corresponding to superluminal velocities. These phenomena are explicitly
analyzed for four-wave mixing, stimulated Raman scattering and parametric
downconversion.
| [
{
"version": "v1",
"created": "Thu, 14 May 1998 09:03:30 GMT"
}
] | 2011-04-15T00:00:00 | [
[
"Kurizki",
"G.",
"",
"Weizmann Inst. of Science,\n Israel"
],
[
"Kozhekin",
"A. E.",
"",
"Weizmann Inst. of Science,\n Israel"
],
[
"Kofman",
"A. G.",
"",
"Weizmann Inst. of Science,\n Israel"
],
[
"Blaauboer",
"M.",
"",
"Vrije Universiteit, The Netherlands"
]
] |
quant-ph/9805041 | Jens Bolte | Jens Bolte and Stefan Keppeler | Semiclassical Time Evolution and Trace Formula for Relativistic Spin-1/2
Particles | 8 pages, no figures | Phys.Rev.Lett. 81 (1998) 1987-1991 | 10.1103/PhysRevLett.81.1987 | ULM-TP/98-3 | quant-ph chao-dyn math-ph math.MP nlin.CD | null | We investigate the Dirac equation in the semiclassical limit \hbar --> 0. A
semiclassical propagator and a trace formula are derived and are shown to be
determined by the classical orbits of a relativistic point particle. In
addition, two phase factors enter, one of which can be calculated from the
Thomas precession of a classical spin transported along the particle orbits.
For the second factor we provide an interpretation in terms of dynamical and
geometric phases.
| [
{
"version": "v1",
"created": "Thu, 14 May 1998 13:37:48 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bolte",
"Jens",
""
],
[
"Keppeler",
"Stefan",
""
]
] |
quant-ph/9805042 | Asim Gangopadhyaya | Asim Gangopadhyaya, Jeffry V. Mallow and Uday P. Sukhatme | Shape Invariance and Its Connection to Potential Algebra | Latex File, 10 pages, One figure available on request. Appeared in
the proceedings of the workshop on "Supersymmetric Quantum Mechanics and
Integrable Models" held at University of Illinois, June 12-14, 1997; Ed. H.
Aratyn et al | null | 10.1007/BFb0105329 | null | quant-ph | null | Exactly solvable potentials of nonrelativistic quantum mechanics are known to
be shape invariant. For these potentials, eigenvalues and eigenvectors can be
derived using well known methods of supersymmetric quantum mechanics. The
majority of these potentials have also been shown to possess a potential
algebra, and hence are also solvable by group theoretical techniques. In this
paper, for a subset of solvable problems, we establish a connection between the
two methods and show that they are indeed equivalent.
| [
{
"version": "v1",
"created": "Thu, 14 May 1998 14:29:08 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Gangopadhyaya",
"Asim",
""
],
[
"Mallow",
"Jeffry V.",
""
],
[
"Sukhatme",
"Uday P.",
""
]
] |
quant-ph/9805043 | Dan Ventura | Dan Ventura and Tony Martinez | Quantum Harmonic Sieve: Learning DNF with a Classical Example Oracle | 33 pages | null | null | null | quant-ph | null | This paper has been withdrawn by the authors due to a problem with
*efficiently* predicting the large fourier coefficients. It is being reworked
and will be resubmitted in the near future.
| [
{
"version": "v1",
"created": "Fri, 15 May 1998 03:54:47 GMT"
},
{
"version": "v2",
"created": "Thu, 11 Jun 1998 18:59:20 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ventura",
"Dan",
""
],
[
"Martinez",
"Tony",
""
]
] |
quant-ph/9805044 | Astrid Lambrecht | A. Lambrecht, M.T.Jaekel, S. Reynaud | Frequency up-converted radiation from a cavity moving in vacuum | 10 pages, 3 figures, LaTeX, to appear in European Physical Journal
D3, replaced version with few minor grammatical changes | Eur.Phys.J. D3 (1998) 95-104 | 10.1007/s100530050152 | null | quant-ph | null | We calculate the photon emission of a high finesse cavity moving in vacuum.
The cavity is treated as an open system. The field initially in the vacuum
state accumulates a dephasing depending on the mirrors motion when bouncing
back and forth inside the cavity. The dephasing is not linearized in our
calculation, so that qualitatively new effects like pulse shaping in the time
domain and frequency up-conversion in the spectrum are found. Furthermore we
predict the existence of a threshold above which the system should show
self-sustained oscillations.
| [
{
"version": "v1",
"created": "Fri, 15 May 1998 07:50:09 GMT"
},
{
"version": "v2",
"created": "Thu, 18 Jun 1998 12:45:25 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lambrecht",
"A.",
""
],
[
"Jaekel",
"M. T.",
""
],
[
"Reynaud",
"S.",
""
]
] |
quant-ph/9805045 | Molotkov S. | S.N.Molotkov (Institute of Solid State Physics, Russian Academy of
Sciences) | Quantum teleportation of a single-photon wave packet | 6 pages, no figures | Phys.Lett. A245 (1998) 339-344 | 10.1016/S0375-9601(98)00423-X | null | quant-ph | null | A quantum teleportation scheme based on the EPR-pair entangled with respect
to the ``energy+time'' variables is proposed. Teleportation of the multimode
state of a single-photon wave packet is considered.
| [
{
"version": "v1",
"created": "Fri, 15 May 1998 11:17:03 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Molotkov",
"S. N.",
"",
"Institute of Solid State Physics, Russian Academy of\n Sciences"
]
] |
quant-ph/9805046 | Lars M. Johansen | Lars M. Johansen | Hydrodynamical quantum state reconstruction | 4 pages, 3 figures, to appear in Phys. Rev. Lett | Phys.Rev.Lett.80:5461-5464,1998 | 10.1103/PhysRevLett.80.5461 | null | quant-ph | null | The density matrix of a nonrelativistic wave-packet in an arbitrary,
one-dimensional and time-dependent potential can be reconstructed by measuring
hydrodynamical moments of the Wigner distribution. An n-th order Taylor
polynomial in the off-diagonal variable is obtained by measuring the
probability distribution at n+1 discrete time values.
| [
{
"version": "v1",
"created": "Fri, 15 May 1998 21:49:52 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Johansen",
"Lars M.",
""
]
] |
quant-ph/9805047 | Henry Stapp | Henry P. Stapp | Is quantum mechanics non-local? | Reply to the revised (April 27, 1998) version of quant-ph/9710032
Unruh's paper has been accepted by Phys. Rev. A: My reply submitted 5/15/98 | null | null | LBNL-41813 | quant-ph | null | A recent proof, couched in the symbolic language of modal logic, shows that a
well-defined formulation of the question posed in the title is answered
affirmatively. In a paper with the same title Unruh has tried in various ways
to translate the symbolic proof into normal prose, and has claimed that the
proof must fail in some way or another. A correct translation is given here,
and it is explained why the difficulties encountered by Unruh do not actually
arise.
| [
{
"version": "v1",
"created": "Fri, 15 May 1998 23:48:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Stapp",
"Henry P.",
""
]
] |
quant-ph/9805048 | M. Dakna | M. Dakna, J. Clausen, L. Knoll, and D.-G. Welsch | Generating and monitoring Schr\"odinger cats in conditional measurement
on a beam splitter | 6 figures using a4.sty | null | null | null | quant-ph | null | Preparation of Schr\"odinger-cat-like states via conditional output
measurement on a beam splitter is studied. In the scheme, a mode prepared in a
squeezed vacuum is mixed with a mode prepared in a Fock state and photocounting
is performed in one of the output channels of the beam splitter. In this way
the mode in the other output channel is prepared in a Schr\"odinger-cat-like
state that is either a photon-subtracted or a photon-added Jacobi polynomial
squeezed vacuum state, depending upon the difference between the number of
photons in the input Fock state and the number of photons in the output Fock
state onto which it is projected. Two possible photocounting schemes are
considered, and the problem of monitoring cats that are ``hidden'' in a
statistical mixture of states is studied.
| [
{
"version": "v1",
"created": "Sat, 16 May 1998 11:38:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dakna",
"M.",
""
],
[
"Clausen",
"J.",
""
],
[
"Knoll",
"L.",
""
],
[
"Welsch",
"D. -G.",
""
]
] |
quant-ph/9805049 | Philip Pearle | Philip Pearle | True Collapse and False Collapse | 14 pages, Tex | Quantum Classical Correspondence: Proceedings of the 4th Drexel
Symposium on Quantum Nonintegrability, Philadelphia, PA, USA, September 8-11,
1994, pp. 51-68. Edited by Da Hsuan Feng and Bei Lok Hu. Cambridge, MA:
International Press, 1997 | null | null | quant-ph | null | We emphasize that standard quantum theory (SQT) is incomplete because it
doesn't describe what is experimentally observed, namely events, nor does it
satisfactorily define the circumstances under which events may occur. Simple
models are given (all of which have the same density matrix evolution) to
illustrate schemes which claim to complete SQT. It is shown how the model based
upon the Continuous Spontaneous Localization (CSL) theory, in which an
individual statevector undergoes "True Collapse," gives a satisfactory
description of events. It is argued that various "decoherence" based
approaches, illustrated by models in which a density matrix undergoes "False
Collapse," do not satisfactorily resolve these problems of SQT.
| [
{
"version": "v1",
"created": "Sun, 17 May 1998 12:17:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pearle",
"Philip",
""
]
] |
quant-ph/9805050 | Philip Pearle | Philip Pearle | Tales and Tails and Stuff and Nonsense | 14 pages, Tex | Experimental Metaphysics-Quantum Mechanical Studies in Honor of
Abner Shimony, volume 1, edited by R. S. Cohen, M. A. Horne and J. S. Stachel
(Kluwer, Great Britain 1997) pp.143-156 | null | null | quant-ph | null | In an informal way I review collapse models and my part in constructing them,
and I recall some encounters with Abner Shimony. In particular, I address the
question of the nature of spacetime reality in collapse models, stimulated by
Abner's criticism of the "tail" possessed by statevectors in such models.
| [
{
"version": "v1",
"created": "Sun, 17 May 1998 13:05:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pearle",
"Philip",
""
]
] |
quant-ph/9805051 | Boris F. Samsonov | Boris F. Samsonov | On a Resolution of the Identity in Terms of Coherent States | null | null | null | null | quant-ph | null | Transformations of coherent states of the free particle by bounded and
semibounded symmetry operators are considered. Resolution of the identity
operator in terms of the transformed states is analyzed. A generalized identity
resolution is formulated. Darboux transformation operators are analyzed as
operators defined in a Hilbert space. Coherent states of multisoliton
potentials are studied.
| [
{
"version": "v1",
"created": "Mon, 18 May 1998 01:40:44 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Samsonov",
"Boris F.",
""
]
] |
quant-ph/9805052 | Lev F. M. | Felix M. Lev | On the problem of interactions in quantum theory | 35 pages, Latex | J.Phys.A32:1225-1239,1999 | 10.1088/0305-4470/32/7/012 | null | quant-ph gr-qc | null | The structure of representations describing systems of free particles in the
theory with the invariance group SO(1,4) is investigated. The property of the
particles to be free means as usual that the representation describing a
many-particle system is the tensor product of the corresponding single-particle
representations (i.e. no interaction is introduced). It is shown that the mass
operator contains only continuous spectrum in the interval $(-\infty,\infty)$
and such representations are unitarily equivalent to ones describing
interactions (gravitational, electromagnetic etc.). This means that there are
no bound states in the theory and the Hilbert space of the many-particle system
contains a subspace of states with the following property: the action of free
representation operators on these states is manifested in the form of different
interactions. Possible consequences of the results are discussed.
| [
{
"version": "v1",
"created": "Mon, 18 May 1998 11:13:33 GMT"
}
] | 2011-03-28T00:00:00 | [
[
"Lev",
"Felix M.",
""
]
] |
quant-ph/9805053 | Robert Myska | Z. Hradil and R. Myska | Reconstruction of diagonal elements of density matrix using maximum
likelihood estimation | LaTeX, 5 pages, 7 figures; to be published in acta physica slovaca | Acta Phys.Slov. 48 (1998) 199-205 | null | null | quant-ph | null | The data of the experiment of Schiller et al., Phys. Rev. Lett. 77 (1996)
2933, are alternatively evaluated using the maximum likelihood estimation. The
given data are fitted better than by the standard deterministic approach.
Nevertheless, the data are fitted equally well by a whole family of states.
Standard deterministic predictions correspond approximately to the envelope of
these maximum likelihood solutions.
| [
{
"version": "v1",
"created": "Mon, 18 May 1998 14:09:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hradil",
"Z.",
""
],
[
"Myska",
"R.",
""
]
] |
quant-ph/9805054 | David Marcus Appleby | D. M. Appleby | Generalized Husimi Functions: Analyticity and Information Content | 16 pages, 2 figures, AMS-latex. Replaced with published version | J.Mod.Opt. 46 (1999) 825-841 | 10.1080/09500349908231307 | QMW-PH-98-21 | quant-ph | null | The analytic properties of a class of generalized Husimi functions are
discussed, with particular reference to the problem of state reconstruction.
The class consists of the subset of Wodkiewicz's operational probability
distributions for which the filter reference state is a squeezed vacuum state.
The fact that the function is analytic means that perfectly precise knowledge
of its values over any small region of phase space provides enough information
to reconstruct the density matrix. If, however, one only has imprecise
knowledge of its values, then the amplification of statistical errors which
occurs when one attempts to carry out the continuation seriously limits the
amount of information which can be extracted. To take account of this fact a
distinction is made between explicate, or experimentally accessible
information, and information which is only present in implicate, experimentally
inaccessible form. It is shown that an explicate description of various aspects
of the system can be found localised on various 2 real dimensional surfaces in
complexified phase space. In particular, the continuation of the function to
the purely imaginary part of complexified phase space provides an explicate
description of the Wigner function.
| [
{
"version": "v1",
"created": "Mon, 18 May 1998 18:49:05 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Nov 1999 22:54:23 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Appleby",
"D. M.",
""
]
] |
quant-ph/9805055 | C. Anastopoulos | C. Anastopoulos | Information measures and classicality in quantum mechanics | 35 pages, LATEX | Phys.Rev. D59 (1999) 045001 | 10.1103/PhysRevD.59.045001 | FFN, University of Barcelona Preprint | quant-ph gr-qc | null | We study information measures in quantu mechanics, with particular emphasis
on providing a quantification of the notions of classicality and
predictability. Our primary tool is the Shannon - Wehrl entropy I. We give a
precise criterion for phase space classicality and argue that in view of this
a) I provides a measure of the degree of deviation from classicality for closed
system b) I - S (S the von Neumann entropy) plays the same role in open systems
We examine particular examples in non-relativistic quantum mechanics. Finally,
(this being one of our main motivations) we comment on field classicalisation
on early universe cosmology.
| [
{
"version": "v1",
"created": "Tue, 19 May 1998 12:15:49 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Anastopoulos",
"C.",
""
]
] |
quant-ph/9805056 | Robert B. Griffiths | Robert B. Griffiths (Carnegie Mellon University) | Consistent Quantum Counterfactuals | Minor modifications to make it agree with published version. Latex 8
pages, 2 figures | Phys.Rev. A60 (1999) 5-8 | 10.1103/PhysRevA.60.R5 | null | quant-ph | null | An analysis using classical stochastic processes is used to construct a
consistent system of quantum counterfactual reasoning. When applied to a
counterfactual version of Hardy's paradox, it shows that the probabilistic
character of quantum reasoning together with the ``one framework'' rule
prevents a logical contradiction, and there is no evidence for any mysterious
nonlocal influences. Counterfactual reasoning can support a realistic
interpretation of standard quantum theory (measurements reveal what is actually
there) under appropriate circumstances.
| [
{
"version": "v1",
"created": "Tue, 19 May 1998 20:46:49 GMT"
},
{
"version": "v2",
"created": "Sat, 20 Mar 1999 22:30:36 GMT"
},
{
"version": "v3",
"created": "Wed, 15 Sep 1999 20:40:29 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Griffiths",
"Robert B.",
"",
"Carnegie Mellon University"
]
] |
quant-ph/9805057 | Jonathan Halliwell | J. J. Halliwell (Imperial College, London) | Arrival Times in Quantum Theory from an Irreversible Detector Model | 19 pages, plain Tex (Fourth revision). To appear in Prog.Th.Phys.
Vol. 102, No. 4 | Prog.Theor.Phys. 102 (1999) 707-717 | 10.1143/PTP.102.707 | null | quant-ph | null | We investigate a detector scheme designed to measure the arrival of a
particle at $x=0$ during a finite time interval. The detector consists of a two
state system which undergoes a transition from one state to the other when the
particle crosses $x=0$, and possesses the realistic feature that it is
effectively irreversible as a result of being coupled to a large environment.
The probabilities for crossing or not crossing $x=0$ thereby derived coincide
with earlier phenomenologically proposed expressions involving a complex
potential. The probabilities are compared with similar previously proposed
expressions involving sums over paths, and a connection with time operator
approaches is also indicated.
| [
{
"version": "v1",
"created": "Tue, 19 May 1998 16:56:13 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Jun 1998 19:17:10 GMT"
},
{
"version": "v3",
"created": "Thu, 4 Feb 1999 14:16:32 GMT"
},
{
"version": "v4",
"created": "Tue, 6 Apr 1999 17:31:59 GMT"
},
{
"version": "v5",
"created": "Tue, 24 Aug 1999 10:49:48 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Halliwell",
"J. J.",
"",
"Imperial College, London"
]
] |
quant-ph/9805058 | Vicente Delgado | V. Delgado (Univ. La Laguna) | Quantum probability distribution of arrival times and probability
current density | 21 pages, 7 figures, LaTeX; Revised version to appear in Phys. Rev. A
(many small changes) | Phys. Rev. A 59, 1010 (1999) | 10.1103/PhysRevA.59.1010 | null | quant-ph | null | This paper compares the proposal made in previous papers for a quantum
probability distribution of the time of arrival at a certain point with the
corresponding proposal based on the probability current density. Quantitative
differences between the two formulations are examined analytically and
numerically with the aim of establishing conditions under which the proposals
might be tested by experiment. It is found that quantum regime conditions
produce the biggest differences between the formulations which are otherwise
near indistinguishable. These results indicate that in order to discriminate
conclusively among the different alternatives, the corresponding experimental
test should be performed in the quantum regime and with sufficiently high
resolution so as to resolve small quantum efects.
| [
{
"version": "v1",
"created": "Tue, 19 May 1998 19:51:15 GMT"
},
{
"version": "v2",
"created": "Wed, 9 Dec 1998 20:48:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Delgado",
"V.",
"",
"Univ. La Laguna"
]
] |
quant-ph/9805059 | Haiqing Wei | Haiqing Wei, Xin Xue and S. D. Morgera | NMR Quantum Automata in Doped Crystals | Latex file, one eps figure | null | null | null | quant-ph | null | In a lattice ${\cal L}$ of nuclear spins with ABCABCABC... type periodic
structure embedded in a single-crystal solid, each ABC-unit can be used to
store quantum information and the information can be moved around via some
cellular shifting mechanism. Impurity doping marks a special site
D$\not\in{\cal L}$ which together with the local spin lattice constitute a
quantum automaton where the D site serves as the input/output port and
universal quantum logic is done through two-body interactions between two spins
at D and a nearby site. The novel NMR quantum computer can be easily scaled up
and may work at low temperature to overcome the problem of exponential decay in
signal-to-noise ratio in room temperature NMR.
| [
{
"version": "v1",
"created": "Wed, 20 May 1998 12:32:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wei",
"Haiqing",
""
],
[
"Xue",
"Xin",
""
],
[
"Morgera",
"S. D.",
""
]
] |
quant-ph/9805060 | Lorenza Viola | Roberto Onofrio and Lorenza Viola | Dynamics of decoherence in continuous atom-optical quantum nondemolition
measurements | 9 pages, plain ReVTeX, 4 figures. To be published in Physical Review
A 58, 1 July 1998 | null | 10.1103/PhysRevA.58.69 | null | quant-ph | null | The Lindblad approach to continuous quantum measurements is applied to a
system composed of a two-level atom interacting with a stationary quantized
electromagnetic field through a dispersive coupling fulfilling quantum
nondemolition criteria. Two schemes of measurements are examined. The first one
consists in measuring the atomic electric dipole, which indirectly allows one
to infer the photon distribution inside the cavity. The second one schematizes
a measurement of photon momentum, which permits to describe the atomic level
distribution. Decoherence of the corresponding reduced density matrices is
studied in detail for both cases, and its relationship to recent experiments is
finally discussed.
| [
{
"version": "v1",
"created": "Wed, 20 May 1998 23:36:21 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Onofrio",
"Roberto",
""
],
[
"Viola",
"Lorenza",
""
]
] |
quant-ph/9805061 | W. A. Hofer | W. A. Hofer (TU-Wien) | Electron acceleration due to photon absorption: A possible origin of the
infinity problems in relativistic quantum fields | 4 pages (RevTeX, twocolumn) and 2 figures (eps). Journal reference
updated and the effects of time dilation explained more thoroughly. For a
list of available papers see http://info.tuwien.ac.at/cms/wh/ | null | null | MW-02/98 | quant-ph hep-ph hep-th physics.pop-ph | null | Based on the concept of extended particles recently introduced we perform a
Gedankenexperiment accelerating single electrons with photons of suitably low
frequency. Accounting for relativistic time dilation due to the acquired
velocity and in infinite repetition of single absorption processes it can be
shown that the kinetic energy in the infinite limit is equal to m_{e} c^{2}/2.
However, the inertial mass of the electron seems enhanced, and it can be
established that this enhancement is described by the relativistic mass effect.
It appears, therefore, that although there exists a singularity in interactions
- the frequency required to accelerate the particle near the limit of c becomes
infinite - the energy of the particle itself approaches a finite limit.
Comparing with calculations of the Lamb-shift by Bethe this result seems to
provide the ultimate justification for the renormalization procedures employed.
| [
{
"version": "v1",
"created": "Thu, 21 May 1998 10:37:51 GMT"
},
{
"version": "v2",
"created": "Sat, 20 Jun 1998 12:51:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hofer",
"W. A.",
"",
"TU-Wien"
]
] |
quant-ph/9805062 | Jonathan Halliwell | J. J. Halliwell (Imperial College, London) | Decoherent Histories and Hydrodynamic Equations | 35 pages, plain Tex, revised after refereeing | Phys.Rev. D58 (1998) 105015 | 10.1103/PhysRevD.58.105015 | Imperial College preprint TP/97-98/50 | quant-ph | null | For a system consisting of a large collection of particles, a set of
variables that will generally become effectively classical are the local
densities (number, momentum, energy). That is, in the context of the decoherent
histories approach to quantum theory, it is expected that histories of these
variables will be approximately decoherent, and that their probabilites will be
strongly peaked about hydrodynamic equations. This possibility is explored for
the case of the diffusion of the number density of a dilute concentration of
foreign particles in a fluid. This system has the appealing feature that the
microscopic dynamics of each individual foreign particle is readily obtained
and the approach to local equilibrium may be seen explicitly. It is shown that,
for certain physically reasonable initial states, the probabilities for
histories of number density are strongly peaked about evolution according to
the diffusion equation. Decoherence of these histories is also shown for a
class of initial states which includes non-trivial superpositions of number
density. Histories of phase space densities are also discussed. The case of
histories of number, momentum and energy density for more general systems, such
as a dilute gas, is also discussed in outline. When the initial state is a
local equilibrium state, it is shown that the histories are trivally
decoherent, and that the probabilities for histories are peaked about
hydrodynamic equations. An argument for decoherence of more general initial
states is given.
| [
{
"version": "v1",
"created": "Thu, 21 May 1998 16:21:59 GMT"
},
{
"version": "v2",
"created": "Wed, 15 Jul 1998 15:07:43 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Halliwell",
"J. J.",
"",
"Imperial College, London"
]
] |
quant-ph/9805063 | N. L. Harshman | A. Bohm and N. L. Harshman | Quantum Theory in the Rigged Hilbert Space-Irreversibility from
Causality | 60 pages, to appear in Irreversibility and Causality in Quatum
Theory: Semigroups and Rigged Hilbert Space, Arno Bohm, H.D. Doebner, P.
Kielanowski, eds; Vol. 504 Springer Lecture Notes in Physics | null | 10.1007/BFb0106783 | null | quant-ph | null | After a review of the arrows of time, we describe the possibilities of a
time-asymmetry in quantum theory. Whereas Hilbert space quantum mechanics is
time-symmetric, the rigged Hilbert space formulation, which arose from Dirac's
bra-ket formalism, allows the choice of asymmetric boundary conditions
analogous to the retarded solutions of the Maxwell equations for the radiation
arrow of time. This led to irreversibility on the microphysical level as
exemplified by decaying states or resonances. Resonances are mathematically
represented by Gamow kets, functionals over a space of very well-behaved (Hardy
class) vectors, which have been chosen by a boundary condition (outgoing for
decaying states). Gamow states have all the properties that one heuristically
needs for quasistable states. For them a Golden Rule can be derived from the
fundamental probabilities that fulfills the time-asymmetry condition which
could not be realized in the Hilbert space.
| [
{
"version": "v1",
"created": "Thu, 21 May 1998 16:43:52 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bohm",
"A.",
""
],
[
"Harshman",
"N. L.",
""
]
] |
quant-ph/9805064 | Jonathan Oppenheim | J. Oppenheim, B. Reznik, W. G. Unruh | When does a Measurement or Event Occur | 8 pages, no figures minor wording change | Found.Phys.Lett. 13 (2000) 107-118 | null | null | quant-ph | null | Within quantum mechanics it is possible to assign a probability to the chance
that a measurement has been made at a specific time t. However, the
interpretation of such a probability is far from clear. We argue that a recent
measuring scheme of Rovelli's (quant-ph/9802020) yields probabilities which do
not correspond to the conventional probabilities usually assigned in quantum
mechanics. The same arguments also apply to attempts to use the probability
current to measure the time at which a particle arrives at a given location.
| [
{
"version": "v1",
"created": "Thu, 21 May 1998 21:37:16 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Jun 1998 01:45:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Oppenheim",
"J.",
""
],
[
"Reznik",
"B.",
""
],
[
"Unruh",
"W. G.",
""
]
] |
quant-ph/9805065 | Raymond Laflamme | Wojciech H. Zurek | Decoherence, Einselection, and the Existential Interpretation (the Rough
Guide) | 27 pages in LaTex, 3 figures, to appear in Philosophical Transactions
of the Royal Society; Mathematical, Physical and Engineering Sciences | Phil.Trans.Roy.Soc.Lond.A356:1793-1820,1998 | 10.1098/rsta.1998.0250 | null | quant-ph | null | The roles of decoherence and environment-induced superselection in the
emergence of the classical from the quantum substrate are described. The
stability of correlations between the einselected quantum pointer states and
the environment allows them to exist almost as objectively as classical states
were once thought to exist: There are ways of finding out what is the pointer
state of the system which utilize redundancy of their correlations with the
environment, and which leave einselected states essentially unperturbed. This
relatively objective existence of certain quantum states facilitates
operational definition of probabilities in the quantum setting. Moreover, once
there are states that `exist' and can be `found out', a `collapse' in the
traditional sense is no longer necessary --- in effect, it has already
happened. The records of the observer will contain evidence of an effective
collapse. The role of the preferred states in the processing and storage of
information is emphasized. The existential interpretation based on the
relatively objective existence of stable correlations between the einselected
states of observers memory and in the outside Universe is formulated and
discussed.
| [
{
"version": "v1",
"created": "Thu, 21 May 1998 22:10:53 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Zurek",
"Wojciech H.",
""
]
] |
quant-ph/9805066 | Laszlo E. Szabo | G. Hofer-Szabo (1), M. Redei (2), L. E. Szabo (2) ((1) Technical
University of Budapest, (2) Eotvos University, Budapest) | On Reichenbach's common cause principle and Reichenbach's notion of
common cause | 15 pages, LaTeX | null | null | Eotvos-HPS 98-1 | quant-ph math-ph math.MP math.PR | null | It is shown that, given any finite set of pairs of random events in a Boolean
algebra which are correlated with respect to a fixed probability measure on the
algebra, the algebra can be extended in such a way that the extension contains
events that can be regarded as common causes of the correlations in the sense
of Reichenbach's definition of common cause. It is shown, further, that, given
any quantum probability space and any set of commuting events in it which are
correlated with respect to a fixed quantum state, the quantum probability space
can be extended in such a way that the extension contains common causes of all
the selected correlations, where common cause is again taken in the sense of
Reichenbach's definition. It is argued that these results very strongly
restrict the possible ways of disproving Reichenbach's Common Cause Principle.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 00:34:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hofer-Szabo",
"G.",
""
],
[
"Redei",
"M.",
""
],
[
"Szabo",
"L. E.",
""
]
] |
quant-ph/9805067 | Armen Allahverdyan | A.E. Allahverdyan, D.B. Saakian | The broadcast quantum channel for classical information transmission | LaTex file, 8 pages | null | null | null | quant-ph | null | It is well known that quantum theory forbids the exact copying of an unknown
quantum state. Therefore in broadcasting of classical information by a quantum
channel an additional contribution to the error in the decoding is expected. We
consider the optimal copying transformation which is adapted to classical
information transmission by two linearly independent quantum states, and show
that there is no additional contribution to the error. Instead the clones are
correlated, and this breaks their usefulness: The entanglement increases with
non-orthogonality of the states. The capacity of the corresponding quantum
channel is considered also.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 10:33:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Allahverdyan",
"A. E.",
""
],
[
"Saakian",
"D. B.",
""
]
] |
quant-ph/9805068 | Wladyslaw Adam Majewski | W. A. Majewski | Does quantum chaos exist? (A quantum Lyapunov exponents approach.) | Latex, 28 pages | null | null | null | quant-ph chao-dyn math-ph math.MP nlin.CD | null | We shortly review the progress in the domain of deterministic chaos for
quantum dynamical systems. With the appropriately extended definition of
quantum Lyapunov exponent we analyze various quantum dynamical maps. It is
argued that, within Quantum Mechanics, irregular evolution for properly chosen
observables can coexist with regular and predictable evolution of states.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 12:49:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Majewski",
"W. A.",
""
]
] |
quant-ph/9805069 | Jonathan A. Jones | J. A. Jones, M. Mosca, and R. H. Hansen (University of Oxford, UK) | Implementation of a Quantum Search Algorithm on a Nuclear Magnetic
Resonance Quantum Computer | Six pages, three figures | Nature 393 (1998) 344-346 | 10.1038/30687 | JAJQP-98-02 | quant-ph | null | We demonstrate an implementation of a quantum search algorithm on a two qubit
NMR quantum computer based on cytosine.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 13:51:13 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jones",
"J. A.",
"",
"University of Oxford, UK"
],
[
"Mosca",
"M.",
"",
"University of Oxford, UK"
],
[
"Hansen",
"R. H.",
"",
"University of Oxford, UK"
]
] |
quant-ph/9805070 | Jonathan A. Jones | J. A. Jones, R. H. Hansen, and M. Mosca (University of Oxford, UK) | Quantum Logic Gates and Nuclear Magnetic Resonance Pulse Sequences | Sixteen pages, no figures. Submitted to Journal of Magnetic
Resonance. Primarily pedagogical rather than a description of novel research
results | J.Magn.Resonance 135 (1998) 353-360 | 10.1006/jmre.1998.1606 | JAJQP-98-03 | quant-ph | null | We demonstrate how NMR can in principle be used to implement all the elements
required to build quantum computers, and briefly discuss the potential
applications of insights from quantum logic to the development of novel pulse
sequences with applications in more conventional NMR experiments.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 14:08:08 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jones",
"J. A.",
"",
"University of Oxford, UK"
],
[
"Hansen",
"R. H.",
"",
"University of Oxford, UK"
],
[
"Mosca",
"M.",
"",
"University of Oxford, UK"
]
] |
quant-ph/9805071 | William T. Buttler | W. T. Buttler, R. J. Hughes, P. G. Kwiat, S. K. Lamoreaux, G. G.
Luther, G. L. Morgan, J. E. Nordholt, C. G. Peterson, and C. M. Simmons | Practical free-space quantum key distribution over 1 km | 5 pages, 2 figures, 2 tables. Submitted to Physics Review Letters,
May 1998 | Phys.Rev.Lett.81:3283-3286,1998 | 10.1103/PhysRevLett.81.3283 | LAUR-97-5157 | quant-ph | null | A working free-space quantum key distribution (QKD) system has been developed
and tested over an outdoor optical path of ~1 km at Los Alamos National
Laboratory under nighttime conditions. Results show that QKD can provide secure
real-time key distribution between parties who have a need to communicate
secretly. Finally, we examine the feasibility of surface to satellite QKD.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 15:26:12 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Buttler",
"W. T.",
""
],
[
"Hughes",
"R. J.",
""
],
[
"Kwiat",
"P. G.",
""
],
[
"Lamoreaux",
"S. K.",
""
],
[
"Luther",
"G. G.",
""
],
[
"Morgan",
"G. L.",
""
],
[
"Nordholt",
"J. E.",
""
],
[
"Peterson",
"C. G.",
""
],
[
"Simmons",
"C. M.",
""
]
] |
quant-ph/9805072 | Pawel Horodecki | Pawel Horodecki, Ryszard Horodecki and Michal Horodecki | Entanglement and thermodynamical analogies | RevTeX, 11 pages | Acta Phys.Slov. 48 (1998) 141-156 | null | null | quant-ph | null | We provide some new properties of entanglement of formation. In particular,
we obtain an additive lower bound for entanglement of formation. Subsequently
we develop the concept of local orthogonality of ensembles which leads to the
mixed states with distillable entanglement equal to entanglement of formation.
Then we consider thermodynamical analogies within the entanglement processing
domain. Especially, we exploit analogy entanglement -- energy. In this scheme
the total entanglement i.e. the amount of singlet pairs needed for local
preparation of a state corresponds to internal energy while the free
entanglement defined as the number of pairs which can be recovered from the
state (distillable entanglement) is the counterpart of free energy. In
particular, it leads us to the question about ``temperature'' of entanglement.
We also propose a scheme of the search of representative state for given
entanglement which can be viewed as an analogue of the Jaynes maximum entropy
principle.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 19:07:20 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Horodecki",
"Pawel",
""
],
[
"Horodecki",
"Ryszard",
""
],
[
"Horodecki",
"Michal",
""
]
] |
quant-ph/9805073 | Chi-Sheng Niu | Chi-Sheng Niu, Robert B. Griffiths | Optimal Copying of One Quantum Bit | RevTex, 26 pages, 2 Postscript figures | Phys.Rev. A58 (1998) 4377-4393 | 10.1103/PhysRevA.58.4377 | null | quant-ph | null | A quantum copying machine producing two (in general non-identical) copies of
an arbitrary input state of a two-dimensional Hilbert space (qubit) is studied
using a quality measure based on distinguishability of states, rather than
fidelity. The problem of producing optimal copies is investigated with the help
of a Bloch sphere representation, and shown to have a well-defined solution,
including cases in which the two copies have unequal quality, or the quality
depends upon the input state (is ``anisotropic'' in Bloch sphere language), or
both. A simple quantum circuit yields the optimal copying machine. With a
suitable choice of parameters it becomes an optimal eavesdropping machine for
some versions of quantum cryptography, or reproduces the Buzek and Hillery
result for isotropic copies.
| [
{
"version": "v1",
"created": "Fri, 22 May 1998 20:03:10 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Niu",
"Chi-Sheng",
""
],
[
"Griffiths",
"Robert B.",
""
]
] |
quant-ph/9805074 | Angelo Tartaglia | A. Tartaglia (Dipartimento di Fisica, Politecnico Torino, Italy) | Is the EPR paradox really a paradox? | Latex | European Journal of Physics, 19,307, (1998) | 10.1088/0143-0807/19/3/015 | null | quant-ph | null | The EPR paradox and the meaning of the Bell inequality are discussed. It is
shown that considering the quantum objects as carrying with them ''instruction
kits'' telling them what to do when meeting a measurement apparatus any paradox
disappears. In this view the quantum state is characterized by the prescribed
behaviour rather than by the specific value a parameter assumes as a result of
an interaction.
| [
{
"version": "v1",
"created": "Mon, 25 May 1998 09:46:13 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Tartaglia",
"A.",
"",
"Dipartimento di Fisica, Politecnico Torino, Italy"
]
] |
quant-ph/9805075 | Frank Antonsen | Frank Antonsen, Karsten Bormann | Time Machines and the Breakdown of Unitarity | standard LaTeX | Int.J.Theor.Phys. 37 (1998) 2383-2393 | null | null | quant-ph | null | We present a generic way of thinking about time machines from the view of a
far away observer. In this model the universe consists of three (or more)
regions: One containing the entrance of the time machine, another the exit and
the remaining one(s) the rest of the universe. In the latter we know ordinary
quantum mechanics to be valid and thus are able to write down a Hamiltonian
describing this generic time machine. We prove the time-evolution operator to
be non-symmetric. Various interpretations of this irreversibility are given.
| [
{
"version": "v1",
"created": "Mon, 25 May 1998 12:47:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Antonsen",
"Frank",
""
],
[
"Bormann",
"Karsten",
""
]
] |
quant-ph/9805076 | Hideo Mabuchi | Hideo Mabuchi, Jun Ye, and H. Jeff Kimble | Full observation of single-atom dynamics in cavity QED | Submitted to Applied Physics B. Uses Revtex, 13 pages with 11 EPS
figures | null | 10.1007/s003400050751 | null | quant-ph physics.atom-ph | null | We report the use of broadband heterodyne spectroscopy to perform continuous
measurement of the interaction energy between one atom and a high-finesse
optical cavity, during individual transit events of $\sim 250$ $\mu$s duration.
Measurements over a wide range of atom-cavity detunings reveal the transition
from resonant to dispersive coupling, via the transfer of atom-induced signals
from the amplitude to the phase of light transmitted through the cavity. By
suppressing all sources of excess technical noise, we approach a measurement
regime in which the broadband photocurrent may be interpreted as a classical
record of conditional quantum evolution in the sense of recently developed
quantum trajectory theories.
| [
{
"version": "v1",
"created": "Mon, 25 May 1998 18:34:48 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Mabuchi",
"Hideo",
""
],
[
"Ye",
"Jun",
""
],
[
"Kimble",
"H. Jeff",
""
]
] |
quant-ph/9805077 | Howard M. Wiseman | H.M. Wiseman | In-loop squeezing is real squeezing to an in-loop atom | 4 pages, 2 figures, submitted to PRL | Phys.Rev.Lett. 81 (1998) 3840-3843 | 10.1103/PhysRevLett.81.3840 | null | quant-ph | null | Electro-optical feedback can produce an in-loop photocurrent with arbitrarily
low noise. This is not regarded as evidence of `real' squeezing because
squeezed light cannot be extracted from the loop using a linear beam splitter.
Here I show that illuminating an atom (which is a nonlinear optical element)
with `in-loop' squeezed light causes line-narrowing of one quadrature of the
atom's fluorescence. This has long been regarded as an effect which can only be
produced by squeezing. Experiments on atoms using in-loop squeezing should be
much easier than those with conventional sources of squeezed light.
| [
{
"version": "v1",
"created": "Tue, 26 May 1998 00:44:24 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Wiseman",
"H. M.",
""
]
] |
quant-ph/9805078 | Andrei Kirilyuk | Andrei P. Kirilyuk | New Concept of Dynamic Complexity in Quantum Mechanics and Beyond | 5 pages, PostScript 3.0 from an MS Word file; a non-technical
interpretation of recently published results | Annales Fond.Broglie 21 (1996) 455-480 | null | null | quant-ph chao-dyn nlin.CD | null | The qualitatively new concept of dynamic complexity in quantum mechanics is
based on a new paradigm appearing within a nonperturbational analysis of the
Schroedinger equation for a generic Hamiltonian system. The unreduced analysis
explicitly provides the complete, consistent solution as a set of many
incompatible components ('realisations') which should permanently and
probabilistically replace one another, since each of them is 'complete' in the
ordinary sense. This discovery leads to the universally applicable concept of
dynamic complexity and self-consistent, realistic resolution of the stagnating
problems of quantum chaos, quantum measurement, indeterminacy and wave
reduction. The peculiar, 'mysterious' character of quantum behaviour itself is
seen now as a result of a dynamically complex, intrinsically multivalued
behaviour of interacting fields at the corresponding lowest levels of the (now
completely causal) structure of reality. Incorporating the results of the
canonical theories as an over-simplified limiting case, this new approach
urgently needs support, since its causality and completeness are directly
extendible to arbitrary cases of complex behaviour of real systems, in sharp
contrast to the dominating inefficient empiricism of 'computer experimentation'
with primitive mechanistic (i. e. dynamically single-valued) 'models' of the
irreducibly multivalued reality.
| [
{
"version": "v1",
"created": "Tue, 26 May 1998 08:30:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kirilyuk",
"Andrei P.",
""
]
] |
quant-ph/9805079 | Farhad Ghaboussi | F. Ghaboussi | On Quantum Mechanics | 9 pages, latex, revised version2 | null | null | null | quant-ph | null | We discuss the axiomatic basis of quantum mechanics and show that it is
neither general nor consistent, since its axioms are incompatible with each
other and moreover it does not incorporate the magnetic quantization as in the
cyclotron motion. A general and consistent system of axioms is conjectured
which incorporates also the magnetic quantization.
| [
{
"version": "v1",
"created": "Wed, 27 May 1998 01:30:13 GMT"
},
{
"version": "v2",
"created": "Fri, 29 May 1998 12:21:32 GMT"
},
{
"version": "v3",
"created": "Tue, 2 Jun 1998 12:59:41 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ghaboussi",
"F.",
""
]
] |
quant-ph/9805080 | Hoi-Kwong Lo | Samuel L. Braunstein, Christopher A. Fuchs, Daniel Gottesman, and
Hoi-Kwong Lo | A quantum analog of Huffman coding | Revised version, 7 pages, two-column, RevTex. Presented at 1998 IEEE
International Symposium on Information Theory | null | null | null | quant-ph | null | We analyze a generalization of Huffman coding to the quantum case. In
particular, we notice various difficulties in using instantaneous codes for
quantum communication. Nevertheless, for the storage of quantum information, we
have succeeded in constructing a Huffman-coding inspired quantum scheme. The
number of computational steps in the encoding and decoding processes of N
quantum signals can be made to be of polylogarithmic depth by a massively
parallel implementation of a quantum gate array. This is to be compared with
the O (N^3) computational steps required in the sequential implementation by
Cleve and DiVincenzo of the well-known quantum noiseless block coding scheme of
Schumacher. We also show that O(N^2(log N)^a) computational steps are needed
for the communication of quantum information using another Huffman-coding
inspired scheme where the sender must disentangle her encoding device before
the receiver can perform any measurements on his signals.
| [
{
"version": "v1",
"created": "Wed, 27 May 1998 10:21:24 GMT"
},
{
"version": "v2",
"created": "Tue, 18 May 1999 10:01:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Braunstein",
"Samuel L.",
""
],
[
"Fuchs",
"Christopher A.",
""
],
[
"Gottesman",
"Daniel",
""
],
[
"Lo",
"Hoi-Kwong",
""
]
] |
quant-ph/9805081 | Leo Stodolsky | L. Stodolsky (Max-Planck-Institut fur Physik) | Measurement Process In a Two-Barrier System | Completely revised discussion of transmitted current, otherwise
mostly minor editorial changes | Phys.Lett.B459:193,1999 | 10.1016/S0370-2693(99)00659-0 | MPI-Th/98-40 (corrected report no.) | quant-ph cond-mat | null | The description of a measuring process, such as that which occurs when a
quantum point contact (QPC) detector is influenced by a nearby external
electron which can take up two possible positions, provides a interesting
application of the method of quantum damping. We find a number of new effects,
due to the complete treatment of phases afforded by the formalism, although our
results are generally similiar to those of other treatments, particularly to
those of Buks et al.
These are effects depending on the phase shift in the detector, effects which
depend on the direction of the measuring current, and in addition to damping or
dissipative effects, an energy shift of the measured system. In particular, the
phase shift effect leads to the conclusion that there can be effects of
"observation" even when the two barriers in question pass the same current.
The nature of the current through the barriers and its statistics is
discussed, giving a description of correlations in the current due to
"measurement" and of the origin of "telegraphic" signals.
| [
{
"version": "v1",
"created": "Wed, 27 May 1998 12:16:17 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Aug 1998 14:47:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Stodolsky",
"L.",
"",
"Max-Planck-Institut fur Physik"
]
] |
quant-ph/9805082 | Alain Tapp | Gilles Brassard (1), Peter Hoyer (2), Alain Tapp (1) ((1) Universite
de Montreal, (2) Odense University) | Quantum Counting | 12 pages, LaTeX2e | 25th Intl. Colloquium on Automata, Languages, and Programming
(ICALP), LNCS 1443, pp. 820-831, 1998 | 10.1007/BFb0055105 | null | quant-ph | null | We study some extensions of Grover's quantum searching algorithm. First, we
generalize the Grover iteration in the light of a concept called amplitude
amplification. Then, we show that the quadratic speedup obtained by the quantum
searching algorithm over classical brute force can still be obtained for a
large family of search problems for which good classical heuristics exist.
Finally, as our main result, we combine ideas from Grover's and Shor's quantum
algorithms to perform approximate counting, which can be seen as an amplitude
estimation process.
| [
{
"version": "v1",
"created": "Wed, 27 May 1998 22:35:27 GMT"
}
] | 2017-01-03T00:00:00 | [
[
"Brassard",
"Gilles",
""
],
[
"Hoyer",
"Peter",
""
],
[
"Tapp",
"Alain",
""
]
] |
quant-ph/9805083 | Yu Shi | Yu Shi | Remarks on Universal Quantum Computer | This paper has been withdrawn | null | null | null | quant-ph | null | This paper has been superseded by quant-ph/9908074.
| [
{
"version": "v1",
"created": "Thu, 28 May 1998 11:28:10 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Jun 1998 09:48:41 GMT"
},
{
"version": "v3",
"created": "Mon, 8 Jun 1998 13:44:06 GMT"
},
{
"version": "v4",
"created": "Fri, 23 Oct 1998 12:25:57 GMT"
},
{
"version": "v5",
"created": "Tue, 2 Feb 1999 14:38:56 GMT"
},
{
"version": "v6",
"created": "Mon, 25 Feb 2002 17:36:03 GMT"
}
] | 2019-12-06T00:00:00 | [
[
"Shi",
"Yu",
""
]
] |
quant-ph/9805084 | Hanna E. Makaruk | Micho Durdevich, Hanna E. Makaruk, Robert Owczarek | Generalized Noiseless Quantum Codes utilizing Quantum Enveloping
Algebras | 10 pages, LaTeX, 2 figures Postscript | J.Phys.A34:1423-1438,2001 | 10.1088/0305-4470/34/7/314 | LAUR98-2225 | quant-ph | null | A generalization of the results of Rasetti and Zanardi concerning avoiding
errors in quantum computers by using states preserved by evolution is
presented. The concept of dynamical symmetry is generalized from the level of
classical Lie algebras and groups to the level of dynamical symmetry based on
quantum Lie algebras and quantum groups (in the sense of Woronowicz). A natural
connection is proved between states preserved by representations of a quantum
group and states preserved by evolution with dynamical symmetry of the
appropriate universal enveloping algebra. Illustrative examples are discussed.
| [
{
"version": "v1",
"created": "Thu, 28 May 1998 23:42:08 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Durdevich",
"Micho",
""
],
[
"Makaruk",
"Hanna E.",
""
],
[
"Owczarek",
"Robert",
""
]
] |
quant-ph/9805085 | Georg Junker | Francesco Cannata, Georg Junker, Johannes Trost | Schr\"odinger operators with complex potential but real spectrum | 10, pages, LaTeX 2.09, 6 Postscript figures, uses amsfont, figures
available at http://faupt100.physik.uni-erlangen.de/junker/papers95-99.htm | Phys.Lett. A246 (1998) 219-226 | 10.1016/S0375-9601(98)00517-9 | null | quant-ph hep-th math-ph math.MP | null | Several aspects of complex-valued potentials generating a real and positive
spectrum are discussed. In particular, we construct complex-valued potentials
whose corresponding Schr\"odinger eigenvalue problem can be solved
analytically.
| [
{
"version": "v1",
"created": "Fri, 29 May 1998 07:02:50 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Cannata",
"Francesco",
""
],
[
"Junker",
"Georg",
""
],
[
"Trost",
"Johannes",
""
]
] |
quant-ph/9805086 | Richard Jozsa | Richard Jozsa | Quantum Effects in Algorithms | 10 pages, Latex. For Proceedings of First NASA International
Conference on Quantum Computation and Quantum Communication (Palm Springs,
February 1998) | null | null | null | quant-ph | null | We discuss some seemingly paradoxical yet valid effects of quantum physics in
information processing. Firstly, we argue that the act of ``doing nothing'' on
part of an entangled quantum system is a highly non-trivial operation and that
it is the essential ingredient underlying the computational speedup in the
known quantum algorithms. Secondly, we show that the watched pot effect of
quantum measurement theory gives the following novel computational possibility:
suppose that we have a quantum computer with an on/off switch, programmed ready
to solve a decision problem. Then (in certain circumstances) the mere fact that
the computer would have given the answer if it were run, is enough for us to
learn the answer, even though the computer is in fact not run.
| [
{
"version": "v1",
"created": "Fri, 29 May 1998 07:14:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Jozsa",
"Richard",
""
]
] |
quant-ph/9805087 | E. Persson | E. Persson, K. Pichugin, I. Rotter, P. Seba | Interfering resonances in a quantum billiard | 2 pages, 3 figures | Phys.Rev.E58:8001-8004,1998 | 10.1103/PhysRevE.58.8001 | Mpipks: 9805007 | quant-ph | null | We present a method for numerically obtaining the positions, widths and
wavefunctions of resonance states in a two dimensional billiard connected to a
waveguide. For a rectangular billiard, we study the dynamics of three resonance
poles lying separated from the other ones. As a function of increasing coupling
strength between the waveguide and the billiard two of the states become
trapped while the width of the third one continues to increase for all coupling
strengths. This behavior of the resonance poles is reflected in the time delay
function which can be studied experimentally.
| [
{
"version": "v1",
"created": "Fri, 29 May 1998 07:49:40 GMT"
}
] | 2011-03-15T00:00:00 | [
[
"Persson",
"E.",
""
],
[
"Pichugin",
"K.",
""
],
[
"Rotter",
"I.",
""
],
[
"Seba",
"P.",
""
]
] |
quant-ph/9805088 | Adrian Kent | Adrian Kent | Entangled Mixed States and Local Purification | 3 pages, Latex with Revtex. Small clarifications and reference added | Phys.Rev.Lett. 81 (1998) 2839-2841 | 10.1103/PhysRevLett.81.2839 | DAMTP/97-128 | quant-ph | null | Linden, Massar and Popescu have recently given an optimization argument to
show that a single two-qubit Werner state, or any other mixture of the
maximally entangled Bell states, cannot be purified by local operations and
classical communications. We generalise their result and give a simple
explanation. In particular, we show that no purification scheme using local
operations and classical communications can produce a pure singlet from any
mixed state of two spin-1/2 particles. More generally, no such scheme can
produce a maximally entangled state of any pair of finite-dimensional systems
from a generic mixed state. We also show that the Werner states belong to a
large class of states whose fidelity cannot be increased by such a scheme.
| [
{
"version": "v1",
"created": "Fri, 29 May 1998 17:48:18 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Jun 1998 16:13:40 GMT"
},
{
"version": "v3",
"created": "Sun, 23 Aug 1998 20:53:30 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kent",
"Adrian",
""
]
] |
quant-ph/9806001 | Yuri I. Ozhigov | Yuri Ozhigov | Lower Bounds of Quantum Search for Extreme Point | Some minor changes | Proc.Roy.Soc.Lond. A455 (1999) 2165-2172 | 10.1098/rspa.1999.0397 | null | quant-ph | null | We show that Durr-Hoyer's quantum algorithm of searching for extreme point of
integer function can not be sped up for functions chosen randomly. Any other
algorithm acting in substantially shorter time $o(\sqrt{2^n})$ gives incorrect
answer for the functions with the single point of maximum chosen randomly with
probability converging to 1. The lower bound as $\Omega (\sqrt{2^n /b})$ was
established for the quantum search for solution of equations $f(x)=1$ where $f$
is a Boolean function with $b$ such solutions chosen at random with probability
converging to 1.
| [
{
"version": "v1",
"created": "Sun, 31 May 1998 19:40:48 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Jun 1998 15:58:50 GMT"
},
{
"version": "v3",
"created": "Fri, 18 Dec 1998 10:03:39 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Ozhigov",
"Yuri",
""
]
] |
quant-ph/9806002 | R. E. Kastner | R. E. Kastner | Time-Symmetrized Quantum Theory, Counterfactuals, and `Advanced Action' | Minor editorial changes and correction to figure 4. To appear in
"Studies in History and Philosophy of Modern Physics" | Stud.Hist.Philos.Mod.Phys. 30 (1999) 237-259 | null | UMCP-CHPS-1001 | quant-ph | null | Recent authors have raised objections to the counterfactual interpretation of
the Aharonov-Bergmann-Lebowitz (ABL) rule of time symmetrized quantum theory
(TSQT). I distinguish between two different readings of the ABL rule,
counterfactual and non-counterfactual, and confirm that TSQT advocate L.
Vaidman is employing the counterfactual reading to which these authors object.
Vaidman has responded to the objections by proposing a new kind of
time-symmetrized counterfactual, which he has defined in two different ways. It
is argued that neither definition succeeds in overcoming the objections, except
in a special case previously noted by Cohen and Hiley. In addition, a
connection is made between TSQT and Price's concept of `advanced action', which
further supports the special case discussed.
| [
{
"version": "v1",
"created": "Mon, 1 Jun 1998 06:44:44 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Jun 1998 12:39:55 GMT"
},
{
"version": "v3",
"created": "Wed, 3 Jun 1998 03:55:30 GMT"
},
{
"version": "v4",
"created": "Thu, 2 Jul 1998 02:41:27 GMT"
},
{
"version": "v5",
"created": "Sat, 18 Jul 1998 20:50:35 GMT"
},
{
"version": "v6",
"created": "Tue, 22 Sep 1998 02:12:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kastner",
"R. E.",
""
]
] |
quant-ph/9806003 | Dmitri E. Nikonov | Dmitri E. Nikonov and Atac Imamoglu | Bose condensation in two dimensions with disorder: Gross-Pitaevskii
approach | 10 pages, 5 figures, LaTeX 2e | null | null | QUEST not available | quant-ph | null | Bose condensation of interacting bosons in a two-dimensional random potential
is studied. The Gross-Pitaevskii equation is solved to determine the
spatially-varying order parameter and the localization length as a function of
the disorder, the interaction strength, and the condensate density. A finite
temperature of condensation is obtained thereby. The results are applied to
determination of the superradiant decay of excitons in a GaAs quantum well.
| [
{
"version": "v1",
"created": "Tue, 2 Jun 1998 00:39:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nikonov",
"Dmitri E.",
""
],
[
"Imamoglu",
"Atac",
""
]
] |
quant-ph/9806004 | null | Shi-Hai dong (IHEP, Beijing, P.R.China) Xi-Wen Hou and Zhong-Qi Ma | Levinson's theorem for the Schr\"{o}dinger equation in two dimensions | Latex 11 pages, no figure and accepted by P.R.A (in August); Email:
[email protected], [email protected] | null | 10.1103/PhysRevA.58.2790 | null | quant-ph | null | Levinson's theorem for the Schr\"{o}dinger equation with a cylindrically
symmetric potential in two dimensions is re-established by the Sturm-Liouville
theorem. The critical case, where the Schr\"{o}dinger equation has a finite
zero-energy solution, is analyzed in detail. It is shown that, in comparison
with Levinson's theorem in non-critical case, the half bound state for $P$
wave, in which the wave function for the zero-energy solution does not decay
fast enough at infinity to be square integrable, will cause the phase shift of
$P$ wave at zero energy to increase an additional $\pi$.
| [
{
"version": "v1",
"created": "Tue, 2 Jun 1998 08:32:52 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"dong",
"Shi-Hai",
"",
"IHEP, Beijing, P.R.China"
],
[
"Hou",
"Xi-Wen",
""
],
[
"Ma",
"Zhong-Qi",
""
]
] |
quant-ph/9806005 | null | Shi-Hai dong, Xi-Wen Hou and Zhong-Qi Ma | Levinson's Theorem for Non-local Interactions in Two Dimensions | Latex 11 pages, no figure, submitted to J. Phys. A Email:
[email protected], [email protected] | J.Phys.A31:7501-7510,1998 | 10.1088/0305-4470/31/37/010 | null | quant-ph | null | In the light of the Sturm-Liouville theorem, the Levinson theorem for the
Schr\"{o}dinger equation with both local and non-local cylindrically symmetric
potentials is studied. It is proved that the two-dimensional Levinson theorem
holds for the case with both local and non-local cylindrically symmetric cutoff
potentials, which is not necessarily separable. In addition, the problems
related to the positive-energy bound states and the physically redundant state
are also discussed in this paper.
| [
{
"version": "v1",
"created": "Tue, 2 Jun 1998 08:37:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"dong",
"Shi-Hai",
""
],
[
"Hou",
"Xi-Wen",
""
],
[
"Ma",
"Zhong-Qi",
""
]
] |
quant-ph/9806006 | null | Shi-Hai dong, Xi-Wen Hou and Zhong-Qi Ma | The Relativistic Levinson Theorem in Two Dimensions | Latex 14 pages, no figure, submitted to Phys.Rev.A; Email:
[email protected], [email protected] | null | 10.1103/PhysRevA.58.2160 | null | quant-ph | null | In the light of the generalized Sturm-Liouville theorem, the Levinson theorem
for the Dirac equation in two dimensions is established as a relation between
the total number $n_{j}$ of the bound states and the sum of the phase shifts
$\eta_{j}(\pm M)$ of the scattering states with the angular momentum $j$:
$$\eta_{j}(M)+\eta_{j}(-M)~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~$$
$$~~~=\left\{\begin{array}{ll} (n_{j}+1)\pi &{\rm
when~a~half~bound~state~occurs~at}~E=M ~~{\rm and}~~ j=3/2~{\rm or}~-1/2\\
(n_{j}+1)\pi &{\rm when~a~half~bound~state~occurs~at}~E=-M~~{\rm and}~~
j=1/2~{\rm or}~-3/2\\ n_{j}\pi~&{\rm the~rest~cases} . \end{array} \right. $$
\noindent The critical case, where the Dirac equation has a finite
zero-momentum solution, is analyzed in detail. A zero-momentum solution is
called a half bound state if its wave function is finite but does not decay
fast enough at infinity to be square integrable.
| [
{
"version": "v1",
"created": "Tue, 2 Jun 1998 08:40:02 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"dong",
"Shi-Hai",
""
],
[
"Hou",
"Xi-Wen",
""
],
[
"Ma",
"Zhong-Qi",
""
]
] |
quant-ph/9806007 | Demosthenes Ellinas U. Crete Depart. Maths | D. Ellinas and E. G. Floratos | Prime decomposition and correlation measure of finite quantum systems | 9 pages LaTeX. Revised version: changes in the terminology, updates
in refs | J.Phys.A32:L63-L69,1999 | 10.1088/0305-4470/32/5/001 | null | quant-ph math-ph math.MP math.QA | null | Under the name prime decomposition (pd), a unique decomposition of an
arbitrary $N$-dimensional density matrix $\rho$ into a sum of seperable density
matrices with dimensions given by the coprime factors of $N$ is introduced. For
a class of density matrices a complete tensor product factorization is
achieved. The construction is based on the Chinese Remainder Theorem and the
projective unitary representation of $Z_N$ by the discrete Heisenberg group
$H_N$. The pd isomorphism is unitarily implemented and it is shown to be
coassociative and to act on $H_N$ as comultiplication. Density matrices with
complete pd are interpreted as grouplike elements of $H_N$. To quantify the
distance of $\rho$ from its pd a trace-norm correlation index $\cal E$ is
introduced and its invariance groups are determined.
| [
{
"version": "v1",
"created": "Tue, 2 Jun 1998 12:23:27 GMT"
},
{
"version": "v2",
"created": "Mon, 5 Jul 1999 10:19:48 GMT"
}
] | 2011-07-19T00:00:00 | [
[
"Ellinas",
"D.",
""
],
[
"Floratos",
"E. G.",
""
]
] |
quant-ph/9806008 | Norbert Luetkenhaus | Norbert L\"utkenhaus | Estimates for practical quantum cryptography | Authentication scheme corrected. Other improvements of presentation | Phys.Rev. A59 (1999) 3301-3319 | 10.1103/PhysRevA.59.3301 | null | quant-ph | null | In this article I present a protocol for quantum cryptography which is secure
against attacks on individual signals. It is based on the Bennett-Brassard
protocol of 1984 (BB84). The security proof is complete as far as the use of
single photons as signal states is concerned. Emphasis is given to the
practicability of the resulting protocol. For each run of the quantum key
distribution the security statement gives the probability of a successful key
generation and the probability for an eavesdropper's knowledge, measured as
change in Shannon entropy, to be below a specified maximal value.
| [
{
"version": "v1",
"created": "Tue, 2 Jun 1998 17:48:14 GMT"
},
{
"version": "v2",
"created": "Mon, 18 Jan 1999 11:41:15 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lütkenhaus",
"Norbert",
""
]
] |
quant-ph/9806009 | null | Guang-jiong Ni (Department of Physics, Fudan University, Shanghai, P.
R. China) | To Enjoy the Morning Flower in the Evening - What does the Appearance of
Infinity in Physics Imply? | 13 pages, LaTex, no figure | Kexue Zazhi 50 (1998) 36 | null | null | quant-ph | null | A new regularization - renormalization method with no explicit divergence, no
counterterm, no bare parameter and no arbitrary running mass scale is discussed
>. There is no difficulty of triviality and the Higgs mass in the standard
model is calculated to be 138 Gev.
| [
{
"version": "v1",
"created": "Wed, 3 Jun 1998 08:37:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ni",
"Guang-jiong",
"",
"Department of Physics, Fudan University, Shanghai, P.\n R. China"
]
] |
quant-ph/9806010 | Castagnoli Giuseppe | Giuseppe Castagnoli (Information Technology Dept., Elsag Bailey,
Genova, Italy), Dalida Monti (Universita` di Genova and Elsag Bailey, Genova,
Italy) | Quantum computation based on particle statistics | 1 figure | null | null | null | quant-ph | null | In spite of their evident logical character, particle statistics symmetries
are not among the inherently quantum features exploited in quantum computation.
A difficulty may be that, being a constant of motion of a unitary evolution, a
particle statistics symmetry cannot affect the course of such an evolution. We
try to avoid this possible deadlock by introducing a generalized
(counterfactual, blunt) formulation where this type of symmetry becomes a
watchdog effect shaping the evolution of a unitary computation process. The
work is an exploration.
| [
{
"version": "v1",
"created": "Wed, 3 Jun 1998 09:44:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Castagnoli",
"Giuseppe",
"",
"Information Technology Dept., Elsag Bailey,\n Genova, Italy"
],
[
"Monti",
"Dalida",
"",
"Universita` di Genova and Elsag Bailey, Genova,\n Italy"
]
] |
quant-ph/9806011 | Maciej Kuna | Maciej Kuna (Politechnika Gdanska) | Entanglement and pseudomixtures | to be published in special issue of Acta Phys.Slov. on Q.Optics and
Q.Information (June 98) | Acta Phys.Slov. 48 (1998) 163-168 | null | null | quant-ph | null | In a recent paper Sanpera et al. have shown, that for the simplest binary
composite systems any density matrix can be described in terms of only product
vectors. The purpose of this note is to show that posibillity of decomposing
any state as pseudomixtures does not depend on dimension of the subsystems.
| [
{
"version": "v1",
"created": "Wed, 3 Jun 1998 11:45:10 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Kuna",
"Maciej",
"",
"Politechnika Gdanska"
]
] |
quant-ph/9806012 | Q. A. Turchette | Q.A. Turchette, C.S. Wood, B.E. King, C.J. Myatt, D. Leibfried, W.M.
Itano, C. Monroe, D.J. Wineland (Time and Frequency Division, National
Institute of Standards and Technology, Boulder, CO) | Deterministic entanglement of two trapped ions | 5 pages, 4 figures, revtex | Phys.Rev.Lett. 81 (1998) 3631-3634 | 10.1103/PhysRevLett.81.3631 | B98-0198 | quant-ph | null | We have prepared the internal states of two trapped ions in both the
Bell-like singlet and triplet entangled states. In contrast to all other
experiments with entangled states of either massive particles or photons, we do
this in a deterministic fashion, producing entangled states on demand without
selection. The deterministic production of entangled states is a crucial
prerequisite for large-scale quantum computation.
| [
{
"version": "v1",
"created": "Wed, 3 Jun 1998 20:48:51 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Turchette",
"Q. A.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
],
[
"Wood",
"C. S.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
],
[
"King",
"B. E.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
],
[
"Myatt",
"C. J.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
],
[
"Leibfried",
"D.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
],
[
"Itano",
"W. M.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
],
[
"Monroe",
"C.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
],
[
"Wineland",
"D. J.",
"",
"Time and Frequency Division, National\n Institute of Standards and Technology, Boulder, CO"
]
] |
quant-ph/9806013 | Michael J. W. Hall | Michael J.W. Hall | Volume of classical and quantum ensembles: geometric approach to entropy
and information | 11 pages, 2 figures (warning: rejected by PRL!) | null | null | qp-250398mh | quant-ph physics.data-an | null | It is shown for classical and quantum ensembles that there is a unique
quantity which has the properties of a "volume". This quantity is a function of
the ensemble entropy, and hence provides a geometric interpretation for the
latter. It further provides a geometric picture for deriving and unifying a
number of results in classical and quantum information theory, and for
discussing entropic uncertainty relations.
| [
{
"version": "v1",
"created": "Thu, 4 Jun 1998 10:26:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hall",
"Michael J. W.",
""
]
] |
quant-ph/9806014 | Robert Myska | Z. Hradil, J. Summhammer, H. Rauch | Quantum tomography as normalization of incompatible observations | RevTeX, 4 pages, 3 figures | Phys.Lett.A261:20-24,1999 | 10.1016/S0375-9601(99)00619-2 | null | quant-ph | null | Quantum states are successfully reconstructed using the maximum likelihood
estimation on the subspace where the measured projectors reproduce the identity
operator. Reconstruction corresponds to normalization of incompatible
observations. The proposed approach handles the noisy data corresponding to
realistic incomplete observation with finite resolution.
| [
{
"version": "v1",
"created": "Thu, 4 Jun 1998 11:07:21 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hradil",
"Z.",
""
],
[
"Summhammer",
"J.",
""
],
[
"Rauch",
"H.",
""
]
] |
quant-ph/9806015 | Bronius Kaulakys | V. Gontis and B. Kaulakys | Quantum Zeno and quantum anti-Zeno effects | LaTex, 6 pages | Lith.Phys.J. 38 (1998) 118-121 | null | null | quant-ph chao-dyn nlin.CD | null | Consequences of the deviation from the linear on time quantum transition
probabilities leading to the nonexponential decay law and to the so-called Zeno
effect are analysed. Main features of the quantum Zeno and quantum anti-Zeno
effects for induced transitions are revealed on simple model systems.
| [
{
"version": "v1",
"created": "Thu, 4 Jun 1998 16:32:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gontis",
"V.",
""
],
[
"Kaulakys",
"B.",
""
]
] |
quant-ph/9806016 | Hagen Kleinert | Hagen Kleinert, Werner Kuerzinger and Axel Pelster | Smearing Formula for Higher-Order Effective Classical Potentials | Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of
paper also at
http://www.physik.fu-berlin.de/~kleinert/kleiner_re267/preprint.html | J.Phys.A31:8307-8321,1998 | 10.1088/0305-4470/31/41/005 | null | quant-ph | null | In the variational approach to quantum statistics, a smearing formula
describes efficiently the consequences of quantum fluctuations upon an
interaction potential. The result is an effective classical potential from
which the partition function can be obtained by a simple integral. In this
work, the smearing formula is extended to higher orders in the variational
perturbation theory. An application to the singular Coulomb potential exhibits
the same fast convergence with increasing orders that has been observed in
previous variational perturbation expansions of the anharmonic oscillator with
quartic potential.
| [
{
"version": "v1",
"created": "Fri, 5 Jun 1998 05:14:37 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kleinert",
"Hagen",
""
],
[
"Kuerzinger",
"Werner",
""
],
[
"Pelster",
"Axel",
""
]
] |
quant-ph/9806017 | A. Yu. Trifonov | V.G.Bagrov, V.V.Belov and A.Yu.Trifonov | Semiclassical trajectory-coherent approximation in quantum mechanics:
II. High order corrections to the Dirac operators in external electromagnetic
field | Submitted to Ann. Phys. (NY), 27 pages AMS- LaTEX, no figures | null | null | null | quant-ph | null | High approximations of semiclassical trajectory-coherent states (TCS) and of
semiclassical Green function (in the class of semiclassically concentrated
states) for the Dirac operator with anomalous Pauli interaction are obtained.
For Schrodinger and Dirac operators trajectory-coherent representations are
constructed up to any precision with respect to h, h-->0.
| [
{
"version": "v1",
"created": "Fri, 5 Jun 1998 08:13:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bagrov",
"V. G.",
""
],
[
"Belov",
"V. V.",
""
],
[
"Trifonov",
"A. Yu.",
""
]
] |
quant-ph/9806018 | Jochen Dittmann | J. Dittmann | Yang-Mills Equation and Bures Metric | 6 pages, Latex | Lett.Math.Phys. 46 (1998) 281-287 | null | UL 980120 | quant-ph math-ph math.MP | null | It is shown that the connection form (gauge field) related to the
generalization of the Berry phase to mixed states proposed by Uhlmann satisfies
the source-free Yang-Mills equation *D*Dw=0, where the Hodge star is taken with
respect to the Bures metric on the space of finite dimensional nondegenerate
density matrices.
| [
{
"version": "v1",
"created": "Fri, 5 Jun 1998 08:41:50 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dittmann",
"J.",
""
]
] |
quant-ph/9806019 | Mikhail Ioffe | A.A. Andrianov (1), F. Cannata (2), J.-P. Dedonder (3) and M.V. Ioffe
(1) ((1) St. Petersburg State University, (2) Dipartimento di Fisica and
INFN, Bologna, (3) Universit\'e Paris7 - Denis Diderot and Division de
Physique Th\'eorique, IPN, Orsay) | SUSY Quantum Mechanics with Complex Superpotentials and Real Energy
Spectra | 22 pages, Latex | Int.J.Mod.Phys. A14 (1999) 2675-2688 | 10.1142/S0217751X99001342 | SPbU-IP-97-24 | quant-ph hep-th nlin.SI solv-int | null | We extend the standard intertwining relations used in Supersymmetrical (SUSY)
Quantum Mechanics which involve real superpotentials to complex
superpotentials. This allows to deal with a large class of non-hermitean
Hamiltonians and to study in general the isospectrality between complex
potentials. In very specific cases we can construct in a natural way
"quasi-complex" potentials which we define as complex potentials having a
global property such as to lead to a Hamiltonian with real spectrum. We also
obtained a class of complex transparent potentials whose Hamiltonian can be
intertwined to a free Hamiltonian. We provide a variety of examples both for
the radial problem (half axis) and for the standard one-dimensional problem
(the whole axis), including remarks concerning scattering problems.
| [
{
"version": "v1",
"created": "Fri, 5 Jun 1998 11:07:09 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Andrianov",
"A. A.",
""
],
[
"Cannata",
"F.",
""
],
[
"Dedonder",
"J. -P.",
""
],
[
"Ioffe",
"M. V.",
""
]
] |
quant-ph/9806020 | Jose Oscar Rosas-Ortiz | J. Oscar Rosas-Ortiz | Exactly Solvable Hydrogen-like Potentials and Factorization Method | LaTex file, 21 pages, 2 PostScript figures and some references added.
To be published in J. Phys. A: Math. Gen. (1998) | J.Phys.A31:10163-10179,1998 | 10.1088/0305-4470/31/50/012 | null | quant-ph | null | A set of factorization energies is introduced, giving rise to a
generalization of the Schr\"{o}dinger (or Infeld and Hull) factorization for
the radial hydrogen-like Hamiltonian. An algebraic intertwining technique
involving such factorization energies leads to derive $n$-parametric families
of potentials in general almost-isospectral to the hydrogen-like radial
Hamiltonians. The construction of SUSY partner Hamiltonians with ground state
energies greater than the corresponding ground state energy of the initial
Hamiltonian is also explicitly performed.
| [
{
"version": "v1",
"created": "Fri, 5 Jun 1998 15:29:55 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Jul 1998 16:42:48 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Oct 1998 10:40:20 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Rosas-Ortiz",
"J. Oscar",
""
]
] |
quant-ph/9806021 | Ivan H. Deutsch | Gavin K. Brennen, Carlton M. Caves, Poul S. Jessen, and Ivan H.
Deutsch | Quantum Logic Gates in Optical Lattices | Revised version, To appear in Phys. Rev. Lett. Three separate
postscript figures | Phys.Rev.Lett. 82 (1999) 1060-1063 | 10.1103/PhysRevLett.82.1060 | null | quant-ph | null | We propose a new system for implementing quantum logic gates: neutral atoms
trapped in a very far-off-resonance optical lattice. Pairs of atoms are made to
occupy the same well by varying the polarization of the trapping lasers, and
then a near-resonant electric dipole is induced by an auxiliary laser. A
controlled-NOT can be implemented by conditioning the target atomic resonance
on a resolvable level shift induced by the control atom. Atoms interact only
during logical operations, thereby suppressing decoherence.
| [
{
"version": "v1",
"created": "Sat, 6 Jun 1998 00:16:44 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Jun 1998 00:35:06 GMT"
},
{
"version": "v3",
"created": "Tue, 23 Jun 1998 22:29:53 GMT"
},
{
"version": "v4",
"created": "Sat, 12 Dec 1998 00:38:55 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Brennen",
"Gavin K.",
""
],
[
"Caves",
"Carlton M.",
""
],
[
"Jessen",
"Poul S.",
""
],
[
"Deutsch",
"Ivan H.",
""
]
] |
quant-ph/9806022 | Dr. BG Sidharth | B.G. Sidharth | The Anomalous Behaviour of Fermions in a Thin Wire | 7 pages, TeX, BMBSC-TR 08-06-97 | null | null | null | quant-ph | null | Motivated by the recent development of insulated nano-tubes and the attempts
to develop conducting nano wires in such tubes, we examine the Fermionic
behaviour in extremely thin wires. Although the one- dimensional problem has
been studied in detail over the years, it is an extreme idealization: We
consider the more realistic scenario of thin wires which are nevertheless three
dimensional. We show that the assembly of Fermions behaves as if it is below
the Fermi temperature, and in the limit of one dimension, in the ground state
as well. Thus there are indeed Bosonization features. These conclusions are
checked from an independent stand point.
| [
{
"version": "v1",
"created": "Sat, 6 Jun 1998 07:22:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sidharth",
"B. G.",
""
]
] |
quant-ph/9806023 | Tony Smith | Frank Tony Smith | Bohm Confirmed by NonRelativistic Quark Model | 4 pages LaTeX | null | null | TS-TH-98-1 | quant-ph | null | The effectiveness of the NonRelativistic Quark Model of hadrons can be
explained by Bohm's quantum theory applied to a fermion confined in a box, in
which the fermion is at rest because its kinetic energy is transformed into
PSI-field potential energy. Since that aspect of Bohm's quantum theory is not a
property of most other formulations of quantum theory, the effectiveness of the
NonRelativistic Quark Model confirms Bohm's quantum theory as opposed to those
others.
| [
{
"version": "v1",
"created": "Sat, 6 Jun 1998 20:29:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Smith",
"Frank Tony",
""
]
] |
quant-ph/9806024 | Asher Peres | Asher Peres and Daniel Terno | Convex probability domain of generalized quantum measurements | 7 pages LaTeX, one PostScript figure on separate page | J.Phys. A31 (1998) L671-L675 | 10.1088/0305-4470/31/38/003 | null | quant-ph | null | Generalized quantum measurements with N distinct outcomes are used for
determining the density matrix, of order d, of an ensemble of quantum systems.
The resulting probabilities are represented by a point in an N-dimensional
space. It is shown that this point lies in a convex domain having at most d^2-1
dimensions.
| [
{
"version": "v1",
"created": "Sun, 7 Jun 1998 14:11:36 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Peres",
"Asher",
""
],
[
"Terno",
"Daniel",
""
]
] |
quant-ph/9806025 | S. Y. Ren | Shang Yuan Ren (Peking University) | Relativistic corrections to the energy spectra of completely confined
particles | 6 pages, no figures | null | null | null | quant-ph | null | An analytical expression for the relativistic corrections to the energy
spectra of particles completely confined in an one-dimensional limited length
in real space is given, based upon the wave property of particles, the
relativistic energy-momentum relation and two mathematical equations.
| [
{
"version": "v1",
"created": "Mon, 8 Jun 1998 08:14:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ren",
"Shang Yuan",
"",
"Peking University"
]
] |
quant-ph/9806026 | B. Kappler | H. P. Breuer, B. Kappler and F. Petruccione | Stochastic wave function approach to generalized master equations | RevTex, 7 pages, 4 Postscript figures, uses multicol. To appear in
the proceedings of the "International workshop on macroscopic quantum
tunneling and coherence", Naples, 1998 | null | null | THEP 98/13 | quant-ph cond-mat.mes-hall | null | A generalization of the stochastic wave function method is presented which
allows the unravelling of arbitrary linear quantum master equations which are
not necessarily in Lindblad form and, moreover, the explicit treatment of
memory effects by employing the time-convolutionless projection operator
technique. The crucial point of this construction is the description of the
open system in a doubled Hilbert space, which has already been successfully
used for the computation of multitime correlation functions.
| [
{
"version": "v1",
"created": "Mon, 8 Jun 1998 10:32:20 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Jul 1998 10:17:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Breuer",
"H. P.",
""
],
[
"Kappler",
"B.",
""
],
[
"Petruccione",
"F.",
""
]
] |
quant-ph/9806027 | K. | Kei Inoue, Takashi Matsuoka and Masanori Ohya | New approach to Epsilon-entropy and Its comparison with Kolmogorov's
Epsilon-entropy | 17 pages, Latex, Submitted to Journal of Mathematical Physics | null | null | null | quant-ph | null | Kolmogorov introduced a concept of Epsilon-entropy to analyze information in
classical continuous system. The fractal dimension of geometrical sets was
introduced by Mandelbrot as a new criterion to analyze the complexity of these
sets. The Epsilon-entropy and the fractal dimension of a state in general
quantum system were introduced by one of the present authors in order to
characterize chaotic properties of general states.
In this paper, we show that Epsilon-entropy of a state includes Kolmogorov
Epsilon-entropy, and the fractal dimension of a state describe fractal
structure of Gaussian measures.
| [
{
"version": "v1",
"created": "Mon, 8 Jun 1998 11:11:03 GMT"
},
{
"version": "v2",
"created": "Fri, 12 Jun 1998 09:13:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Inoue",
"Kei",
""
],
[
"Matsuoka",
"Takashi",
""
],
[
"Ohya",
"Masanori",
""
]
] |
quant-ph/9806028 | Jochen Dittmann | J. Dittmann, A. Uhlmann | Connections and Metrics Respecting Standard Purification | Latex, 27 pages | J.Math.Phys. 40 (1999) 3246-3267 | 10.1063/1.532884 | null | quant-ph | null | Standard purification interlaces Hermitian and Riemannian metrics on the
space of density operators with metrics and connections on the purifying
Hilbert-Schmidt space. We discuss connections and metrics which are well
adopted to purification, and present a selected set of relations between them.
A connection, as well as a metric on state space, can be obtained from a metric
on the purification space. We include a condition, with which this
correspondence becomes one-to-one. Our methods are borrowed from elementary
*-representation and fibre space theory. We lift, as an example, solutions of a
von Neumann equation, write down holonomy invariants for cyclic ones, and ``add
noise'' to a curve of pure states.
| [
{
"version": "v1",
"created": "Mon, 8 Jun 1998 15:30:35 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Dittmann",
"J.",
""
],
[
"Uhlmann",
"A.",
""
]
] |
quant-ph/9806029 | Dorit Aharonov | Dorit Aharonov (Physics and Computer science, The Hebrew University),
Alexei Kitaev (L.D.Landau Institute for Theoretical Physics), Noam Nisan
(Institute of Computer science, The Hebrew University) | Quantum Circuits with Mixed States | 20 pages, Latex. In ``Proceedings of the Thirtieth Annual ACM
Symposium on Theory of Computation (STOC)'', pages 20-30, 1997 | null | null | null | quant-ph | null | We define the model of quantum circuits with density matrices, where
non-unitary gates are allowed. Measurements in the middle of the computation,
noise and decoherence are implemented in a natural way in this model, which is
shown to be equivalent in computational power to standard quantum circuits.
The main result in this paper is a solution for the subroutine problem: The
general function that a quantum circuit outputs is a probabilistic function,
but using pure state language, such a function can not be used as a black box
in other computations. We give a natural definition of using general
subroutines, and analyze their computational power.
We suggest convenient metrics for quantum computing with mixed states. For
density matrices we analyze the so called ``trace metric'', and using this
metric, we define and discuss the ``diamond metric'' on superoperators. These
metrics enable a formal discussion of errors in the computation.
Using a ``causality'' lemma for density matrices, we also prove a simple
lower bound for probabilistic functions.
| [
{
"version": "v1",
"created": "Mon, 8 Jun 1998 15:39:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Aharonov",
"Dorit",
"",
"Physics and Computer science, The Hebrew University"
],
[
"Kitaev",
"Alexei",
"",
"L.D.Landau Institute for Theoretical Physics"
],
[
"Nisan",
"Noam",
"",
"Institute of Computer science, The Hebrew University"
]
] |
quant-ph/9806030 | Volodymyr Tkachuk | V. M. Tkachuk | Supersymmetric Method for Constructing Quasi-Exactly Solvable Potentials | 11 pages, latex, to appear in Cond. Matt. Phys. (Lviv) (Proceedings
of INTAS-Ukraine Workshop on Condensed Matter Physics, May, Lviv, 1998) | null | null | null | quant-ph math-ph math.MP | null | We propose a new method for constructing the quasi-exactly solvable (QES)
potentials with two known eigenstates using supersymmetric quantum mechanics.
General expression for QES potentials with explicitly known energy levels and
wave functions of ground state and excited state are obtained. Examples of new
QES potentials are considered.
| [
{
"version": "v1",
"created": "Tue, 9 Jun 1998 17:38:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Tkachuk",
"V. M.",
""
]
] |
quant-ph/9806031 | Claude Crepeau | Gilles Brassard, Claude Cr\'epeau, Dominic Mayers, Louis Salvail | Defeating classical bit commitments with a quantum computer | 13 pages. Supersedes quant-ph/9712023 | null | null | null | quant-ph | null | It has been recently shown by Mayers that no bit commitment scheme is secure
if the participants have unlimited computational power and technology. However
it was noticed that a secure protocol could be obtained by forcing the cheater
to perform a measurement. Similar situations had been encountered previously in
the design of Quantum Oblivious Transfer. The question is whether a classical
bit commitment could be used for this specific purpose. We demonstrate that,
surprisingly, classical unconditionally concealing bit commitments do not help.
| [
{
"version": "v1",
"created": "Tue, 9 Jun 1998 19:16:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Brassard",
"Gilles",
""
],
[
"Crépeau",
"Claude",
""
],
[
"Mayers",
"Dominic",
""
],
[
"Salvail",
"Louis",
""
]
] |
quant-ph/9806032 | Chau Hoi Fung | H. F. Chau | Good Quantum Convolutional Error Correction Codes And Their Decoding
Algorithm Exist | Minor changes, to appear in PRA | null | 10.1103/PhysRevA.60.1966 | null | quant-ph | null | Quantum convolutional code was introduced recently as an alternative way to
protect vital quantum information. To complete the analysis of quantum
convolutional code, I report a way to decode certain quantum convolutional
codes based on the classical Viterbi decoding algorithm. This decoding
algorithm is optimal for a memoryless channel. I also report three simple
criteria to test if decoding errors in a quantum convolutional code will
terminate after a finite number of decoding steps whenever the Hilbert space
dimension of each quantum register is a prime power. Finally, I show that
certain quantum convolutional codes are in fact stabilizer codes. And hence,
these quantum stabilizer convolutional codes have fault-tolerant
implementations.
| [
{
"version": "v1",
"created": "Wed, 10 Jun 1998 09:21:34 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Jan 1999 10:19:43 GMT"
},
{
"version": "v3",
"created": "Thu, 24 Jun 1999 10:12:31 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Chau",
"H. F.",
""
]
] |
quant-ph/9806033 | Irene Marzoli | I. Marzoli (1), F. Saif (1), I. Bialynicki-Birula (2), O. M. Friesch
(1), A. E. Kaplan (3), W. P. Schleich (1) ((1) Universitaet Ulm, Ulm,
Germany, (2) Center for Theoretical Physics, Warsaw, Poland, (3) The Johns
Hopkins University, Baltimore, USA) | Quantum Carpets made simple | 12 pages, 2 figures | Acta Phys.Slov. 48 (1998) 323-333 | null | null | quant-ph | null | We show that the concept of degeneracy is the key idea for understanding the
quantum carpet woven by a particle in the box.
| [
{
"version": "v1",
"created": "Wed, 10 Jun 1998 11:17:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Marzoli",
"I.",
""
],
[
"Saif",
"F.",
""
],
[
"Bialynicki-Birula",
"I.",
""
],
[
"Friesch",
"O. M.",
""
],
[
"Kaplan",
"A. E.",
""
],
[
"Schleich",
"W. P.",
""
]
] |
quant-ph/9806034 | null | Stefano Mancini and Paolo Tombesi (Univ. Camerino, Italy) Vladimir I.
Man'ko (Lebedev Phisical Institute, Russia) | Collective spontaneous emission in a q-deformed Dicke model | 11 pages, RevTeX file, 2 figures available from authors, accepted for
publication in Mod. Phys. Lett. B | Mod.Phys.Lett. B12 (1998) 403 | 10.1142/S0217984998000494 | null | quant-ph | null | The q-deformation of a single quantized radiation mode interacting with a
collection of two level atoms is introduced, analysing its effects on the
cooperative behavior of the system.
| [
{
"version": "v1",
"created": "Wed, 10 Jun 1998 12:30:10 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Mancini",
"Stefano",
"",
"Univ. Camerino, Italy"
],
[
"Tombesi",
"Paolo",
"",
"Univ. Camerino, Italy"
],
[
"Man'ko",
"Vladimir I.",
"",
"Lebedev Phisical Institute, Russia"
]
] |
quant-ph/9806035 | null | Stefano Mancini and Paolo Tombesi (Univ. Camerino, Italy) Vladimir I.
Man'ko (Lebedev Physical Institute, Russia) | Relativistic properties of marginal distributions | 13 pages, LaTeX file, no figures, accepted for publication in Physica
Scripta | Phys.Scripta 58 (1998) 421 | 10.1088/0031-8949/58/5/002 | null | quant-ph | null | We study the properties of marginal distributions-projections of the phase
space representation of a physical system-under relativistic transforms. We
consider the Galileo case as well as the Lorentz transforms exploiting the
relativistic oscillator model used for describing the mass spectrum of
elementary particles.
| [
{
"version": "v1",
"created": "Wed, 10 Jun 1998 12:30:33 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Mancini",
"Stefano",
"",
"Univ. Camerino, Italy"
],
[
"Tombesi",
"Paolo",
"",
"Univ. Camerino, Italy"
],
[
"Man'ko",
"Vladimir I.",
"",
"Lebedev Physical Institute, Russia"
]
] |
quant-ph/9806036 | Gerhard Hegerfeldt | Gerhard C. Hegerfeldt | Causality, particle localization and positivity of the energy | To appear in: Irreversibility and Causality in Quantum Theory --
Semigroups and Rigged Hilbert Spaces, edited by A. Bohm, H.-D. Doebner and P.
Kielanowski, Springer Lecture Notes in Physics, Vol. 504 (1998) | null | 10.1007/BFb0106784 | null | quant-ph | null | Positivity of the Hamiltonian alone is used to show that particles, if
initially localized in a finite region, immediately develop infinite tails.
| [
{
"version": "v1",
"created": "Thu, 11 Jun 1998 12:15:53 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Hegerfeldt",
"Gerhard C.",
""
]
] |
quant-ph/9806037 | Gerhard Hegerfeldt | Almut Beige and Gerhard C. Hegerfeldt | Transition from antibunching to bunching for two dipole-interacting
atoms | Submitted to Phys. Rev. A; 15 pages Latex + 4 figures | Phys.Rev. A58 (1998) 4133 | 10.1103/PhysRevA.58.4133 | null | quant-ph | null | It is known that there is a transition from photon antibunching to bunching
in the resonance fluorescence of a driven system of two two-level atoms with
dipole-dipole interaction when the atomic distance decreases and the other
parameters are kept fixed. We give a simple explanation for the underlying
mechanism which in principle can also be applied to other systems. PACS numbers
42.50.Ar, 42.50Fx
| [
{
"version": "v1",
"created": "Thu, 11 Jun 1998 12:37:49 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Beige",
"Almut",
""
],
[
"Hegerfeldt",
"Gerhard C.",
""
]
] |
quant-ph/9806038 | Nipun Vats | Nipun Vats and Sajeev John (University of Toronto) | Non-Markovian Quantum Fluctuations and Superradiance Near a Photonic
Band Edge | 16 pages, 15 Postscript figures. Submitted to Phys. Rev. A | Phys.Rev. A58 (1998) 4168-4185 | 10.1103/PhysRevA.58.4168 | null | quant-ph physics.atom-ph | null | We discuss a point model for the collective emission of light from N
two-level atoms in a photonic bandgap material, each with an atomic resonant
frequency near the edge of the gap. In the limit of a low initial occupation of
the excited atomic state, our system is shown to possess novel atomic spectra
and population statistics. For a high initial excited state population, mean
field theory suggests a fractionalized inversion and a macroscopic polarization
for the atoms in the steady state, both of which can be controlled by an
external d.c. field. This atomic steady state is accompanied by a non--zero
expectation value of the electric field operators for field modes located in
the vicinity of the atoms. The nature of homogeneous broadening near the band
edge is shown to differ markedly from that in free space due to non-Markovian
memory effects in the radiation dynamics. Non-Markovian vacuum fluctuations are
shown to yield a partially coherent steady state polarization with a random
phase. In contrast with the steady state of a conventional laser, near a
photonic band edge this coherence occurs as a consequence of photon
localization in the absence of a conventional cavity mode. We also introduce a
classical stochastic function with the same temporal correlations as the
electromagnetic reservoir, in order to stochastically simulate the effects of
vacuum fluctuations near a photonic band edge.
| [
{
"version": "v1",
"created": "Thu, 11 Jun 1998 21:27:32 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Vats",
"Nipun",
"",
"University of Toronto"
],
[
"John",
"Sajeev",
"",
"University of Toronto"
]
] |
quant-ph/9806039 | Paul Slater | Paul B. Slater (University of California) | Exact Eigenanalyses of Certain N^m x N^m Density Matrices | We are withdrawing this paper because we have now been able to
conduct analyses for the case N=3, m =3 and wish to incorporate these further
results. Accordingly, a new paper will shortly be issued, tentatively
entitled, "SU(N) x S_{m}-Invariant Eigenspaces of N^{m} x N^{m} Mean Density
Matrices" | null | null | null | quant-ph | null | We apply and extend recent results of Krattenthaler and Slater
(quant-ph/9612043), who sought quantum analogs of seminal work on universal
data compression of Clarke and Barron. KS obtained explicit formulas for the
eigenvalues and eigenvectors of the 2^m x 2^m density matrices gotten by
averaging the m-fold tensor products with themselves of the 2 x 2 density
matrices. The weighting was done with respect to a one-parameter family of
probability distributions, all the members of which are spherically-symmetric
over the "Bloch sphere" of two-level quantum systems. This family includes the
normalized volume element of the minimal monotone (Bures) metric. In this
letter, we conduct parallel analyses (for m =2,3,4), based on a natural measure
on the density matrices recently proposed by Zyczkowski, Horodecki, Sanpera and
Lewenstein (quant-ph/9804024) and find interesting similarities and differences
with the findings of KS. In addition, we are able to obtain exact analogous
results, based on the measure of ZHSL, for the twofold tensor products of the 3
x 3 density matrices.
| [
{
"version": "v1",
"created": "Thu, 11 Jun 1998 22:14:44 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Jun 1998 22:57:01 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Slater",
"Paul B.",
"",
"University of California"
]
] |
quant-ph/9806040 | Mohammad Ardehali | M. Ardehali | Verifiable quantum oblivious transfer protocol based on entangled states | This paper has been withdrawn, due to possbility of cheating by Alice
by sending the state $\mid\uparrow \uparrow>$$ | null | null | null | quant-ph | null | This paper has been withdrawn.
| [
{
"version": "v1",
"created": "Fri, 12 Jun 1998 06:25:36 GMT"
},
{
"version": "v2",
"created": "Thu, 18 Jun 1998 07:08:48 GMT"
},
{
"version": "v3",
"created": "Wed, 24 Jun 1998 03:06:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ardehali",
"M.",
""
]
] |
quant-ph/9806041 | Taksu Cheon de Caracorum | Taksu Cheon (Kochi Tech & KEK, Tsukuba), T. Shigehara (Saitama U) | Fermion-Boson Duality of One-dimensional Quantum Particles with
Generalized Contact Interaction | 4 pages ReVTeX 4 epsf figures included, new Refs | Physical Review Letters 82 (1999) 2536-2539 | 10.1103/PhysRevLett.82.2536 | null | quant-ph cond-mat nlin.SI nucl-th solv-int | null | For a system of spinless one-dimensional fermions, the non-vanishing
short-range limit of two-body interaction is shown to induce the wave-function
discontinuity. We prove the equivalence of this fermionic system and the
bosonic particle system with two-body $\delta$-function interaction with the
reversed role of strong and weak couplings.
KEYWORDS: one-dimensional system, $\epsilon$-interaction, solvable many-body
problem, exact bosonization
| [
{
"version": "v1",
"created": "Fri, 12 Jun 1998 16:33:21 GMT"
},
{
"version": "v2",
"created": "Mon, 31 Aug 1998 07:02:59 GMT"
}
] | 2009-02-27T00:00:00 | [
[
"Cheon",
"Taksu",
"",
"Kochi Tech & KEK, Tsukuba"
],
[
"Shigehara",
"T.",
"",
"Saitama U"
]
] |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.