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quant-ph/9705029 | Isaac E. Lagaris | I. E. Lagaris, A. Likas and D. I. Fotiadis | Artificial Neural Network Methods in Quantum Mechanics | Latex file, 29pages, 11 psfigs, submitted in CPC | Comput.Phys.Commun. 104 (1997) 1-14 | 10.1016/S0010-4655(97)00054-4 | null | quant-ph comp-gas nlin.CG physics.comp-ph | null | In a previous article we have shown how one can employ Artificial Neural
Networks (ANNs) in order to solve non-homogeneous ordinary and partial
differential equations. In the present work we consider the solution of
eigenvalue problems for differential and integrodifferential operators, using
ANNs. We start by considering the Schr\"odinger equation for the Morse
potential that has an analytically known solution, to test the accuracy of the
method. We then proceed with the Schr\"odinger and the Dirac equations for a
muonic atom, as well as with a non-local Schr\"odinger integrodifferential
equation that models the $n+\alpha$ system in the framework of the resonating
group method. In two dimensions we consider the well studied Henon-Heiles
Hamiltonian and in three dimensions the model problem of three coupled
anharmonic oscillators. The method in all of the treated cases proved to be
highly accurate, robust and efficient. Hence it is a promising tool for
tackling problems of higher complexity and dimensionality.
| [
{
"version": "v1",
"created": "Thu, 15 May 1997 17:19:52 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Lagaris",
"I. E.",
""
],
[
"Likas",
"A.",
""
],
[
"Fotiadis",
"D. I.",
""
]
] |
quant-ph/9705030 | Masanao Ozawa | Masanao Ozawa (Nagoya University) | Quantum State Reduction and the Quantum Bayes Principle | 10 pages, LaTeX, no figures, to appear in Quantum Communication,
Computing and Measurement (Kluwer, New York, 1997), 233-241 [Proc. 3rd Int'l
Conf. on Quantum Communication and Measurement---QCM'96 (Hakone, 1996)] | Quantum Communication, Computing and Measurement (Kluwer, New
York, 1997), 233 | null | null | quant-ph | null | This paper gives new foundations of quantum state reduction without appealing
to the projection postulate for the probe measurement. For this purpose, the
quantum Bayes principle is formulated as the most fundamental principle for
determining the state of a quantum system, and the joint probability
distribution for the outcomes of local successive measurements on a
noninteracting entangled system is derived without assuming the projection
postulate.
| [
{
"version": "v1",
"created": "Fri, 16 May 1997 09:47:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ozawa",
"Masanao",
"",
"Nagoya University"
]
] |
quant-ph/9705031 | John Preskill | John Preskill (Caltech) | Reliable Quantum Computers | 24 pages, LaTeX, submitted to Proc. Roy. Soc. Lond. A, minor
corrections | Proc.Roy.Soc.Lond. A454 (1998) 385-410 | 10.1098/rspa.1998.0167 | CALT-68-2112, QUIC-97-030 | quant-ph | null | The new field of quantum error correction has developed spectacularly since
its origin less than two years ago. Encoded quantum information can be
protected from errors that arise due to uncontrolled interactions with the
environment. Recovery from errors can work effectively even if occasional
mistakes occur during the recovery procedure. Furthermore, encoded quantum
information can be processed without serious propagation of errors. Hence, an
arbitrarily long quantum computation can be performed reliably, provided that
the average probability of error per quantum gate is less than a certain
critical value, the accuracy threshold. A quantum computer storing about 10^6
qubits, with a probability of error per quantum gate of order 10^{-6}, would be
a formidable factoring engine. Even a smaller, less accurate quantum computer
would be able to perform many useful tasks. (This paper is based on a talk
presented at the ITP Conference on Quantum Coherence and Decoherence, 15-18
December 1996.)
| [
{
"version": "v1",
"created": "Fri, 16 May 1997 19:00:55 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jun 1997 03:20:46 GMT"
},
{
"version": "v3",
"created": "Tue, 26 Aug 1997 21:28:13 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Preskill",
"John",
"",
"Caltech"
]
] |
quant-ph/9705032 | John Preskill | John Preskill (Caltech) | Quantum Computing: Pro and Con | 17 pages, LaTeX, submitted to Proc. Roy. Soc. Lond. A, minor
corrections | Proc.Roy.Soc.Lond. A454 (1998) 469-486 | 10.1098/rspa.1998.0171 | CALT-68-2113, QUIC-97-031 | quant-ph | null | I assess the potential of quantum computation. Broad and important
applications must be found to justify construction of a quantum computer; I
review some of the known quantum algorithms and consider the prospects for
finding new ones. Quantum computers are notoriously susceptible to making
errors; I discuss recently developed fault-tolerant procedures that enable a
quantum computer with noisy gates to perform reliably. Quantum computing
hardware is still in its infancy; I comment on the specifications that should
be met by future hardware. Over the past few years, work on quantum computation
has erected a new classification of computational complexity, has generated
profound insights into the nature of decoherence, and has stimulated the
formulation of new techniques in high-precision experimental physics. A broad
interdisciplinary effort will be needed if quantum computers are to fulfill
their destiny as the world's fastest computing devices. (This paper is an
expanded version of remarks that were prepared for a panel discussion at the
ITP Conference on Quantum Coherence and Decoherence, 17 December 1996.)
| [
{
"version": "v1",
"created": "Fri, 16 May 1997 19:09:53 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Jun 1997 03:22:05 GMT"
},
{
"version": "v3",
"created": "Tue, 26 Aug 1997 21:27:04 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Preskill",
"John",
"",
"Caltech"
]
] |
quant-ph/9705033 | Richard Cleve | Harry Buhrman and Richard Cleve and Wim van Dam | Quantum Entanglement and Communication Complexity | 10 pages, latex, no figures | SIAM J.Comput. 30 (2001) 1829-1841 | 10.1137/S0097539797324886 | null | quant-ph | null | We consider a variation of the multi-party communication complexity scenario
where the parties are supplied with an extra resource: particles in an
entangled quantum state. We show that, although a prior quantum entanglement
cannot be used to simulate a communication channel, it can reduce the
communication complexity of functions in some cases. Specifically, we show
that, for a particular function among three parties (each of which possesses
part of the function's input), a prior quantum entanglement enables them to
learn the value of the function with only three bits of communication occurring
among the parties, whereas, without quantum entanglement, four bits of
communication are necessary. We also show that, for a particular two-party
probabilistic communication complexity problem, quantum entanglement results in
less communication than is required with only classical random correlations
(instead of quantum entanglement). These results are a noteworthy contrast to
the well-known fact that quantum entanglement cannot be used to actually
simulate communication among remote parties.
| [
{
"version": "v1",
"created": "Sun, 18 May 1997 19:58:41 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Buhrman",
"Harry",
""
],
[
"Cleve",
"Richard",
""
],
[
"van Dam",
"Wim",
""
]
] |
quant-ph/9705034 | Masanao Ozawa | Masanao Ozawa (Nagoya University) | Phase Operator Problem and Macroscopic Extension of Quantum Mechanics | 26 pages, LaTeX, no figures, to appear in Ann. Phys. (N.Y.) | Annals Phys. 257 (1997) 65 | 10.1006/aphy.1997.5685 | null | quant-ph | null | To find the Hermitian phase operatorof a single-mode electromagnetic field in
quantum mechanics, the Schroedinger representation is extended to a larger
Hilbert space augmented by states with infinite excitation by nonstandard
analysis. The Hermitian phase operator is shown to exist on the extended
Hilbert space. This operator is naturally considered as the controversial limit
of the approximate phase operators on finite dimensional spaces proposed by
Pegg and Barnett. The spectral measure of this operator is a Naimark extension
of the optimal probability operator-valued measure for the phase parameter
found by Helstrom. Eventually, the two promising approaches to the statistics
of the phase in quantum mechanics is unified by means of the Hermitian phase
operator in the macroscopic extension of the Schroedinger representation.
| [
{
"version": "v1",
"created": "Mon, 19 May 1997 11:46:32 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Ozawa",
"Masanao",
"",
"Nagoya University"
]
] |
quant-ph/9705035 | Gabriel Drobny | G. Drobny and B. Hladky (Institute of Physics, Bratislava) | Realization of nonlinear oscillators with a trapped ion | 7 pages, RevTeX, no figures | Acta Phys.Slov. 47 (1997) 277-280 | null | null | quant-ph | null | We consider a trapped ion with a quantized center-of-mass motion in 2D trap
potential. With external laser fields the effective (non)linear coupling of two
orthogonal vibrational modes can be established via stimulated Raman
transition. Nonclassical vibrational states such as squeezed states or two-mode
entangled states (Schroedinger cat-like states) can be generated. When the
vibrational modes are entangled with internal energy levels the
Greenberger-Horne-Zeilinger (GHZ) states can be prepared.
| [
{
"version": "v1",
"created": "Wed, 21 May 1997 08:58:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Drobny",
"G.",
"",
"Institute of Physics, Bratislava"
],
[
"Hladky",
"B.",
"",
"Institute of Physics, Bratislava"
]
] |
quant-ph/9705036 | Davit Saakian | A.E. Allahverdyan, D.B. Saakian | Data processing in quantum information theory | LaTex file, 7 pages, no figures | null | null | null | quant-ph | null | The strengthened data processing inequality have been proved. The general
theory have been illustrated on the simple example.
| [
{
"version": "v1",
"created": "Wed, 21 May 1997 10:37:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Allahverdyan",
"A. E.",
""
],
[
"Saakian",
"D. B.",
""
]
] |
quant-ph/9705037 | Alexei Ashikhmin | Alexei Ashikhmin | Remarks on Bounds for Quantum Codes | null | null | null | null | quant-ph | null | We present some results that show that bounds from classical coding theory
still work in many cases of quantum coding theory.
| [
{
"version": "v1",
"created": "Wed, 21 May 1997 23:18:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ashikhmin",
"Alexei",
""
]
] |
quant-ph/9705038 | Dagmar Bruss | D. Bruss, D. P. DiVincenzo, A. Ekert, C. A. Fuchs, C. Macchiavello, J.
A. Smolin | Optimal Universal and State-Dependent Quantum Cloning | 30 pages (RevTeX), 2 figures (epsf), further results and further
authors added, to appear in Physical Review A | PRA 57 (1998) 2368 | 10.1103/PhysRevA.57.2368 | null | quant-ph | null | We establish the best possible approximation to a perfect quantum cloning
machine which produces two clones out of a single input. We analyze both
universal and state-dependent cloners. The maximal fidelity of cloning is shown
to be 5/6 for universal cloners. It can be achieved either by a special unitary
evolution or by a novel teleportation scheme. We construct the optimal
state-dependent cloners operating on any prescribed two non-orthogonal states,
discuss their fidelities and the use of auxiliary physical resources in the
process of cloning. The optimal universal cloners permit us to derive a new
upper bound on the quantum capacity of the depolarizing quantum channel.
| [
{
"version": "v1",
"created": "Thu, 22 May 1997 14:20:40 GMT"
},
{
"version": "v2",
"created": "Wed, 19 Nov 1997 19:48:28 GMT"
},
{
"version": "v3",
"created": "Sat, 6 Dec 1997 18:51:26 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Bruss",
"D.",
""
],
[
"DiVincenzo",
"D. P.",
""
],
[
"Ekert",
"A.",
""
],
[
"Fuchs",
"C. A.",
""
],
[
"Macchiavello",
"C.",
""
],
[
"Smolin",
"J. A.",
""
]
] |
quant-ph/9705039 | Rui Vilela Mendes | V. I. Man'ko and R. Vilela Mendes (Grupo de Fisica-Matematica,
Universidade de Lisboa, Portugal) | On the nonlinearity interpretation of q- and f-deformation and some
applications | 11 pages Latex | J.Phys.A31:6037-6044,1998 | 10.1088/0305-4470/31/28/017 | null | quant-ph | null | q-oscillators are associated to the simplest non-commutative example of Hopf
algebra and may be considered to be the basic building blocks for the symmetry
algebras of completely integrable theories. They may also be interpreted as a
special type of spectral nonlinearity, which may be generalized to a wider
class of f-oscillator algebras. In the framework of this nonlinear
interpretation, we discuss the structure of the stochastic process associated
to q-deformation, the role of the q-oscillator as a spectrum-generating algebra
for fast growing point spectrum, the deformation of fermion operators in
solid-state models and the charge-dependent mass of excitations in f-deformed
relativistic quantum fields.
| [
{
"version": "v1",
"created": "Thu, 22 May 1997 14:34:01 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Man'ko",
"V. I.",
"",
"Grupo de Fisica-Matematica,\n Universidade de Lisboa, Portugal"
],
[
"Mendes",
"R. Vilela",
"",
"Grupo de Fisica-Matematica,\n Universidade de Lisboa, Portugal"
]
] |
quant-ph/9705040 | Rui Vilela Mendes | R. Vilela Mendes (Grupo de Fisica-Matematica, Universidade de Lisboa,
Portugal) | Collision states and scar effects in charged three-body problems | 14 pages Latex, 15 ps-figures | Physics Letters A 233 (1997) 265 | 10.1016/S0375-9601(97)00557-4 | null | quant-ph | null | Semiclassical methods form a bridge between classical systems and their
quantum counterparts. An interesting phenomenon discovered in this connection
is the scar effect, whereby energy eigenstates display enhancement structures
resembling the path of unstable periodic orbits. This paper deals with
collision states in charged three-body problems, in periodic media, which are
scarred by unstable classical orbits. The scar effect has a potential for
practical applications because orbits corresponding to zero measure classical
configurations may be reached and stabilized by resonant excitation. It may be
used, for example, to induce reactions that are favoured by unstable
configurations.
| [
{
"version": "v1",
"created": "Thu, 22 May 1997 12:23:47 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Mendes",
"R. Vilela",
"",
"Grupo de Fisica-Matematica, Universidade de Lisboa,\n Portugal"
]
] |
quant-ph/9705041 | John Smolin | B.M. Terhal and J.A. Smolin | Single quantum querying of a database | Replaced with expanded version, 6 pages revtex, 12 November 1997.
Replaced again to fix small typographical errors, submitted to Phys. Rev. A | Phys.Rev.A58:1822,1998 | 10.1103/PhysRevA.58.1822 | null | quant-ph | null | We present a class of fast quantum algorithms, based on Bernstein and
Vazirani's parity problem, that retrieve the entire contents of a quantum
database $Y$ in a single query. The class includes binary search problems and
coin-weighing problems. Our methods far exceed the efficiency of classical
algorithms which are bounded by the classical information-theoretic bound. We
show the connection between classical algorithms based on several compression
codes and our quantum-mechanical method.
| [
{
"version": "v1",
"created": "Fri, 23 May 1997 20:52:03 GMT"
},
{
"version": "v2",
"created": "Fri, 30 May 1997 19:25:48 GMT"
},
{
"version": "v3",
"created": "Wed, 12 Nov 1997 20:24:05 GMT"
},
{
"version": "v4",
"created": "Fri, 14 Nov 1997 15:17:28 GMT"
}
] | 2008-12-30T00:00:00 | [
[
"Terhal",
"B. M.",
""
],
[
"Smolin",
"J. A.",
""
]
] |
quant-ph/9705042 | Hagen Kleinert | Hagen Kleinert and Sergei V. Shabanov | Supersymmetry in Stochastic Processes with Higher-Order Time Derivatives | Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Paper also at
http://physik.fu-berlin.de/~kleinert/kleiner_re256/preprint.html | Phys.Lett. A235 (1997) 105-112 | 10.1016/S0375-9601(97)00660-9 | null | quant-ph | null | A supersymmetric path integral representation is developed for stochastic
processes whose Langevin equation contains any number N of time derivatives,
thus generalizing the Langevin equation with inertia studied by Kramers, where
N=2. The supersymmetric action contains N fermion fields with first-order time
derivatives whose path integral is evaluated for fermionless asymptotic states.
| [
{
"version": "v1",
"created": "Sat, 24 May 1997 06:31:40 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Kleinert",
"Hagen",
""
],
[
"Shabanov",
"Sergei V.",
""
]
] |
quant-ph/9705043 | Masahide Sasaki | Masahide Sasaki (1), Kentaro Kato (2), Masayuki Izutsu (1), and Osamu
Hirota (2) ((1)Communication Research Laboratory, Tokyo, (2) Tamagawa Univ.,
Tokyo) | A simple quantum channel having superadditivity of channel capacity | 5 pages, LaTeX, 3 eps figures | Phys.Lett. A236 (1997) 1 | 10.1016/S0375-9601(97)00740-8 | qphys-97-1 | quant-ph | null | When classical information is sent through a quantum channel of nonorthogonal
states, there is a possibility that transmittable classical information exceeds
a channel capacity in a single use of the initial channel by extending it into
multi-product channel. In this paper, it is shown that this remarkable feature
of a quantum channel, so-called superadditivity, appears even in as low as the
third extended coding of the simplest binary input channel. A physical
implementation of this channel is indicated based on cavity QED techniques.
| [
{
"version": "v1",
"created": "Mon, 26 May 1997 09:33:05 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Sasaki",
"Masahide",
""
],
[
"Kato",
"Kentaro",
""
],
[
"Izutsu",
"Masayuki",
""
],
[
"Hirota",
"Osamu",
""
]
] |
quant-ph/9705044 | Paolo Zanardi | P. Zanardi (1,3) and M. Rasetti (2,3) ((1) ISI Foundation, Torino (2)
Dipartimento di fisica, Politecnico di Torino, (3) INFM Politecnico di
Torino) | Noiseless Quantum Codes | Revised version (to make it accessible to a broader readership) to
appear on PRL (4 pages, REVTEX) | Phys.Rev.Lett.79:3306-3309,1997 | 10.1103/PhysRevLett.79.3306 | null | quant-ph | null | In this paper we study a model quantum register $\cal R$ made of $N$ replicas
(cells) of a given finite-dimensional quantum system S. Assuming that all cells
are coupled with a common environment with equal strength we show that, for $N$
large enough, in the Hilbert space of $\cal R$ there exists a linear subspace
${\cal C}_N$ which is dynamically decoupled from the environment. The states in
${\cal C}_N$ evolve unitarily and are therefore decoherence-dissipation free.
The space ${\cal C}_N$ realizes a noiseless quantum code in which information
can be stored, in principle, for arbitrarily long time without being affected
by errors.
| [
{
"version": "v1",
"created": "Mon, 26 May 1997 10:11:06 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Sep 1997 08:17:28 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Zanardi",
"P.",
""
],
[
"Rasetti",
"M.",
""
]
] |
quant-ph/9705045 | Paolo Zanardi | Paolo Zanardi (1) ((1) Institute for Scientific Interchange
Foundation, Torino, Italy and Unit\`a INFM, Politecnico di Torino, Torino,
Italy) | Dissipation and Decoherence in a Quantum Register | minor corrections, references added, to appear in PRA (10 pages + 5
figures LaTeX) | Phys.Rev.A57:3276,1998 | 10.1103/PhysRevA.57.3276 | null | quant-ph | null | A model for a quantum register $\cal R$ made of $N$ replicas of a
$d$-dimensional quantum system (cell) coupled with the environment, is studied
by means of a Born-Markov Master Equation (ME). Dissipation and decoherence are
discussed in various cases in which a sub-decoherent enconding can be
rigorously found. For the qubit case ($d=2$) we have solved, for small $N,$ the
ME by numerical direct integration and studied, as a function of the coherence
length $\xi_c$ of the bath, fidelity and decoherence rates of states of the
register. For large enough $\xi_c$ the singlet states of the global $su(2)$
pseudo-spin algebra of the register (noiseless at $\xi_c=\infty$) are shown to
have a much smaller decoherence rates than the rest of the Hilbert space.
| [
{
"version": "v1",
"created": "Mon, 26 May 1997 10:40:01 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Feb 1998 10:23:14 GMT"
}
] | 2011-07-19T00:00:00 | [
[
"Zanardi",
"Paolo",
""
]
] |
quant-ph/9705046 | Serge Massar | N. Gisin and S. Massar | Optimal Quantum Cloning Machines | 4 pages, Latex, 1 postscript figure, (very) minor modifications | Phys.Rev.Lett.79:2153-2156,1997 | 10.1103/PhysRevLett.79.2153 | TAUP 2426-97 | quant-ph | null | We present Quantum Cloning Machines (QCM) that transform N identical qubits
into $M>N$ identical copies and we prove that the fidelity (quality) of these
copies is optimal. The connection between cloning and measurement is discussed
in detail. When the number of clones M tends towards infinity, the fidelity of
each clone tends towards the optimal fidelity that can be obtained by a
measurement on the input qubits. More generally, the QCM are universal devices
to translate quantum information into classical information.
| [
{
"version": "v1",
"created": "Tue, 27 May 1997 07:39:51 GMT"
},
{
"version": "v2",
"created": "Thu, 17 Jul 1997 12:03:41 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Gisin",
"N.",
""
],
[
"Massar",
"S.",
""
]
] |
quant-ph/9705047 | Yu Shi | Yu Shi | Non-partial Reality | 4 pages, revtex | null | null | null | quant-ph | null | Study on pre- and postselected quantum system indicates that ``product rule''
and ``sum rule'' for elements of reality should be abandoned. We show that this
so-called non-partial realism can refute arguments against hidden variables in
a unified way, and might save local realism.
| [
{
"version": "v1",
"created": "Tue, 27 May 1997 11:43:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Shi",
"Yu",
""
]
] |
quant-ph/9705048 | Preprints Libr/pam | Y. Orlov | Redefintions of Histories by Measurements - An Explanation of
"Nonlocality" Observed in EPR-Bohm Experiments | 7 pages, postscript file also available through
http://w4.lns.cornell.edu/public/CLNS | null | null | CLNS 97/1475 | quant-ph | null | It is proved in the frame of standard quantum mechanics that selection of
different ensembles emerging from measurements of an observable leads to
identification of corresponding reductions of the initial, premeasured state.
This solves the problem of ``nonlocality`` observed in EPR-Bohm-type
experiments.
| [
{
"version": "v1",
"created": "Tue, 27 May 1997 19:57:07 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Orlov",
"Y.",
""
]
] |
quant-ph/9705049 | Preprints Libr/pam | Y. Orlov | Quantum-type Coherence as a Combination of Symmetry and Semantics | 6 pages, postscript file also available through
http://w4.lns.cornell.edu/public/CLNS | null | null | CLNS 97/1476 | quant-ph | null | It is shown that quantum-type coherence, leading to indeterminism and
interference of probabilities, may in principle exist in the absence of the
Planck constant and a Hamiltonian. Such coherence is a combined effect of a
symmetry (not necessary physical) and semantics. The crucial condition is that
symmetries should apply to logical statements about observables. A theoretical
example of a non-quantum system with quantum-type properties is analysed.
| [
{
"version": "v1",
"created": "Tue, 27 May 1997 20:06:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Orlov",
"Y.",
""
]
] |
quant-ph/9705050 | Mayburov S. N. | S.N.Mayburov | Asymptotic State Vector Collapse and QED Nonequivalent Representations | 8 pages, Latex, Talk given at 'Quantum Structures -96' Conference To
appear in Proceedings | Int.J.Theor.Phys.37:401-409,1998 | 10.1023/A:1026695508031 | null | quant-ph | null | The state vector evolution in the interaction of measured pure state with the
collective quantum system or the field is analyzed in a nonperturbative QED
formalism. As the model example the measurement of the electron final state
scattered on nucleus or neutrino is considered. The produced electromagnetic
bremsstrahlung contains the unrestricted number of soft photons resulting in
the total radiation flux becoming the classical observable, which means the
state vector collapse. The evolution from the initial to the final system state
is nonunitary and formally irreversible in the limit of the infinite time.
| [
{
"version": "v1",
"created": "Wed, 28 May 1997 10:26:59 GMT"
}
] | 2011-04-15T00:00:00 | [
[
"Mayburov",
"S. N.",
""
]
] |
quant-ph/9705051 | M. Czachor | Marek Czachor | Can absolute freedom save quantum mechanics? | complementarity is less essential for this example than I thought,
the role of local interaction is made more clear | null | null | null | quant-ph | null | A classical system violating the Bell inequality is discussed. The system is
local, deterministic, observers have free will, and detectors are ideal so that
no data are lost. The trick is based on two elements. First, a state of one
observer is locally influenced by a "particle". Second, random variables used
in the experiment are complementary. A relation of this effect to nonlocality
is discussed.
| [
{
"version": "v1",
"created": "Wed, 28 May 1997 12:19:18 GMT"
},
{
"version": "v2",
"created": "Fri, 30 May 1997 12:11:19 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Czachor",
"Marek",
""
]
] |
quant-ph/9705052 | Daniel Gottesman | Daniel Gottesman | Stabilizer Codes and Quantum Error Correction | 114 pages, LaTeX. Caltech Ph.D. Thesis | null | null | null | quant-ph | null | Controlling operational errors and decoherence is one of the major challenges
facing the field of quantum computation and other attempts to create specified
many-particle entangled states. The field of quantum error correction has
developed to meet this challenge. A group-theoretical structure and associated
subclass of quantum codes, the stabilizer codes, has proved particularly
fruitful in producing codes and in understanding the structure of both specific
codes and classes of codes. I will give an overview of the field of quantum
error correction and the formalism of stabilizer codes. In the context of
stabilizer codes, I will discuss a number of known codes, the capacity of a
quantum channel, bounds on quantum codes, and fault-tolerant quantum
computation.
| [
{
"version": "v1",
"created": "Wed, 28 May 1997 23:51:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gottesman",
"Daniel",
""
]
] |
quant-ph/9705053 | M. Czachor | Marek Czachor | Bell inequality and complementarity loophole | revtex, 2 eps figures | null | null | null | quant-ph | null | A simple classical, deterministic, local situation violating the Bell
inequality is described. The detectors used in the experiment are ideal and the
observers who decide which pair of measuring devices to choose for a given pair
of particles have free will. The construction uses random variables which are
not jointly measurable in a single run of an experiment and the hidden
variables have a nonsymmetric probability density. Such random variables are
complementary but still fully classical. An assumption that classical random
variables cannot satisfy any form of complementarity principle is false, and
this is the loophole used in this example. A relationship to the detector
inefficiency loophole is discussed.
| [
{
"version": "v1",
"created": "Fri, 30 May 1997 12:31:45 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Czachor",
"Marek",
""
]
] |
quant-ph/9705054 | Alexandre Kholevo | A. S. Holevo | On Quantum Communication Channels with Constrained Inputs | 17 pages, latex209 | null | null | null | quant-ph | null | The purpose of this work is to extend the result of previous papers
quant-ph/9611023, quant-ph/9703013 to quantum channels with additive
constraints onto the input signal, by showing that the capacity of such channel
is equal to the supremum of the entropy bound with respect to all apriori
distributions satisfying the constraint. We also make an extension to channels
with continuous alphabet. As an application we prove the formula for the
capacity of the quantum Gaussian channel with constrained energy of the signal,
establishing the asymptotic equivalence of this channel to the semiclassical
photon channel. We also study the lower bounds for the reliability function of
the pure-state Gaussian channel.
| [
{
"version": "v1",
"created": "Fri, 30 May 1997 20:16:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Holevo",
"A. S.",
""
]
] |
quant-ph/9706001 | Oliver Rudolph | Oliver Rudolph and J.D. Maitland Wright | On Tracial Operator Representations of Quantum Decoherence Functionals | 14 pages, LaTeX2e | J.Math.Phys. 38 (1997) 5643-5652 | 10.1063/1.532157 | null | quant-ph funct-an gr-qc math.FA | null | A general `quantum history theory' can be characterised by the space of
histories and by the space of decoherence functionals. In this note we consider
the situation where the space of histories is given by the lattice of
projection operators on an infinite dimensional Hilbert space $H$. We study
operator representations for decoherence functionals on this space of
histories. We first give necessary and sufficient conditions for a decoherence
functional being representable by a trace class operator on $H \otimes H$, an
infinite dimensional analogue of the Isham-Linden-Schreckenberg representation
for finite dimensions. Since this excludes many decoherence functionals of
physical interest, we then identify the large and physically important class of
decoherence functionals which can be represented, canonically, by bounded
operators on $H \otimes H$.
| [
{
"version": "v1",
"created": "Sat, 31 May 1997 13:06:20 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Rudolph",
"Oliver",
""
],
[
"Wright",
"J. D. Maitland",
""
]
] |
quant-ph/9706002 | Daniel I. Fivel | Daniel I. Fivel | How to Probe for Dynamical Structure in the Collapse of Entangled States
Using Nuclear Magnetic Resonance | 6 pages, 4 figures, PDF, submitted to PRL | Phys.Lett. A248 (1998) 139-144 | 10.1016/S0375-9601(98)00661-6 | null | quant-ph | null | The spin state of two magnetically inequivalent protons in contiguous atoms
of a molecule becomes entangeled by the indirect spin-spin interaction
(j-coupling). The degree of entanglement oscillates at the beat frequency
resulting from the splitting of a degeneracy. This beating is manifest in NMR
spectroscopy as an envelope of the transverse magnetization and should be
visible in the free induction decay signal. The period (approximately 1 sec) is
long enough for interference between the linear dynamics and collapse of the
wave-function induced by a Stern-Gerlach inhomogeneity to significantly alter
the shape of that envelope. Various dynamical collapse theories can be
distinguished by their observably different predictions with respect to this
alteration. Adverse effects of detuning due to the Stern-Gerlach inhomogeneity
can be reduced to an acceptable level by having a sufficiently thin sample or a
strong rf field.
| [
{
"version": "v1",
"created": "Sun, 1 Jun 1997 03:29:05 GMT"
},
{
"version": "v2",
"created": "Sat, 7 Jun 1997 21:12:58 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Fivel",
"Daniel I.",
""
]
] |
quant-ph/9706003 | Yuri I. Ozhigov | Yuri Ozhigov | About the quantum mechanical speeding up of classical algorithms | 9 pages, LATEX, 2 figures in one GIF-file (the essential revision of
the previous version, some errors are corrected) | null | null | null | quant-ph | null | This work introduces a relative diffusion transformation (RDT) - a simple
unitary transformation which acts in a subspace, localized by an oracle. Such a
transformation can not be fulfilled on quantum Turing machines with this oracle
in polynomial time in general case. It is proved, that every function
computable in time T and space S on classical 1-dimensional cellular automaton,
can be computed with certainty in time O(S \sqrt T) on quantum computer with
RDTs over the parts of intermediate products of classical computation. This
requires multiprocessor, which consists of \sqrt T quantum devices each of O(S)
size, working in parallel-serial mode and interacting by classical lows.
| [
{
"version": "v1",
"created": "Mon, 2 Jun 1997 19:58:16 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Jun 1997 04:49:47 GMT"
},
{
"version": "v3",
"created": "Fri, 6 Jun 1997 21:25:14 GMT"
},
{
"version": "v4",
"created": "Sun, 6 Jul 1997 08:52:07 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Ozhigov",
"Yuri",
""
]
] |
quant-ph/9706004 | null | Roberto Onofrio and Lorenza Viola | Gravitation at the mesoscopic scale | 4 Pages, no figures; Plain REVTeX; to be published in Modern Physics
Letters A | Mod.Phys.Lett. A12 (1997) 1411-1417 | 10.1142/S0217732397001436 | null | quant-ph gr-qc | null | Free fall experiments are discussed by using test masses associated to
quantum states not necessarily possessing a classical counterpart. The times of
flight of the Galileian experiments using classical test masses are replaced in
the quantum case by probability distributions which, although still not defined
in an uncontroversial manner, become manifestly dependent upon the mass and the
initial state. Such a dependence is also expected in non inertial frames of
reference if the weak equivalence principle still holds. This last could be
tested, merging recent achievements in mesoscopic physics, by using cooled
atoms in free fall and accelerated frames initially prepared in nonclassical
quantum states.
| [
{
"version": "v1",
"created": "Mon, 2 Jun 1997 22:53:41 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Onofrio",
"Roberto",
""
],
[
"Viola",
"Lorenza",
""
]
] |
quant-ph/9706005 | Lov K. Grover | Lov K. Grover (Bell Labs, Murray Hill NJ) | Quantum computers can search arbitrarily large databases by a single
query | Several enhancements to the original paper | null | 10.1103/PhysRevLett.79.4709 | null | quant-ph | null | This paper shows that a quantum mechanical algorithm that can query
information relating to multiple items of the database, can search a database
in a single query (a query is defined as any question to the database to which
the database has to return a (YES/NO) answer). A classical algorithm will be
limited to the information theoretic bound of at least O(log N) queries (which
it would achieve by using a binary search).
| [
{
"version": "v1",
"created": "Tue, 3 Jun 1997 00:30:54 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jun 1997 21:43:26 GMT"
},
{
"version": "v3",
"created": "Tue, 12 Aug 1997 18:51:03 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Grover",
"Lov K.",
"",
"Bell Labs, Murray Hill NJ"
]
] |
quant-ph/9706006 | Michael Nielsen | M. A. Nielsen | Computable functions, quantum measurements, and quantum dynamics | 4 pages, REVTEX | Phys.Rev.Lett. 79 (1997) 2915-2918 | 10.1103/PhysRevLett.79.2915 | null | quant-ph | null | We construct quantum mechanical observables and unitary operators which, if
implemented in physical systems as measurements and dynamical evolutions, would
contradict the Church-Turing thesis which lies at the foundation of computer
science. We conclude that either the Church-Turing thesis needs revision, or
that only restricted classes of observables may be realized, in principle, as
measurements, and that only restricted classes of unitary operators may be
realized, in principle, as dynamics.
| [
{
"version": "v1",
"created": "Tue, 3 Jun 1997 03:16:09 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Nielsen",
"M. A.",
""
]
] |
quant-ph/9706007 | Jeong-Young Ji | Jeong-Young Ji, Hyun-Hee Jung, Jong-Woong Park, Kwang-Sup Soh (S.N.U.) | Production of photons by the parametric resonance in the dynamical
Casimir effect | 15 pages, RevTeX, no figures | Phys.Rev. A56 (1997) 4440-4444 | 10.1103/PhysRevA.56.4440 | SNUTP 97-072 | quant-ph hep-th | null | We calculate the number of photons produced by the parametric resonance in a
cavity with vibrating walls. We consider the case that the frequency of
vibrating wall is $n \omega_1 (n=1,2,3,...)$ which is a generalization of other
works considering only $2 \omega_1$, where $\omega_1$ is the fundamental-mode
frequency of the electromagnetic field in the cavity. For the calculation of
time-evolution of quantum fields, we introduce a new method which is borrowed
from the time-dependent perturbation theory of the usual quantum mechanics.
This perturbation method makes it possible to calculate the photon number for
any $n$ and to observe clearly the effect of the parametric resonance.
| [
{
"version": "v1",
"created": "Tue, 3 Jun 1997 06:46:29 GMT"
},
{
"version": "v2",
"created": "Mon, 14 Jul 1997 09:02:07 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Ji",
"Jeong-Young",
"",
"S.N.U."
],
[
"Jung",
"Hyun-Hee",
"",
"S.N.U."
],
[
"Park",
"Jong-Woong",
"",
"S.N.U."
],
[
"Soh",
"Kwang-Sup",
"",
"S.N.U."
]
] |
quant-ph/9706008 | null | Hideyasu Yamashita (Nagoya University) | Hyperfinite-Dimensional Representations of Canonical Commutation
Relation | 18 pages, LaTeX | J.Math.Phys. 39 (1998) 2682-2692 | 10.1063/1.532413 | null | quant-ph | null | This paper presents some methods of representing canonical commutation
relations in terms of hyperfinite-dimensional matrices, which are constructed
by nonstandard analysis. The first method uses representations of a nonstandard
extension of finite Heisenberg group, called hyperfinite Heisenberg group. The
second is based on hyperfinite-dimensional representations of so(3). Then, the
cases of infinite degree of freedom are argued in terms of the algebra of
hyperfinite parafermi oscillators, which is mathematically equivalent to a
hyperfinite-dimensional representation of so(n).
| [
{
"version": "v1",
"created": "Wed, 4 Jun 1997 04:14:16 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Jun 1997 08:07:39 GMT"
},
{
"version": "v3",
"created": "Fri, 20 Jun 1997 04:22:07 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Yamashita",
"Hideyasu",
"",
"Nagoya University"
]
] |
quant-ph/9706009 | Adan Cabello Quintero | Adan Cabello, Jose M. Estebaranz, Guillermo Garcia Alcaine | Bell-Kochen-Specker theorem: A proof with 18 vectors | LaTeX, 10 pages | Phys.Lett. A212 (1996) 183 | 10.1016/0375-9601(96)00134-X | null | quant-ph | null | We present a ``state-independent'' proof of the Bell-Kochen-Specker theorem
using only 18 four-dimensional vectors, which is a record for this kind of
proof. This set of vectors contains subsets which allow us to develop a
``state-specific'' proof with 10 vectors (also a record) and a
``probabilistic'' proof with 7 vectors which reflects the algebraic structure
of Hardy's nonlocality theorem.
| [
{
"version": "v1",
"created": "Tue, 3 Jun 1997 16:56:27 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Cabello",
"Adan",
""
],
[
"Estebaranz",
"Jose M.",
""
],
[
"Alcaine",
"Guillermo Garcia",
""
]
] |
quant-ph/9706010 | Adan Cabello Quintero | Adan Cabello, Jose M. Estebaranz, Guillermo Garcia Alcaine | New variants of the Bell-Kochen-Specker theorem | LaTeX, 7 pages | Phys.Lett. A218 (1996) 115 | 10.1016/0375-9601(96)00457-4 | null | quant-ph | null | We discuss two new demonstrations of the Bell-Kochen-Specker theorem: a
state-independent proof using 14 four-dimensional propositions, based on a
suggestion made by Clifton, and a state-specific proof involving 5 propositions
on the singlet state of two spin-1/2 particles.
| [
{
"version": "v1",
"created": "Tue, 3 Jun 1997 16:56:48 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Cabello",
"Adan",
""
],
[
"Estebaranz",
"Jose M.",
""
],
[
"Alcaine",
"Guillermo Garcia",
""
]
] |
quant-ph/9706011 | Ruediger Schack | Ruediger Schack (Royal Holloway, University of London) and Carlton M.
Caves (University of New Mexico) | Hypersensitivity to perturbation: An information-theoretical
characterization of classical and quantum chaos | 14 pages, LaTeX, 1 figure | Quantum Communication, Computing, and Measurement, edited by O.
Hirota, A. S. Holevo, and C. M. Caves, (Plenum Press, New York, 1997), pp.
317-330 | null | null | quant-ph | null | Hypersensitivity to perturbation is a criterion for chaos based on the
question of how much information about a perturbing environment is needed to
keep the entropy of a Hamiltonian system from increasing. In this paper we give
a brief overview of our work on hypersensitivity to perturbation in classical
and quantum systems.
| [
{
"version": "v1",
"created": "Wed, 4 Jun 1997 14:33:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Schack",
"Ruediger",
"",
"Royal Holloway, University of London"
],
[
"Caves",
"Carlton M.",
"",
"University of New Mexico"
]
] |
quant-ph/9706012 | Paul Benioff | Paul Benioff (Physics Divison, Argonne National Laboratory) | Quantum Robots and Quantum Computers | 18 pages, RevTex, one postscript figure. Paper considerably revised
and enlarged. submitted to Phys. Rev. A | in "Feynman and Computation, A.J.G.Hey, Ed. Perseus books,
(1999),pp 155-176 | null | null | quant-ph | null | Validation of a presumably universal theory, such as quantum mechanics,
requires a quantum mechanical description of systems that carry out theoretical
calculations and experiments. The description of quantum computers is under
active development. No description of systems to carry out experiments has been
given. A small step in this direction is taken here by giving a description of
quantum robots as mobile systems with on board quantum computers that interact
with environments. Some properties of these systems are discussed. A specific
model based on the literature descriptions of quantum Turing machines is
presented.
| [
{
"version": "v1",
"created": "Wed, 4 Jun 1997 15:15:44 GMT"
},
{
"version": "v2",
"created": "Fri, 19 Sep 1997 20:36:39 GMT"
},
{
"version": "v3",
"created": "Thu, 18 Dec 1997 16:17:25 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Benioff",
"Paul",
"",
"Physics Divison, Argonne National Laboratory"
]
] |
quant-ph/9706013 | Paul Slater | Paul B. Slater (University of California, Santa Barbara) | Quantum Statistical Thermodynamics of Two-Level Systems | 21 pages, LaTeX, 6 postscript figures. We show (in the concluding
section) that the exponent for the power law behavior of the order parameter
(twice the average polarization minus 1) for our (standard complex)
alternative (proportional to a ratio of gamma functions) to the hyperbolic
tangent Brillouin function of paramagnetism, equals one-half, being the same
in both these cases | null | null | null | quant-ph cond-mat | null | We study four distinct families of Gibbs canonical distributions defined on
the standard complex, quaternionic, real and classical (nonquantum) two-level
systems. The structure function or density of states for any two-level system
is a simple power (1, 3, 0 or -1) of the length of its polarization vector,
while the magnitude of the energy of the system, in all four cases, is the
negative of the logarithm of the determinant of the corresponding
two-dimensional density matrix. Functional relationships (proportional to
ratios of gamma functions) are found between the average polarizations with
respect to the Gibbs distributions and the effective polarization temperature
parameters. In the standard complex case, this yields an interesting
alternative, meeting certain probabilistic requirements recently set forth by
Lavenda, to the more conventional (hyperbolic tangent) Brillouin function of
paramagnetism (which, Lavenda argues, fails to meet such specifications).
| [
{
"version": "v1",
"created": "Wed, 4 Jun 1997 21:23:17 GMT"
},
{
"version": "v10",
"created": "Thu, 3 Jul 1997 20:19:43 GMT"
},
{
"version": "v11",
"created": "Mon, 7 Jul 1997 20:36:54 GMT"
},
{
"version": "v12",
"created": "Fri, 18 Jul 1997 20:26:25 GMT"
},
{
"version": "v13",
"created": "Thu, 24 Jul 1997 20:41:49 GMT"
},
{
"version": "v14",
"created": "Fri, 1 Aug 1997 21:17:15 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Jun 1997 23:30:08 GMT"
},
{
"version": "v3",
"created": "Sat, 7 Jun 1997 00:00:31 GMT"
},
{
"version": "v4",
"created": "Fri, 13 Jun 1997 20:31:07 GMT"
},
{
"version": "v5",
"created": "Fri, 20 Jun 1997 22:08:37 GMT"
},
{
"version": "v6",
"created": "Thu, 26 Jun 1997 20:05:10 GMT"
},
{
"version": "v7",
"created": "Fri, 27 Jun 1997 21:58:17 GMT"
},
{
"version": "v8",
"created": "Mon, 30 Jun 1997 21:51:34 GMT"
},
{
"version": "v9",
"created": "Tue, 1 Jul 1997 19:28:47 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Slater",
"Paul B.",
"",
"University of California, Santa Barbara"
]
] |
quant-ph/9706014 | Rui Vilela Mendes | R. Vilela Mendes (Grupo de Fisica-Matematica, Universidade de Lisboa,
Portugal) | Saddle scars: Existence and applications | 9 pages Latex, 1 ps figure | Phys.Lett. A239 (1998) 223-227 | 10.1016/S0375-9601(98)00063-2 | null | quant-ph | null | A quantum scar is a wave function which displays an high intensity in the
region of a classical unstable periodic orbit. Saddle scars are states related
to the unstable harmonic motions along the stable manifold of a saddle point of
the potential. Using a semiclassical method it is shown that, independently of
the overall structure of the potential, the local dynamics of the saddle point
is sufficient to insure the general existence of this type of scars and their
factorized structure is obtained. Potentially useful situations are identified,
where these states appear (directly or in disguise) and might be used for
quantum control purposes.
| [
{
"version": "v1",
"created": "Thu, 5 Jun 1997 11:31:33 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Mendes",
"R. Vilela",
"",
"Grupo de Fisica-Matematica, Universidade de Lisboa,\n Portugal"
]
] |
quant-ph/9706015 | Lorenzo Luis Salcedo Moreno | L. L. Salcedo | Minimum uncertainty for antisymmetric wave functions | 20 pages RevTeX, 1 Postscript figure (epsf) | Lett.Math.Phys. 43 (1998) 233-249 | 10.1023/A:1007464229188 | UG-DFM-1/97 | quant-ph funct-an math.FA | null | We study how the entropic uncertainty relation for position and momentum
conjugate variables is minimized in the subspace of one-dimensional
antisymmetric wave functions. Based partially on numerical evidence and
partially on analytical results, a conjecture is presented for the sharp bound
and for the minimizers. Conjectures are also presented for the corresponding
sharp Hausdorff-Young inequality.
| [
{
"version": "v1",
"created": "Thu, 5 Jun 1997 11:50:38 GMT"
}
] | 2025-01-10T00:00:00 | [
[
"Salcedo",
"L. L.",
""
]
] |
quant-ph/9706016 | Adan Cabello Quintero | Adan Cabello | No-hidden-variables proof for two spin-1/2 particles preselected and
postselected in unentangled states | LaTeX, 8 pages | Phys.Rev. A55 (1997) 4109-4111 | 10.1103/PhysRevA.55.4109 | null | quant-ph | null | It is a well-known fact that all the statistical predictions of quantum
mechanics on the state of any physical system represented by a two-dimensional
Hilbert space can always be duplicated by a noncontextual hidden-variables
model. In this paper, I show that, in some cases, when we consider an
additional independent (unentangled) two-dimensional system, the quantum
description of the resulting composite system cannot be reproduced using
noncontextual hidden variables. In particular, a no-hidden-variables proof is
presented for two individual spin-1/2 particles preselected in an uncorrelated
state AB and postselected in another uncorrelated state aB, B being the same
state for the second particle in both preselection and postselection.
| [
{
"version": "v1",
"created": "Fri, 6 Jun 1997 16:49:58 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Cabello",
"Adan",
""
]
] |
quant-ph/9706017 | Giovanna Morigi | G. Morigi, J. I. Cirac, M. Lewenstein, and P. Zoller | Ground State Laser Cooling Beyond the Lamb-Dicke Limit | 6 pages, 4 figures, to appear in Europhysics Letters | Europhys. Lett. 39, 13 (1997) | 10.1209/0295-5075/23/1/001 | null | quant-ph | null | We propose a laser cooling scheme that allows to cool a single atom confined
in a harmonic potential to the trap ground state $|0>$. The scheme assumes
strong confinement, where the oscillation frequency in the trap is larger than
the effective spontaneous decay width, but is not restricted to the Lamb-Dicke
limit, i.e. the size of the trap ground state can be larger than the optical
wavelength. This cooling scheme may be useful in the context of quantum
computations with ions and Bose-Einstein condensation.
| [
{
"version": "v1",
"created": "Sat, 7 Jun 1997 14:03:29 GMT"
}
] | 2020-05-14T00:00:00 | [
[
"Morigi",
"G.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Lewenstein",
"M.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9706018 | Mark J. Hadley | Mark J. Hadley (Univ. of Warwick, UK) | The Logic of Quantum Mechanics Derived from Classical General Relativity | 16 pages Latex | Found.Phys.Lett. 10 (1997) 43-60 | 10.1007/BF02764119 | null | quant-ph gr-qc hep-th | null | For the first time it is shown that the logic of quantum mechanics can be
derived from Classical Physics. An orthomodular lattice of propositions,
characteristic of quantum logic, is constructed for manifolds in Einstein's
theory of general relativity. A particle is modelled by a topologically
non-trivial 4-manifold with closed timelike curves - a 4-geon, rather than as
an evolving 3-manifold. It is then possible for both the state preparation and
measurement apparatus to constrain the results of experiments. It is shown that
propositions about the results of measurements can satisfy a non-distributive
logic rather than the Boolean logic of classical systems. Reasonable
assumptions about the role of the measurement apparatus leads to an
orthomodular lattice of propositions characteristic of quantum logic.
| [
{
"version": "v1",
"created": "Mon, 9 Jun 1997 12:04:30 GMT"
}
] | 2024-01-03T00:00:00 | [
[
"Hadley",
"Mark J.",
"",
"Univ. of Warwick, UK"
]
] |
quant-ph/9706019 | Bella Andrea | Giuseppe Castagnoli | Quantum Computation Based on Retarded and Advanced Propagation | Reference of particle statistics to computation speed up better
formalized after referee's suggestions. Modified: second half of Section I,
Section IIC after eq.(7), Section IID and E. Figure unchanged | null | 10.1016/S0167-2789(98)00044-X | null | quant-ph | null | Computation is currently seen as a forward propagator that evolves (retards)
a completely defined initial vector into a corresponding final vector. Initial
and final vectors map the (logical) input and output of a reversible Boolean
network respectively, whereas forward propagation maps a one-way propagation of
logical implication, from input to output. Conversely, hard NP-complete
problems are characterized by a two-way propagation of logical implication from
input to output and vice versa, given that both are partly defined from the
beginning. Logical implication can be propagated forward and backward in a
computation by constructing the gate array corresponding to the entire
reversible Boolean network and constraining output bits as well as input bits.
The possibility of modeling the physical process undergone by such a network by
using a retarded and advanced in time propagation scheme is investigated. PACS
numbers: 89.70.+c, 02.50.-r, 03.65.-w, 89.80.+h
| [
{
"version": "v1",
"created": "Mon, 9 Jun 1997 15:06:25 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jun 1997 12:02:38 GMT"
},
{
"version": "v3",
"created": "Thu, 26 Jun 1997 14:56:00 GMT"
},
{
"version": "v4",
"created": "Tue, 5 Aug 1997 15:46:43 GMT"
},
{
"version": "v5",
"created": "Thu, 20 Nov 1997 16:12:30 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Castagnoli",
"Giuseppe",
""
]
] |
quant-ph/9706020 | Guo Guangcan | Lu-Ming Duan and Guang-Can Guo (University of Science and Technology
of China) | Perturbative expansions for the fidelities and spatially correlated
dissipation of quantum bits | Minor changes in discussions | Phys. Rev. A 56 (6), 4466 (1997) | 10.1103/PhysRevA.56.4466 | null | quant-ph | null | We construct generally applicable short-time perturbative expansions for some
fidelities, such as the input-output fidelity, the entanglement fidelity, and
the average fidelity. Successive terms of these expansions yield characteristic
times for the damping of the fidelities involving successive powers of the
Hamiltonian. The second-order results, which represent the damping rates of the
fidelities, are extensively discussed. As an interesting application of these
expansions, we use them to study the spatially-correlated dissipation of
quantum bits. Spatial correlations in the dissipation are described by a
correlation function. Explicit conditions are derived for independent
decoherence and for collective decoherence.
| [
{
"version": "v1",
"created": "Tue, 10 Jun 1997 09:24:05 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Feb 1998 08:08:31 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Duan",
"Lu-Ming",
"",
"University of Science and Technology\n of China"
],
[
"Guo",
"Guang-Can",
"",
"University of Science and Technology\n of China"
]
] |
quant-ph/9706021 | Igor V. Volovich | L.Accardi, S.V.Kozyrev and I.V.Volovich | Dynamics of Dissipative Two-Level Systems in the Stochastic
Approximation | 13 pages, plaintex | Phys.Rev. A56 (1997) 2557-2562 | 10.1103/PhysRevA.56.2557 | N.280, Centro V.Volterra, Universita di Roma Tor Vergata | quant-ph | null | The dynamics of the spin-boson Hamiltonian is considered in the stochastic
approximation. The Hamiltonian describes a two-level system coupled to an
environment and is widely used in physics, chemistry and the theory of quantum
measurement. We demonstrate that the method of the stochastic approximation
which is a general method of consideration of dynamics of an arbitrary system
interacting with environment is powerful enough to reproduce qualitatively
striking results by Leggett at al. found earlier for this model. The result
include an exact expression of the dynamics in terms of the spectral density
and show an appearance of two most interesting regimes for the system, i.e.
pure oscillating and pure damping ones. Correlators describing environment are
also computed.
| [
{
"version": "v1",
"created": "Tue, 10 Jun 1997 12:20:31 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Accardi",
"L.",
""
],
[
"Kozyrev",
"S. V.",
""
],
[
"Volovich",
"I. V.",
""
]
] |
quant-ph/9706022 | Nicolas Cerf | N. J. Cerf (Caltech), C. Adami (Caltech), and P. G. Kwiat (LANL) | Optical Simulation of Quantum Logic | 4 pages RevTex with psfig, 3 Postscript figures | Phys.Rev. A57 (1998) 1477 | 10.1103/PhysRevA.57.R1477 | KRL MAP-211 | quant-ph | null | A systematic method for simulating small-scale quantum circuits by use of
linear optical devices is presented. It relies on the representation of several
quantum bits by a single photon, and on the implementation of universal quantum
gates using simple optical components (beam splitters, phase shifters, etc.).
This suggests that the optical realization of small quantum networks is
reasonable given the present technology in quantum optics, and could be a
useful technique for testing simple quantum algorithms or error-correction
schemes. The optical circuit for quantum teleportation is presented as an
illustration.
| [
{
"version": "v1",
"created": "Thu, 12 Jun 1997 02:16:40 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Cerf",
"N. J.",
"",
"Caltech"
],
[
"Adami",
"C.",
"",
"Caltech"
],
[
"Kwiat",
"P. G.",
"",
"LANL"
]
] |
quant-ph/9706023 | Davor Palle | D. Palle (Rugjer Boskovic Institute, Zagreb, Croatia) | Quantum mechanics in the noncontractible space | 4 pages, LaTeX style; IL NUOVO CIMENTO B, N.B.(1997) in press | Nuovo Cim. B112 (1997) 943-945 | null | null | quant-ph | null | We show that the impact of the fundamental length in quantum mechanics can be
studied within the formalism of Berry's geometrical phase with the line
broadening as a resulting physical effect.
| [
{
"version": "v1",
"created": "Thu, 12 Jun 1997 09:57:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Palle",
"D.",
"",
"Rugjer Boskovic Institute, Zagreb, Croatia"
]
] |
quant-ph/9706024 | Giacomo Mauro D'Ariano | Alfred W\"unsche (Arbeitsgruppe "Nichtklassische Strahlung" der
Max-Planck-Gesellschaft, Berlin, Germany) | Radon transform and pattern functions in quantum tomography | To appear on Journal of Modern Optics.Submitted to | null | 10.1080/09500349708231885 | null | quant-ph | null | The two-dimensional Radon transform of the Wigner quasiprobability is
introduced in canonical form and the functions playing a role in its inversion
are discussed. The transformation properties of this Radon transform with
respect to displacement and squeezing of states are studied and it is shown
that the last is equivalent to a symplectic transformation of the variables of
the Radon transform with the contragredient matrix to the transformation of the
variables in the Wigner quasiprobability. The reconstruction of the density
operator from the Radon transform and the direct reconstruction of its
Fock-state matrix elements and of its normally ordered moments are discussed.
It is found that for finite-order moments the integration over the angle can be
reduced to a finite sum over a discrete set of angles. The reconstruction of
the Fock-state matrix elements from the normally ordered moments leads to a new
representation of the pattern functions by convergent series over even or odd
Hermite polynomials which is appropriate for practical calculations. The
structure of the pattern functions as first derivatives of the products of
normalizable and nonnormalizable eigenfunctions to the number operator is
considered from the point of view of this new representation.
| [
{
"version": "v1",
"created": "Thu, 12 Jun 1997 14:53:00 GMT"
}
] | 2016-06-29T00:00:00 | [
[
"Wünsche",
"Alfred",
"",
"Arbeitsgruppe \"Nichtklassische Strahlung\" der\n Max-Planck-Gesellschaft, Berlin, Germany"
]
] |
quant-ph/9706025 | Dr. Luca Salasnich, . D. | Luca Salasnich | Quantum Chaos in a Yang-Mills-Higgs System | Latex, 13 pages, 2 figures (available upon request), accepted for
publication in Modern Physics Letters A | Mod.Phys.Lett. A12 (1997) 1473-1480 | 10.1142/S0217732397001503 | Preprint DMPA/97, Univ. of Padova | quant-ph hep-th nucl-th | null | We study the energy fluctuations of a spatially homogeneous SU(2)
Yang-Mills-Higgs system. In particular, we analyze the nearest-neighbour
spacing distribution which shows a Wigner-Poisson transition by increasing the
value of the Higgs field in the vacuum. This transition is a clear quantum
signature of the classical chaos-order transition of the system.
| [
{
"version": "v1",
"created": "Thu, 12 Jun 1997 19:27:56 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Salasnich",
"Luca",
""
]
] |
quant-ph/9706026 | Dmitri Averin | D.V. Averin | Adiabatic quantum computation with Cooper pairs | 18 pages, 3 figures not supplied by author | null | 10.1016/S0038-1098(97)10001-1 | null | quant-ph cond-mat | null | We propose a new variant of the controlled-NOT quantum logic gate based on
adiabatic level-crossing dynamics of the q-bits. The gate has a natural
implementation in terms of the Cooper pair transport in arrays of small
Josephson tunnel junctions. An important advantage of the adiabatic approach is
that the gate dynamics is insensitive to the unavoidable spread of junction
parameters.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 05:10:19 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Averin",
"D. V.",
""
]
] |
quant-ph/9706027 | Masanao Ozawa | Masanao Ozawa (Nagoya University) | An Operational Approach to Quantum State Reduction | 17 pages, LaTeX, no figures, to appear in Ann. Phys. (N.Y.) | Annals Phys.259:121,1997 | 10.1006/aphy.1997.5706 | null | quant-ph | null | An operational approach to quantum state reduction, the state change of the
measured system caused by a measurement of an observable conditional upon the
outcome of measurement, is founded without assuming the projection postulate in
any stages of the measuring process. Whereas the conventional formula assumes
that the probe measurement satisfies the projection postulate, a new formula
for determining the state reduction shows that the state reduction does not
depend on how the probe observable is measured, or in particular does not
depend on whether the probe measurement satisfies the projection postulate or
not, contrary to the longstanding attempts in showing how the macroscopic
nature of probe detection provokes state reduction.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 04:09:56 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Ozawa",
"Masanao",
"",
"Nagoya University"
]
] |
quant-ph/9706028 | D. Trifonov | D.A. Trifonov | Barut-Girardello coherent states for sp(N,C) and multimode Schr\"odinger
cat states | Latex, 11 pages, no figures | null | null | INRNE-TH-97/5 (Sofia) | quant-ph | null | Overcomplete families of states of the type of Barut-Girardello coherent
states (BG CS) are constructed for noncompact algebras $u(p,q)$ and $sp(N,C)$
in quadratic bosonic representation. The $sp(N,C)$ BG CS are obtained in the
form of multimode ordinary Schr\"odinger cat states. A set of such macroscopic
superpositions is pointed out which is overcomplete in the whole $N$ mode
Hilbert space (while the associated $sp(N,C)$ representation is reducible). The
multimode squared amplitude Schr\"odinger cat states are introduced as
macroscopic superpositions of the obtained $sp(N,C)$ BG CS.}
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 10:40:50 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Trifonov",
"D. A.",
""
]
] |
quant-ph/9706029 | null | A. Angelow (Institute of Solid State Physics, Sofia, Bulgaria) | Light Propagation in Nonlinear Waveguide and Classical Two-Dimensional
Oscillator | 14 pages, including one Table, 29 bibliographic references; E-mail:
[email protected] | null | 10.1016/S0378-4371(98)00198-8 | null | quant-ph | null | The quantum optical problem of the propagation of electromagnetic waves in a
nonlinear waveguide is related to the solutions of the classical nonstationary
harmonic oscillator using the method of linear integrals of motion [ Malkin
et.al., Phys Rev. 2D (1970) p.1371 ]. An explicit solution of the classical
oscillator with a varying frequency, corresponding to the light propagation in
an anisotropic waveguide is obtained using the expressions for the quantum
field fluctuations. Substitutions have been found which allow to establish
connections of the linear and quadratic invariants of Malkin et.al. to several
types of invariants of quadratic systems, considered in later papers. These
substitutions give the opportunity to relate the corresponding quantum problem
to that of the classical two-dimensional nonstationary oscillator, which is
physically more informative.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 13:52:53 GMT"
},
{
"version": "v2",
"created": "Thu, 8 Jan 1998 10:43:00 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Angelow",
"A.",
"",
"Institute of Solid State Physics, Sofia, Bulgaria"
]
] |
quant-ph/9706030 | Dorje C. Brody | Dorje C. Brody and Lane P. Hughston | Geometry of Thermodynamic States | 7 pages, RevTex | Phys.Lett. A245 (1998) 73-78 | 10.1016/S0375-9601(98)00385-5 | null | quant-ph | null | A novel geometric formalism for statistical estimation is applied here to the
canonical distribution of classical statistical mechanics. In this scheme
thermodynamic states, or equivalently, statistical mechanical states, can be
characterised concisely in terms of the geometry of a submanifold ${\cal M}$ of
the unit sphere ${\cal S}$ in a real Hilbert space ${\cal H}$. The measurement
of a thermodynamic variable then corresponds to the reduction of a state vector
in ${\cal H}$ to an eigenstate, where the transition probability is the
Boltzmann weight. We derive a set of uncertainty relations for conjugate
thermodynamic variables in the equilibrium thermodynamic states. These follow
as a consequence of a striking thermodynamic analogue of the Anandan-Aharonov
relations in quantum mechanics. As a result we are able to provide a resolution
to the controversy surrounding the status of `temperature fluctuations' in the
canonical ensemble. By consideration of the curvature of the thermodynamic
trajectory in its state space we are then able to derive a series of higher
order variance bounds, which we calculate explicitly to second order.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 11:47:02 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Brody",
"Dorje C.",
""
],
[
"Hughston",
"Lane P.",
""
]
] |
quant-ph/9706031 | null | N. L\"utkenhaus, J.I. Cirac, and P. Zoller | Mimicking a Squeezed Bath Interaction: Quantum Reservoir Engineering
with Atoms | 24 pages, 8 figures | Phys.Rev. A57 (1998) 548-558 | 10.1103/PhysRevA.57.548 | null | quant-ph | null | The interaction of an atomic two-level system and a squeezed vacuum leads to
interesting novel effects in atomic dynamics, including line narrowing in
resonance fluorescence and absorption spectra, and a suppressed (enhanced)
decay of the in-phase and out-of phase component of the atomic polarization. On
the experimental side these predictions have so far eluded observation,
essentially due to the difficulty of embedding atoms in a 4 pi squeezed vacuum.
In this paper we show how to ``engineer'' a squeezed-bath-type interaction for
an effective two-level system. In the simplest example, our two-level atom is
represented by the two ground levels of an atom with angular momentum J=1/2 ->
J=1/2 transition (a four level system) which is driven by (weak) laser fields
and coupled to the vacuum reservoir of radiation modes. Interference between
the spontaneous emission channels in optical pumping leads to a squeezed bath
type coupling, and thus to symmetry breaking of decay on the Bloch sphere. With
this system it should be possible to observe the effects predicted in the
context of squeezed bath - atom interactions. The laser parameters allow one to
choose properties of the squeezed bath interaction, such as the (effective)
photon number expectation number N and the squeezing phase phi. We present
results of a detailed analytical and numerical study.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 13:31:18 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Lütkenhaus",
"N.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9706032 | null | F. Benatti and R. Floreanini | Testing complete positivity | 12 pages, latex, no figures, to appear in Mod. Phys. Lett. A | Mod.Phys.Lett. A12 (1997) 1465-1472 | 10.1142/S0217732397001497 | null | quant-ph | null | We study the modified dynamical evolution of the neutral kaon system under
the condition of complete positivity. The accuracy of the data from planned
future experiments is expected to be sufficiently precise to test such a
hypothesis.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 12:17:41 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Benatti",
"F.",
""
],
[
"Floreanini",
"R.",
""
]
] |
quant-ph/9706033 | Lov K. Grover | Lov K. Grover (Bell Labs, Murray Hill, NJ) | Quantum Mechanics helps in searching for a needle in a haystack | Postscript, 4 pages. This is a modified version of the STOC paper
(quant-ph/9605043) and is modified to make it more comprehensible to
physicists. It appeared in Phys. Rev. Letters on July 14, 1997. (This paper
was originally put out on quant-ph on June 13, 1997, the present version has
some minor typographical changes) | Phys.Rev.Lett.79:325-328,1997 | 10.1103/PhysRevLett.79.325 | null | quant-ph | null | Quantum mechanics can speed up a range of search applications over unsorted
data. For example imagine a phone directory containing N names arranged in
completely random order. To find someone's phone number with a probability of
50%, any classical algorithm (whether deterministic or probabilistic) will need
to access the database a minimum of O(N) times. Quantum mechanical systems can
be in a superposition of states and simultaneously examine multiple names. By
properly adjusting the phases of various operations, successful computations
reinforce each other while others interfere randomly. As a result, the desired
phone number can be obtained in only O(sqrt(N)) accesses to the database.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 14:26:36 GMT"
},
{
"version": "v2",
"created": "Thu, 17 Jul 1997 18:54:39 GMT"
}
] | 2009-10-05T00:00:00 | [
[
"Grover",
"Lov K.",
"",
"Bell Labs, Murray Hill, NJ"
]
] |
quant-ph/9706034 | Ignacio Cirac | J.I. Cirac, M. Lewenstein, K. Moelmer, and P. Zoller | Quantum Superposition States of Bose-Einstein Condensates | 24 pages, 6 figures | null | 10.1103/PhysRevA.57.1208 | null | quant-ph | null | We propose a scheme to create a macroscopic ``Sch\"odinger cat'' state formed
by two interacting Bose condensates. In analogy with quantum optics, where the
control and engineering of quantum states can be maintained to a large extend,
we consider the present scheme to be an example of quantum atom optics at work.
| [
{
"version": "v1",
"created": "Fri, 13 Jun 1997 16:35:25 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Cirac",
"J. I.",
""
],
[
"Lewenstein",
"M.",
""
],
[
"Moelmer",
"K.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9706035 | Marc Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique Th\'eorique de l'Ecole
Normale Sup\'erieure) and Serge Reynaud (Laboratoire Kastler-Brossel) | Movement and Fluctuations of the Vacuum | 17 pages, to appear in Reports on Progress in Physics | Rep. Prog. Phys. 60 (1997) 863-887 | 10.1088/0034-4885/60/9/001 | LPTENS 97/22 | quant-ph gr-qc | null | Quantum fields possess zero-point or vacuum fluctuations which induce
mechanical effects, namely generalised Casimir forces, on any scatterer.
Symmetries of vacuum therefore raise fundamental questions when confronted
with the principle of relativity of motion in vacuum. The specific case of
uniformly accelerated motion is particularly interesting, in connection with
the much debated question of the appearance of vacuum in accelerated frames.
The choice of Rindler representation, commonly used in General Relativity,
transforms vacuum fluctuations into thermal fluctuations, raising difficulties
of interpretation. In contrast, the conformal representation of uniformly
accelerated frames fits the symmetry properties of field propagation and
quantum vacuum and thus leads to extend the principle of relativity of motion
to uniform accelerations.
Mirrors moving in vacuum with a non uniform acceleration are known to
radiate. The associated radiation reaction force is directly connected to
fluctuating forces felt by motionless mirrors through fluctuation-dissipation
relations. Scatterers in vacuum undergo a quantum Brownian motion which
describes irreducible quantum fluctuations. Vacuum fluctuations impose ultimate
limitations on measurements of position in space-time, and thus challenge the
very concept of space-time localisation within a quantum framework.
For test masses greater than Planck mass, the ultimate limit in localisation
is determined by gravitational vacuum fluctuations. Not only positions in
space-time, but also geodesic distances, behave as quantum variables,
reflecting the necessary quantum nature of an underlying geometry.
| [
{
"version": "v1",
"created": "Mon, 16 Jun 1997 09:15:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Jaekel",
"Marc-Thierry",
"",
"Laboratoire de Physique Théorique de l'Ecole\n Normale Supérieure"
],
[
"Reynaud",
"Serge",
"",
"Laboratoire Kastler-Brossel"
]
] |
quant-ph/9706036 | Marc Jaekel | Marc-Thierry Jaekel (Laboratoire de Physique Th\'eorique de l'Ecole
Normale Sup\'erieure) and Serge Reynaud (Laboratoire Kastler-Brossel) | Conformal Symmetry and Quantum Relativity | 8 pages | Found.Phys. 28 (1998) 439-456 | 10.1023/A:1018716111971 | LPTENS 97/23 | quant-ph gr-qc | null | The relativistic conception of space and time is challenged by the quantum
nature of physical observables. It has been known for a long time that
Poincar\'e symmetry of field theory can be extended to the larger conformal
symmetry. We use these symmetries to define quantum observables associated with
positions in space-time, in the spirit of Einstein theory of relativity. This
conception of localisation may be applied to massive as well as massless
fields. Localisation observables are defined as to obey Lorentz covariant
commutations relations and in particular include a time observable conjugated
to energy. Whilst position components do not commute in presence of a
non-vanishing spin, they still satisfy quantum relations which generalise the
differential laws of classical relativity. We also give of these observables a
representation in terms of canonical spatial positions, canonical spin
components and a proper time operator conjugated to mass. These results plead
for a new representation not only of space-time localisation but also of
motion.
| [
{
"version": "v1",
"created": "Mon, 16 Jun 1997 09:16:15 GMT"
}
] | 2013-02-27T00:00:00 | [
[
"Jaekel",
"Marc-Thierry",
"",
"Laboratoire de Physique Théorique de l'Ecole\n Normale Supérieure"
],
[
"Reynaud",
"Serge",
"",
"Laboratoire Kastler-Brossel"
]
] |
quant-ph/9706037 | Dorje C. Brody | Dorje C. Brody and Lane P. Hughston | Generalised Heisenberg Relations | 7 pages, RevTex | null | null | null | quant-ph | null | A geometric framework for quantum statistical estimation is used to establish
a series of higher order corrections to the Heisenberg uncertainty relations
associated with pairs of canonically conjugate variables. These corrections can
be expressed in terms of linear combinations of higher order cumulants for the
distributions, and thus vanish for Gaussian distributions. Estimates for
typical numerical values arising from these corrections are indicated in the
case of a gamma distribution.
| [
{
"version": "v1",
"created": "Tue, 17 Jun 1997 10:45:15 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Brody",
"Dorje C.",
""
],
[
"Hughston",
"Lane P.",
""
]
] |
quant-ph/9706038 | null | L. Lanz and O. Melsheimer | Time scale, objectivity and irreversibility in quantum mechanics | 13 pages, latex, no figures, to appear in the Proceedings of the XXI
International Colloquium on Group Theoretical Methods in Physics, 1996
(Goslar, Germany) | Lect.Notes Phys. 504 (1998) 345-358 | 10.1007/BFb0106792 | null | quant-ph | null | It is argued that setting isolated systems as primary scope of field theory
and looking at particles as derived entities, the problem of an objective
anchorage of quantum mechanics can be solved and irreversibility acquires a
fundamental role. These general ideas are checked in the case of the Boltzmann
description of a dilute gas.
| [
{
"version": "v1",
"created": "Tue, 17 Jun 1997 17:17:24 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Lanz",
"L.",
""
],
[
"Melsheimer",
"O.",
""
]
] |
quant-ph/9706039 | Robert R. Tucci | Robert R. Tucci | Quantum Bayesian Nets | 1 LaTeX file (34 pages), 41 gif files, 1 HTML file with Figure
Captions linked to figures. Before downloading to a Mac, please read warning
at http://www.ar-tiste.com/macusers_gifs.html | Int.J.Mod.Phys. B9 (1995) 295-337 | 10.1142/S0217979295000148 | null | quant-ph | null | We begin with a review of a well known class of networks, Classical Bayesian
(CB) nets (also called causal probabilistic nets by some). Given a situation
which includes randomness, CB nets are used to calculate the probabilities of
various hypotheses about the situation, conditioned on the available evidence.
We introduce a new class of networks, which we call Quantum Bayesian (QB) nets,
that generalize CB nets to the quantum mechanical regime. We explain how to use
QB nets to calculate quantum mechanical conditional probabilities (in case of
either sharp or fuzzy observations), and discuss the connection of QB nets to
Feynman Path integrals. We give examples of QB nets that involve a single
spin-half particle passing through a configuration of two or three
Stern-Gerlach magnets. For the examples given, we present the numerical values
of various conditional probabilities, as calculated by a general computer
program especially written for this purpose.
| [
{
"version": "v1",
"created": "Tue, 17 Jun 1997 20:29:56 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Tucci",
"Robert R.",
""
]
] |
quant-ph/9706040 | Yihren Wu | Yihren Wu | Quantization of a particle in a background Yang-Mills field | 11 pages, amstex file, removed a condition placed on the metric in
the previous version | J.Math.Phys.39:867-875,1998 | 10.1063/1.532357 | null | quant-ph | null | Two classes of observables defined on the configuration space of a particle
are quantized, and the effects of the Yang-Mills field are discussed in the
context of geometric quantization.
| [
{
"version": "v1",
"created": "Wed, 18 Jun 1997 03:20:02 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Nov 1997 03:38:56 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Wu",
"Yihren",
""
]
] |
quant-ph/9706041 | Chang-Pu Sun | C.P.Sun J. M. Li, H. Zhan, Y. X. Miao, S. R. Zhao, G. Xu | A Linear Quantum Dynamic Theory for Coherent Output of Bose-Einstain
Condensation | 9 pages,Latex, E-mail address available after July 5: [email protected] | null | null | ITP.AC.97-6-20 | quant-ph | null | A model for the coherent output coupler of the Bose-Einstein condensed atoms
from a trap in the recent MIT experiment (Phys. Rev. Lett., 78 (1997) 582) is
established with a simple many-boson system of two states with linear coupling.
Its exact solution for the many-body problem shows a factorization of dynamical
evolution process, i.e., the wave function initially prepared in a direct
product of a vacuum state and a coherent state remains in a direct product of
two coherent states at any instance in the evolution of the total system. This
conclusion always holds even for a system with a finite average particle number
in the initial state. Its thermodynamical limit can be directly dealt with in
the Bogoliubov approximation and manifests that an ideal condensate in the trap
will remain in a coherent state after the r.f. interaction while the
output-coupler pulse of atoms is also in a coherent state, which means a
coherent output of atomic beam to form a macroscopic quantum state in a
propagating mode.
| [
{
"version": "v1",
"created": "Wed, 18 Jun 1997 05:32:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Li",
"C. P. Sun J. M.",
""
],
[
"Zhan",
"H.",
""
],
[
"Miao",
"Y. X.",
""
],
[
"Zhao",
"S. R.",
""
],
[
"Xu",
"G.",
""
]
] |
quant-ph/9706042 | Guo Guangcan | Lu-Ming Duan and Guang-Can Guo (University of Science and Technology
of China) | Correlations in interference and diffraction | 16 pages, 2 figures, Latex, to appear in J. Mod. Opt | null | 10.1080/09500349808231671 | null | quant-ph | null | Quantum formalism of Fraunhofer diffraction is obtained. The state of the
diffraction optical field is connected with the state of the incident optical
field by a diffraction factor. Based on this formalism, correlations of the
diffraction modes are calculated with different kinds of incident optical
fields. Influence of correlations of the incident modes on the diffraction
pattern is analyzed and an explanation of the ''ghost'' diffraction is
proposed.
| [
{
"version": "v1",
"created": "Wed, 18 Jun 1997 10:34:45 GMT"
}
] | 2017-07-12T00:00:00 | [
[
"Duan",
"Lu-Ming",
"",
"University of Science and Technology\n of China"
],
[
"Guo",
"Guang-Can",
"",
"University of Science and Technology\n of China"
]
] |
quant-ph/9706043 | Gyula Bene | Gyula Bene (Institute for Solid State Physics, Eo"tvo"s University,
Budapest) | Quantum phenomena do not violate the principle of locality - a new
interpretation with physical consequences - | 31 pages, LATEX, submitted to Am.J.Phys | null | null | null | quant-ph | null | A new interpretation of nonrelativistic quantum mechanics explains the
violation of Bell's inequality by maintaining realism and the principle of
locality.
| [
{
"version": "v1",
"created": "Wed, 18 Jun 1997 14:11:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bene",
"Gyula",
"",
"Institute for Solid State Physics, Eo\"tvo\"s University,\n Budapest"
]
] |
quant-ph/9706044 | Jose Oscar Rosas | David J. Fernandez C., Oscar Rosas-Ortiz | Dynamical Manipulation for spin-1/2 Systems | 6 pages, LaTeX, Proceedings' macros included in source-file, 1
PostScript figure | ``Fifth International Conference on Squeezed States and
Uncertainty Relations'', Balatonfured, Hungary (May 1997); D. Han, J.
Janszky, Y. S. Kim and V.I. Man'ko (Editors). NASA/CP-1998-206855, pages
583-588 | null | null | quant-ph | null | By means of the inverse techniques we analyse the evolution of purely
spin-1/2 systems in homogeneous magnetic fields as well as the generation of
exact solutions. Some ``evolution loops'', dynamical processes for which any
state evolves cyclically, are presented, and their corresponding geometric
phases are evaluated
| [
{
"version": "v1",
"created": "Wed, 18 Jun 1997 19:18:41 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jun 1997 04:40:12 GMT"
},
{
"version": "v3",
"created": "Tue, 24 Jun 1997 03:39:29 GMT"
},
{
"version": "v4",
"created": "Mon, 16 Nov 1998 18:28:51 GMT"
}
] | 2008-10-13T00:00:00 | [
[
"C.",
"David J. Fernandez",
""
],
[
"Rosas-Ortiz",
"Oscar",
""
]
] |
quant-ph/9706045 | Jonathan Halliwell | J. J. Halliwell and E. Zafiris | Decoherent Histories Approach to the Arrival Time Problem | 42 pages, plain Tex | Phys.Rev. D57 (1998) 3351-3364 | 10.1103/PhysRevD.57.3351 | Imperial College preprint 96-97/04 | quant-ph gr-qc | null | We use the decoherent histories approach to quantum theory to compute the
probability of a non-relativistic particle crossing $x=0$ during an interval of
time. For a system consisting of a single non-relativistic particle, histories
coarse-grained according to whether or not they pass through spacetime regions
are generally not decoherent, except for very special initial states, and thus
probabilities cannot be assigned. Decoherence may, however, be achieved by
coupling the particle to an environment consisting of a set of harmonic
oscillators in a thermal bath. Probabilities for spacetime coarse grainings are
thus calculated by considering restricted density operator propagators of the
quantum Brownian motion model. We also show how to achieve decoherence by
replicating the system $N$ times and then projecting onto the number density of
particles that cross during a given time interval, and this gives an
alternative expression for the crossing probability. The latter approach shows
that the relative frequency for histories is approximately decoherent for
sufficiently large $N$, a result related to the Finkelstein-Graham-Hartle
theorem.
| [
{
"version": "v1",
"created": "Thu, 19 Jun 1997 15:38:35 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Halliwell",
"J. J.",
""
],
[
"Zafiris",
"E.",
""
]
] |
quant-ph/9706046 | null | Won Young Hwang and In Gyu Koh (KAIST) and Yeong Deok Han (Woosuk
University) | Quantum Coin Tossing | withdrawl | null | null | null | quant-ph | null | We show that a secure quantum protocol for coin tossing exist. The existence
of quantum coin tossing support the conjecture of D.Mayers [Phys.Rev.Lett. 78,
3414(1997)] that only asymmetrical tasks as quantum bit commitment are
impossible.
| [
{
"version": "v1",
"created": "Fri, 20 Jun 1997 03:06:20 GMT"
},
{
"version": "v2",
"created": "Tue, 8 Jul 1997 04:14:38 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Hwang",
"Won Young",
"",
"KAIST"
],
[
"Koh",
"In Gyu",
"",
"KAIST"
],
[
"Han",
"Yeong Deok",
"",
"Woosuk\n University"
]
] |
quant-ph/9706047 | Chang-Pu Sun | C.P.Sun H.B.Gao, H.F.Dong, S.R.Zhao | Partial Factorization of Wave Function for A Quantum Dissipation System | 9 pages,Latex, E-mail address available after July 5: [email protected] | Phys.Rev. E57 (1998) 3900-3904 | 10.1103/PhysRevE.57.3900 | ITP.AC.97-6-19 | quant-ph | null | The microscopic approach quantum dissipation process presented by Yu and Sun
[Phys. Rev., A49(1994)592, A51(1995)1845] is developed to analyze the wave
function structure of dynamic evolution of a typical dissipative system, a
single mode boson soaked in a bath of many bosons. In this paper, the wave
function of total system is explicitly obtained as a product of two components
of the system and the bath in the coherent state representation. It not only
describes the influence of the bath on the variable of the system through the
Brownian motion, but also manifests the back- action of the system on the bath
and the effects of the mutual interaction among the bosons of the bath. Due to
the back-action, the total wave function can only be partially factorizable
even for the Brownian motion can be ignored in certain senses, such as the
cases with weak coupling and large detuning
| [
{
"version": "v1",
"created": "Fri, 20 Jun 1997 07:57:40 GMT"
}
] | 2019-08-17T00:00:00 | [
[
"Gao",
"C. P. Sun H. B.",
""
],
[
"Dong",
"H. F.",
""
],
[
"Zhao",
"S. R.",
""
]
] |
quant-ph/9706048 | Hiromichi Nakazato | Hiromichi Nakazato (Dept. of Phys, Waseda Univ., Japan) | Time development of a wave packet and the time delay | 13 pages, plain TeX, 2 eps figures, tar+gzip+uuencoded | Found.Phys. 27 (1997) 1709-1723 | 10.1007/BF02551447 | WU-HEP-97-1 | quant-ph | null | A one-dimensional scattering problem off a $\delta$-shaped potential is
solved analytically and the time development of a wave packet is derived from
the time-dependent Schr\"odinger equation. The exact and explicit expression of
the scattered wave packet supplies us with interesting information about the
"time delay" by potential scattering in the asymptotic region. It is
demonstrated that a wave packet scattered by a spin-flipping potential can give
us quite a different value for the delay times from that obtained without
spin-degrees of freedom.
| [
{
"version": "v1",
"created": "Fri, 20 Jun 1997 09:46:59 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Nakazato",
"Hiromichi",
"",
"Dept. of Phys, Waseda Univ., Japan"
]
] |
quant-ph/9706049 | Keiko Kurokawa | K. Kurokawa, M. Sasaki, M. Osaki, and O. Hirota | Some properties of quantum reiliablity function for quantum
communication channel | 8 pages, 7 figures, LaTex, change items, 1. author: M.Ban was
deleted. 2. misstype of Eq(21) was corrected | null | null | Tamagawa university preprint 97/01 | quant-ph | null | This paper presents some examples of quantum reliability function for the
quantum communication system in which classical information is transmitted by
quantum states. In addition, the quantum Cut off rate is defined. They will be
compared with Gallager's reliability function for the same system.
| [
{
"version": "v1",
"created": "Fri, 20 Jun 1997 12:45:11 GMT"
},
{
"version": "v2",
"created": "Sat, 21 Jun 1997 07:27:59 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Kurokawa",
"K.",
""
],
[
"Sasaki",
"M.",
""
],
[
"Osaki",
"M.",
""
],
[
"Hirota",
"O.",
""
]
] |
quant-ph/9706050 | Walter T. Strunz | Lajos Diosi and Walter T. Strunz | The non-Markovian stochastic Schrodinger equation for open systems | 9 pages, RevTeX | null | 10.1016/S0375-9601(97)00717-2 | null | quant-ph | null | We present the non-Markovian generalization of the widely used stochastic
Schrodinger equation. Our result allows to describe open quantum systems in
terms of stochastic state vectors rather than density operators, without
approximation. Moreover, it unifies two recent independent attempts towards a
stochastic description of non-Markovian open systems, based on path integrals
on the one hand and coherent states on the other. The latter approach utilizes
the analytical properties of coherent states and enables a microscopic
interpretation of the stochastic states. The alternative first approach is
based on the general description of open systems using path integrals as
originated by Feynman and Vernon.
| [
{
"version": "v1",
"created": "Sun, 22 Jun 1997 11:01:15 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Diosi",
"Lajos",
""
],
[
"Strunz",
"Walter T.",
""
]
] |
quant-ph/9706051 | Nikolaos Mavromatos | John Ellis, N.E. Mavromatos, and D.V. Nanopoulos | Vacuum Fluctuations and Decoherence in Mesoscopic and Microscopic
Systems | 17 pages LATEX, 1 macro (sprocl.sty) required. Contribution to the
Symposium on Flavour-Changing Neutral Currents: Present and Future Studies,
UCLA (USA), February 1997 | null | null | CERN-TH/97-133, CTP-TAMU-28/97, ACT-10/97, OUTP-29P | quant-ph gr-qc hep-ph hep-th | null | We discuss recent experimental evidence of decoherence in a laboratory
mesoscopic system in a cavity, from which we draw analogies with the
decoherence that we argue is induced by microscopic quantum-gravity
fluctuations in the space-time background. We emphasize the parallel r\^oles
played in both cases by dissipation through non-trivial vacuum fluctuations
that trigger the collapse of an initially coherent quantum state. We review a
phenomenological parametrization of possible effects of this kind in the
neutral kaon system, where they would induce CPT violation, and describe some
epxerimental tests.
| [
{
"version": "v1",
"created": "Mon, 23 Jun 1997 16:26:01 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ellis",
"John",
""
],
[
"Mavromatos",
"N. E.",
""
],
[
"Nanopoulos",
"D. V.",
""
]
] |
quant-ph/9706052 | Markus Grassl | Markus Grassl and Thomas Beth (Universitaet Karlsruhe) | On the Complexity of Quantum Searching Using Complex Queries | 4 pages, RevTeX, no figures | null | null | null | quant-ph | null | We discuss the quantum search algorithm using complex queries that has
recently been published by Grover (quant-ph/9706005). We recall the algorithm
adding some details showing which complex query has to be evaluated. Based on
this version of the algorithm we discuss its complexity.
| [
{
"version": "v1",
"created": "Mon, 23 Jun 1997 20:17:16 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Grassl",
"Markus",
"",
"Universitaet Karlsruhe"
],
[
"Beth",
"Thomas",
"",
"Universitaet Karlsruhe"
]
] |
quant-ph/9706053 | Raymond Laflamme | Emanuel Knill, Isaac Chuang and Raymond Laflamme | Effective Pure States for Bulk Quantum Computation | 24 pages in LaTex, 14 figures, the paper is also avalaible at
http://qso.lanl.gov/qc/ | null | 10.1103/PhysRevA.57.3348 | null | quant-ph | null | In bulk quantum computation one can manipulate a large number of
indistinguishable quantum computers by parallel unitary operations and measure
expectation values of certain observables with limited sensitivity. The initial
state of each computer in the ensemble is known but not pure. Methods for
obtaining effective pure input states by a series of manipulations have been
described by Gershenfeld and Chuang (logical labeling) and Cory et al. (spatial
averaging) for the case of quantum computation with nuclear magnetic resonance.
We give a different technique called temporal averaging. This method is based
on classical randomization, requires no ancilla qubits and can be implemented
in nuclear magnetic resonance without using gradient fields. We introduce
several temporal averaging algorithms suitable for both high temperature and
low temperature bulk quantum computing and analyze the signal to noise behavior
of each.
| [
{
"version": "v1",
"created": "Tue, 24 Jun 1997 16:53:08 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Knill",
"Emanuel",
""
],
[
"Chuang",
"Isaac",
""
],
[
"Laflamme",
"Raymond",
""
]
] |
quant-ph/9706054 | Gyula Bene | Gyula Bene (Institute for Solid State Physics, Eo"tvo"s University,
Budapest) | On the failure of Bell's theorem | 4 pages, RevTeX | null | null | null | quant-ph | null | Using a new approach to quantum mechanics we revisit Hardy's proof for Bell's
theorem and point out a loophole in it. We also demonstrate on this example
that quantum mechanics is a local realistic theory.
| [
{
"version": "v1",
"created": "Tue, 24 Jun 1997 13:22:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bene",
"Gyula",
"",
"Institute for Solid State Physics, Eo\"tvo\"s University,\n Budapest"
]
] |
quant-ph/9706055 | Helen Bukina | E. N. Bukina (Joint Institue for Nuclear Rearch), N. N. Shtykov
(Irkutsk State University) | Evaluation of Vacuum Energy for Tensor Fields on Spherical Spaces | LaTex, 4 pages. Published in the Proceedings of the Int. Seminar
"Path Integrals and Applications" | null | null | null | quant-ph | null | The effective one-loop potential on $R^{m+1}\times S^N$ spaces for massless
tensor fields is evaluated. The Casimir energy is given as a value of $\zeta-$
function by means of which regularization is made. In even- dimensional spaces
the vacuum energy contains divergent terms coming from poles of $\zeta(s,q)$ at
$s=1$, whereas in odd-dimensional spaces it becomes finite.
| [
{
"version": "v1",
"created": "Wed, 25 Jun 1997 14:06:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bukina",
"E. N.",
"",
"Joint Institue for Nuclear Rearch"
],
[
"Shtykov",
"N. N.",
"",
"Irkutsk State University"
]
] |
quant-ph/9706056 | Ali Mostafazadeh | Ali Mostafazadeh | Eigenvalue Problem for Schroedinger Operators and Time-Dependent
Harmonic Oscillator | Plain Latex | null | null | University of Alberta preprint no: Thy -97 | quant-ph | null | It is shown that the eigenvalue problem for the Hamiltonians of the standard
form, $H=p^2/(2m)+V(x)$, is equivalent to the classical dynamical equation for
certain harmonic oscillators with time-dependent frequency. This is another
indication of the central role played by time-dependent harmonic oscillators in
quantum mechanics. The utility of the known results for eigenvalue problem in
the solution of the dynamical equations of a class of time-dependent harmonic
oscillators is also pointed out.
| [
{
"version": "v1",
"created": "Thu, 26 Jun 1997 00:21:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mostafazadeh",
"Ali",
""
]
] |
quant-ph/9706057 | Feng Pan | Feng Pan, J. P. Draayer | Exact solution for generalized pairing | 9 pages Latex (Some mistakes were corrected) | null | null | null | quant-ph | null | An infinite dimensional algebra, which is useful for deriving exact solutions
of the generalized pairing problem, is introduced. A formalism for
diagonalizing the corresponding Hamiltonian is also proposed. The theory is
illustrated with some numerical examples.
| [
{
"version": "v1",
"created": "Thu, 26 Jun 1997 07:45:20 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Jun 1997 10:32:10 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Pan",
"Feng",
""
],
[
"Draayer",
"J. P.",
""
]
] |
quant-ph/9706058 | Valery Rupasov | Sajeev John and Valery I. Rupasov | Multiphoton localization and propagating quantum gap solitons in a
frequency gap medium | 8 pages, RevTEX, to appear in Phys. Rev. Lett | Phys.Rev.Lett.79:821-824,1997 | 10.1103/PhysRevLett.79.821 | null | quant-ph cond-mat | null | The many-particle spectrum of an isotropic frequency gap medium doped with
impurity resonance atoms is studied using the Bethe ansatz technique. The
spectrum is shown to contain pairs of quantum correlated ``gap excitations''
and their heavy bound complexes (``gap solitons''), enabling the propagation of
quantum information within the classically forbidden gap. In addition,
multiparticle localization of the radiation and the medium polarization occurs
when such a gap soliton is pinned to the impurity atom.
| [
{
"version": "v1",
"created": "Thu, 26 Jun 1997 18:26:38 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"John",
"Sajeev",
""
],
[
"Rupasov",
"Valery I.",
""
]
] |
quant-ph/9706059 | null | Ruy A. H. Farias and Erasmo Recami | Introduction of a Quantum of Time ("chronon"), and its Consequences for
Quantum Mechanics | standard LaTeX file, with 11 figures (in postscript) attached | null | null | null | quant-ph | null | In this review-article, we discuss the consequences of the introduction of a
quantum of time tau_0 in the formalism of non-relativistic quantum mechanics
(QM) by referring ourselves in particular to the theory of the "chronon" as
proposed by P.Caldirola. Such an interesting "finite difference" theory,
forwards --at the classical level-- a solution for the motion of a particle
endowed with a non-negligible charge in an external electromagnetic field,
overcoming all the known difficulties met by Abraham-Lorentz's and Dirac's
approaches (and even allowing a clear answer to the question whether a free
falling charged particle does or does not emit radiation), and --at the quantum
level-- yields a remarkable mass spectrum for leptons. After having briefly
reviewed Caldirola's approach, we compare one another the new Schroedinger,
Heisenberg and density-operator (Liouville-von Neumann) pictures resulting from
it. Moreover, for each representation, three (retarded, symmetric and advanced)
formulations are possible, which refer either to times t and t-tau_0, or to
times t-tau_0/2 and t+tau_0/2, or to times t and t+tau_0, respectively. It is
interesting to notice that, e.g., the "retarded" QM does naturally appear to
describe QM with friction, i.e., to describe dissipative quantum systems (like
a particle moving in an absorbing medium). In this sense, discretized QM is
much richer than the ordinary one. When the density matrix formalism is applied
to the solution of the measurement problem in QM, very interesting results are
met, so as a natural explication of "decoherence".
| [
{
"version": "v1",
"created": "Fri, 27 Jun 1997 06:32:53 GMT"
},
{
"version": "v2",
"created": "Sat, 28 Jun 1997 07:08:14 GMT"
},
{
"version": "v3",
"created": "Mon, 23 Jul 2007 11:37:31 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Farias",
"Ruy A. H.",
""
],
[
"Recami",
"Erasmo",
""
]
] |
quant-ph/9706060 | David Barclay | D. T. Barclay (University of Liverpool) | The Structure of the SWKB Series | 9 pages, LaTex, no figures | null | null | LTH 397 | quant-ph | null | The supersymmetric-WKB series is shown to be such that the SWKB quantisation
condition has corrections in powers of h^2 only and with explicit overall
factors of E. The results also suggest more efficient methods of calculating
the corrections.
| [
{
"version": "v1",
"created": "Fri, 27 Jun 1997 14:12:28 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Barclay",
"D. T.",
"",
"University of Liverpool"
]
] |
quant-ph/9706061 | John Smolin | David P. DiVincenzo, Peter W. Shor and John A. Smolin | Quantum Channel Capacity of Very Noisy Channels | 31 pages including epsf postscript figures. Replaced to correct
important typographical errors in equations 36, 37 and in text | null | 10.1103/PhysRevA.57.830 | null | quant-ph | null | We present a family of additive quantum error-correcting codes whose
capacities exceeds that of quantum random coding (hashing) for very noisy
channels. These codes provide non-zero capacity in a depolarizing channel for
fidelity parameters $f$ when $f> .80944$. Random coding has non-zero capacity
only for $f>.81071$; by analogy to the classical Shannon coding limit, this
value had previously been conjectured to be a lower bound. We use the method
introduced by Shor and Smolin of concatenating a non-random (cat) code within a
random code to obtain good codes. The cat code with block size five is shown to
be optimal for single concatenation. The best known multiple-concatenated code
we found has a block size of 25. We derive a general relation between the
capacity attainable by these concatenation schemes and the coherent information
of the inner code states.
| [
{
"version": "v1",
"created": "Fri, 27 Jun 1997 19:23:39 GMT"
},
{
"version": "v2",
"created": "Mon, 29 Sep 1997 18:58:37 GMT"
},
{
"version": "v3",
"created": "Tue, 3 Nov 1998 19:32:19 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"DiVincenzo",
"David P.",
""
],
[
"Shor",
"Peter W.",
""
],
[
"Smolin",
"John A.",
""
]
] |
quant-ph/9706062 | Edward Farhi | Edward Farhi (MIT), Sam Gutmann (Northeastern) | Quantum Computation and Decision Trees | Revised version to appear in Phys Rev A; technical error corrected,
methods and conclusions remain the same; 28 pages, 11 figures, REVTeX,
amsmath, BoxedEPSF | null | 10.1103/PhysRevA.58.915 | MIT-CTP-2651 | quant-ph | null | Many interesting computational problems can be reformulated in terms of
decision trees. A natural classical algorithm is to then run a random walk on
the tree, starting at the root, to see if the tree contains a node n levels
from the root. We devise a quantum mechanical algorithm that evolves a state,
initially localized at the root, through the tree. We prove that if the
classical strategy succeeds in reaching level n in time polynomial in n, then
so does the quantum algorithm. Moreover, we find examples of trees for which
the classical algorithm requires time exponential in n, but for which the
quantum algorithm succeeds in polynomial time. The examples we have so far,
however, could also be solved in polynomial time by different classical
algorithms.
| [
{
"version": "v1",
"created": "Fri, 27 Jun 1997 18:47:34 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Mar 1998 20:46:44 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Farhi",
"Edward",
"",
"MIT"
],
[
"Gutmann",
"Sam",
"",
"Northeastern"
]
] |
quant-ph/9706063 | Kiyoung Kim | Kiyoung Kim (Department of Physics, University of Utah) | Schrodinger Equation and Phase Space in Quantum Mechanics | 8 pages, no figure, LATEX | null | null | null | quant-ph | null | Using classical statistics, Schrodinger equation in quantum mechanics is
derived from complex space model. Phase-space probability amplitude, that can
be defined on classical point of view, has connections to probability amplitude
in internal space and to wave function in quantum mechanics. In addition, the
physical entity of wave function in quantum mechanics is confirmed once again.
| [
{
"version": "v1",
"created": "Fri, 27 Jun 1997 20:11:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kim",
"Kiyoung",
"",
"Department of Physics, University of Utah"
]
] |
quant-ph/9706064 | Carlton Caves | M. A. Nielsen (1), Carlton M. Caves (1), Benjamin Schumacher (2), and
Howard Barnum (1) ((1) Center for Advanced Studies, University of New Mexico,
(2) Physics Department, Kenyon College) | Information-theoretic approach to quantum error correction and
reversible measurement | 31 pages, REVTEX, one figure in LaTeX, submitted to Proceedings of
the ITP Conference on Quantum Coherence and Decoherence | null | 10.1098/rspa.1998.0160 | null | quant-ph | null | Quantum operations provide a general description of the state changes allowed
by quantum mechanics. The reversal of quantum operations is important for
quantum error-correcting codes, teleportation, and reversing quantum
measurements. We derive information-theoretic conditions and equivalent
algebraic conditions that are necessary and sufficient for a general quantum
operation to be reversible. We analyze the thermodynamic cost of error
correction and show that error correction can be regarded as a kind of
``Maxwell demon,'' for which there is an entropy cost associated with
information obtained from measurements performed during error correction. A
prescription for thermodynamically efficient error correction is given.
| [
{
"version": "v1",
"created": "Mon, 30 Jun 1997 20:04:29 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Nielsen",
"M. A.",
""
],
[
"Caves",
"Carlton M.",
""
],
[
"Schumacher",
"Benjamin",
""
],
[
"Barnum",
"Howard",
""
]
] |
quant-ph/9707001 | T. Pellizzari | T. Pellizzari (University of Oxford) | Quantum Networking with Optical Fibres | 4 pages, 3 figures, RevTeX, submitted to PRL | null | 10.1103/PhysRevLett.79.5242 | null | quant-ph | null | I propose a scheme which allows for reliable transfer of quantum information
between two atoms via an optical fibre in the presence of decoherence. The
scheme is based on performing an adiabatic passage through two cavities which
remain in their respective vacuum states during the whole operation. The scheme
may be useful for networking several ion-trap quantum computers, thereby
increasing the number of quantum bits involved in a computation.
| [
{
"version": "v1",
"created": "Tue, 1 Jul 1997 17:26:16 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Pellizzari",
"T.",
"",
"University of Oxford"
]
] |
quant-ph/9707002 | Eric Rains | Eric M. Rains | Entanglement purification via separable superoperators | 4 pages, RevTeX, one EPS figure, revised for greater clarity, and to
add references to new work. Revised 4/23/98 to fix a serious systematic typo | null | null | null | quant-ph | null | One of the fundamental concepts of quantum information theory is that of
entanglement purification; that is, the transformation of a partially entangled
state into a smaller-dimensional, more completely entangled state. Of
particular interest are protocols for entanglement purification (EPPs) that
alternate purely local operations with one- or two-way classical communication.
In the present work, we consider a more general, but simpler, class of
transformations, called separable superoperators. Since every EPP is a
separable superoperator, bounds on separable superoperators apply as well to
EPPs; we use this fact to give a new upper bound on the rate of EPPs on
Bell-diagonal states, and thus on the capacity of Bell-diagonal channels.
| [
{
"version": "v1",
"created": "Tue, 1 Jul 1997 17:36:38 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Feb 1998 18:16:54 GMT"
},
{
"version": "v3",
"created": "Thu, 23 Apr 1998 17:20:48 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Rains",
"Eric M.",
""
]
] |
quant-ph/9707003 | Kotel'nikov Gennadii | G. A. Kotel'nikov (RRC "Kurchatov Institute", Moscow, Russia) | "Minus c" Symmetry in Classical and Quantum Theories | 12 pages, LaTeX, Poster at the Fifth International Conference on
Squeezed States and Uncertainty Relations, May 27-31, 1997, Balatonfured,
Hungary | Phys.Atom.Nucl.63:688-691,2000; Yad.Fiz.63:753-756,2000 | 10.1134/1.855691 | IAE-6030/1 | quant-ph physics.class-ph | null | It is shown that the transformations of the charge conjugation in classical
electrodynamics and in quantum theory can be interpreted as the consequences of
the symmetry of Maxwell and Dirac equations with respect to the inversion of
the speed of light: c to -c; t to t; (x,y,z) to (x,y,z), where c is the speed
of light; t is the time; x, y, z are the spatial variables.
The elements of physical interpretation are given.
| [
{
"version": "v1",
"created": "Wed, 2 Jul 1997 11:54:15 GMT"
}
] | 2011-04-15T00:00:00 | [
[
"Kotel'nikov",
"G. A.",
"",
"RRC \"Kurchatov Institute\", Moscow, Russia"
]
] |
quant-ph/9707004 | A. Andrianov | A. A. Andrianov(1), F.Cannata(2), D.N.Nishnianidze(1), M.V.Ioffe(1)
((1) St.Petersburg University; (2) INFN -Bologna) | Matrix Hamiltonians: SUSY approach to hidden symmetries | 20 pages, LaTeX | J.Phys.A30:5037-5050,1997 | 10.1088/0305-4470/30/14/015 | null | quant-ph | null | A new supersymmetric approach to the analysis of dynamical symmetries for
matrix quantum systems is presented. Contrary to standard one dimensional
quantum mechanics where there is no role for an additional symmetry due to
nondegeneracy, matrix hamiltonians allow for non-trivial residual symmetries.
This approach is based on a generalization of the intertwining relations
familiar in SUSY Quantum Mechanics. The corresponding matrix supercharges, of
first or of second order in derivatives, lead to an algebra which incorporates
an additional block diagonal differential matrix operator (referred to as a
"hidden" symmetry operator) found to commute with the superhamiltonian. We
discuss some physical interpretations of such dynamical systems in terms of
spin 1/2 particle in a magnetic field or in terms of coupled channel problem.
Particular attention is paid to the case of transparent matrix potentials.
| [
{
"version": "v1",
"created": "Wed, 2 Jul 1997 14:27:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Andrianov",
"A. A.",
"",
"St.Petersburg University;"
],
[
"Cannata",
"F.",
"",
"INFN -Bologna"
],
[
"Nishnianidze",
"D. N.",
"",
"St.Petersburg University;"
],
[
"Ioffe",
"M. V.",
"",
"St.Petersburg University;"
]
] |
quant-ph/9707005 | C. J. Tymczak | C. J. Tymczak, G. S. Japaridze, C. R. Handy and Xiao-Qian Wang (Center
for Theoretical Studies of Physical Systems, Clark Atlanta University) | A Nonperturbative Perspective on Inner Product Quantization: Highly
Accurate Solutions to the Schr{\"o}dinger Equation | Four Pages REVTEX, Three Postscript figures | null | null | null | quant-ph | null | We devise a new and highly accurate quantization procedure for the inner
product representation, both in configuration and momentum space. Utilizing the
representation $\Psi(\xi) = \sum_{i}a_i[E]\xi^i R_{\beta}(\xi)$, for an
appropriate reference function, $R_{\beta}(\xi)$, we demonstrate that the
(convergent) zeroes of the coefficient functions, $a_i[E] = 0$, approximate the
exact bound/resonance state energies with increasing accuracy as $i \to
\infty$. The validity of the approach is shown to be based on an extension of
the Hill determinant quantization procedure. Our method has been applied, with
remarkable success, to various quantum mechanical problems.
| [
{
"version": "v1",
"created": "Wed, 2 Jul 1997 18:28:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Tymczak",
"C. J.",
"",
"Center\n for Theoretical Studies of Physical Systems, Clark Atlanta University"
],
[
"Japaridze",
"G. S.",
"",
"Center\n for Theoretical Studies of Physical Systems, Clark Atlanta University"
],
[
"Handy",
"C. R.",
"",
"Center\n for Theoretical Studies of Physical Systems, Clark Atlanta University"
],
[
"Wang",
"Xiao-Qian",
"",
"Center\n for Theoretical Studies of Physical Systems, Clark Atlanta University"
]
] |
quant-ph/9707006 | Vesselin I. Dimitrov | Vesselin I. Dimitrov (Faculty of Physics, Sofia University, Bulgaria) | Puzzlement about thermal redshift | 4 pages RevTeX, 1 postscript figure | Phys.Lett. A241 (1998) 218-222 | 10.1016/S0375-9601(98)00168-6 | null | quant-ph | null | Discussed is the classical theoretical description of the experimentally
established thermal redshift of spectral lines. Straightforward calculation of
the observable spectrum from a canonical ensamble of monochromatic radiators
yileds overall blueshift rather than redshift. It is concluded that the
customary explanation of the thermal redshift as a second order Doppler effect
does not bear closer examination, and that in fact, the phenomenon ''thermal
redshift'' is not yet fully uderstood in classical terms.
| [
{
"version": "v1",
"created": "Thu, 3 Jul 1997 09:16:12 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Dimitrov",
"Vesselin I.",
"",
"Faculty of Physics, Sofia University, Bulgaria"
]
] |
quant-ph/9707007 | Vesselin I. Dimitrov | Vesselin I. Dimitrov (Faculty of Physics, Sofia University, Bulgaria) | ''Averaged'' statistical thermodynamics, energy equipartition and the
third law | 5 pages RevTeX, no figures | null | null | null | quant-ph | null | Arguments are presented that the assumption, implicit to traditional
statistical thermodynamics, that at zero temperature all erratic motions cease,
should be dispensed with. Assuming instead a random ultrarelativistic
unobservable motion, similar to zitterbewegung, it is demonstrated that in an
ideal gas of classical particles the energy equipartition fails in a way that
complies with the third law of thermodynamics.
| [
{
"version": "v1",
"created": "Thu, 3 Jul 1997 08:46:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dimitrov",
"Vesselin I.",
"",
"Faculty of Physics, Sofia University, Bulgaria"
]
] |
quant-ph/9707008 | Dr. G. Plunien | G. Plunien, T. Beier, G. Soff (ITP, TU Dresden, Dresden, Germany) H.
Persson (Depart. Physics, Chalmers University, Goeteborg, Sweden) | Exact two-loop vacuum polarization correctionto the Lamb shift in
hydrogen-like ions | 23 pages, LaTeX (RevTeX), 5 eps-figures | null | null | null | quant-ph | null | We present a calculation scheme for the two-loop vacuum polarization
correction of order $\alpha^2$ to the Lamb shift of hydrogen-like high-Z atoms.
The interaction with the external Coulomb field is taken into account to all
orders in $(Z\alpha)$. By means of a modified potential approach the problem is
reduced to the evaluation of effective one-loop vacuum polarization potentials.
An expression for the energy shift is deduced within the framework of partial
wave decomposition performing appropriate subtractions. Exact results for the
two-loop vacuum polarization contribution to the Lamb shift of K- and L-shell
electron states in hydrogen-like Lead and Uranium are presented.
| [
{
"version": "v1",
"created": "Thu, 3 Jul 1997 17:01:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Plunien",
"G.",
"",
"ITP, TU Dresden, Dresden, Germany"
],
[
"Beier",
"T.",
"",
"ITP, TU Dresden, Dresden, Germany"
],
[
"Soff",
"G.",
"",
"ITP, TU Dresden, Dresden, Germany"
],
[
"Persson",
"H.",
"",
"Depart. Physics, Chalmers University, Goeteborg, Sweden"
]
] |
quant-ph/9707009 | Brif Constantin | C. Brif, A. Mann (Technion, Haifa) | Generation of single-mode SU(1,1) intelligent states and an analytic
approach to their quantum statistical properties | to appear in Quantum Semiclass. Opt., LaTeX, epsf style, 21 pages
including 5 Postscript figures. More information on
http://www.technion.ac.il/~brif/science.html | Quant.Semiclass.Opt. 9 (1997) 899 | 10.1088/1355-5111/9/6/004 | null | quant-ph | null | We discuss a scheme for generation of single-mode photon states associated
with the two-photon realization of the SU(1,1) algebra. This scheme is based on
the process of non-degenerate down-conversion with the signal prepared
initially in the squeezed vacuum state and with a measurement of the photon
number in one of the output modes. We focus on the generation and properties of
single-mode SU(1,1) intelligent states which minimize the uncertainty relations
for Hermitian generators of the group. Properties of the intelligent states are
studied by using a ``weak'' extension of the analytic representation in the
unit disk. Then we are able to obtain exact analytical expressions for
expectation values describing quantum statistical properties of the SU(1,1)
intelligent states. Attention is mainly devoted to the study of photon
statistics and linear and quadratic squeezing.
| [
{
"version": "v1",
"created": "Thu, 3 Jul 1997 17:07:43 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Brif",
"C.",
"",
"Technion, Haifa"
],
[
"Mann",
"A.",
"",
"Technion, Haifa"
]
] |
quant-ph/9707010 | Brif Constantin | C. Brif, A. Mann (Technion, Haifa) | A General Theory of Phase-Space Quasiprobability Distributions | REVTeX, 4 pages. More information on
http://www.technion.ac.il/~brif/science.html | J.Phys. A31 (1998) L9-L17 | 10.1088/0305-4470/31/1/002 | null | quant-ph | null | We present a general theory of quasiprobability distributions on phase spaces
of quantum systems whose dynamical symmetry groups are (finite-dimensional) Lie
groups. The family of distributions on a phase space is postulated to satisfy
the Stratonovich-Weyl correspondence with a generalized traciality condition.
The corresponding family of the Stratonovich-Weyl kernels is constructed
explicitly. In the presented theory we use the concept of the generalized
coherent states, that brings physical insight into the mathematical formalism.
| [
{
"version": "v1",
"created": "Thu, 3 Jul 1997 17:13:31 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Brif",
"C.",
"",
"Technion, Haifa"
],
[
"Mann",
"A.",
"",
"Technion, Haifa"
]
] |
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