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quant-ph/9711072 | Gyula Bene | Gyula Bene (Eotvos University, Budapest) | On the nature of the quantum states of macroscopic systems | 4 pages, RevTex, 2 figures (as postscript files), submitted to
Phys.Rev.Lett | null | null | null | quant-ph | null | It is assumed that the quantum state that may describe a macroscopic system
at a given instant of time is one of the eigenstates of the reduced density
matrix calculated from the wave function of the system plus its environment.
This implies that the above quantum state is a member of a special orthonormed
set of states. Using a suitable Monte-Carlo simulation, this property is shown
to be consistent with the extremely small standard deviation for the
coordinates and the momenta of macroscopic systems. Consequences for
statistical mechanics and possible observable effects are discussed.
| [
{
"version": "v1",
"created": "Fri, 28 Nov 1997 13:18:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bene",
"Gyula",
"",
"Eotvos University, Budapest"
]
] |
quant-ph/9711073 | Robert Bluhm | Robert Bluhm, Alan Kostelecky, and Bogdan Tudose | Revivals of Rydberg Wave Packets | Talk presented by Robert Bluhm at the VIII International Conference
on Symmetry Methods in Physics, Dubna, Russia, July, 1997 | Phys.Atom.Nucl.61:1948-1953,1998; Yad.Fiz.61:2057-2061,1998 | null | COLBY 97-07, IUHET 371 | quant-ph | null | We examine the revival structure of Rydberg wave packets. These wave packets
exhibit initial classical periodic motion followed by a sequence of collapse,
fractional/full revivals, and fractional/full superrevivals. The effects of
quantum defects on wave packets in alkali-metal atoms and a squeezed-state
description of the initial wave packets are also described. We then examine the
revival structure of Rydberg wave packets in the presence of an external
electric field, i.e., the revival structure of Stark wave packets. These wave
packets have energies that depend on two quantum numbers and exhibit new types
of interference behavior.
| [
{
"version": "v1",
"created": "Fri, 28 Nov 1997 19:32:04 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Bluhm",
"Robert",
""
],
[
"Kostelecky",
"Alan",
""
],
[
"Tudose",
"Bogdan",
""
]
] |
quant-ph/9712001 | Trevor Marshall | Trevor W. Marshall (Mathematics Dept., Manchester Univ., UK) | The myth of the down converted photon | See also http://xxx.lanl.gov/abs/quant-ph/9711029
http://xxx.lanl.gov/abs/quant-ph/9711046 http://www.keyinnov.demon.co.uk | null | null | MUM-97-15 | quant-ph | null | Parametric down conversion (PDC) is widely interpreted in terms of photons,
but, even among supporters of this interpretation, many properties of the
photon pairs have been described as "mind-boggling" and even "absurd". In this
article we argue that a classical description of the light field, taking
account of its vacuum fluctuations, leads us to a consistent and rational
account of all PDC phenomena. "Nonlocality" in quantum optics is simply an
artifact of the Photon Concept. We also predict a new phenomenon, namely the
appearance of a second, or satellite PDC rainbow.
| [
{
"version": "v1",
"created": "Sat, 29 Nov 1997 12:00:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Marshall",
"Trevor W.",
"",
"Mathematics Dept., Manchester Univ., UK"
]
] |
quant-ph/9712002 | Adrian Kent | Adrian Kent | Permanently Secure Quantum Bit Commitment from a Temporary Computation
Bound | null | null | null | DAMTP/97-137 | quant-ph | null | This paper has been withdrawn. See quant-ph/9806031 for a discussion.
| [
{
"version": "v1",
"created": "Mon, 1 Dec 1997 20:11:56 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Aug 1999 16:49:23 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kent",
"Adrian",
""
]
] |
quant-ph/9712003 | N. David Mermin | N. David Mermin | Nonlocality and Bohr's reply to EPR | 3 pages | null | null | null | quant-ph | null | Henry Stapp's commentary (quant-ph/9711060) does not capture the point I was
trying to make in my essay (quant-ph/9711052) on how a subtle flaw in his
``proof of quantum nonlocality'' clearly illustrates a central issue in Bohr's
reply to EPR. I therefore wish to emphasize what I do and do not say in that
essay and even, with some trepidation, what Bohr did and did not say in his
reply to EPR.
| [
{
"version": "v1",
"created": "Mon, 1 Dec 1997 19:59:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mermin",
"N. David",
""
]
] |
quant-ph/9712004 | Kevin M. Obenland | Kevin M. Obenland and Alvin M. Despain | Models to Reduce the Complexity of Simulating a Quantum Computer | 25 pages | null | null | ISI Technical Report | quant-ph | null | Recently Quantum Computation has generated a lot of interest due to the
discovery of a quantum algorithm which can factor large numbers in polynomial
time. The usefulness of a quantum com puter is limited by the effect of errors.
Simulation is a useful tool for determining the feasibility of quantum
computers in the presence of errors. The size of a quantum computer that can be
simulat ed is small because faithfully modeling a quantum computer requires an
exponential amount of storage and number of operations. In this paper we define
simulation models to study the feasibility of quantum computers. The most
detailed of these models is based directly on a proposed imple mentation. We
also define less detailed models which are exponentially less complex but still
pro duce accurate results. Finally we show that the two different types of
errors, decoherence and inaccuracies, are uncorrelated. This decreases the
number of simulations which must be per formed.
| [
{
"version": "v1",
"created": "Tue, 2 Dec 1997 03:45:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Obenland",
"Kevin M.",
""
],
[
"Despain",
"Alvin M.",
""
]
] |
quant-ph/9712005 | Guo Guangcan | Lu-Ming Duan and Guang-Can Guo (University of Science and Technology
of China) | Prevention of dissipation with two particles | 12 pages, Latex | null | 10.1103/PhysRevA.57.2399 | null | quant-ph | null | An error prevention procedure based on two-particle encoding is proposed for
protecting an arbitrary unknown quantum state from dissipation, such as phase
damping and amplitude damping. The schemes, which exhibits manifestation of the
quantum Zeno effect, is effective whether quantum bits are decohered
independently or cooperatively. We derive the working condition of the scheme
and argue that this procedure has feasible practical implementation.
| [
{
"version": "v1",
"created": "Tue, 2 Dec 1997 08:56:42 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/9712006 | null | Roy Ringo(Argonne) | A Possible Einstein-Podolsky-Rosen Probe of the Momentum-Position
Uncertainty Relation | 12 pages (LaTex),1 figure (Postscript) | null | null | null | quant-ph | null | It is suggested that a measurement of the products of photoemission by alkali
atoms excited after extraction from a trap, might, using the EPR strategy, show
a significant violation of the momentum-position uncertainty relation. If this
failed, as is quite likely, possible causes, such as retroactive propagation of
influences and retrodiction failure, could be tested on the proposed apparatus.
| [
{
"version": "v1",
"created": "Tue, 2 Dec 1997 18:23:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ringo",
"Roy",
"",
"Argonne"
]
] |
quant-ph/9712007 | T. Pradhan | T. Pradhan | Fabrication of Magnetic Charge From Excited States of H-atom | 8 pages, revised substantially | null | null | null | quant-ph hep-th | null | It is shown that the excited states of hydrogen atom in a uniform electric
field (Stark States) posess magnetic charge whose magnitude is given by a
Dirac-Saha type relation: $$ {eg\over \hbar c} = \sqrt 3 n $$ An experiment is
proposed to fabricate such states and to detect their magnetic charge.
| [
{
"version": "v1",
"created": "Wed, 3 Dec 1997 06:15:19 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Jul 2000 04:40:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pradhan",
"T.",
""
]
] |
quant-ph/9712008 | Yang Guang-can | Guangcan Yang | Semiclassical Green Function in Mixed Spaces | 8 pages, typeset by Scientific Word | null | 10.1103/PhysRevA.58.2600 | null | quant-ph | null | A explicit formula on semiclassical Green functions in mixed position and
momentum spaces is given, which is based on Maslov's multi-dimensional
semiclassical theory. The general formula includes both coordinate and momentum
representations of Green functions as two special cases of the form.
| [
{
"version": "v1",
"created": "Wed, 3 Dec 1997 13:48:27 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Feb 1998 10:41:50 GMT"
},
{
"version": "v3",
"created": "Wed, 11 Feb 1998 03:26:45 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Yang",
"Guangcan",
""
]
] |
quant-ph/9712009 | Marc A. Rieffel | Marc A. Rieffel (U. C. Berkeley) | Questions on quantization | 14 pages LATEX. Submitted to the Proceedings of the International
Conference on Operator Algebras and Operator Theory held in Shanghai (July
4-July 9, 1997) | Contemp.Math. 228 (1998) 315-326 | null | null | quant-ph funct-an math.FA | null | We pose 22 relatively general questions about quantization in the operator
algebra setting. In the process we briefly survey some recent developments.
| [
{
"version": "v1",
"created": "Wed, 3 Dec 1997 15:38:07 GMT"
},
{
"version": "v2",
"created": "Thu, 23 Apr 1998 15:45:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rieffel",
"Marc A.",
"",
"U. C. Berkeley"
]
] |
quant-ph/9712010 | Michael G. Moore | M. G. Moore and P. Meystre | Wave atom optics theory of the Collective Atomic-Recoil Laser | plain tex, 4 pages, 3 figures | null | null | null | quant-ph physics.atom-ph physics.optics | null | We present a wave atom optics theory of the Collective Atomic-Recoil Laser,
where the atomic center-of-mass motion is treated quantum mechanically. It
extends the previous ray atom optics theory, which treated the center-of-mass
atomic motion classically, to the realm of ultracold atoms. For the case of a
far off resonant pump laser we derive an analytical solution which gives the
linear response of the CARL system for both the quantum and classical regimes.
A linear stability analysis reveals significant qualitative differences between
these two regimes, which arise from the effects of diffraction on the atomic
center-of-mass motion.
| [
{
"version": "v1",
"created": "Wed, 3 Dec 1997 16:51:37 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Moore",
"M. G.",
""
],
[
"Meystre",
"P.",
""
]
] |
quant-ph/9712011 | Lov K. Grover | Lov K. Grover (Bell Labs, Murray Hill, NJ) | Quantum computers can search rapidly by using almost any transformation | This paper is an adapted version of quant-ph/9711043. It has been
modified to make it more readable for physicists. 9 pages, postscript | Phys.Rev.Lett.80:4329-4332,1998 | 10.1103/PhysRevLett.80.4329 | null | quant-ph | null | A quantum computer has a clear advantage over a classical computer for
exhaustive search. The quantum mechanical algorithm for exhaustive search was
originally derived by using subtle properties of a particular quantum
mechanical operation called the Walsh-Hadamard (W-H) transform. This paper
shows that this algorithm can be implemented by replacing the W-H transform by
almost any quantum mechanical operation. This leads to several new applications
where it improves the number of steps by a square-root. It also broadens the
scope for implementation since it demonstrates quantum mechanical algorithms
that can readily adapt to available technology.
| [
{
"version": "v1",
"created": "Wed, 3 Dec 1997 22:06:53 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Grover",
"Lov K.",
"",
"Bell Labs, Murray Hill, NJ"
]
] |
quant-ph/9712012 | Juan Fernando Poyatos | J. F. Poyatos (1,2), J.I. Cirac (1,2), and P. Zoller (2) ((1)
Departamento de Fisica Aplicada, Universidad de Castilla-La Mancha, Spain (2)
Institut fuer Theoretische Physik, Universitaet Innsbruck, Austria) | Quantum gates with "hot" trapped ions | 4 pages, 2 eps figures | Phys.Rev.Lett.81:1322-1325,1998 | 10.1103/PhysRevLett.81.1322 | SlikeiH-02 | quant-ph | null | We propose a scheme to perform a fundamental two-qubit gate between two
trapped ions using ideas from atom interferometry. As opposed to the scheme
considered by J. I. Cirac and P. Zoller, Phys. Rev. Lett. 74, 4091 (1995), it
does not require laser cooling to the motional ground state.
| [
{
"version": "v1",
"created": "Thu, 4 Dec 1997 11:28:46 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Poyatos",
"J. F.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9712013 | Alan Kostelecky | Alan Kostelecky and Neil Russell | Quantum-Mechanical Supersymmetry in Traps | talk presented at the UIC Workshop on Integrable Models and
Supersymmetry, June 1997 | null | null | IUHET 369, August 1997 | quant-ph | null | We discuss the application of quantum-mechanical supersymmetry to particle
traps. The supersymmetric-partner wave functions may be used to describe a
valence fermion in a trap system with an isotropic harmonic-oscillator
potential. Interactions with the core are incorporated analytically. The close
similarity of this approach to the application of supersymmetry in atomic
systems is made explicit by means of a radial mapping between the two systems.
| [
{
"version": "v1",
"created": "Thu, 4 Dec 1997 19:46:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kostelecky",
"Alan",
""
],
[
"Russell",
"Neil",
""
]
] |
quant-ph/9712014 | null | Y.M. Hakobyan, M. Kibler, G.S. Pogosyan and A.N. Sissakian | On a Generalized Oscillator: Invariance Algebra and Interbasis
Expansions | 13 pages, Latex file. Submitted for publication to Yadernaya Fizika | Phys.Atom.Nucl.61:1782-1788,1998; Yad.Fiz.61:1893-1899,1998 | null | null | quant-ph math-ph math.MP physics.atm-clus physics.atom-ph physics.chem-ph | null | This article deals with a quantum-mechanical system which generalizes the
ordinary isotropic harmonic oscillator system. We give the coefficients
connecting the polar and Cartesian bases for D=2 and the coefficients
connecting the Cartesian and cylindrical bases as well as the cylindrical and
spherical bases for D=3. These interbasis expansion coefficients are found to
be analytic continuations to real values of their arguments of the
Clebsch-Gordan coefficients for the group SU(2). For D=2, the superintegrable
character for the generalized oscillator system is investigated from the points
of view of a quadratic invariance algebra.
| [
{
"version": "v1",
"created": "Fri, 5 Dec 1997 15:28:10 GMT"
}
] | 2011-04-15T00:00:00 | [
[
"Hakobyan",
"Y. M.",
""
],
[
"Kibler",
"M.",
""
],
[
"Pogosyan",
"G. S.",
""
],
[
"Sissakian",
"A. N.",
""
]
] |
quant-ph/9712015 | Kamenev D. I. | V. Ya. Demikhovskii, D. I. Kamenev | Localization of Quantum States at the Cyclotron Resonance | 6 pages of Latex, 6 figures | Phys.Lett. A228 (1997) 391-398 | 10.1016/S0375-9601(97)00131-X | null | quant-ph | null | A new type of localization - localization over the quantum resonance cells -
in an intrinsically degenerate system is explored by using the quasienergy
eigenstates.
| [
{
"version": "v1",
"created": "Sat, 6 Dec 1997 06:39:55 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Demikhovskii",
"V. Ya.",
""
],
[
"Kamenev",
"D. I.",
""
]
] |
quant-ph/9712016 | Yuri I. Ozhigov | Yuri Ozhigov | Protection of information in quantum qatabases | 10 pages, Latex | Complex Syst. 11 (1997) 223-232 | null | null | quant-ph | null | The conventional protection of information by cryptographical keys makes no
sense if a key can be quickly discovered by an unauthorized person. This way of
penetration to the protected systems was made possible by a quantum computers
in view of results of P.Shor and L.Grover. This work presents the method of
protection of an information in a database from a spy even he knows all about
its control system and has a quantum computer, whereas a database can not
distinguish between operations of spy and legal user.
| [
{
"version": "v1",
"created": "Sun, 7 Dec 1997 23:14:15 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ozhigov",
"Yuri",
""
]
] |
quant-ph/9712017 | Sougato Bose | S. Bose, K. Jacobs and P. L. Knight | A Scheme to Probe the Decoherence of a Macroscopic Object | Much expanded version, macroscopic mirror masses, to appear in Phys.
Rev. A (tent: May 99) | Phys.Rev.A59:3204,1999 | 10.1103/PhysRevA.59.3204 | null | quant-ph | null | We propose a quantum optical version of Schr\"{o}dinger's famous gedanken
experiment in which the state of a microscopic system (a cavity field) becomes
entangled with and disentangled from the state of a massive object (a movable
mirror). Despite the fact that a mixture of Schr\"{o}dinger cat states is
produced during the evolution (due to the fact that the macroscopic mirror
starts off in a thermal state), this setup allows us to systematically probe
the rules by which a superposition of spatially separated states of a
macroscopic object decoheres. The parameter regime required to test
environment-induced decoherence models is found to be close to those currently
realizable, while that required to detect gravitationally induced collapse is
well beyond current technology.
| [
{
"version": "v1",
"created": "Mon, 8 Dec 1997 14:56:38 GMT"
},
{
"version": "v2",
"created": "Sun, 18 Apr 1999 18:13:52 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Bose",
"S.",
""
],
[
"Jacobs",
"K.",
""
],
[
"Knight",
"P. L.",
""
]
] |
quant-ph/9712018 | A. B. Balantekin | A.B. Balantekin | Algebraic Approach to Shape Invariance | Submitted to Physical Review A. Latex file, 9 pages. Manuscript is
also available at http://nucth.physics.wisc.edu/preprints/ | Phys.Rev. A57 (1998) 4188-4191 | 10.1103/PhysRevA.57.4188 | MAD-NT-97-08, DOE/ER/40561-346-INT97-00-185 | quant-ph | null | The integrability condition called shape invariance is shown to have an
underlying algebraic structure and the associated Lie algebras are identified.
These shape-invariance algebras transform the parameters of the potentials such
as strength and range. Shape-invariance algebras, in general, are shown to be
infinite-dimensional. The conditions under which they become finite-dimensional
are explored.
| [
{
"version": "v1",
"created": "Mon, 8 Dec 1997 20:22:02 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Balantekin",
"A. B.",
""
]
] |
quant-ph/9712019 | Dagmar Bruss | D. Bruss, A. Ekert, C. Macchiavello | Optimal universal quantum cloning and state estimation | 4 pages (RevTeX) | Phys.Rev.Lett.81:2598-2601,1998 | 10.1103/PhysRevLett.81.2598 | null | quant-ph | null | We derive a tight upper bound for the fidelity of a universal N to M qubit
cloner, valid for any M \geq N, where the output of the cloner is required to
be supported on the symmetric subspace. Our proof is based on the concatenation
of two cloners and the connection between quantum cloning and quantum state
estimation. We generalise the operation of a quantum cloner to mixed and/or
entangled input qubits described by a density matrix supported on the symmetric
subspace of the constituent qubits. We also extend the validity of optimal
state estimation methods to inputs of this kind.
| [
{
"version": "v1",
"created": "Tue, 9 Dec 1997 11:16:03 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Jun 1998 15:43:58 GMT"
},
{
"version": "v3",
"created": "Thu, 8 Oct 1998 09:02:25 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Bruss",
"D.",
""
],
[
"Ekert",
"A.",
""
],
[
"Macchiavello",
"C.",
""
]
] |
quant-ph/9712020 | Yinqi Feng | Yinqi Feng and Allan I. Solomon (Open University) | Optimal Signal-to-Quantum Noise Ratio for Nonclassical Number States | 7 Page (LaTeX), 1 figure(Postscript); changed body of paper | Opt.Commun. 152 (1998) 299-301 | 10.1016/S0030-4018(98)00202-8 | OU-APP-970101 | quant-ph physics.optics | null | We analyze the properties of nonclassical number states, specifically
squeezed number states D(a)S(z)|n >, and find their maximum signal-to-quantum
noise ratio. It is shown that the optimal signal-to-quantum noise ratio for
these states decreases as 1/(2n+1)2, where n is the photon number, from the
optimal value as derived by Yuen.
| [
{
"version": "v1",
"created": "Tue, 9 Dec 1997 17:02:14 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Dec 1997 15:38:21 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Feng",
"Yinqi",
"",
"Open University"
],
[
"Solomon",
"Allan I.",
"",
"Open University"
]
] |
quant-ph/9712021 | Martin Plenio | S. Bose, P.L. Knight, M. Murao, M.B. Plenio and V. Vedral (Optics
Section, The Blackett Laboratory, Imperial College, London, UK) | Implementations of Quantum Logic: Fundamental and Experimental Limits | 16 pages, for the proceedings of the Royal Society meeting on quantum
computation | Phil.Trans.Roy.Soc.Lond. A356 (1998) 1823 | 10.1098/rsta.1998.0251 | null | quant-ph | null | Quantum information processing rests on our ability to manipulate quantum
superpositions through coherent unitary transformations. In reality the quantum
information processor (a linear ion trap, or cavity qed implementation for
example) exists in a dissipative environment. Dephasing, and other technical
sources of noise, as well as more fundamental sources of dissipation severely
restrict quantum processing capabilities. The strength of the coherent coupling
needed to implement quantum logic is not always independent of dissipation. The
limitations these dissipative influences present will be described and the need
for efficient error correction noted. Even if long and involved quantum
computations turn out to be hard to realize, one can perform interesting
manipulations of entanglement involving only a few gates and qubits, of which
we give examples. Quantum communication also involves manipulations of
entanglement which are simpler to implement than elaborate computations. We
briefly analyse the notion of the capacity of a quantum communication channel.
| [
{
"version": "v1",
"created": "Wed, 10 Dec 1997 17:43:01 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Bose",
"S.",
"",
"Optics\n Section, The Blackett Laboratory, Imperial College, London, UK"
],
[
"Knight",
"P. L.",
"",
"Optics\n Section, The Blackett Laboratory, Imperial College, London, UK"
],
[
"Murao",
"M.",
"",
"Optics\n Section, The Blackett Laboratory, Imperial College, London, UK"
],
[
"Plenio",
"M. B.",
"",
"Optics\n Section, The Blackett Laboratory, Imperial College, London, UK"
],
[
"Vedral",
"V.",
"",
"Optics\n Section, The Blackett Laboratory, Imperial College, London, UK"
]
] |
quant-ph/9712022 | Ashot S. Gevorkyan | Alexander V. Bogdanov and Ashot S. Gevorkyan | Three Body Multichannel Scattering as a Model of Irreversible Quantum
Mechanics | 4 pages, LaTeX, uses nolta.sty, accepted for presentation in the
NOLTA'97 | null | null | null | quant-ph | null | The new formulation of the theory of multichannel scattering on the example
of collinear model is proposed. It is shown, that in the closed three-body
scattering system the principle of quantum determinism in general case breaks
down and we have a micro- irreversible quantum mechanics.
| [
{
"version": "v1",
"created": "Wed, 10 Dec 1997 19:36:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bogdanov",
"Alexander V.",
""
],
[
"Gevorkyan",
"Ashot S.",
""
]
] |
quant-ph/9712023 | Dominic Mayers | Gilles Brassard, Claude Cr\'epeau, Dominic Mayers, Louis Salvail | A brief review on the impossibility of quantum bit commitment | 11 pages | null | null | null | quant-ph | null | The desire to obtain an unconditionally secure bit commitment protocol in
quantum cryptography was expressed for the first time thirteen years ago. Bit
commitment is sufficient in quantum cryptography to realize a variety of
applications with unconditional security. In 1993, a quantum bit commitment
protocol was proposed together with a security proof. However, a basic flaw in
the protocol was discovered by Mayers in 1995 and subsequently by Lo and Chau.
Later the result was generalized by Mayers who showed that unconditionally
secure bit commitment is impossible. A brief review on quantum bit commitment
which focuses on the general impossibility theorem and on recent attempts to
bypass this result is provided.
| [
{
"version": "v1",
"created": "Wed, 10 Dec 1997 20:16:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Brassard",
"Gilles",
""
],
[
"Crépeau",
"Claude",
""
],
[
"Mayers",
"Dominic",
""
],
[
"Salvail",
"Louis",
""
]
] |
quant-ph/9712024 | Ralf F. Salzgeber | R. F. Salzgeber, V. Mandelshtam, Ch. Schlier and H. S. Taylor | All bound states of NO_2 (J=0) | 18 pages of LaTeX including 4 figures. A Postscript of HTML version
of this paper can be obtained via:
http://phya3.physik.uni-freiburg.de/~rfs/rfs.html This paper was submitted to
Journ. Chem. Phys | null | null | null | quant-ph | null | We calculated all 2967 even and odd bound states of the adiabatic ground
state of NO_2, using a modification of the ab initio potential energy surface
of Leonardi et al. [J. Chem. Phys. 105, 9051 (1996)]. The calculation was
performed by harmonic inversion of the Chebyshev correlation function generated
by a DVR Hamiltonian in Radau coordinates. The relative error for the computed
eigenenergies is $10^{-4}$ or better. Near the dissociation threshold the
density of states is about 0.3cm$^{-1}$. Statistical analysis of the states
shows some interesting structure of the rigidity parameter $\Delta_3$ as a
function of energy.
| [
{
"version": "v1",
"created": "Thu, 11 Dec 1997 12:36:44 GMT"
},
{
"version": "v2",
"created": "Fri, 12 Dec 1997 08:01:02 GMT"
},
{
"version": "v3",
"created": "Fri, 6 Feb 1998 15:05:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Salzgeber",
"R. F.",
""
],
[
"Mandelshtam",
"V.",
""
],
[
"Schlier",
"Ch.",
""
],
[
"Taylor",
"H. S.",
""
]
] |
quant-ph/9712025 | Paul Cockhott | Paul Cockshott | Quantum Relational Databases | 7 pages 3 figures | null | null | null | quant-ph | null | The approach given by Grover can be generalised to set an upper complexity
limit to the basic operations of relational algebra on a quantum computer.
Except in special cases where indices can be used on a classical machine, the
quantum upper complexity limit is lower than the classical one.
| [
{
"version": "v1",
"created": "Thu, 11 Dec 1997 13:06:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Cockshott",
"Paul",
""
]
] |
quant-ph/9712026 | Abdullah | A. Ver\c{c}in | Ordered Products, $W_{\infty}$-Algebra, and Two-Variable,
Definite-Parity, Orthogonal Polynomials | 17 pages,no figure. to appear in J. Math.Phys | J.Math.Phys. 39 (1998) 2418-2427 | 10.1063/1.532295 | null | quant-ph | null | It has been shown that the Cartan subalgebra of $W_{\infty}$- algebra is the
space of the two-variable, definite-parity polynomials. Explicit expressions of
these polynomials, and their basic properties are presented. Also has been
shown that they carry the infinite dimensional irreducible representation of
the $su(1,1)$ algebra having the spectrum bounded from below. A realization of
this algebra in terms of difference operators is also obtained. For particular
values of the ordering parameter $s$ they are identified with the classical
orthogonal polynomials of a discrete variable, such as the Meixner,
Meixner-Pollaczek, and Askey-Wilson polynomials. With respect to variable $s$
they satisfy a second order eigenvalue equation of hypergeometric type. Exact
scattering states with zero energy for a family of potentials are expressed in
terms of these polynomials. It has been put forward that it is the
\.{I}n\"{o}n\"{u}-Wigner contraction and its inverse that form bridge between
the difference and differential calculus.
| [
{
"version": "v1",
"created": "Thu, 11 Dec 1997 14:10:53 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Verçin",
"A.",
""
]
] |
quant-ph/9712027 | Hans Juergen Briegel | H.-J. Briegel, W. D\"ur, S. J. van Enk, J. I. Cirac and P. Zoller | Quantum communication and the creation of maximally entangled pairs of
atoms over a noisy channel | 12 pages, latex, rspublic.sty, 4 figures, uses epsf macro. For the
Royal Society meeting on quantum computation | null | null | HJB-97-01 | quant-ph | null | We show how to create maximally entangled EPR pairs between spatially distant
atoms, each of them inside a high-Q optical cavity, by sending photons through
a general, noisy channel, such as a standard optical fiber. An error correction
scheme that uses few auxiliary atoms in each cavity effectively eliminates
photoabsorption and other transmission errors. This realizes the `absorption
free channel.' A concatenation protocol using the absorption free channel
allows for quantum communication with single qubits over distances much larger
than the coherence length of the channel.
| [
{
"version": "v1",
"created": "Thu, 11 Dec 1997 19:15:16 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Briegel",
"H. -J.",
""
],
[
"Dür",
"W.",
""
],
[
"van Enk",
"S. J.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9712028 | Grosa | V. V. Dodonov, V. I. Man'ko, and L. Rosa | Quantum singular oscillator as a model of two-ion trap: an amplification
of transition probabilities due to small time variations of the binding
potential | 19 pages, LaTeX, 5 eps-figures, to appear on Phys. Rev. A, one
reference corrected | Phys.Rev. A57 (1998) 2851 | 10.1103/PhysRevA.57.2851 | Napoli Preprint DSF-48/97 | quant-ph | null | Following the paper by M. Combescure [Ann. Phys. (NY) 204, 113 (1990)], we
apply the quantum singular time dependent oscillator model to describe the
relative one dimensional motion of two ions in a trap. We argue that the model
can be justified for low energy excited states with the quantum numbers $n\ll
n_{max}\sim 100$, provided that the dimensionless constant characterizing the
strength of the repulsive potential is large enough, $g_*\sim 10^5$. Time
dependent Gaussian-like wave packets generalizing odd coherent states of the
harmonic oscillator, and excitation number eigenstates are constructed. We show
that the relative motion of the ions, in contradistinction to its center of
mass counterpart, is extremely sensitive to the time dependence of the binding
harmonic potential, since the large value of $g_*$ results in a significant
amplification of the transition probabilities between energy eigenstate even
for slow time variations of the frequency.
| [
{
"version": "v1",
"created": "Fri, 12 Dec 1997 18:48:28 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Dec 1997 12:21:34 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Dodonov",
"V. V.",
""
],
[
"Man'ko",
"V. I.",
""
],
[
"Rosa",
"L.",
""
]
] |
quant-ph/9712029 | Chau Hoi Fung | H. F. Chau | Quantum Convolutional Error Correcting Codes | Minor revisions and clarifications. To appear in Phys. Rev. A | null | 10.1103/PhysRevA.58.905 | null | quant-ph | null | I report two general methods to construct quantum convolutional codes for
$N$-state quantum systems. Using these general methods, I construct a quantum
convolutional code of rate 1/4, which can correct one quantum error for every
eight consecutive quantum registers.
| [
{
"version": "v1",
"created": "Sat, 13 Dec 1997 07:32:54 GMT"
},
{
"version": "v2",
"created": "Sun, 21 Dec 1997 14:06:55 GMT"
},
{
"version": "v3",
"created": "Sun, 28 Dec 1997 08:57:23 GMT"
},
{
"version": "v4",
"created": "Mon, 18 May 1998 09:42:05 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Chau",
"H. F.",
""
]
] |
quant-ph/9712030 | Dr. Luca Salasnich, . D. | Luca Salasnich | The Role of dimensionality in the stability of a confined Bose gas | 10 pages, Latex, no figures, to be published in Mod. Phys. Lett. B | null | 10.1142/S0217984997001493 | null | quant-ph | null | We study analytically the ground-state stability of a Bose-Einstein
condensate (BEC) confined in an harmonic trap with repulsive or attractive
zero-range interaction by minimizing the energy functional of the system. In
the case of repulsive interaction the BEC mean radius grows by increasing the
number of bosons, instead in the case of attractive interaction the BEC mean
radius decreases by increasing the number of bosons: to zero if the system is
one-dimensional and to a minimum radius, with a maximum number of bosons, if
the system is three-dimensional.
| [
{
"version": "v1",
"created": "Sat, 13 Dec 1997 22:58:19 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Salasnich",
"Luca",
""
]
] |
quant-ph/9712031 | Ashot S. Gevorkyan | Alexander V. Bogdanov and Ashot S. Gevorkyan | Random motion of quantum reactive harmonic oscillator. Thermodynamics of
Vacuum of Asymptotic Subspace | LaTeX, 19 pages, 5 figures, title changed | IHPCDB-3(97) | null | null | quant-ph | null | The system of oscillator interacting with vacuum is considered as a problem
of random motion of quantum reactive harmonic oscillator (QRHO). It is
formulated in terms of a wave functional regarded as complex probability
process in the extended space. This wave functional obeys some stochastic
differential equation (SDE). Based on the nonlinear Langevin type SDE of second
order, introduced in the functional space R{W(t)}, the variables in original
equation are separated. The general measure in the space R{W(t)} of the
Fokker-Plank type is obtained and expression for total wave function (wave
mixture) of random QRHO is constructed as functional expansion over the
stochastic basis set. The pertinent transition matrix S_br is constructed. For
Wiener type measure W(t) of functional space the exact representation for
''vacuum-vacuum'' transition probability is obtained. The thermodynamics of
vacuum is described in detail for the asymptotic space R1_as. The exact values
for Energy, shift and expansion of ground state of oscillator and its Entropy
are calculated.
| [
{
"version": "v1",
"created": "Sun, 14 Dec 1997 14:37:55 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Dec 1997 11:48:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bogdanov",
"Alexander V.",
""
],
[
"Gevorkyan",
"Ashot S.",
""
]
] |
quant-ph/9712032 | Marcia T. Fontenelle | Marcia T. Fontenelle, Samuel L. Braunstein, Wolfgang P. Schleich, and
Mark Hillery | Direct and indirect strategies for phase measurement | RevTeX + 3 postscript figures, 11 pages, submitted to Physical Review
A | null | null | null | quant-ph | null | Recently, Torgerson and Mandel [Phys. Rev. Lett. 76, 3939 (1996)] have
reported a disagreement between two schemes for measuring the phase difference
of a pair of optical fields. We analyze these schemes and derive their
associated phase-difference probability distributions, including both their
strong and weak field limits. Our calculation confirms the main point of
Torgerson and Mandel of the non-uniqueness of an operational definition of the
phase distribution. We further discuss the role of postselection of data and
argue that it cannot meaningfully improve the sensitivity.
| [
{
"version": "v1",
"created": "Tue, 16 Dec 1997 12:46:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Fontenelle",
"Marcia T.",
""
],
[
"Braunstein",
"Samuel L.",
""
],
[
"Schleich",
"Wolfgang P.",
""
],
[
"Hillery",
"Mark",
""
]
] |
quant-ph/9712033 | Wojciech Burkot | Wojciech Burkot | Reversible Mapping for Tree Structured Quantum Computation | Typeset using Revtex, 8 pages including 2 fullpage PostScript
figures, submitted to Phys.Rev.Lett | null | null | KA-97/81 | quant-ph | null | A hierarchical, reversible mapping between levels of tree structured
computation, applicable for structuring the Quantum Computation algorithm for
NP-complete problem is presented. It is proven that confining the state of a
quantum computer to a subspace of the available Hilbert space, where states are
consistent with the problem constraints, can be done in polynomial time. The
proposed mapping, together with the method of state reduction can be
potentially used for solving NP-complete problems in polynomial time.
| [
{
"version": "v1",
"created": "Wed, 17 Dec 1997 12:26:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Burkot",
"Wojciech",
""
]
] |
quant-ph/9712034 | Armen Allahverdyan | A.E. Allahverdyan, D.B. Saakian | Multi-access channels in quantum information theory | LaTex file, 12 pages | null | null | null | quant-ph | null | The multi-access channels in quantum information theory are considered.
Classical messages from independent sources, which are represented as some
quantum states, are transported by a channel to one address. The messages can
interact with each other and with external environment. After statement of
problem and proving some general results we investigate physically important
case when information is transported by states of electromagnetic field.
One-way communication by noisy quantum channels is also considered.
| [
{
"version": "v1",
"created": "Wed, 17 Dec 1997 12:18:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Allahverdyan",
"A. E.",
""
],
[
"Saakian",
"D. B.",
""
]
] |
quant-ph/9712035 | Michal Horodecki | Michal Horodecki | Limits for compression of quantum information carried by ensembles of
mixed states | RevTeX, 8 pages | Phys.Rev. A57 (1998) 3364-3369 | 10.1103/PhysRevA.57.3364 | null | quant-ph | null | We consider the problem of compression of the quantum information carried by
ensemble of mixed states. We prove that for arbitrary coding schemes the least
number of qubits needed to convey the signal states asymptotically faithfully
is bounded from below by the Holevo function
$S(\varrho)-\sum_ip_iS(\varrho_i)$. We also show that a compression protocol
can be composed with another one, provided that the latter offers perfect
transmission. Such a compound protocol is applied to the case of binary source.
It is conjectured to reach the obtained bound. Finally, we point out that in
the case of mixed signal states there could be a difference between the maximal
compression rates at the coding schemes which are ``blind'' to the signal and
the ones which assume the knowledge about the identities of the signal states.
| [
{
"version": "v1",
"created": "Wed, 17 Dec 1997 12:30:31 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Horodecki",
"Michal",
""
]
] |
quant-ph/9712036 | Henry Stapp | Henry P. Stapp | Nonlocality and Bohr's Reply to EPR | This paper was composed in accordance with guidelines from Amer. J.
Physics as a reply to a paper (quant-ph/9712003) with the same title by N.
David Mermin | null | null | LBNL 41139 | quant-ph | null | David Mermin's recent paper with the same title as this one makes it clear
that his claim to have found a gap in my reasoning rests on his claim that my
argument violates a criterion for meaningfulness of counterfactual statements
that I myself had set down. I set down no such requirement. But I am willing to
accept it as a conservative sufficient condition. This already entails, within
my proof, that nature must have a deep structure that extends beyond what
actually occurs. It imposes, without appeal to the notion of determinism or
hidden variables, constraints connecting, at the macroscopic level, what did
occur to what would have occurred if certain quantum choices had gone
differently. All the statements in the proof have natural meanings within the
context of an examination of that deep structure.
| [
{
"version": "v1",
"created": "Wed, 17 Dec 1997 18:55:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Stapp",
"Henry P.",
""
]
] |
quant-ph/9712037 | Andrew Gray | Andrew Gray | A Solution to the Quantum Measurement Problem | 21 pages, 7 figures The theory in this version is the same as in the
original, however presentation has been improved, additional points
discussed, and minor errors corrected | null | null | null | quant-ph | null | A new formulation of quantum mechanics is developed which does not require
the concept of the wave-particle duality. Rather than assigning probabilities
to outcomes, probabilities are instead assigned to entire fine-grained
histories. The formulation is fully relativistic and applicable to
multi-particle systems. It shall be shown that this new formulation makes the
same experimental predictions as quantum field theory, but without having to
rely upon the notion of a system evolving in a superposition of quantum states
until collapsed by an observation. It is thus free from the problem of deciding
what exactly constitutes an observation (the measurement problem) and may
therefore be applied just as readily to the macroscopic world as to the
microscopic.
| [
{
"version": "v1",
"created": "Thu, 18 Dec 1997 00:16:30 GMT"
},
{
"version": "v2",
"created": "Sun, 8 Aug 2004 18:06:39 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Gray",
"Andrew",
""
]
] |
quant-ph/9712038 | Paul Patuleanu | A. Bohm, H. Kaldass, P. Patuleanu | Hilbert Space or Gelfand Triplet - Time Symmetric or Time Asymmetric
Quantum Mechanics | 28 pages; to be published in Int. J. Theor. Phys | Int.J.Theor.Phys. 38 (1999) 115-130 | null | null | quant-ph | null | Intrinsic microphysical irreversibility is the time asymmetry observed in
exponentially decaying states. It is described by the semigroup generated by
the Hamiltonian $\QTR{it}{H}$ of the quantum physical system, not by the
semigroup generated by a Liouvillian $\QTR{it}{L}$ which describes the
irreversibility due to the influence of an external reservoir or measurement
apparatus. The semigroup time evolution generated by $\QTR{it}{H}$ is
impossible in the Hilbert Space (HS) theory, which allows only time symmetric
boundary conditions and an unitary group time evolution. This leads to problems
with decay probabilities in the HS theory. To overcome these and other problems
(non-existence of Dirac kets) caused by the Lebesgue integrals of the HS, one
extends the HS to a Gel'fand triplet, which contains not only Dirac kets, but
also generalized eigenvectors of the self-adjoint $\QTR{it}{H}$ with complex
eigenvalues ($E_R-i\Gamma /2$) and a Breit-Wigner energy distribution. These
Gamow states $\psi ^G$ have a time asymmetric exponential evolution. One can
derive the decay probability of the Gamow state into the decay products
described by $\Lambda $ from the basic formula of quantum mechanics
$\QTR{cal}{P}(t)=Tr(|\psi ^G> < \psi ^G|\Lambda)$, which in HS quantum
mechanics is identically zero. From this result one derives the decay rate
$\QTR{group}{\dot c}(t)$ and all the standard relations between
$\QTR{group}{\dot c}(0)$, $\Gamma $ and the lifetime $\tau_R$ used in the
phenomenology of resonance scattering and decay. In the Born approximation one
obtains Dirac's Golden Rule.
| [
{
"version": "v1",
"created": "Thu, 18 Dec 1997 00:22:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bohm",
"A.",
""
],
[
"Kaldass",
"H.",
""
],
[
"Patuleanu",
"P.",
""
]
] |
quant-ph/9712039 | Jezykmil | Stefan Giller and Piotr Milczarski (Theoretical Physics Department II,
University of Lodz, Poland) | Change of Variable as Borel Resummation of Semiclassical Series | 7 pages, uses article.sty art11.sty, 1 EPS figure | J.Phys.A32:955-976,1999 | 10.1088/0305-4470/32/6/009 | null | quant-ph | null | It is shown that a change of variable in 1-dim Schroedinger equation applied
to the Borel summable fundamental solutions [Giller] is equivalent to Borel
resummation of the fundamental solutions multiplied by suitably chosen
$\hbar$-dependent constant. This explains why change of variable can improve
JWKB formulae [Giller, Milczarski]. It is shown also that a change of variable
alone cannot provide us with the exact JWKB formulae.
| [
{
"version": "v1",
"created": "Thu, 18 Dec 1997 15:39:43 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Jul 1998 13:28:21 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Giller",
"Stefan",
"",
"Theoretical Physics Department II,\n University of Lodz, Poland"
],
[
"Milczarski",
"Piotr",
"",
"Theoretical Physics Department II,\n University of Lodz, Poland"
]
] |
quant-ph/9712040 | Markus Grassl | Markus Grassl, Martin Roetteler, and Thomas Beth (Universitaet
Karlsruhe) | Computing Local Invariants of Qubit Systems | 8 pages, RevTeX, submitted to PRA; example added to demonstrate the
application of the invariants | Phys.Rev.A58:1833-1839,1998 | 10.1103/PhysRevA.58.1833 | null | quant-ph cs.ET | null | We investigate means to describe the non-local properties of quantum systems
and to test if two quantum systems are locally equivalent. For this we consider
quantum systems that consist of several subsystems, especially multiple qubits.
We compute invariant polynomials, i. e., polynomial functions of the entries of
the density operator which are invariant under local unitary operations.
As an example, we consider a system of two qubits. We compute the Molien
series for the corresponding representation which gives information about the
number of linearly independent invariants. Furthermore, we present a set of
polynomials which generate all invariants (at least) up to degree 23. Finally,
the use of invariants to check whether two density operators are locally
equivalent is demonstrated.
| [
{
"version": "v1",
"created": "Thu, 18 Dec 1997 16:09:09 GMT"
},
{
"version": "v2",
"created": "Fri, 29 May 1998 13:00:10 GMT"
}
] | 2023-11-27T00:00:00 | [
[
"Grassl",
"Markus",
"",
"Universitaet\n Karlsruhe"
],
[
"Roetteler",
"Martin",
"",
"Universitaet\n Karlsruhe"
],
[
"Beth",
"Thomas",
"",
"Universitaet\n Karlsruhe"
]
] |
quant-ph/9712041 | Jezykmil | Mariusz Dudek, Stefan Giller and Piotr Milczarski (Theoretical Physics
Department II, University of Lodz, Poland) | Rectangular Well as Perturbation | 19 pages, 5 Postscript figures, uses psfig.sty | J.Math.Phys. 40 (1999) 1163-1179 | 10.1063/1.532794 | null | quant-ph | null | We discuss a finite rectangular well as a perturbation for the infinite one
with a depth $\lambda^2$ of the former as a perturbation parameter. In
particular we consider a behaviour of energy levels in the well as functions of
complex $\lambda$. It is found that all the levels of the same parity are
defined on infinitely sheeted Riemann surfaces which topological structures are
described in details. These structures differ considerably from those found in
models investigated earlier. It is shown that perturbation series for all the
levels converge what is in contrast with the known results of Bender and Wu.
The last property is shown to hold also for the finite rectangular well with
Dirac delta barier as a perturbation considered earlier by Ushveridze.
| [
{
"version": "v1",
"created": "Thu, 18 Dec 1997 16:21:28 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Dudek",
"Mariusz",
"",
"Theoretical Physics\n Department II, University of Lodz, Poland"
],
[
"Giller",
"Stefan",
"",
"Theoretical Physics\n Department II, University of Lodz, Poland"
],
[
"Milczarski",
"Piotr",
"",
"Theoretical Physics\n Department II, University of Lodz, Poland"
]
] |
quant-ph/9712042 | Christopher A. Fuchs | Christopher A. Fuchs and Jeroen van de Graaf | Cryptographic Distinguishability Measures for Quantum Mechanical States | 28 pages, 3 figures, minor typographical changes, submitted to IEEE
Transactions on Information Theory | null | null | null | quant-ph | null | This paper, mostly expository in nature, surveys four measures of
distinguishability for quantum-mechanical states. This is done from the point
of view of the cryptographer with a particular eye on applications in quantum
cryptography. Each of the measures considered is rooted in an analogous
classical measure of distinguishability for probability distributions: namely,
the probability of an identification error, the Kolmogorov distance, the
Bhattacharyya coefficient, and the Shannon distinguishability (as defined
through mutual information). These measures have a long history of use in
statistical pattern recognition and classical cryptography. We obtain several
inequalities that relate the quantum distinguishability measures to each other,
one of which may be crucial for proving the security of quantum cryptographic
key distribution. In another vein, these measures and their connecting
inequalities are used to define a single notion of cryptographic exponential
indistinguishability for two families of quantum states. This is a tool that
may prove useful in the analysis of various quantum cryptographic protocols.
| [
{
"version": "v1",
"created": "Thu, 18 Dec 1997 22:32:29 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Apr 1998 17:31:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Fuchs",
"Christopher A.",
""
],
[
"van de Graaf",
"Jeroen",
""
]
] |
quant-ph/9712043 | Henry Stapp | Henry P. Stapp | Reply to Unruh | 3 pages Subject: Bohr-EPR | null | null | LBNL | quant-ph | null | William Unruh has suggested (quant-ph/9710032) that a certain counterfactual
statement in my recent nonlocality proof should be re-interpreted in a way that
would block the proof. I give reason's why that statement should not be
re-interpreted.
| [
{
"version": "v1",
"created": "Fri, 19 Dec 1997 00:44:06 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Stapp",
"Henry P.",
""
]
] |
quant-ph/9712044 | Asher Peres | Ori Hay and Asher Peres | Quantum and classical descriptions of a measuring apparatus | 18 pages LaTeX (including one encapsulated PostScript figure) | Phys.Rev. A58 (1998) 116 | 10.1103/PhysRevA.58.116 | null | quant-ph | null | A measuring apparatus is described by quantum mechanics while it interacts
with the quantum system under observation, and then it must be given a
classical description so that the result of the measurement appears as
objective reality. Alternatively, the apparatus may always be treated by
quantum mechanics, and be measured by a second apparatus which has such a dual
description. This article examines whether these two different descriptions are
mutually consistent. It is shown that if the dynamical variable used in the
first apparatus is represented by an operator of the Weyl-Wigner type (for
example, if it is a linear coordinate), then the conversion from quantum to
classical terminology does not affect the final result. However, if the first
apparatus encodes the measurement in a different type of operator (e.g., the
phase operator), the two methods of calculation may give different results.
| [
{
"version": "v1",
"created": "Fri, 19 Dec 1997 08:35:19 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Hay",
"Ori",
""
],
[
"Peres",
"Asher",
""
]
] |
quant-ph/9712045 | Martin Plenio | M. Murao(1), M.B. Plenio(1), S. Popescu(2,3), V. Vedral(1) and P.L.
Knight(1) ((1) Optics Section, Blackett Laboratory, Imperial College, London,
UK (2) Isaac Newton Institute for Mathematical Sciences, Cambridge, UK (3)
BRIMS, Hewlett-Packard Laboratories, Stoke Gifford, Bristol, UK) | Multi-Particle Entanglement Purification Protocols | 5 pages, 2 figures and 1 table | Phys.Rev. A57 (1998) 4075 | 10.1103/PhysRevA.57.R4075 | null | quant-ph | null | Purification schemes for multi-particle entangled states cannot be treated as
straightforward extensions of those for two particles because of the lack of
symmetry they possess. We propose purification protocols for a wide range of
mixed entangled states of many particles. These are useful for understanding
entanglement, and will be of practical significance in multi-user cryptographic
schemes or distributed quantum computation and communication. We show that
operating locally on multi-particle entangled states directly is more efficient
than relying on two-particle purification.
| [
{
"version": "v1",
"created": "Fri, 19 Dec 1997 10:31:08 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Murao",
"M.",
""
],
[
"Plenio",
"M. B.",
""
],
[
"Popescu",
"S.",
""
],
[
"Vedral",
"V.",
""
],
[
"Knight",
"P. L.",
""
]
] |
quant-ph/9712046 | Brosens | F. Brosens, J. T. Devreese, L. F. Lemmens | Note on the stability of a confined Bose gas: Comment on
quant-ph/9712030 by L. Salasnich | 2 pages, Revtex, no figures | null | null | null | quant-ph | null | We demonstrate analytically that a Bose-Einstein condensate confined in a
harmonic trap with zero-range attractive interparticle interactions is unstable
if there is more than 1 boson. Replacing the zero-range interaction by a
short-range attractive interaction lifts the instability, and leads to a
pronounced clustering, by which the particles leak out of the condensate.
| [
{
"version": "v1",
"created": "Fri, 19 Dec 1997 15:04:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Brosens",
"F.",
""
],
[
"Devreese",
"J. T.",
""
],
[
"Lemmens",
"L. F.",
""
]
] |
quant-ph/9712047 | Tristan Hubsch | Tristan H\"ubsch | Quantum Mechanics is Either Non-Linear Or Non-Introspective | 8 pages, plain TeX + harvmac.tex + included macros | Mod.Phys.Lett. A13 (1998) 2503-2512 | 10.1142/S0217732398002667 | null | quant-ph | null | The measurement conundrum seems to have plagued quantum mechanics for so long
that impressions of an inconsistency amongst its axioms have spawned.
A demonstration that such purported inconsistency is fictitious may then be
in order and is presented here.
An exclusion principle of sorts emerges, stating that quantum mechanics
cannot be simultaneously linear and introspective (self-observing).
| [
{
"version": "v1",
"created": "Fri, 19 Dec 1997 21:38:48 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Hübsch",
"Tristan",
""
]
] |
quant-ph/9712048 | John Preskill | John Preskill | Fault-tolerant quantum computation | 58 pages with 7 PostScript figures, LaTeX, uses sprocl.sty and psfig,
to appear in "Introduction to Quantum Computation," edited by H.-K. Lo, S.
Popescu, and T. P. Spiller | null | null | CALT-68-2150, QUIC-97-034 | quant-ph | null | The discovery of quantum error correction has greatly improved the long-term
prospects for quantum computing technology. Encoded quantum information can be
protected from errors that arise due to uncontrolled interactions with the
environment, or due to imperfect implementations of quantum logical operations.
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. In principle, an arbitrarily
long quantum computation can be performed reliably, provided that the average
probability of error per gate is less than a certain critical value, the
accuracy threshold. It may be possible to incorporate intrinsic fault tolerance
into the design of quantum computing hardware, perhaps by invoking topological
Aharonov-Bohm interactions to process quantum information.
| [
{
"version": "v1",
"created": "Fri, 19 Dec 1997 22:58:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Preskill",
"John",
""
]
] |
quant-ph/9712049 | Antoine Suarez | Antoine Suarez (Center for Quantum Philosophy, Zurich) | Relativistic Nonlocality in experiments with successive impacts | 5 pages Latex, 1 eps figure. The argument in version 2 against the
possibility of 2 non-before events in the proposed experiment does not hold:
the original version with minor changes is restored | null | null | null | quant-ph | null | Relativistic Nonlocality is applied to experiments in which one of the
photons impacts successively at two beam-splitters. It is discussed whether a
time series with 2 non-before impacts can be produced with beam-splitters at
rest, and such an experiment may allow us to decide between Quantum Mechanics
(QM) and Relativistic Nonlocality (RNL).
| [
{
"version": "v1",
"created": "Sat, 20 Dec 1997 20:58:55 GMT"
},
{
"version": "v2",
"created": "Mon, 12 Jan 1998 17:22:22 GMT"
},
{
"version": "v3",
"created": "Wed, 14 Jan 1998 17:38:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Suarez",
"Antoine",
"",
"Center for Quantum Philosophy, Zurich"
]
] |
quant-ph/9712050 | Trevor Marshall | Trevor W. Marshall (Mathematics Dept., Manchester Univ., U. K.) | The zeropoint field - no longer a ghost | See also http://www.keyinnov.demon.co.uk | null | null | MUM-97-16 | quant-ph | null | We develop a local realist analysis of parametric down conversion, based on
the recognition that the pump field, instead of down converting spontaneously,
does so through its nonlinear coupling with a real zeropoint, or "vacuum"
electromagnetic field. The theory leads tothe prediction of a new phenomenon -
that, in addition to the main down-conversion rainbow, there is a satellite
rainbow, whose intensity is about 3 per cent of the main one. Confirmation of
this prediction will call seriously into question the current description of
the light field in terms of photons.
The present article extends the analysis of its predecessors (this archive,
numbers 9711029 and 9712001) to take account of the pump's polarization>
| [
{
"version": "v1",
"created": "Sun, 21 Dec 1997 18:01:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Marshall",
"Trevor W.",
"",
"Mathematics Dept., Manchester Univ., U. K."
]
] |
quant-ph/9712051 | Yuri I. Ozhigov | Yuri Ozhigov | Quantum Computer Can Not Speed Up Iterated Applications of a Black Box | 8 pages, Latex | null | null | null | quant-ph | null | Let a classical algorithm be determined by sequential applications of a black
box performing one step of this algorithm. If we consider this black box as an
oracle which gives a value F(a) for any query a, we can compute T sequential
applications of F on a classical computer relative to this oracle in time T.
It is proved that if T=O(2^{n/7}), where n is the length of input, then the
result of T sequential applications of F can not be computed on quantum
computer with oracle for F for all possible F faster than in time \Omega (T).
This means that there is no general method of quantum speeding up of classical
algorithms provided in such a general method a classical algorithm is regarded
as iterated applications of a given black box.
For an arbitrary time complexity T a lower bound for the time of quantum
simulation was found to be \Omega (T^{1/2}).
| [
{
"version": "v1",
"created": "Mon, 22 Dec 1997 14:49:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ozhigov",
"Yuri",
""
]
] |
quant-ph/9712052 | David Meyer | David A. Meyer | Quantum mechanics of lattice gas automata. II. Boundary conditions and
other inhomogeneities | 24 pages, plain TeX, 9 PostScript figures included with epsf.tex
(ignore the under/overfull \vbox error messages), 3 additional large figures
available upon request or from
http://math.ucsd.edu/~dmeyer/papers/papers.html | J.Phys.A31:2321-2340,1998 | 10.1088/0305-4470/31/10/009 | null | quant-ph | null | We continue our analysis of the physics of quantum lattice gas automata
(QLGA). Previous work has been restricted to periodic or infinite lattices;
simulation of more realistic physical situations requires finite sizes and
non-periodic boundary conditions. Furthermore, envisioning a QLGA as a
nanoscale computer architecture motivates consideration of inhomogeneities in
the `substrate'; this translates into inhomogeneities in the local evolution
rules. Concentrating on the one particle sector of the model, we determine the
various boundary conditions and rule inhomogeneities which are consistent with
unitary global evolution. We analyze the reflection of plane waves from
boundaries, simulate wave packet refraction across inhomogeneities, and
conclude by discussing the extension of these results to multiple particles.
| [
{
"version": "v1",
"created": "Tue, 23 Dec 1997 07:16:09 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Meyer",
"David A.",
""
]
] |
quant-ph/9712053 | Castagnoli Giuseppe | Giuseppe Castagnoli, Dalida Monti | A diakoptic approach to quantum computation | Short version of quant-ph/9711045 20 Nov 1997 "A reductionistic
approach to quantum computation", hopefully clarified, after various comments
(see acknowledgements). One (changed) figure | null | null | null | quant-ph | null | In the diakoptic approach, mechanisms are divided into simpler parts
interconnected in some standard way (say by a "mechanical connection''). We
explore the possibility of applying this approach to quantum mechanisms: the
specialties of the quantum domain seem to yield a richer result. First parts
are made independent of each other by assuming that connections are removed.
The overall state would thus become a superposition of tensor products of the
eigenstates of the independent parts. Connections are restored by projecting
off all the tensor products which violate them. This would be performed by
particle statistics, under a special interpretation thereof. The NP-complete
problem of testing the satisfiability of a Boolean network is approached in
this way. The diakoptic approach appears to be able of taming the quantum whole
without clipping its richness.
| [
{
"version": "v1",
"created": "Tue, 23 Dec 1997 16:54:16 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Castagnoli",
"Giuseppe",
""
],
[
"Monti",
"Dalida",
""
]
] |
quant-ph/9712054 | Richard J. Hughes | Richard J. Hughes | Cryptography, Quantum Computation and Trapped Ions | 17 pages. Submitted to "Philosophical Transactions of the Royal
Society," proceedings of the Royal Society Discussion Meeting on "Quantum
Computation: Theory and Experiment," London, England, November 1997 | Phil.Trans.Roy.Soc.Lond.A365:1853-1868,1998 | 10.1002/(SICI)1521-3978(199811)46:6/8<759::AID-PROP759>3.0.CO;2-E | LA-UR-97-4986 | quant-ph | null | The significance of quantum computation for cryptography is discussed.
Following a brief survey of the requirements for quantum computational
hardware, an overview of the ion trap quantum computation project at Los Alamos
is presented. The physical limitations to quantum computation with trapped ions
are analyzed and an assessment of the computational potential of the technology
is made.
| [
{
"version": "v1",
"created": "Tue, 23 Dec 1997 19:24:04 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Hughes",
"Richard J.",
""
]
] |
quant-ph/9712055 | Adan Cabello Quintero | Adan Cabello | Ladder proof of nonlocality without inequalities and without
probabilities | 26 pages, 5 figures. Minor changes. To appear in Phys. Rev. A | Phys.Rev. A58 (1998) 1687 | 10.1103/PhysRevA.58.1687 | null | quant-ph | null | The ladder proof of nonlocality without inequalities for two spin half
particles proposed by Hardy et al. (Phys. Rev. Lett. 79 (1997) 2755) works only
for nonmaximally entangled states and goes through for 50% of pairs at the
most. A similar ladder proof for two spin-1 particles in a maximally entangled
state is presented. In its simplest form, the proof goes through for 17% of
pairs. An extended version works for 100% of pairs. The proof can be extended
to any maximally entangled state of two spin-s particles (with s equal or
greater than 1).
| [
{
"version": "v1",
"created": "Tue, 23 Dec 1997 23:44:37 GMT"
},
{
"version": "v2",
"created": "Thu, 21 May 1998 00:28:30 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"Cabello",
"Adan",
""
]
] |
quant-ph/9712056 | Sang Koo You | Sang Koo You, Kwang Joe Jeon, Chul Koo Kim, and Kyun Nahm (Yonsei
University) | A new approximation scheme in quantum mechanics | 14pages, to be published in Eur. J. Phys | Eur.J.Phys. 19 (1998) 179-186 | 10.1088/0143-0807/19/2/012 | null | quant-ph | null | An approximation method which combines the perturbation theory with the
variational calculation is constructed for quantum mechanical problems. Using
the anharmonic oscillator and the He atom as examples, we show that the present
method provides an efficient scheme in estimating both the ground and the
excited states. We also discuss the limitations of the present method.
| [
{
"version": "v1",
"created": "Tue, 30 Dec 1997 11:19:44 GMT"
}
] | 2009-10-30T00:00:00 | [
[
"You",
"Sang Koo",
"",
"Yonsei\n University"
],
[
"Jeon",
"Kwang Joe",
"",
"Yonsei\n University"
],
[
"Kim",
"Chul Koo",
"",
"Yonsei\n University"
],
[
"Nahm",
"Kyun",
"",
"Yonsei\n University"
]
] |
quant-ph/9712057 | Ashot S. Gevorkyan | Alexander V. Bogdanov and Ashot S. Gevorkyan | New Perturbation Theory for Nonstationary Anharmonic Oscillator | LaTeX, 13 pages | null | 10.1088/0305-4470/30/21/015 | null | quant-ph | null | The new perturbation theory for the problem of nonstationary anharmonic
oscillator with polynomial nonstationary perturbation is proposed. As a zero
order approximation the exact wave function of harmonic oscillator with
variable frequency in external field is used. Based on some intrinsic
properties of unperturbed wave function the variational-iterational method is
proposed, that make it possible to correct both the amplitude and the phase of
wave function. As an application the first order correction are proposed both
for wave function and S-matrix elements for asymmetric perturbation potential
of type $V(x,\tau)=\alpha (\tau)x^3+\beta (\tau)x^4.$ The transition amplitude
''ground state - ground state'' $W_{00}(\lambda ;\rho)$ is analyzed in detail
depending on perturbation parameter $\lambda $ (including strong coupling
region $% \lambda $ $\sim 1$) and one-dimensional refraction coefficient $\rho
$.
| [
{
"version": "v1",
"created": "Wed, 31 Dec 1997 12:39:57 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Bogdanov",
"Alexander V.",
""
],
[
"Gevorkyan",
"Ashot S.",
""
]
] |
quant-ph/9712058 | Igor Kanatczikow | Igor V. Kanatchikov | Towards the Born-Weyl Quantization of Fields | 12pp, LaTeX2e. Talk at "Quantum Structures-96", Berlin, Aug. 1996. To
appear in Int. J. Theor. Phys. (1998), January | Int.J.Theor.Phys. 37 (1998) 333-342 | null | null | quant-ph gr-qc hep-th math-ph math.MP | null | Elements of the quantization in field theory based on the covariant
polymomentum Hamiltonian formalism (the De Donder-Weyl theory), a possibility
of which was originally discussed in 1934 by Born and Weyl, are developed. The
approach is based on a recently proposed graded Poisson bracket on differential
forms in field theory (see e.g. hep-th/9709229). A covariant analogue of the
Schr\"odinger equation for a hypercomplex wave function on the space of field
and space-time variables is put forward. It is shown to lead to the De
Donder-Weyl Hamilton-Jacobi equations in quasiclassical limit. A possible
relation to the functional Schr\"odinger picture in quantum field theory is
outlined.
| [
{
"version": "v1",
"created": "Wed, 31 Dec 1997 19:30:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kanatchikov",
"Igor V.",
""
]
] |
quant-ph/9801001 | Dr. Luca Salasnich, . D. | Luca Salasnich | Reply to a Comment on "the Role of Dimensionality in the Stability of a
Confined Condensed Bose Gas" | 4 pages, Latex, no figures | Mod.Phys.Lett. B12 (1998) 649-651 | 10.1142/S0217984998000767 | null | quant-ph | null | As pointed out by the authors of the comment quant-ph/9712046, in our paper
quant-ph/9712030 we studied in detail the metastability of a Bose-Einstein
Condensate (BEC) confined in an harmonic trap with zero-range interaction. As
well known, the BEC with attractive zero-range interaction is not stable but
can be metastable. In our paper we analyzed the role of dimensionality for the
metastability of the BEC with attractive and repulsive interaction.
| [
{
"version": "v1",
"created": "Fri, 2 Jan 1998 16:47:58 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Salasnich",
"Luca",
""
]
] |
quant-ph/9801002 | Timothy F. Havel | Shyamal S. Somaroo, David G. Cory and Timothy F. Havel | Expressing the operations of quantum computing in multiparticle
geometric algebra | RevTeX, 10 pages, no figures; Physics Letters A, in press | Phys.Lett. A240 (1998) 1-7 | 10.1016/S0375-9601(98)00010-3 | null | quant-ph | null | We show how the basic operations of quantum computing can be expressed and
manipulated in a clear and concise fashion using a multiparticle version of
geometric (aka Clifford) algebra. This algebra encompasses the product operator
formalism of NMR spectroscopy, and hence its notation leads directly to
implementations of these operations via NMR pulse sequences.
| [
{
"version": "v1",
"created": "Sat, 3 Jan 1998 19:57:32 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Somaroo",
"Shyamal S.",
""
],
[
"Cory",
"David G.",
""
],
[
"Havel",
"Timothy F.",
""
]
] |
quant-ph/9801003 | null | Bernd A. Berg | Quantum Theory and Spacelike Measurements | 14 pages latex and 1 postscript figure in one file | null | null | null | quant-ph hep-th | null | Experimentally observed violations of Bell inequalities rule out local
realistic theories. Consequently, the quantum state vector becomes a strong
candidate for providing an objective picture of reality. However, such an
ontological view of quantum theory faces difficulties when spacelike
measurements on entangled states have to be described, because time ordering of
spacelike events can change under Lorentz-Poincar\'e transformations. In the
present paper it is shown that a necessary condition for consistency is to
require state vector reduction on the backward light-cone. A fresh approach to
the quantum measurement problem appears feasible within such a framework.
| [
{
"version": "v1",
"created": "Sun, 4 Jan 1998 13:27:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Berg",
"Bernd A.",
""
]
] |
quant-ph/9801004 | Jerry Finkelstein | J. Finkelstein | Does Schrodinger's Cat Know Something That Schrodinger Does Not Know? | LaTex, 8 pages, no figures | null | null | SJSU/TP-98-15 | quant-ph | null | Macroscopic objects appear to have definite positions. In a many-worlds
interpretation of quantum theory, this appearance is an illusion; the correct
view is the "view from outside" in which even macroscopic objects are in
general in a superposition of different positions. In the Bohm model, objects
really are in definite positions. This additional aspect of reality is
accessible only from the "inside"; thus in the Bohm model the view from inside
can be more correct than is the view from outside.
| [
{
"version": "v1",
"created": "Sun, 4 Jan 1998 18:28:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Finkelstein",
"J.",
""
]
] |
quant-ph/9801005 | Nicolas Gisin | Nicolas Gisin | Quantum cloning without signaling | null | Phys.Lett. A242 (1998) 1-3 | 10.1016/S0375-9601(98)00170-4 | null | quant-ph | null | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality
for arbitrary fast signaling. However perfect QCM cannot exist. We derive a
bound on the fidelity of QCM compatible with the no-signaling constraint. This
bound equals the fidelity of the Bu\v{z}ek-Hillery QCM.
| [
{
"version": "v1",
"created": "Tue, 6 Jan 1998 16:43:07 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Gisin",
"Nicolas",
""
]
] |
quant-ph/9801006 | William T. Buttler | W. T. Buttler, R. J. Hughes, P. G. Kwiat, G. G. Luther, G. L. Morgan,
J. E. Nordholt, C. G. Peterson, and C. M. Simmons | Free-space quantum key distribution | 5 pages, 2 figures, 2 tables. To be published in Physical review A on
or about 1 April 1998 | null | 10.1103/PhysRevA.57.2379 | LA-UR-97-1975 | quant-ph | null | A working free-space quantum key distribution (QKD) system has been developed
and tested over a 205-m indoor optical path at Los Alamos National Laboratory
under fluorescent lighting conditions. Results show that free-space QKD can
provide secure real-time key distribution between parties who have a need to
communicate secretly.
| [
{
"version": "v1",
"created": "Tue, 6 Jan 1998 21:23:45 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Buttler",
"W. T.",
""
],
[
"Hughes",
"R. J.",
""
],
[
"Kwiat",
"P. G.",
""
],
[
"Luther",
"G. G.",
""
],
[
"Morgan",
"G. L.",
""
],
[
"Nordholt",
"J. E.",
""
],
[
"Peterson",
"C. G.",
""
],
[
"Simmons",
"C. M.",
""
]
] |
quant-ph/9801007 | Kentaro Kato | Masahide Sasaki, Tsuyoshi Sasaki-Usuda, Masayuki Izutsu, Osamu Hirota | Realization of a collective decoding of codeword states | 6 pages, RevTeX, 4 figures(EPS) | null | 10.1103/PhysRevA.58.159 | null | quant-ph | null | This was also extended from the previous article quant-ph/9705043, especially
in a realization of the decoding process.
| [
{
"version": "v1",
"created": "Wed, 7 Jan 1998 07:53:28 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Sasaki",
"Masahide",
""
],
[
"Sasaki-Usuda",
"Tsuyoshi",
""
],
[
"Izutsu",
"Masayuki",
""
],
[
"Hirota",
"Osamu",
""
]
] |
quant-ph/9801008 | Gabriel Drobny | G. Drobny, B.Hladky and V. Buzek (Institute of Physics, Bratislava) | Quantum-state synthesis of multi-mode bosonic fields: Preparation of
arbitrary states of 2-D vibrational motion of trapped ions | 8 pages, revtex, including 2 ps-figures, section about physical
implementation added, references updated, submitted to Phys. Rev. A, computer
program available at http://www.savba.sk/sav/inst/fyzi/qo/ | null | 10.1103/PhysRevA.58.2481 | null | quant-ph | null | We present a universal algorithm for an efficient deterministic preparation
of an arbitrary two--mode bosonic state. In particular, we discuss in detail
preparation of entangled states of a two-dimensional vibrational motion of a
trapped ion via a sequence of laser stimulated Raman transitions. Our formalism
can be generalized for multi-mode bosonic fields. We examine stability of our
algorithm with respect to a technical noise.
| [
{
"version": "v1",
"created": "Wed, 7 Jan 1998 14:08:17 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Apr 1998 11:00:11 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Drobny",
"G.",
"",
"Institute of Physics, Bratislava"
],
[
"Hladky",
"B.",
"",
"Institute of Physics, Bratislava"
],
[
"Buzek",
"V.",
"",
"Institute of Physics, Bratislava"
]
] |
quant-ph/9801009 | Vladimir Buzek | Vladimir Buzek and Mark Hillery (Institute of Physics, SAS,
Bratislava, Slovakia & Department of Physics and Astronomy, Hunter College,
CUNY, New York, USA) | Universal optimal cloning of qubits and quantum registers | To be presented at the First NASA Conference on Quantum Computing and
Quantum Communications, 17-20 February 1998, Palm Springs, USA | null | null | null | quant-ph | null | We review our recent work on the universal (i.e. input state independent)
optimal quantum copying (cloning) of qubits. We present unitary transformations
which describe the optimal cloning of a qubit and we present the corresponding
quantum logical network. We also present network for an optimal quantum copying
``machine'' (transformation) which produces N+1 identical copies from the
original qubit. Here again the quality (fidelity) of the copies does not depend
on the state of the original and is only a function of the number of copies, N.
In addition, we present the machine which universaly and optimally clones
states of quantum objects in arbitrary-dimensional Hilbert spaces. In
particular, we discuss universal cloning of quantum registers.
| [
{
"version": "v1",
"created": "Wed, 7 Jan 1998 14:40:49 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Buzek",
"Vladimir",
"",
"Institute of Physics, SAS,\n Bratislava, Slovakia & Department of Physics and Astronomy, Hunter College,\n CUNY, New York, USA"
],
[
"Hillery",
"Mark",
"",
"Institute of Physics, SAS,\n Bratislava, Slovakia & Department of Physics and Astronomy, Hunter College,\n CUNY, New York, USA"
]
] |
quant-ph/9801010 | Valery Kalatsky | V. A. Kalatsky (Texas A&M University), V. L. Pokrovsky (Texas A&M
University and Landau Institute) | Large moments in external fields of cubic group symmetry | 4 pages, RevTeX, 4 figures, uses EPSF.sty | Europhys.Lett. 44 (1998) 539-545 | 10.1209/epl/i1998-00507-2 | null | quant-ph cond-mat | null | We predict that large moments $J$, placed into a crystal field with the cubic
point symmetry group, differ by their spectrum and magnetic properties. E. g.,
properties of the odd-integer moments are different from those of the
even-integer. The effect is due to Berry's phases gained by the moment, when it
tunnels between minima of the external field. Two cases of the group $O$ are
classified, namely, 6- and 8-fold coordinations. The spectrum and degeneration
of energy levels depend on a remainder $\{J/n\}$, where the divisor $n=4$ and 3
for 6-fold and 8-fold coordination respectively. %High symmetry results in a
finite magnetic moment for half-integer %and some integer moments, for example
odd $J$ at 6-fold coordination. Large moments in the cubic environment can be
realized by diluted alloys ${R}_{1-x}{R}_{x}'$Sb, where R=Lu, La, and R$'$=Tb,
Dy, Ho, Er.
| [
{
"version": "v1",
"created": "Wed, 7 Jan 1998 18:46:53 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kalatsky",
"V. A.",
"",
"Texas A&M University"
],
[
"Pokrovsky",
"V. L.",
"",
"Texas A&M\n University and Landau Institute"
]
] |
quant-ph/9801011 | Jerry Finkelstein | J. Finkelstein | Yet another comment on "Nonlocal character of quantum theory" | LateX, 6 pages, no figures | null | null | SJSU/TP-98-16 | quant-ph | null | There has been considerable discussion of the claim by Stapp [Am. J. Phys.
65, 300 (1997)] that quantum theory is incompatible with locality. In this note
I analyze the meaning of some of the statements used in this discussion.
| [
{
"version": "v1",
"created": "Wed, 7 Jan 1998 23:05:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Finkelstein",
"J.",
""
]
] |
quant-ph/9801012 | Kentaro Kato | Masahide Sasaki, Kentaro Kato, Masayuki Izutsu, Osamu Hirota | Quantum channels showing superadditivity in capacity | 16 pages, RevTeX, 8 figures(EPS) | null | 10.1103/PhysRevA.58.146 | null | quant-ph | null | This was significantly extended from the previous article
quant-ph/9705043,especially in an information theoretic aspect, by adding new
results.
| [
{
"version": "v1",
"created": "Thu, 8 Jan 1998 08:47:16 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Sasaki",
"Masahide",
""
],
[
"Kato",
"Kentaro",
""
],
[
"Izutsu",
"Masayuki",
""
],
[
"Hirota",
"Osamu",
""
]
] |
quant-ph/9801013 | Gonzalo Garcia de Polavieja | Gonzalo Garcia de Polavieja, Erik Sjoeqvist | Extending the quantal adiabatic theorem: Geometry of noncyclic motion | Minor stylistic changes in text and Fig. 3. Forthcoming in American
Journal of Physics (March 98) | Forthcoming in American Journal of Physics (March 98) | 10.1119/1.18799 | null | quant-ph | null | We show that a noncyclic phase of geometric origin has to be included in the
approximate adiabatic wave function. The adiabatic noncyclic geometric phase
for systems exhibiting a conical intersection as well as for an Aharonov-Bohm
situation is worked out in detail. A spin-1/2 experiment to measure the
adiabatic noncyclic geometric phase is discussed. We also analyze some
misconceptions in the literature and textbooks concerning noncyclic geometric
phases.
| [
{
"version": "v1",
"created": "Thu, 8 Jan 1998 14:44:57 GMT"
},
{
"version": "v2",
"created": "Wed, 28 Jan 1998 18:56:47 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"de Polavieja",
"Gonzalo Garcia",
""
],
[
"Sjoeqvist",
"Erik",
""
]
] |
quant-ph/9801014 | Michael Westmoreland | Michael D. Westmoreland (Denison University), Benjamin Schumacher
(Kenyon College) | Quantum Entanglement and the Nonexistence of Superluminal Signals | 5 pages text plus 1 figure, revised 5 March 1998 to include
additional remarks and diagrams | null | null | null | quant-ph | null | This paper shows that ordinary quantum mechanics is not consistent with the
superluminal transmission of classical information.
| [
{
"version": "v1",
"created": "Thu, 8 Jan 1998 22:21:21 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Mar 1998 17:18:23 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Westmoreland",
"Michael D.",
"",
"Denison University"
],
[
"Schumacher",
"Benjamin",
"",
"Kenyon College"
]
] |
quant-ph/9801015 | D. Trifonov | D.A. Trifonov | Canonical equivalence of quantum systems, multimode squeezed states and
Robertson relation | 19 pages, LaTex, no figures | null | null | INRNE-TH-95/4 | quant-ph | null | It is shown that any two Hamiltonians H(t) and H'(t) of N dimensional quantum
systems can be related by means of time-dependent canonical transformations
(CT). The dynamical symmetry group of system with Hamiltonian H(t) coincides
with the invariance group of H(t). Quadratic Hamiltonians can be diagonalized
by means of linear time-dependent CT. The diagonalization can be explicitly
carried out in the case of stationary and some nonstationary quadratic H.
Linear CT can diagonalize the uncertainty matrix \sigma(\rho) for canonical
variables p_k, q_j in any state \rho, i.e., \sigma(\rho) is symplectically
congruent to a diagonal uncertainty matrix. For multimode squeezed canonical
coherent states (CCS) and squeezed Fock states with equal photon numbers in
each mode \sigma is symplectic itself. It is proved that the multimode
Robertson uncertainty relation is minimized only in squeezed CCS.
| [
{
"version": "v1",
"created": "Fri, 9 Jan 1998 10:02:32 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Trifonov",
"D. A.",
""
]
] |
quant-ph/9801016 | M. Iosifescu | Mircea Iosifescu | Annihilators of Irreducible Modules and Kinematical Constraints of Pair
Operators | 12 pages, LATEX, no figures, submitted to Progress in Yheoretical
Physics January 1998 | null | null | FT-418-July 1996 | quant-ph | null | The kinematical constraints of pair operators in nuclear collective motion,
pointed out by Yamamura and identified by Nishiyama as relations between so(2n)
generators, are recognized as equations satisfied by second-degree annihilators
(deduced in previous work) of irreducible so(2n)-modules. The recursion
relations for Nishiyama's tensors and their dependence on the parity of the
tensor degree are explained. An explanation is also given for the recursion
relation for the sp(2n) tensors pointed out by Hwa and Nuyts. The statements
for the algebras so(2n) and sp(2n) are proved simultaneously.
| [
{
"version": "v1",
"created": "Fri, 9 Jan 1998 12:21:49 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Iosifescu",
"Mircea",
""
]
] |
quant-ph/9801017 | Wojciech Florek | Wojciech Florek | Center of the charged particle orbit for any linear gauge | RevTeX, 5 pages, submitted to Int. J. Mod. Phys. B | null | null | null | quant-ph cond-mat.mes-hall math-ph math.MP | null | In the case of a constant uniform magnetic field it can be assumed, without
the loss of generality, that the vector potential (the gauge) is a linear
function of position, i.e. it could be considered as a three-dimensional real
matrix or, more generally in an n-dimensional space, as a tensor A of the rank
two. The magnetic tensor H is obtained from A by antisymmetrization, i.e.
H=A-A^T. It is shown that the transpose of A plays a special role, since it
determines the operator of the orbit center of a charged particle moving in an
external magnetic field H. Moreover, this movement can be considered as a
combination of N<=n independent cyclotronic movements in orthogonal planes
(cyclotron orbits) with quantized energies, whereas in other n-2N dimensions
the particle is completely free with a continuous energy spectrum. The proposed
approach enables introduction of the four-dimensional space-time and, after
some generalizations, non-linear gauges.
| [
{
"version": "v1",
"created": "Sat, 10 Jan 1998 18:34:36 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Dec 2002 09:01:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Florek",
"Wojciech",
""
]
] |
quant-ph/9801018 | Piotr Rozmej | P. Rozmej (University MCS, Lublin, Poland) and R. Arvieu(ISN,
Grenoble, France) | Clones and other interferance effects in the evolution of angular
momentum coherent states | 20 pages, ReVTeX, additionally 11 postscript figures (gziped, the
biggest fig4,6,7 about 60kB each). Submitted to Phys. Rev. A. (revised
version, presentation of the theory largely changes and extended, 1 new
figure7 added) | Phys.Rev. A58 (1998) 4314-4329 | 10.1103/PhysRevA.58.4314 | null | quant-ph math-ph math.MP nucl-th physics.atom-ph physics.chem-ph | null | The aim of this article is to present the interference effects which occur
during the time evolution of simple angular wave packets (WP) which can be
associated to a diatomic rigid molecule (heteronuclear) or to a quantum rigid
body with axial symmetry like a molecule or a nucleus. The time evolution is
understood entirely within the frame of fractional revivals discovered by
Averbukh and Perelman since the energy spectrum is exactly quadratic. Our
objectives are to study how these interference effects differ when there is a
change of the initial WP. For this purpose we introduce a two parameter set of
angular momentum coherent states. From one hand this set emerge quite naturally
from the three dimensional coherent states of the harmonic oscillator, from
another hand this set is shown to be buit from intelligent spin states.We have
also compared our coherent states to some previously constructed using boson
representation of angular momentum. The time evolution of coherent states for
symmetric top is also discussed.
| [
{
"version": "v1",
"created": "Sun, 11 Jan 1998 14:18:43 GMT"
},
{
"version": "v2",
"created": "Mon, 13 Jul 1998 10:35:31 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Rozmej",
"P.",
"",
"University MCS, Lublin, Poland"
],
[
"Arvieu",
"R.",
"",
"ISN,\n Grenoble, France"
]
] |
quant-ph/9801019 | V. P. Karasev | Valery P. Karassiov (Lebedev Physical Institute, Moscow) | Symmetry as a source of hidden coherent structures in quantum physics:
general outlook and examples | 10 pages, LATEX; Proceedings of VIII Int. Conf. on Symmetry Methods
in Physics (Dubna, July 28-August 2, 1997) | Phys.Atom.Nucl.63:648-656,2000; Yad.Fiz.63:714-722,2000 | 10.1134/1.855681 | FIAN-OD-98-01 | quant-ph | null | A general algebraic approach, incorporating both invariance groups and
dynamic symmetry algebras, is developed to reveal hidden coherent structures
(closed complexes and configurations) in quantum many-body physics models due
to symmetries of their Hamiltonians $H$. Its general ideas are manifested on
some recent new examples: 1) G-invariant bi-photons and a related
SU(2)-invariant treatment of unpolarized light; 2) quasi-spin clusters in
nonlinear models of quantum optics; 3) construction of composite particles and
(para)fields from G-invariant clusters due to internal symmetries.
| [
{
"version": "v1",
"created": "Mon, 12 Jan 1998 09:14:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Karassiov",
"Valery P.",
"",
"Lebedev Physical Institute, Moscow"
]
] |
quant-ph/9801020 | Marek Nowakowski | Marek Nowakowski | The Electromagnetic Coupling in Kemmer-Duffin-Petiau Theory | 14 pages, Latex | Phys.Lett. A244 (1998) 329-337 | 10.1016/S0375-9601(98)00365-X | UAB-FT-435 | quant-ph | null | We analyse the electromagnetic coupling in the Kemmer-Duffin-Petiau (KDP)
equation. Since the KDP--equation which describes spin-0 and spin-1 bosons is
of Dirac-type, we examine some analogies and differences from the Dirac
equation. The main difference to the Dirac equation is that the KDP equation
contains redundant components. We will show that as a result certain
interaction terms in the Hamilton form of the KDP equation do not have a
physical meaning and will not affect the calculation of physical observables.
We point out that a second order KDP equation derived by Kemmer as an analogy
to the second order Dirac equation is of limited physical applicability as (i)
it belongs to a class of second order equations which can be derived from the
original KDP equation and (ii) it lacks a back-transformation which would allow
one to obtain solutions of the KDP equation out of solutions of the second
order equation. We therefore suggest a different higher order equation which,
as far as the solutions for the wave functions are concerned, is equivalent to
the orginal first order KDP wave equation.
| [
{
"version": "v1",
"created": "Mon, 12 Jan 1998 14:54:04 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Nowakowski",
"Marek",
""
]
] |
quant-ph/9801021 | Volodymyr Tkachuk | V. M. Tkachuk (Ivan Franko Lviv State University, Ukraine) | Quasi-Exactly Solvable Potentials with Two Known Eigenstates | 13 pages, Latex, replaced by revised version | Phys. Lett. A 245 (1998) 177-182 | 10.1016/S0375-9601(98)00455-1 | null | quant-ph | null | A new supersymmetry method for the generation of the quasi-exactly solvable
(QES) potentials with two known eigenstates is proposed. Using this method we
obtained new QES potentials for which we found in explicit form the energy
levels and wave functions of the ground state and first excited state.
| [
{
"version": "v1",
"created": "Mon, 12 Jan 1998 18:13:59 GMT"
},
{
"version": "v2",
"created": "Wed, 23 Dec 1998 09:29:34 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Tkachuk",
"V. M.",
"",
"Ivan Franko Lviv State University, Ukraine"
]
] |
quant-ph/9801022 | Tal Mor | Eli Biham, Michel Boyer, Gilles Brassard, Jeroen van de Graaf and Tal
Mor | Security of Quantum Key Distribution Against All Collective Attacks | 5 pages, RevTeX | null | null | null | quant-ph | null | Security of quantum key distribution against sophisticated attacks is among
the most important issues in quantum information theory. In this work we prove
security against a very important class of attacks called collective attacks
(under a compatible noise model) which use quantum memories and gates, and
which are directed against the final key. Although attacks stronger than the
collective attacks can exist in principle, no explicit example was found and it
is conjectured that security against collective attacks implies also security
against any attack.
| [
{
"version": "v1",
"created": "Mon, 12 Jan 1998 22:59:30 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Biham",
"Eli",
""
],
[
"Boyer",
"Michel",
""
],
[
"Brassard",
"Gilles",
""
],
[
"van de Graaf",
"Jeroen",
""
],
[
"Mor",
"Tal",
""
]
] |
quant-ph/9801023 | Ivan H. Deutsch | I. H. Deutsch and P. S. Jessen | Quantum-state control in optical lattices | 35 pages including 8 figures. To appear in Phys. Rev. A. March 1998 | null | 10.1103/PhysRevA.57.1972 | null | quant-ph | null | We study the means to prepare and coherently manipulate atomic wave packets
in optical lattices, with particular emphasis on alkali atoms in the
far-detuned limit. We derive a general, basis independent expression for the
lattice operator, and show that its off-diagonal elements can be tailored to
couple the vibrational manifolds of separate magnetic sublevels. Using these
couplings one can evolve the state of a trapped atom in a quantum coherent
fashion, and prepare pure quantum states by resolved-sideband Raman cooling. We
explore the use of atoms bound in optical lattices to study quantum tunneling
and the generation of macroscopic superposition states in a double-well
potential. Far-off-resonance optical potentials lend themselves particularly
well to reservoir engineering via well controlled fluctuations in the
potential, making the atom/lattice system attractive for the study of
decoherence and the connection between classical and quantum physics.
| [
{
"version": "v1",
"created": "Tue, 13 Jan 1998 01:38:55 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Deutsch",
"I. H.",
""
],
[
"Jessen",
"P. S.",
""
]
] |
quant-ph/9801024 | Anna Sanpera | Anna Sanpera, Rolf Tarrach and Guifre Vidal | Quantum inseparability as local pseudomixture | 5 pages latex | Phys.Rev. A58 (1998) 826-830 | 10.1103/PhysRevA.58.826 | null | quant-ph | null | We show how to decompose any density matrix of the simplest binary composite
systems, whether separable or not, in terms of only product vectors. We
determine for all cases the minimal number of product vectors needed for such a
decomposition. Separable states correspond to mixing from one to four pure
product states. Inseparable states can be described as pseudomixtures of four
or five pure product states, and can be made separable by mixing them with one
or two pure product states.
| [
{
"version": "v1",
"created": "Tue, 13 Jan 1998 13:46:26 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Sanpera",
"Anna",
""
],
[
"Tarrach",
"Rolf",
""
],
[
"Vidal",
"Guifre",
""
]
] |
quant-ph/9801025 | Ivan H. Deutsch | S. E. Hamann, D. L. Haycock, G. Klose, P. H. Pax, I. H. Deutsch and P.
S. Jessen | Resolved-sideband Raman cooling to the ground state of an optical
lattice | PDF file, 13 pages including 3 figures | Phys.Rev.Lett. 80 (1998) 4149-4152 | 10.1103/PhysRevLett.80.4149 | null | quant-ph | null | We trap neutral Cs atoms in a two-dimensional optical lattice and cool them
close to the zero-point of motion by resolved-sideband Raman cooling. Sideband
cooling occurs via transitions between the vibrational manifolds associated
with a pair of magnetic sublevels and the required Raman coupling is provided
by the lattice potential itself. We obtain mean vibrational excitations
\bar{n}_x \approx \bar{n}_y \approx 0.01, corresponding to a population \sim
98% in the vibrational ground state. Atoms in the ground state of an optical
lattice provide a new system in which to explore quantum state control and
subrecoil laser cooling
| [
{
"version": "v1",
"created": "Tue, 13 Jan 1998 17:52:20 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Hamann",
"S. E.",
""
],
[
"Haycock",
"D. L.",
""
],
[
"Klose",
"G.",
""
],
[
"Pax",
"P. H.",
""
],
[
"Deutsch",
"I. H.",
""
],
[
"Jessen",
"P. S.",
""
]
] |
quant-ph/9801026 | Atushi Tanaka | Atushi Tanaka (University of Tsukuba) | Phase space caustics in multi-component systems | 6 pages, 7 ps figures, To appear in Phys. Rev. Lett | Phys. Rev. Lett. 80, 1414 (1998) | 10.1103/PhysRevLett.80.1414 | null | quant-ph chao-dyn nlin.CD | null | As examples of quantum-"classical" coupling systems, multi-component systems
are studied by semiclassical evaluations of the Feynman kernels in the
coherent-state representation. From the observation of the phase space caustics
due to the presence of the internal degree of freedom (IDF), two phenomena are
explained in terms of the semiclassical theory: (1) The quantum oscillations of
the IDF induce quantum interference patterns in the Hushimi representation; (2)
Chaotic dynamics destroys the coherence of the quantum oscillations.
| [
{
"version": "v1",
"created": "Wed, 14 Jan 1998 09:00:42 GMT"
}
] | 2009-03-19T00:00:00 | [
[
"Tanaka",
"Atushi",
"",
"University of Tsukuba"
]
] |
quant-ph/9801027 | Jonathan A. Jones | J. A. Jones and M. Mosca (University of Oxford, UK) | Implementation of a Quantum Algorithm to Solve Deutsch's Problem on a
Nuclear Magnetic Resonance Quantum Computer | 16 pages including 6 figures. Minor clarifications as requested by
the referee plus updated references. Journal of Chemical Physics, in press
(expected publication date August 1st 1998) | J.Chem.Phys. 109 (1998) 1648-1653 | 10.1063/1.476739 | JAJQP-98-01 | quant-ph | null | We demonstrate the use of an NMR quantum computer based on the pyrimidine
base cytosine, and the implementation of a quantum algorithm to solve Deutsch's
problem.
| [
{
"version": "v1",
"created": "Wed, 14 Jan 1998 09:36:24 GMT"
},
{
"version": "v2",
"created": "Thu, 30 Apr 1998 11:46:38 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jones",
"J. A.",
"",
"University of Oxford, UK"
],
[
"Mosca",
"M.",
"",
"University of Oxford, UK"
]
] |
quant-ph/9801028 | Tamas Kiss | T. Kiss, U. Herzog, and U. Leonhardt | Reply on the ``Comment on `Loss-error compensation in quantum- state
measurements' '' | LaTex, 2 pages, 1 Figure; to be published in Physical Review A | null | 10.1103/PhysRevA.57.3134 | QP-97-01 | quant-ph | null | The authors of the Comment [G. M. D'Ariano and C. Macchiavello to be
published in Phys. Rev. A, quant-ph/9701009] tried to reestablish a 0.5
efficiency bound for loss compensation in optical homodyne tomography. In our
reply we demonstrate that neither does such a rigorous bound exist nor is the
bound required for ruling out the state reconstruction of an individual system
[G. M. D'Ariano and H. P. Yuen, Phys. Rev. Lett. 76, 2832 (1996)].
| [
{
"version": "v1",
"created": "Wed, 14 Jan 1998 09:55:06 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kiss",
"T.",
""
],
[
"Herzog",
"U.",
""
],
[
"Leonhardt",
"U.",
""
]
] |
quant-ph/9801029 | Krzysztof Kowalski | K. Kowalski, J. Rembielinski and L.C. Papaloucas | Coherent states for a quantum particle on a circle | 23 pages LaTeX, uses ioplppt.sty | J.Phys.A29:4149-4167,1996 | 10.1088/0305-4470/29/14/034 | kft-96-55 | quant-ph | null | The coherent states for the quantum particle on the circle are introduced.
The Bargmann representation within the actual treatment provides the
representation of the algebra $[\hat J,U]=U$, where $U$ is unitary, which is a
direct consequence of the Heisenberg algebra $[\hat \phi, \hat J]=i$, but it is
more adequate for the study of the circlular motion.
| [
{
"version": "v1",
"created": "Wed, 14 Jan 1998 14:04:39 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kowalski",
"K.",
""
],
[
"Rembielinski",
"J.",
""
],
[
"Papaloucas",
"L. C.",
""
]
] |
quant-ph/9801030 | Toralf Gruner | T. Gruner and D.-G. Welsch (FSU Jena) | Antibunching of distorted optical wave packets at a beam splitter | 16 pages, LaTex, 6 figures | null | 10.1016/S0030-4018(98)00233-8 | null | quant-ph | null | Interference of single-photon wave packets at a beam splitter usually leads
to an anticorrelation of the light intensity in the two output ports of the
beam splitter. The effect may be regarded as ``bunching'' of the photons at the
beam splitter and has widely been interpreted as a result of quantum mechanical
interference between the probability amplitudes of indistinguishable bosonic
particles. Here we show that when the wave packets are sufficiently distorted,
then the opposite behaviour is observed, i.e., simultaneous clicks of the
photodetectors in the two output ports are favoured, which may be regarded as
``antibunching'' of the photons at the beam splitter.
| [
{
"version": "v1",
"created": "Thu, 15 Jan 1998 09:17:26 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Gruner",
"T.",
"",
"FSU Jena"
],
[
"Welsch",
"D. -G.",
"",
"FSU Jena"
]
] |
quant-ph/9801031 | Jezykmil | Stefan Giller and Piotr Milczarski (Theoretical Physics Department II,
University of Lodz, Poland) | Borel Summable Solutions to 1D Schr\"odinger Equation | 39 pages, 20 Postscript figures, uses epsfig.sty article.sty, figure
caption added and misprints corrected | J.Math.Phys. 42 (2001) 608-640 | 10.1063/1.1331099 | null | quant-ph | null | It is shown that so called fundamental solutions the semiclassical expansions
of which have been established earlier to be Borel summable to the solutions
themselves appear also to be the unique solutions to the 1D Schr\"odinger
equation having this property. Namely, it is shown in this paper that for the
polynomial potentials the Borel function defined by the fundamental solutions
can be considered as the canonical one. The latter means that any Borel
summable solution can be obtained by the Borel transformation of this unique
canonical Borel function multiplied by some $\hbar$-dependent and Borel
summable constant. This justify the exceptional role the fundamental solutions
play in 1D quantum mechanics and completes the relevant semiclassical theory
relied on the Borel resummation technique and developed in our other papers.
| [
{
"version": "v1",
"created": "Thu, 15 Jan 1998 17:06:53 GMT"
},
{
"version": "v2",
"created": "Sat, 14 Aug 1999 10:27:20 GMT"
},
{
"version": "v3",
"created": "Thu, 12 Oct 2000 16:31:01 GMT"
},
{
"version": "v4",
"created": "Thu, 26 Oct 2000 16:47:53 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Giller",
"Stefan",
"",
"Theoretical Physics Department II,\n University of Lodz, Poland"
],
[
"Milczarski",
"Piotr",
"",
"Theoretical Physics Department II,\n University of Lodz, Poland"
]
] |
quant-ph/9801032 | null | Vladimir S. Mashkevich (Institute of Physics, Kiev) | On Stapp-Unruh-Mermin Discussion on Quantum Nonlocality: Quantum Jumps
and Relativity | 9 pages, LATEX 2.09 | null | null | IP 1/98 | quant-ph | null | We argue that the participants of the discussion have overlooked an essential
circumstance, in view of which Stapp's fifth proposition fails. The
circumstance is that though $L$ and $R$ measurements, being causally separated,
are not invariantly time ordered, quantum-jump hypersurfaces associated with
the measurements are causelikewise ordered. Stapp's fifth proposition is true
iff $L$ hypersurface precedes $R$ one; but within the limits of special
relativity, it is impossible to determine the causelike order of those
hypersurfaces. The entire Stapp's construct is revised.
| [
{
"version": "v1",
"created": "Thu, 15 Jan 1998 20:19:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mashkevich",
"Vladimir S.",
"",
"Institute of Physics, Kiev"
]
] |
quant-ph/9801033 | Ricardo Moritz Cavalcanti | R. M. Cavalcanti | Exact Green's functions for delta-function potentials and
renormalization in quantum mechanics | 9 pages, REVTEX | Rev.Bras.Ens.Fis. 21 (1999) 336 | null | null | quant-ph | null | We present a simple recipe to construct the Green's function associated with
a Hamiltonian of the form H=H_0+V, where H_0 is a Hamiltonian for which the
associated Green's function is known and V is a delta-function potential. We
apply this result to the case in which H_0 is the Hamiltonian of a free
particle in D dimensions. Field theoretic concepts such as regularization,
renormalization, dimensional transmutation and triviality are introduced
naturally in order to deal with an infinity which shows up in the formal
expression of the Green's function for D>1.
| [
{
"version": "v1",
"created": "Thu, 15 Jan 1998 22:50:29 GMT"
},
{
"version": "v2",
"created": "Mon, 27 Mar 2000 19:21:15 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Cavalcanti",
"R. M.",
""
]
] |
quant-ph/9801034 | Jonathan Oppenheim | J. Oppenheim, B. Reznik, W.G. Unruh | Minimum Inaccuracy for Traversal-Time | Discussion on dwell time added, qualitative proof added, minor
modifications | null | null | LA-UR-974752 | quant-ph gr-qc | null | Using various model clocks it has been shown that the time-of-arrival cannot
be measured more accurately than 1/E where E is the kinetic energy of a free
particle. However, this result has never been proved. In this paper, we show
that a violation of the above limitation for the transit-time, implies a
violation of the Heisenberg uncertainty relation.
| [
{
"version": "v1",
"created": "Fri, 16 Jan 1998 03:48:18 GMT"
},
{
"version": "v2",
"created": "Thu, 21 May 1998 23:49:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Oppenheim",
"J.",
""
],
[
"Reznik",
"B.",
""
],
[
"Unruh",
"W. G.",
""
]
] |
quant-ph/9801035 | Ralf Schuetzhold | Ralf Sch\"utzhold, Guenter Plunien and Gerhard Soff | Quantum radiation in external background fields | 20 pages | Phys.Rev. A58 (1998) 1783 | 10.1103/PhysRevA.58.1783 | null | quant-ph | null | A canonical formalism is presented which allows for investigations of quantum
radiation induced by localized, smooth disturbances of classical background
fields by means of a perturbation theory approach. For massless,
non-selfinteracting quantum fields at zero temperature we demonstrate that the
low-energy part of the spectrum of created particles exhibits a non-thermal
character. Applied to QED in varying dielectrics the response theory approach
facilitates to study two distinct processes contributing to the production of
photons: the squeezing effect due to space-time varying properties of the
medium and of the velocity effect due to its motion. The generalization of this
approach to finite temperatures as well as the relation to sonoluminescence is
indicated.
| [
{
"version": "v1",
"created": "Fri, 16 Jan 1998 13:00:37 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Schützhold",
"Ralf",
""
],
[
"Plunien",
"Guenter",
""
],
[
"Soff",
"Gerhard",
""
]
] |
quant-ph/9801036 | Gonzalo Garcia de Polavieja | Fernando M. Maroto | Solving in the quantum computer every classical NP problem in polynomial
time | WITHDRAWN | null | null | null | quant-ph | null | This paper has been withdrawn by the author due to a crucial error in eq.59.
I apologize for the inconveniences.
| [
{
"version": "v1",
"created": "Fri, 16 Jan 1998 13:22:18 GMT"
},
{
"version": "v2",
"created": "Tue, 20 Jan 1998 15:10:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Maroto",
"Fernando M.",
""
]
] |
quant-ph/9801037 | Lieven Vandersypen | Isaac L. Chuang (1), Lieven M.K. Vandersypen (2), Xinlan Zhou (2),
Debbie W. Leung (3) and Seth Lloyd (4) ((1) IBM Almaden Research Center (2)
Solid State Electronics Laboratory, Stanford (3) Ginzton Laboratory, Stanford
(4) MIT Dept. of Mechanical Engineering.) | Experimental realization of a quantum algorithm | 4 pages, 3 figures, mypsfig2, revtex, revised version (no major
changes), published in Nature, 393, 143-146 (1998) | null | 10.1038/30181 | null | quant-ph | null | Nuclear magnetic resonance techniques are used to realize a quantum algorithm
experimentally. The algorithm allows a simple NMR quantum computer to determine
global properties of an unknown function requiring fewer function ``calls''
than is possible using a classical computer.
| [
{
"version": "v1",
"created": "Mon, 19 Jan 1998 08:48:41 GMT"
},
{
"version": "v2",
"created": "Sat, 6 Jun 1998 23:12:41 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Chuang",
"Isaac L.",
""
],
[
"Vandersypen",
"Lieven M. K.",
""
],
[
"Zhou",
"Xinlan",
""
],
[
"Leung",
"Debbie W.",
""
],
[
"Lloyd",
"Seth",
""
]
] |
quant-ph/9801038 | Cristopher Moore | Cristopher Moore (Santa Fe Institute) | Another Way to Perform the Quantum Fourier Transform in Linear Parallel
Time | WITHDRAWN | null | null | null | quant-ph | null | This paper has been withdrawn.
| [
{
"version": "v1",
"created": "Mon, 19 Jan 1998 23:55:15 GMT"
},
{
"version": "v2",
"created": "Tue, 20 Jan 1998 23:46:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Moore",
"Cristopher",
"",
"Santa Fe Institute"
]
] |
quant-ph/9801039 | Hideo Mabuchi | Hideo Mabuchi | Standard Quantum Limits for broadband position measurement | Replaced version: changed title, fixed algebra error at the very end,
conclusions modified accordingly. Four pages, one eps figure | null | 10.1103/PhysRevA.58.123 | null | quant-ph math-ph math.MP | null | I utilize the Caves-Milburn model for continuous position measurements to
formulate a broadband version of the Standard Quantum Limit (SQL) for
monitoring the position of a free mass, and illustrate the use of Kalman
filtering to recover the SQL for estimating a weak classical force that acts on
a quantum-mechanical test particle under continuous observation. These
derivations are intended to clarify the interpretation of SQL's in the context
of continuous quantum measurement.
| [
{
"version": "v1",
"created": "Tue, 20 Jan 1998 03:42:02 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Jan 1998 17:51:18 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Jan 1998 18:13:21 GMT"
}
] | 2012-01-20T00:00:00 | [
[
"Mabuchi",
"Hideo",
""
]
] |
quant-ph/9801040 | Dieter Maison | S.Schlieder | Remarks concerning an Entropy-like Quantity $S_q$ especially for Quantum
Systems with a Particle Picture; Model with pure Point Spectra | 17 pages | Nuovo Cim. B114 (1999) 1225-1238 | null | MPI-PhT/97-83 | quant-ph | null | For quantum mechanical systems an entropy-like quantity $S_q$ is defined.
$S_q$ can differ from the usually defined entropy $S$ and $S_q$ may increase
with time for an isolated system. The essential condition for the difference
between $S$ and $S_q$ is the assumption that the set {\bf A} of observables
which can be represented by a measurement is a proper subset of the set of
selfadjoint operators. The underlying idea is made visible in the case of
particle systems with non-trivial scattering. The model-character of the
reasoning comes from the fact that continuous spectra are replaced by
point-spectra. So it seems evident, that no direct connection exists between
$S_q$ and the Sinai-Kolmogorov-Entropy at least in this model with pure
point-spectra.
| [
{
"version": "v1",
"created": "Tue, 20 Jan 1998 11:07:41 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Schlieder",
"S.",
""
]
] |
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