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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
quant-ph/9902035 | Jan M. Rost | John S Briggs and Jan M Rost | Time Dependence in Quantum Mechanics | 7 pages, no figures | null | 10.1007/s100530050554 | null | quant-ph | null | It is shown that the time-dependent equations (Schr\"odinger and Dirac) for a
quantum system can be always derived from the time-independent equation for the
larger object of the system interacting with its environment, in the limit that
the dynamical variables of the environment can be treated semiclassically. The
time which describes the quantum evolution is then provided parametrically by
the classical evolution of the environment variables. The method used is a
generalization of that known for a long time in the field of ion-atom
collisions, where it appears as a transition from the full quantum mechanical
{\it perturbed stationary states} to the {impact parameter} method in which the
projectile ion beam is treated classically.
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 17:43:43 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Briggs",
"John S",
""
],
[
"Rost",
"Jan M",
""
]
] |
quant-ph/9902036 | Julia Kempe | Julia Kempe | Multi-particle entanglement and its applications to cryptography | 7 pages, REVTEX, no figures, minor changes and corrections, accepted
for publication in Phys. Rev. A | Phys.Rev.A60:910-916,1999 | 10.1103/PhysRevA.60.910 | null | quant-ph | null | Entanglement between three or more parties exhibits a realm of properties
unknown to two-party states. Bipartite states are easily classified using the
Schmidt decomposition. The Schmidt coefficients of a bipartite pure state
encompass all the non-local properties of the state and can be "seen" by
looking at one party's density matrix only.
Pure states of three and more parties however lack such a simple form. They
have more invariants under local unitary transformations than any one party can
"see" on their sub-system. These "hidden non-localities" will allow us to
exhibit a class of multipartite states that cannot be distinguished from each
other by any party. Generalizing a result of BPRST and using a recent result by
Nielsen we will show that these states cannot be transformed into each other by
local actions and classical communication. Furthermore we will use an
orthogonal subset of such states to hint at applications to cryptography and
illustrate an extension to quantum secret sharing (using recently suggested
((n,k))-threshold schemes).
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 19:37:42 GMT"
},
{
"version": "v2",
"created": "Mon, 3 May 1999 23:56:53 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Kempe",
"Julia",
""
]
] |
quant-ph/9902037 | Xiaodong Chen | Xiaodong Chen | A New Interpretation of Quantum Theory -- Time as Hidden Variable | 4 pages revtex, 1 figure. [email protected] | null | null | null | quant-ph | null | Using 2 more time variables as the quantum hidden variables, we derive the
equation of Dirac field under the principle of classical physics, then we
extend our method into the quantum fields with arbitrary spin number. The spin
of particle is shown naturally as the topological property of 3-dimensional
time + 3-dimensional space . One will find that the quantum physics of single
particle can be interpreted as the behavior of the single particle in 3+3
time-space .
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 20:36:53 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Feb 1999 17:56:06 GMT"
},
{
"version": "v3",
"created": "Thu, 11 Feb 1999 23:47:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Chen",
"Xiaodong",
""
]
] |
quant-ph/9902038 | Subhash Kak | Subhash Kak | Quantum Key Distribution Using Three Basis States | 6 pages | Pramana 54:709-713,2000 | null | null | quant-ph | null | This note presents a method of public key distribution using quantum
communication of n photons that simultaneously provides a high probability that
the bits have not been tampered. It is a three-state variant of the quantum
method of Bennett and Brassard (BB84) where the transmission states have been
decreased from 4 to 3 and the detector states have been increased from 2 to 3.
Under certain assumptions regarding method of attack, it provides superior
performance (in terms of the number of usable key bits) for n < 18 m, where m
is the number of key bits used to verify the integrity of the process in the
BB84-protocol.
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 21:28:04 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Feb 1999 02:41:12 GMT"
},
{
"version": "v3",
"created": "Tue, 6 Jun 2000 21:09:26 GMT"
}
] | 2009-06-19T00:00:00 | [
[
"Kak",
"Subhash",
""
]
] |
quant-ph/9902039 | Tim Newman | Will Loinaz and T. J. Newman | Quantum revivals and carpets in some exactly solvable systems | 5 pages, 5 figures (1 new), minor additions, to appear in J. Phys. A | J.Phys.A32:8889-8895,1999 | 10.1088/0305-4470/32/50/309 | IPPAP-9901 | quant-ph | null | We consider the revival properties of quantum systems with an eigenspectrum
E_{n} proportional to n^{2}, and compare them with the simplest member of this
class - the infinite square well. In addition to having perfect revivals at
integer multiples of the revival time t_{R}, these systems all enjoy perfect
fractional revivals at quarterly intervals of t_{R}. A closer examination of
the quantum evolution is performed for the Poeschel-Teller and Rosen-Morse
potentials, and comparison is made with the infinite square well using quantum
carpets.
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 22:04:30 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Nov 1999 20:48:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Loinaz",
"Will",
""
],
[
"Newman",
"T. J.",
""
]
] |
quant-ph/9902040 | Kurt Jacobs | K. Jacobs, I. Tittonen, H. M. Wiseman and S. Schiller | Quantum noise in the position measurement of a cavity mirror undergoing
Brownian motion | 12 pages revtex, 2 figures | Phys.Rev. A60 (1999) 538 | 10.1103/PhysRevA.60.538 | null | quant-ph | null | We perform a quantum theoretical calculation of the noise power spectrum for
a phase measurement of the light output from a coherently driven optical cavity
with a freely moving rear mirror. We examine how the noise resulting from the
quantum back action appears among the various contributions from other noise
sources. We do not assume an ideal (homodyne) phase measurement, but rather
consider phase modulation detection, which we show has a different shot noise
level. We also take into account the effects of thermal damping of the mirror,
losses within the cavity, and classical laser noise. We relate our theoretical
results to experimental parameters, so as to make direct comparisons with
current experiments simple. We also show that in this situation, the standard
Brownian motion master equation is inadequate for describing the thermal
damping of the mirror, as it produces a spurious term in the steady-state phase
fluctuation spectrum. The corrected Brownian motion master equation [L. Diosi,
Europhys. Lett. {\bf 22}, 1 (1993)] rectifies this inadequacy.
| [
{
"version": "v1",
"created": "Wed, 10 Feb 1999 00:02:58 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jacobs",
"K.",
""
],
[
"Tittonen",
"I.",
""
],
[
"Wiseman",
"H. M.",
""
],
[
"Schiller",
"S.",
""
]
] |
quant-ph/9902041 | Dave Bacon | D. Bacon, D. A. Lidar, K. B. Whaley | Robustness of Decoherence-Free Subspaces for Quantum Computation | 16 pages, no figures. Several changes, including a clarification of
the derivation of the Lindblad equation from the operator sum representation.
To appear in Phys. Rev A | Phys.Rev. A60 (1999) 1944 | 10.1103/PhysRevA.60.1944 | null | quant-ph | null | It was shown recently [D.A. Lidar et al., Phys. Rev. Lett. 81, 2594 (1998)]
that within the framework of the semigroup Markovian master equation,
decoherence-free (DF) subspaces exist which are stable to first order in time
to a perturbation. Here this result is extended to the non-Markovian regime and
generalized. In particular, it is shown that within both the semigroup and the
non-Markovian operator sum representation, DF subspaces are stable to all
orders in time to a symmetry-breaking perturbation. DF subspaces are thus ideal
for quantum memory applications. For quantum computation, however, the
stability result does not extend beyond the first order. Thus, to perform
robust quantum computation in DF subspaces, they must be supplemented with
quantum error correcting codes.
| [
{
"version": "v1",
"created": "Wed, 10 Feb 1999 00:49:00 GMT"
},
{
"version": "v2",
"created": "Tue, 15 Jun 1999 02:22:50 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bacon",
"D.",
""
],
[
"Lidar",
"D. A.",
""
],
[
"Whaley",
"K. B.",
""
]
] |
quant-ph/9902042 | Svozil Karl | Karl Svozil | Quantum logic. A brief outline | 31 pages. First presented in 1997 in Karlovassi, Samos and Brno,
Czech Republic. Revised version presented at the 4th International Summer
School on Philosophy, Probability and Physics at the University of Konstanz,
Germany, 7-13 August 2005 | null | null | null | quant-ph math-ph math.LO math.MP | null | Quantum logic has been introduced by Birkhoff and von Neumann as an attempt
to base the logical primitives, the propositions and the relations and
operations among them, on quantum theoretical entities, and thus on the related
empirical evidence of the quantum world. We give a brief outline of quantum
logic, and some of its algebraic properties, such as nondistributivity, whereby
emphasis is given to concrete experimental setups related to quantum logical
entities. A probability theory based on quantum logic is fundamentally and
sometimes even spectacularly different from probabilities based on classical
Boolean logic. We give a brief outline of its nonclassical aspects; in
particular violations of Boole-Bell type consistency constraints on joint
probabilities, as well as the Kochen-Specker theorem, demonstrating in a
constructive, finite way the scarcity and even nonexistence of two-valued
states interpretable as classical truth assignments. A more complete
introduction of the author can be found in the book "Quantum Logic" (Springer,
1998)
| [
{
"version": "v1",
"created": "Wed, 10 Feb 1999 09:22:01 GMT"
},
{
"version": "v2",
"created": "Sun, 31 Jul 2005 21:21:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Svozil",
"Karl",
""
]
] |
quant-ph/9902043 | Ting Yu | Ting Yu, Lajos Di\'osi, Nicolas Gisin and Walter T. Strunz | Non-Markovian quantum state diffusion: Perturbation approach | 23 pages, 4 figures | Phys.Rev. A60 (1999) 91-103 | 10.1103/PhysRevA.60.91 | null | quant-ph | null | We present a perturbation theory for non-Markovian quantum state diffusion
(QSD), the theory of diffusive quantum trajectories for open systems in a
bosonic environment [Physical Review {\bf A 58}, 1699, (1998)]. We establish a
systematic expansion in the ratio between the environmental correlation time
and the typical system time scale. The leading order recovers the Markov
theory, so here we concentrate on the next-order correction corresponding to
first-order non-Markovian master equations. These perturbative equations
greatly simplify the general non-Markovian QSD approach, and allow for
efficient numerical simulations beyond the Markov approximation. Furthermore,
we show that each perturbative scheme for QSD naturally gives rise to a
perturbative scheme for the master equation which we study in some detail.
Analytical and numerical examples are presented, including the quantum Brownian
motion model.
| [
{
"version": "v1",
"created": "Wed, 10 Feb 1999 12:30:50 GMT"
}
] | 2016-08-15T00:00:00 | [
[
"Yu",
"Ting",
""
],
[
"Diósi",
"Lajos",
""
],
[
"Gisin",
"Nicolas",
""
],
[
"Strunz",
"Walter T.",
""
]
] |
quant-ph/9902044 | Piotr Kochanski | Piotr Kochanski, Krzysztof Wodkiewicz | Operational Time of Arrival in Quantum Phase Space | 23 pages, 5 figures, to appear in Phys. Rev. A | null | 10.1103/PhysRevA.61.029901 | null | quant-ph | null | An operational time of arrival is introduced using a realistic position and
momentum measurement scheme. The phase space measurement involves the dynamics
of a quantum particle probed by a measuring device. For such a measurement an
operational positive operator valued measure in phase space is introduced and
investigated. In such an operational formalism a quantum mechanical time
operator is constructed and analyzed. A phase space time and energy uncertainty
relation is derived.
| [
{
"version": "v1",
"created": "Wed, 10 Feb 1999 11:35:00 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kochanski",
"Piotr",
""
],
[
"Wodkiewicz",
"Krzysztof",
""
]
] |
quant-ph/9902045 | Hoi-Kwong Lo | Hoi-Kwong Lo (Hewlett-Packard Labs, Bristol), Sandu Popescu (Isaac
Newton Institute, Cambridge and BRIMS, Hewlett-Packard Labs, Bristol) | The classical communication cost of entanglement manipulation: Is
entanglement an inter-convertible resource? | 8 pages, RevTex, Accepted for Publication in Physical Review Letters | null | 10.1103/PhysRevLett.83.1459 | null | quant-ph | null | Entanglement bits or ``ebits'' have been proposed as a quantitative measure
of a fundamental resource in quantum information processing. For such an
interpretation to be valid, it is important to show that the same number of
ebits in different forms or concentrations are inter-convertible in the
asymptotic limit. Here we draw attention to a very important but hitherto
unnoticed aspect of entanglement manipulation --- the classical communication
cost. We construct an explicit procedure which demonstrates that for bi-partite
pure states, in the asymptotic limit, entanglement can be concentrated or
diluted with vanishing classical communication cost. Entanglement of bi-partite
pure states is thus established as a truly inter-convertible resource.
| [
{
"version": "v1",
"created": "Wed, 10 Feb 1999 18:05:43 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Jul 1999 12:42:30 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lo",
"Hoi-Kwong",
"",
"Hewlett-Packard Labs, Bristol"
],
[
"Popescu",
"Sandu",
"",
"Isaac\n Newton Institute, Cambridge and BRIMS, Hewlett-Packard Labs, Bristol"
]
] |
quant-ph/9902046 | Philip Pearle | Philip Pearle | Relativistic Collapse Model With Tachyonic Features | 25 pages, 5 figures | Phys.Rev. A59 (1999) 80-101 | 10.1103/PhysRevA.59.80 | null | quant-ph | null | A finite relativistic model for free particles, which describes the collapse
of the statevector, is presented.
| [
{
"version": "v1",
"created": "Wed, 10 Feb 1999 20:35:51 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Pearle",
"Philip",
""
]
] |
quant-ph/9902047 | Sang Pyo Kim | Jung Kon Kim, Sang Pyo Kim, Kwang-Gi Park | One-Parameter Gaussian State of Anharmonic Oscillator: Nonlinear
Realization of Bogoliubov Transformation | 8 pages, RevTex, no figures | J.Korean Phys.Soc. 34 (1999) 473-476 | null | null | quant-ph | null | We find a one-parameter Gaussian state for an anharmonic oscillator with
quadratic and quartic terms, which depends on the energy expectation value. For
the weak coupling constant, the Gaussian state is a squeezed state of the
vacuum state. However, for the strong coupling constant, the Gaussian state
represents a different kind of condensation of bosonic particles through a
nonlinear Bogoliubov transformation of the vacuum state.
| [
{
"version": "v1",
"created": "Thu, 11 Feb 1999 06:37:17 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kim",
"Jung Kon",
""
],
[
"Kim",
"Sang Pyo",
""
],
[
"Park",
"Kwang-Gi",
""
]
] |
quant-ph/9902048 | Nicolas Gisin | N. Gisin and S. Wolf | Quantum cryptography on noisy channels: quantum versus classical
key-agreement protocols | 4 pages + 1 figure | Phys.Rev.Lett.83:4200-4203,1999 | 10.1103/PhysRevLett.83.4200 | null | quant-ph | null | When the 4-state or the 6-state protocol of quantum cryptography is carried
out on a noisy (i.e. realistic) quantum channel, then the raw key has to be
processed to reduce the information of an adversary Eve down to an arbitrarily
low value, providing Alice and Bob with a secret key. In principle, quantum
algorithms as well as classical algorithms can be used for this processing. A
natural question is: up to which error rate on the raw key is a secret-key
agreement at all possible? Under the assumption of incoherent eavesdropping, we
find that the quantum and classical limits are precisely the same: as long as
Alice and Bob share some entanglement both quantum and classical protocols
provide secret keys.
| [
{
"version": "v1",
"created": "Thu, 11 Feb 1999 17:25:18 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Gisin",
"N.",
""
],
[
"Wolf",
"S.",
""
]
] |
quant-ph/9902049 | Christof Zalka | Christof Zalka (T-6 LANL) | A Grover-based quantum search of optimal order for an unknown number of
marked elements | 7 pages, Latex, 2 figures | null | null | null | quant-ph | null | We want to find a marked element out of a black box containing N elements.
When the number of marked elements is known this can be done elegantly with
Grover's algorithm, a variant of which even gives a correct result with
certainty. On the other hand, when the number of marked elements is not known
the problem becomes more difficult. For every prescribed success probability I
give an algorithm consisting of several runs of Grover's algorithm that matches
a recent bound by Buhrman and de Wolf on the order of the number of queries to
the black box. The improvement in the order over a previously known algorithm
is small and the number of queries can clearly still be reduced by a constant
factor.
| [
{
"version": "v1",
"created": "Fri, 12 Feb 1999 23:46:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Zalka",
"Christof",
"",
"T-6 LANL"
]
] |
quant-ph/9902050 | Karol Zyczkowski | Karol Zyczkowski (Jagiellonian University, Cracow) | On the volume of the set of mixed entangled states II | 14 pages in Latex, Revtex + epsf; 7 figures in .ps included (one new
figure in the revised version, several minor changes) | Phys.Rev. A60 (1999) 3496 | 10.1103/PhysRevA.60.3496 | null | quant-ph | null | The problem of of how many entangled or, respectively, separable states there
are in the set of all quantum states is investigated. We study to what extent
the choice of a measure in the space of density matrices describing
N--dimensional quantum systems affects the results obtained. We demonstrate
that the link between the purity of the mixed states and the probability of
entanglement is not sensitive to the measure chosen. Since the criterion of
partial transposition is not sufficient to distinguish all separable states for
N > 6, we develop an efficient algorithm to calculate numerically the
entanglement of formation of a given mixed quantum state, which allows us to
compute the volume of separable states for N=8 and to estimate the volume of
the bound entangled states in this case.
| [
{
"version": "v1",
"created": "Fri, 12 Feb 1999 13:17:37 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Jun 1999 15:04:08 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Zyczkowski",
"Karol",
"",
"Jagiellonian University, Cracow"
]
] |
quant-ph/9902051 | Hagen Kleinert | Hagen Kleinert, Axel Pelster, and Michael Bachmann | Generating Functionals for Harmonic Expectation Values of Paths with
Fixed End Points. Feynman Diagrams for Nonpolynomial Interactions | Author Information under
http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of
paper also at http://www.physik.fu-berlin.de/~kleinert/281 | Phys.Rev. E60 (1999) 2510 | 10.1103/PhysRevE.60.2510 | null | quant-ph | null | We introduce a general class of generating functionals for the calculation of
quantum-mechanical expectation values of arbitrary functionals of fluctuating
paths with fixed end points in configuration or momentum space. The generating
functionals are calculated explicitly for harmonic oscillators with
time-dependent frequency, and used to derive a smearing formulas for
correlation functions of polynomial and nonpolynomials functions of
time-dependent positions and momenta. These formulas summarize the effect of
thermal and quantum fluctuations, and serve to derive generalized Wick rules
and Feynman diagrams for perturbation expansions of nonpolynomial interactions.
| [
{
"version": "v1",
"created": "Mon, 15 Feb 1999 06:20:38 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kleinert",
"Hagen",
""
],
[
"Pelster",
"Axel",
""
],
[
"Bachmann",
"Michael",
""
]
] |
quant-ph/9902052 | Konstantin Kladko | Konstantin Kladko | Einstein-Podolsky-Rosen paradox and measurement of quantum system | 2 pages, REVTEX, accepted JETP | null | null | null | quant-ph | null | Einstein-Podolsky-Rosen (EPR) paradox is considered in a relation to a
measurement of an arbitrary quantum system . It is shown that the EPR paradox
always appears in a gedanken experiment with two successively joined measuring
devices.
| [
{
"version": "v1",
"created": "Sat, 13 Feb 1999 08:16:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kladko",
"Konstantin",
""
]
] |
quant-ph/9902053 | Andris Ambainis | Andris Ambainis | A better lower bound for quantum algorithms searching an ordered list | 10 pages, LaTeX | null | null | null | quant-ph cs.CC cs.DS | null | We show that any quantum algorithm searching an ordered list of n elements
needs to examine at least 1/12 log n-O(1) of them. Classically, log n queries
are both necessary and sufficient. This shows that quantum algorithms can
achieve only a constant speedup for this problem. Our result improves lower
bounds of Buhrman and de Wolf(quant-ph/9811046) and Farhi, Goldstone, Gutmann
and Sipser (quant-ph/9812057).
| [
{
"version": "v1",
"created": "Sun, 14 Feb 1999 01:20:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ambainis",
"Andris",
""
]
] |
quant-ph/9902054 | S. V. M. Satyanarayana | S. Sivakumar | Generation of even and odd nonlinear coherent states | RevTex file with 3 Postscript figures. Email address:
[email protected] | J.Phys.A33:2289-2297,2000 | 10.1088/0305-4470/33/11/309 | null | quant-ph | null | We show that a class of even and odd nonlinear coherent states, defined as
the eigenstates of product of a nonlinear function of the number operator and
the square of the boson annihilation operator, can be generated in the
center-of-mass motion of a trapped and bichromatically laser-driven ion. The
nonclasscial properties of the states are studied.
| [
{
"version": "v1",
"created": "Mon, 15 Feb 1999 12:46:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sivakumar",
"S.",
""
]
] |
quant-ph/9902055 | Igor Volovich | I.V. Volovich | Models of Quantum Computers and Decoherence Problem | 14 pages, Latex, Invited talk at the International Conference on
Quantum Information, Meijo University, Nagoya, 4-8 Nov.1997, To be published
in Proc. of the Conference | null | null | SMI-2-02-1999 | quant-ph | null | Mathematical models of quantum computers such as a multidimensional quantum
Turing machine and quantum circuits are described and its relations with
lattice spin models are discussed. One of the main open problems one has to
solve if one wants to build a quantum computer is the decoherence due to the
coupling with the environment. We propose a possible solution of this problem
by using a control of parameters of the system. This proposal is based on the
analysis of the spin-boson Hamiltonian performed in the stochastic limit
approximation.
| [
{
"version": "v1",
"created": "Mon, 15 Feb 1999 18:26:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Volovich",
"I. V.",
""
]
] |
quant-ph/9902056 | Adan Cabello | Adan Cabello and Jose L. Cereceda | Nonlocality without inequalities using unambiguous discrimination
between non-orthogonal states | REVTeX, 4 pages, 1 figure | null | null | null | quant-ph | null | This paper has been withdrawn.
| [
{
"version": "v1",
"created": "Mon, 15 Feb 1999 23:12:58 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Aug 1999 22:14:43 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Cabello",
"Adan",
""
],
[
"Cereceda",
"Jose L.",
""
]
] |
quant-ph/9902057 | Alexandr Andrianov | A. Andrianov, F. Cannata, M. Ioffe, D. Nishnianidze | Systems with Higher-Order Shape Invariance: Spectral and Algebraic
Properties | 18 pages, LaTeX, editorial page is removed | Phys.Lett. A266 (2000) 341-349 | 10.1016/S0375-9601(00)00031-1 | null | quant-ph math-ph math.MP nlin.SI solv-int | null | We study a complex intertwining relation of second order for Schroedinger
operators and construct third order symmetry operators for them. A modification
of this approach leads to a higher order shape invariance. We analyze with
particular attention irreducible second order Darboux transformations which
together with the first order act as building blocks. For the third order
shape-invariance irreducible Darboux transformations entail only one sequence
of equidistant levels while for the reducible case the structure consists of up
to three infinite sequences of equidistant levels and, in some cases, singlets
or doublets of isolated levels.
| [
{
"version": "v1",
"created": "Tue, 16 Feb 1999 15:13:29 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Feb 1999 11:20:08 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Andrianov",
"A.",
""
],
[
"Cannata",
"F.",
""
],
[
"Ioffe",
"M.",
""
],
[
"Nishnianidze",
"D.",
""
]
] |
quant-ph/9902058 | O. B. Zaslavskii | V. V. Ulyanov and O.B.Zaslavskii (Department of Physics, Kharkov State
University) | Spin systems, spin coherent states and quasi-exactly solvable models | 7 pages, RevTex 3.0. Talk given at the 22nd International Colloqium
for Group Theoretical Methods in Physics | `Group22: Proceedings of the XXII International Colloquium on
Group Theoretical Methods in Physics', Eds S P Corney, R Delbourgo and P D
Jarvis (Cambridge, MA: International Press) 1998, pp. 213-217 | null | null | quant-ph cond-mat hep-th math-ph math.MP math.RT math.SP | null | Spin coherent states play a crucial role in defining QESM (quasi-exactly
solvable models) establishing a strict correspondence between energy spectra of
spin systems and low-lying quantum states for a particle moving in a potential
field of a certain form. Spin coherent states are also used for finding the
Wigner-Kirkwood expansion and quantum corrections to energy quantization rules.
The closed equation which governs dynamics of a quantum system is obtained in
the spin coherent representation directly for observable quantities.
| [
{
"version": "v1",
"created": "Tue, 16 Feb 1999 16:25:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ulyanov",
"V. V.",
"",
"Department of Physics, Kharkov State\n University"
],
[
"Zaslavskii",
"O. B.",
"",
"Department of Physics, Kharkov State\n University"
]
] |
quant-ph/9902059 | Robert B. Griffiths | Robert B. Griffiths (Carnegie-Mellon) | Bohmian mechanics and consistent histories | Minor revision of earlier version. Latex, 10 pages, 1 figure | Phys.Lett. A261 (1999) 227-234 | 10.1016/S0375-9601(99)00542-3 | null | quant-ph | null | The interpretations of a particular quantum gedanken experiment provided by
Bohmian mechanics and consistent histories are shown to contradict each other,
both in the absence and in the presence of a measuring device. The consistent
history result seems closer to standard quantum mechanics, and shows no
evidence of the mysterious nonlocal influences present in the Bohmian
description.
| [
{
"version": "v1",
"created": "Wed, 17 Feb 1999 14:03:04 GMT"
},
{
"version": "v2",
"created": "Wed, 28 Apr 1999 21:06:29 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Griffiths",
"Robert B.",
"",
"Carnegie-Mellon"
]
] |
quant-ph/9902060 | O. Yaremchuk | O. Yaremchuk | Quantum phenomenology and the Continuum Problem | 4 pages, no figures | null | null | LPI45(1998) | quant-ph math.LO | null | A new approach to quantum mechanics based on independence of the Continuum
Hypothesis is proposed. In one-dimensional case, it is shown that the
properties of the set of intermediate cardinality coincide with quantum
phenomenology.
| [
{
"version": "v1",
"created": "Wed, 17 Feb 1999 15:56:26 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Jan 2000 13:53:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Yaremchuk",
"O.",
""
]
] |
quant-ph/9902061 | Mark S. Byrd | Mark S. Byrd | Geometric Phases for Three State Systems | 13 pages, LaTeX2e | null | null | null | quant-ph | null | The adiabatic geometric phases for general three state systems are discussed.
An explicit parameterization for space of states of these systems is given. The
abelian and non-abelian connection one-forms or vector potentials that would
appear in a three dimensional quantum system with adiabatic characteristics are
given explicitly. This is done in terms of the Euler angle parameterization of
SU(3) which enables a straight-forward calculation of these quantities and its
immediate generalization.
| [
{
"version": "v1",
"created": "Wed, 17 Feb 1999 20:30:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Byrd",
"Mark S.",
""
]
] |
quant-ph/9902062 | Robert R. Tucci | Robert R. Tucci | A Rudimentary Quantum Compiler(2cnd Ed.) | 1 LaTeX file(49 pages), 11 eps files. This paper comprises two of my
previous papers entitled "A Rudimentary Quantum Compiler" and "An
Optimization for Qubiter", plus a substantial amount of new material | null | null | null | quant-ph | null | We present a new algorithm for reducing an arbitrary unitary matrix U into a
sequence of elementary operations (operations such as controlled-nots and qubit
rotations). Such a sequence of operations can be used to manipulate an array of
quantum bits (i.e., a quantum computer). Our algorithm applies recursively a
mathematical technique called the CS Decomposition to build a binary tree of
matrices whose product, in some order, equals the original matrix U. We show
that the Fast Fourier Transform (FFT) algorithm is a special case of our
algorithm. We report on a C++ program called "Qubiter" that implements the
ideas of this paper. Qubiter(PATENT PENDING) source code is publicly available.
| [
{
"version": "v1",
"created": "Thu, 18 Feb 1999 02:00:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Tucci",
"Robert R.",
""
]
] |
quant-ph/9902063 | Serge Massar | R. D. Gill and S. Massar | State estimation for large ensembles | 23 pages, latex | Phys.Rev.A61:042312,2002 | 10.1103/PhysRevA.61.042312 | ULB-TH/99-04 | quant-ph | null | We consider the problem of estimating the state of a large but finite number
$N$ of identical quantum systems. In the limit of large $N$ the problem
simplifies. In particular the only relevant measure of the quality of the
estimation is the mean quadratic error matrix. Here we present a bound on the
mean quadratic error which is a new quantum version of the Cram\'er-Rao
inequality. This new bound expresses in a succinct way how in the quantum case
one can trade information about one parameter for information about another
parameter. The bound holds for arbitrary measurements on pure states, but only
for separable measurements on mixed states--a striking example of non-locality
without entanglement for mixed but not for pure states. Cram\'er-Rao bounds are
generally derived under the assumption that the estimator is unbiased. We also
prove that under additional regularity conditions our bound also holds for
biased estimators. Finally we prove that when the unknown states belong to a 2
dimensional Hilbert space our quantum Cram\'er-Rao bound can always be attained
and we provide an explicit measurement strategy that attains our bound. This
therefore provides a complete solution to the problem of estimating as
efficiently as possible the unknown state of a large ensemble of qubits in the
same pure state. For qubits in the same mixed state, this also provides an
optimal estimation strategy if one only considers separable measurements.
| [
{
"version": "v1",
"created": "Thu, 18 Feb 1999 14:46:39 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Oct 1999 08:55:07 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Gill",
"R. D.",
""
],
[
"Massar",
"S.",
""
]
] |
quant-ph/9902064 | Abdullah Vercin | A. Vercin | Formulation of the Classical Mechanics in the Ring of Operators | 14 Pages | null | null | FGE-99-1 | quant-ph | null | By making use of the Weyl-Wigner-Groenewold-Moyal association rules, a
commutative product and a new quantum bracket are constructed in the ring of
operators \cal{F}(H). In this way, an isomorphism between Lie algebra of
classical observables (with Poisson bracket) and the Lie algebra of quantum
observables with this new bracket is established. By these observations, a
formulation of the classical mechanics in \cal{F}(H} is obtained and is shown
to be \hbar\to 0 limit of the Heisenberg picture formulation of the quantum
mechanics.
| [
{
"version": "v1",
"created": "Thu, 18 Feb 1999 15:47:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Vercin",
"A.",
""
]
] |
quant-ph/9902065 | Serguei Krasnikov | Roman B. Breslav and Roman R. Zapatrin | Differential structure of Greechie logics | 11 pages, latex | Int.J.Theor.Phys. 39 (2000) 1027-1035 | null | null | quant-ph math-ph math.MP | null | A liaison between quantum logics and non-commutative differential geometry is
outlined: a class of quantum logics are proved to possess the structure of
discrete differential manifolds. We show that the set of proper elements of an
arbitrary atomic Greechie logic is naturally endowed by Koszul's differential
calculus.
| [
{
"version": "v1",
"created": "Fri, 19 Feb 1999 15:26:04 GMT"
},
{
"version": "v2",
"created": "Sun, 28 Feb 1999 16:01:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Breslav",
"Roman B.",
""
],
[
"Zapatrin",
"Roman R.",
""
]
] |
quant-ph/9902066 | Bimalendu Deb | Bimalendu Deb and Gershon Kurizki | Formation of Giant Quasibound Cold Diatoms by Strong Atom-Cavity
Coupling | 4 pages, 3 figures | Phys.Rev.Lett.83:714-717,1999 | 10.1103/PhysRevLett.83.714 | null | quant-ph | null | We show that giant quasi-bound diatomic complexes, whose size is typically
hundreds of nm, can be formed by intra-cavity cold diatom photoassociation or
photodissociation in the strong atom-cavity coupling regime.
| [
{
"version": "v1",
"created": "Fri, 19 Feb 1999 18:45:43 GMT"
},
{
"version": "v2",
"created": "Sun, 21 Feb 1999 16:17:13 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Deb",
"Bimalendu",
""
],
[
"Kurizki",
"Gershon",
""
]
] |
quant-ph/9902067 | Bozhidar Zakhariev Iliev | Bozhidar Z. Iliev (Institute for Nuclear Research and Nuclear Energy,
Bulgarian Academy of Sciences, Sofia, Bulgaria) | Comments on: "Quantum mechanics as a gauge theory of metaplectic spinor
fields" by M. Reuter [Int.J.Mod.Phys. A13 (1998), 3835-3884; hep-th/9804036] | 11 standard (11pt, A4) LaTeX 2e pages. The packages AMS-LaTeX and
amsfonts are required. For related papers, view
http://www.inrne.bas.bg/mathmod/bozhome/ | Int. J. Mod. Phys. A14, No.26 (1999) 4153-4160 | 10.1142/S0217751X99001949 | null | quant-ph hep-th | null | We point out how some mathematically incorrect passages in the paper of M.
Reuter can be formulated in a rigorous way. The fibre bundle approach to
quantum mechanics developed in quant-ph/9803083, quant-ph/9803084,
quant-ph/9804062, quant-ph/9806046, quant-ph/9901039, and quant-ph/9902068 is
compared with the one contained in loc. cit.
| [
{
"version": "v1",
"created": "Sat, 20 Feb 1999 10:24:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Iliev",
"Bozhidar Z.",
"",
"Institute for Nuclear Research and Nuclear Energy,\n Bulgarian Academy of Sciences, Sofia, Bulgaria"
]
] |
quant-ph/9902068 | Bozhidar Zakhariev Iliev | Bozhidar Z. Iliev (Institute for Nuclear Research and Nuclear Energy,
Bulgarian Academy of Sciences, Sofia, Bulgaria) | Fibre bundle formulation of nonrelativistic quantum mechanics. V.
Theory's interpretation, summary and discussion | 17 standard (11pt, A4) LaTeX 2e pages. The packages AMS-LaTeX and
amsfonts are required. Concluding part of the series of works
quant-ph/9803083, quant-ph/9803084, quant-ph/9804062, quant-ph/9806046, and
quant-ph/9901039. For related papers, view
http://www.inrne.bas.bg/mathmod/bozhome/ | Int.J.Mod.Phys. A17 (2002) 245-258 | 10.1142/S0217751X02005712 | null | quant-ph hep-th | null | We propose a new systematic fibre bundle formulation of nonrelativistic
quantum mechanics. The new form of the theory is equivalent to the usual one
but it is in harmony with the modern trends in theoretical physics and
potentially admits new generalizations in different directions. In it a pure
state of some quantum system is described by a state section (along paths) of a
(Hilbert) fibre bundle. It's evolution is determined through the bundle
(analogue of the) Schr\"odinger equation. Now the dynamical variables and the
density operator are described via bundle morphisms (along paths). The
mentioned quantities are connected by a number of relations derived in this
work.
This is the fifth closing part of our investigation. We briefly discuss the
observer's role in the theory and different realizations of the space-time
model used as a base space in the bundle approach to quantum mechanics. We
point the exact conditions for the equivalence of Hilbert bundle and Hilbert
space formulations of the theory. A comparison table between the both
description of nonrelativistic quantum mechanics is presented. We discuss some
principal moments of the Hilbert bundle description and show that it is more
general than the Hilbert space one. Different directions for further research
are pointed too.
| [
{
"version": "v1",
"created": "Sat, 20 Feb 1999 11:40:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Iliev",
"Bozhidar Z.",
"",
"Institute for Nuclear Research and Nuclear Energy,\n Bulgarian Academy of Sciences, Sofia, Bulgaria"
]
] |
quant-ph/9902069 | null | Lajos Diosi, Nicolas Gisin, Walter T. Strunz | Royal Road to Coupling Classical and Quantum Dynamics | 4 pages, RevTeX | Phys.Rev. A61 (2000) 22108 | 10.1103/PhysRevA.61.022108 | null | quant-ph gr-qc | null | We present a consistent framework of coupled classical and quantum dynamics.
Our result allows us to overcome severe limitations of previous
phenomenological approaches, like evolutions that do not preserve the
positivity of quantum states or that allow to activate quantum nonlocality for
superluminal signaling. A `hybrid' quantum-classical density is introduced and
its evolution equation derived. The implications and applications of our result
are numerous: it incorporates the back-reaction of quantum on classical
variables, it resolves fundamental problems encountered in standard mean field
theories, and remarkably, also the quantum measurement process, i.e. the most
controversial example of quantum-classical interaction is consistently
described within our approach, leading to a theory of dynamical collapse.
| [
{
"version": "v1",
"created": "Mon, 22 Feb 1999 22:09:51 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Sep 1999 13:24:36 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Diosi",
"Lajos",
""
],
[
"Gisin",
"Nicolas",
""
],
[
"Strunz",
"Walter T.",
""
]
] |
quant-ph/9902070 | Anatoly Zhiliba | V. N. Gorbachev and A. I. Zhiliba(1) (Dep. of Physics, University of
Sankt-Petersburg, (1) Department of Physics, Tver State University) | Statistics of the single mode light in the transparent medium with cubic
nonlinearity | LaTeX file(18 pages), documentclass{article} | null | null | University of Tver preprint TvSU-Phys-97-01 | quant-ph | null | The quantum statistics of the light in the transparent medium with cubic
nonlinearity is considered. Two types of transparent media are treated, namely,
the cold transparent medium with a ground working level and the inversion-free
medium with the lasing levels of the same population. The spectra of light
fluctuation are found on the basis of both Scully-Lamb and Haken theories. The
conditions for the use of effective Hamiltonian are determined. Basing on the
exact solution of the Fokker-Plank equation for the Glauber-Sudarshan
P-function the inversion-free medium with cubic nonlinearity is shown to be the
source of spontaneous radiation with non-Gaussian statistics.
| [
{
"version": "v1",
"created": "Tue, 23 Feb 1999 13:50:58 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gorbachev",
"V. N.",
""
],
[
"Zhiliba",
"A. I.",
""
]
] |
quant-ph/9902071 | David Vitali | M. Fortunato, J.M. Raimond, P. Tombesi, and D. Vitali | Autofeedback scheme for preservation of macroscopic coherence in
microwave cavities | revtex, 15 pages, 4 eps figures | Phys. Rev. A 60, 1687 (1999) | 10.1103/PhysRevA.60.1687 | null | quant-ph | null | We present a scheme for controlling the decoherence of a linear superposition
of two coherent states with opposite phases in a high-Q microwave cavity, based
on the injection of appropriately prepared ``probe'' and ``feedback'' Rydberg
atoms, improving the one presented in [D. Vitali et al., Phys. Rev. Lett. 79,
2442 (1997)]. In the present scheme, the information transmission from the
probe to the feedback atom is directly mediated by a second auxiliary cavity.
The detection efficiency for the probe atom is no longer a critical parameter,
and the decoherence time of the superposition state can be significantly
increased using presently available technology.
| [
{
"version": "v1",
"created": "Tue, 23 Feb 1999 13:50:22 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Aug 1999 11:41:45 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Fortunato",
"M.",
""
],
[
"Raimond",
"J. M.",
""
],
[
"Tombesi",
"P.",
""
],
[
"Vitali",
"D.",
""
]
] |
quant-ph/9902072 | Uday Sukhatme | Uday Sukhatme and Avinash Khare | Comment on "Self-Isospectral Periodic Potentials and Supersymmetric
Quantum Mechanics" | null | null | null | null | quant-ph cond-mat hep-th | null | We show that the formalism of supersymmetric quantum mechanics applied to the
solvable elliptic function potentials $V(x) = mj(j+1){sn}^2(x,m)$ produces new
exactly solvable one-dimensional periodic potentials.
| [
{
"version": "v1",
"created": "Tue, 23 Feb 1999 22:36:03 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sukhatme",
"Uday",
""
],
[
"Khare",
"Avinash",
""
]
] |
quant-ph/9902073 | Dipankar Home | Somshubhro Bandyopadhyay and Guruprasad Kar | Broadcasting of entanglement and universal quantum cloners | 8 pages, Latex,final version, to appear in Physical Review A | Phys.Rev. A60 (1999) 3296 | 10.1103/PhysRevA.60.3296 | null | quant-ph | null | We study broadcasting of entanglement where we use universal quantum cloners
(in general less optimal) to perform local cloning operations. We show that
there is a lower bound on the fidelity of the universal quantum cloners that
can be used for broadcasting. We prove that an entanglement is optimally
broadcast only when optimal quantum cloners are used for local copying. We also
show that broadcasting of entanglement into more than two entangled pairs is
forbidden using only local operations.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 09:39:49 GMT"
},
{
"version": "v2",
"created": "Thu, 25 Feb 1999 05:33:49 GMT"
},
{
"version": "v3",
"created": "Wed, 2 Jun 1999 09:21:21 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bandyopadhyay",
"Somshubhro",
""
],
[
"Kar",
"Guruprasad",
""
]
] |
quant-ph/9902074 | Wolfgang Schweiger | H. Mitter and D. Robaschik | Thermodynamics of the Casimir effect | 12 pages, 3 EPS-figures | Eur.Phys.J.B13:335-340,2000 | 10.1007/s100510050039 | null | quant-ph | null | A complete thermodynamic treatment of the Casimir effect is presented.
Explicit expressions for the free and the internal energy, the entropy and the
pressure are discussed. As an example we consider the Casimir effect with
different temperatures between the plates ($T$) resp. outside of them ($T'$).
For $T'<T$ the pressure of heat radiation can eventually compensate the Casimir
force and the total pressure can vanish. We consider both an isothermal and an
adiabatic treatment of the interior region. The equilibrium point (vanishing
pressure) turns out instable in the isothermal case. In the adiabatic situation
we have both an instable and a stable equilibrium point, if $T'/T$ is
sufficiently small. Quantitative aspects are briefly discussed.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 09:57:05 GMT"
}
] | 2011-10-11T00:00:00 | [
[
"Mitter",
"H.",
""
],
[
"Robaschik",
"D.",
""
]
] |
quant-ph/9902075 | null | Vladimir Man'ko, Marcos Moshinsky, Anju Sharma | Diffraction in time in terms of Wigner distributions and tomographic
probabilities | latex,16 pages,accepted by Phys.Rev.A | null | 10.1103/PhysRevA.59.1809 | null | quant-ph | null | Long ago appeared a discussion in quantum mechanics of the problem of opening
a completely absorbing shutter on which were impinging a stream of particles of
definite velocity. The solution of the problem was obtained in a form entirely
analogous to the optical one of diffraction by a straight edge. The argument of
the Fresnel integrals was though time dependent and thus the first part in the
title of this article. In section 1 we briefly review the original formulation
of the problem of diffraction in time. In section 2 and 3 we reformulate
respectively this problem in Wigner distributions and tomographical
probabilities. In the former case the probability in phase space is very simple
but, as it takes positive and negative values, the interpretation is ambiguous,
but it gives a classical limit that agrees entirely with our intuition. In the
latter case we can start with our initial conditions in a given reference frame
but obtain our final solution in an arbitrary frame of reference.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 11:50:48 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Man'ko",
"Vladimir",
""
],
[
"Moshinsky",
"Marcos",
""
],
[
"Sharma",
"Anju",
""
]
] |
quant-ph/9902076 | Michael Fleischhauer | Michael Fleischhauer | Spontaneous emission and level shifts in absorbing disordered
dielectrics and dense atomic gases: A Green's function approach | 6 pages no figures | null | 10.1103/PhysRevA.60.2534 | null | quant-ph | null | Spontaneous emission and Lamb shift of atoms in absorbing dielectrics are
discussed. A Green's-function approach is used based on the multipolar
interaction Hamiltonian of a collection of atomic dipoles with the quantised
radiation field. The rate of decay and level shifts are determined by the
retarded Green's-function of the interacting electric displacement field, which
is calculated from a Dyson equation describing multiple scattering. The
positions of the atomic dipoles forming the dielectrics are assumed to be
uncorrelated and a continuum approximation is used. The associated unphysical
interactions between different atoms at the same location is eliminated by
removing the point-interaction term from the free-space Green's-function (local
field correction). For the case of an atom in a purely dispersive medium the
spontaneous emission rate is altered by the well-known Lorentz local-field
factor. In the presence of absorption a result different from previously
suggested expressions is found and nearest-neighbour interactions are shown to
be important.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 12:00:37 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Fleischhauer",
"Michael",
""
]
] |
quant-ph/9902077 | David Vitali | Vittorio Giovannetti, Paolo Tombesi, and David Vitali | Non-Markovian quantum feedback from homodyne measurements: the effect of
a non-zero feedback delay time | RevTeX, 18 pages, 5 figures | Phys.Rev. A60 (1999) 1549-1561 | 10.1103/PhysRevA.60.1549 | null | quant-ph | null | We solve exactly the non-Markovian dynamics of a cavity mode in the presence
of a feedback loop based on homodyne measurements, in the case of a non-zero
feedback delay time. With an appropriate choice of the feedback parameters,
this scheme is able to significantly increase the decoherence time of the
cavity mode, even for delay times not much smaller than the decoherence time
itself.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 12:10:05 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Giovannetti",
"Vittorio",
""
],
[
"Tombesi",
"Paolo",
""
],
[
"Vitali",
"David",
""
]
] |
quant-ph/9902078 | Martti Havukainen | M.Havukainen, G.Drobny, S.Stenholm, V.Buzek | Quantum simulations of optical systems | latex2e, 14 figures, to be published in J.Mod.Opt | null | 10.1080/09500349908231339 | HIP-1999-08/TH | quant-ph | null | We show how two level atoms can be used to build microscopic models for
mirrors and beamsplitters. The mirrors can have arbitrary shape allowing closed
cavities to be built. It is possible to build networks or mirrors and
beamsplitters and follow the time-evolution of the intensity of the radiation
through the system.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 13:48:04 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Havukainen",
"M.",
""
],
[
"Drobny",
"G.",
""
],
[
"Stenholm",
"S.",
""
],
[
"Buzek",
"V.",
""
]
] |
quant-ph/9902079 | null | Vladimir I. Man'ko | Conventional Quantum Mechanics Without Wave Function and Density Matrix | Latex, 37 pages, to be published as lectures given at the Latin
American School of Physics, (XXXI ELAF, July-August, 1998, Mexico) in
Casta\~nos, O., Hacyan, S., Lopez-Pe\~na, R., (Eds.), AIP Conference
Proceedings (American Institute of Physics, New York, 1999) | null | 10.1063/1.58229 | null | quant-ph | null | The tomographic invertable map of the Wigner function onto the positive
probability distribution function is studied. Alternatives to the Schr\"odinger
evolution equation and to the energy level equation written for the positive
probability distribution are discussed. Instead of the transition probability
amplitude (Feynman path integral) a transition probability is introduced.
A new formulation of the conventional quantum mechanics (without wave
function and density matrix) based on the ``probability representation'' of
quantum states is given. An equation for the propagator in the new formulation
of quantum mechanics is derived. Some paradoxes of quantum mechanics are
reconsidered.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 15:37:13 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Man'ko",
"Vladimir I.",
""
]
] |
quant-ph/9902080 | Venkatesh V. Kidambi | V. Kidambi, A. Widom, C. Lerner, Y.N. Srivastava | Photon Polarization Measurements without the Quantum Zeno Effect | RevTeX format, 8 pages, 3 figures | null | 10.1119/1.19462 | MQM 3562-11 | quant-ph | null | We consider a photon beam incident on a stack of polarizers as an example of
a von Neumann projective measurement, theoretically leading to the quantum Zeno
effect. The Maxwell theory (which is equivalent to the single photon
Schr\"odinger equation) describes measured polarization phenomena, but without
recourse to the notion of a projective measurement.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 17:50:51 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kidambi",
"V.",
""
],
[
"Widom",
"A.",
""
],
[
"Lerner",
"C.",
""
],
[
"Srivastava",
"Y. N.",
""
]
] |
quant-ph/9902081 | Esposito Giampiero | Shi-Hai Dong, Zhong-Qi Ma and Giampiero Esposito | Exact Solutions of the Schrodinger Equation with Inverse-Power Potential
in Two Dimensions | 11 pages, plain Tex. Sections 1, 2 and 3 have been revised | Found.Phys.Lett. 12 (1999) 465-474 | null | DSF preprint 99/4 | quant-ph | null | The Schrodinger equation for stationary states is studied in a central
potential V(r) proportional to the inverse power of r of degree beta in an
arbitrary number of spatial dimensions. The presence of a single term in the
potential makes it impossible to use previous algorithms, which only work for
quasi-exactly-solvable problems. Nevertheless, the analysis of the stationary
Schrodinger equation in the neighbourhood of the origin and of the point at
infinity is found to provide relevant information about the desired solutions
for all values of the radial coordinate. The original eigenvalue equation is
mapped into a differential equation with milder singularities, and the role
played by the particular case beta=4 is elucidated. In general, whenever the
parameter beta is even and larger than 4, a recursive algorithm for the
evaluation of eigenfunctions is obtained. Eventually, in the particular case of
two spatial dimensions, the exact form of the ground-state wave function is
obtained for a potential containing a finite number of inverse powers of r,
with the associated energy eigenvalue.
| [
{
"version": "v1",
"created": "Wed, 24 Feb 1999 18:12:48 GMT"
},
{
"version": "v2",
"created": "Thu, 10 Jun 1999 15:53:32 GMT"
},
{
"version": "v3",
"created": "Mon, 26 Jul 1999 13:46:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dong",
"Shi-Hai",
""
],
[
"Ma",
"Zhong-Qi",
""
],
[
"Esposito",
"Giampiero",
""
]
] |
quant-ph/9902082 | Mauro Fortunato | Francesco De Martini (1 and 2), Mauro Fortunato (2 and 3), Paolo
Tombesi (2 and 3), and David Vitali (2 and 3) ((1) University of Rome "La
Sapienza", Italy, (2) INFM, (3) University of Camerino, Italy) | Generating entangled superpositions of macroscopically distinguishable
states within a parametric oscillator | RevTeX 17 pages, 9 eps files for 7 figures. Submitted to Physical
Review A | Phys.Rev.A60:1636,1999 | 10.1103/PhysRevA.60.1636 | null | quant-ph | null | We suggest a variant of the recently proposed experiment for the generation
of a new kind of Schroedinger-cat states, using two coupled parametric
down-converter nonlinear crystals [F. De Martini, Phys. Rev. Lett. 81, 2842
(1998)]. We study the parametric oscillator case and find that an entangled
Schroedinger-cat type state of two cavities, whose mirrors are placed along the
output beams of the nonlinear crystals, can be realized under suitable
conditions.
| [
{
"version": "v1",
"created": "Thu, 25 Feb 1999 03:31:19 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"De Martini",
"Francesco",
"",
"1 and 2"
],
[
"Fortunato",
"Mauro",
"",
"2 and 3"
],
[
"Tombesi",
"Paolo",
"",
"2 and 3"
],
[
"Vitali",
"David",
"",
"2 and 3"
]
] |
quant-ph/9902083 | Subhasis Ghosh | S. Ghosh, G. Kar, A. Roy | Classification of Maximally Entangled States of Spin-1/2 Particles | null | null | null | null | quant-ph | null | This paper has been withdrawn temporarily.
| [
{
"version": "v1",
"created": "Thu, 25 Feb 1999 10:08:07 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Mar 1999 09:03:26 GMT"
},
{
"version": "v3",
"created": "Tue, 18 May 1999 09:34:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ghosh",
"S.",
""
],
[
"Kar",
"G.",
""
],
[
"Roy",
"A.",
""
]
] |
quant-ph/9902084 | Jeff P. Barnes | Jeff P. Barnes and Warren S. Warren | Decoherence and Programmable Quantum Computation | submitted to Phys. Rev. A 35 double-spaced pages, 2 figures, in LaTeX | null | 10.1103/PhysRevA.60.4363 | null | quant-ph | null | An examination of the concept of using classical degrees of freedom to drive
the evolution of quantum computers is given. Specifically, when externally
generated, coherent states of the electromagnetic field are used to drive
transitions within the qubit system, a decoherence results due to the back
reaction from the qubits onto the quantum field. We derive an expression for
the decoherence rate for two cases, that of the single-qubit Walsh-Hadamard
transform, and for an implementation of the controlled-NOT gate. We examine the
impact of this decoherence mechanism on Grover's search algorithm, and on the
proposals for use of error-correcting codes in quantum computation.
| [
{
"version": "v1",
"created": "Thu, 25 Feb 1999 18:20:43 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Barnes",
"Jeff P.",
""
],
[
"Warren",
"Warren S.",
""
]
] |
quant-ph/9902085 | Arno Bohm | A.Bohm | Time Asymmetric Quantum Physics | Tex file with 2 figures | Phys.Rev. A60 (1999) 861 | 10.1103/PhysRevA.60.861 | null | quant-ph | null | Mathematical and phenomenological arguments in favor of asymmetric time
evolution of micro-physical states are presented.
| [
{
"version": "v1",
"created": "Fri, 26 Feb 1999 01:19:36 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bohm",
"A.",
""
]
] |
quant-ph/9902086 | Irena Dobrovolska | I. V. Dobrovolska, R. S. Tutik | Semiclassical treatment of logarithmic perturbation theory | 6 pages, LATEX 2.09 using IOP styles | J.Phys.A32:563-568,1999 | 10.1088/0305-4470/32/3/011 | null | quant-ph | null | The explicit semiclassical treatment of logarithmic perturbation theory for
the nonrelativistic bound states problem is developed. Based upon
$\hbar$-expansions and suitable quantization conditions a new procedure for
deriving perturbation expansions for the one-dimensional anharmonic oscillator
is offered. Avoiding disadvantages of the standard approach, new handy
recursion formulae with the same simple form both for ground and exited states
have been obtained. As an example, the perturbation expansions for the energy
eigenvalues of the harmonic oscillator perturbed by $\lambda x^{6}$ are
considered.
| [
{
"version": "v1",
"created": "Fri, 26 Feb 1999 18:35:15 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dobrovolska",
"I. V.",
""
],
[
"Tutik",
"R. S.",
""
]
] |
quant-ph/9902087 | Diosi Lajos | Lajos Diosi | Emergence of Classicality: From Collapse Phenomenologies to Hybrid
Dynamics | 8pp LaTeX (Springer-macros), to appear in Decoherence: Theoretical,
Experimental and Conceptual Problems (Springer). Minor corrections | Lect.Notes Phys. 538 (2000) 243-250 | null | null | quant-ph | null | In the past ten-fifteen years, stochastic models of continuous wave function
collapse were being proposed to describe the continuous emergence of
classicality from quantum. We advocate that the hybrid dynamics of canonically
coupled quantum and classical systems is a more basic concept. Continuous
collapse formalisms are obtained as special cases. To illustrate our claim we
show how von Neumann collapse follows from hybrid dynamical equations.
| [
{
"version": "v1",
"created": "Fri, 26 Feb 1999 20:23:04 GMT"
},
{
"version": "v2",
"created": "Wed, 12 May 1999 10:43:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Diosi",
"Lajos",
""
]
] |
quant-ph/9903001 | Lucien Hardy | Lucien Hardy | A Method of Areas for Manipulating the Entanglement Properties of One
Copy of a Two-Particle Pure State | 29 pages, 9 figures. Section 2.4 clarified. Error in second colouring
theorem (section 3.2) corrected. Some other minor changes | null | 10.1103/PhysRevA.60.1912 | null | quant-ph | null | We consider the problem of how to manipulate the entanglement properties of a
general two-particle pure state, shared between Alice and Bob, by using only
local operations at each end and classical communication between Alice and Bob.
A method is developed in which this type of problem is found to be equivalent
to a problem involving the cutting and pasting of certain shapes along with a
certain colouring problem. We consider two problems. Firstly we find the most
general way of manipulating the state to obtain maximally entangled states.
After such a manipulation the entangled state |11>+|22>+....|mm> is obtained
with probability p_m. We obtain an expression for the optimal average
entanglement. Also, some results of Lo and Popescu pertaining to this problem
are given simple geometric proofs. Secondly, we consider how to manipulate one
two particle entangled pure state to another with certainty. We derive
Nielsen's theorem (which states the necessary and sufficient condition for this
to be possible) using the method of areas.
| [
{
"version": "v1",
"created": "Sat, 27 Feb 1999 04:05:48 GMT"
},
{
"version": "v2",
"created": "Tue, 30 Mar 1999 02:06:20 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Hardy",
"Lucien",
""
]
] |
quant-ph/9903002 | null | Olga Man'ko, V.I. Man'ko | ``Classical'' Propagator and Path Integral in the Probability
Representation of Quantum Mechanics | LATEX,10 pages,accepted by Journal of Russian Laser Research,1999 | null | null | null | quant-ph | null | In the probability representation of the standard quantum mechanics, the
explicit expression (and its quasiclassical van-Fleck approximation) for the
``classical'' propagator (transition probability distribution), which
completely describes the quantum system's evolution, is found in terms of the
quantum propagator. An expression for the ``classical'' propagator in terms of
path integral is derived. Examples of free motion and harmonic oscillator are
considered. The evolution equation in the Bargmann representation of the
optical tomography approach is obtained.
| [
{
"version": "v1",
"created": "Mon, 1 Mar 1999 21:15:46 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Man'ko",
"Olga",
""
],
[
"Man'ko",
"V. I.",
""
]
] |
quant-ph/9903003 | Timothy C. Ralph | T. C. Ralph, R. E. S. Polkinghorne and P. K. Lam | Characterizing teleportation in optics | 20 pages, 4 figures | J.Optics B1 (1999) 483 | 10.1088/1464-4266/1/4/321 | null | quant-ph | null | We discuss the characterization of continuous variable, optical quantum
teleportation in terms of the two quadrature signal transfer and conditional
variances between the input and output states. We derive criteria which clearly
define the classical limits and highlight interesting operating points which
are not obvious from a calculation of the fidelity of the teleportation alone.
| [
{
"version": "v1",
"created": "Tue, 2 Mar 1999 03:12:38 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Ralph",
"T. C.",
""
],
[
"Polkinghorne",
"R. E. S.",
""
],
[
"Lam",
"P. K.",
""
]
] |
quant-ph/9903004 | Shigeru Furuichi | S. Furuichi and M.Ohya | Entanglement degree for Jaynes-Cummings model | 3 pages, 3 figures, revtex with amsfonts | Lett.Math.Phys. 49 (1999) 279-285 | null | null | quant-ph | null | Recently, it has been known that a quantum entangled state plays an important
role in the field ofquantum information theory such as quantum teleportation
and quantum computation. The research on quantifying entangled states has been
done by several measures. In this letter, we will adopt the method using
quantum mutual entropy to measure the degree of entanglement of Jaynes-Cummings
model.
| [
{
"version": "v1",
"created": "Tue, 2 Mar 1999 05:40:25 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Apr 1999 09:41:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Furuichi",
"S.",
""
],
[
"Ohya",
"M.",
""
]
] |
quant-ph/9903005 | Hans Jacobus Wospakrik | Hans J. Wospakrik | Path Integral Evaluation of the Free Propagator on the (D-1)-dimensional
Pseudosphere | 9 pages, misprints corrected and a note added | null | null | null | quant-ph | null | We present an explicit path integral evaluation of the free Hamiltonian
propagator on the (D-1)-dimensional pseudosphere, in the horicyclic
coordinates, using the integral equation method. This method consists in
deriving an integral equation for the propagator that turns out to be of Abel's
type.
| [
{
"version": "v1",
"created": "Tue, 2 Mar 1999 14:14:56 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Mar 1999 12:55:34 GMT"
},
{
"version": "v3",
"created": "Thu, 22 Apr 1999 09:18:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wospakrik",
"Hans J.",
""
]
] |
quant-ph/9903006 | Fedor Herbut | Fedor Herbut | Quantum counter erasure | 9 pages | null | null | null | quant-ph | null | Interference comes from coherent mixing. It can be suppressed by
entanglement, and the latter can be erased so as to revive interference. If the
entanglement is a mimal-term one (with minimal-term mixing), as is the case in
most thought and real experiments reported, there appears the possibility of
counter erasure and counter interference. This peculiar phenomenon of
minimal-term mixing and minimal-term entanglement is investigated in detail. In
particular, all two-term mixings of an (arbitrary) given minimal-term mixed
state are explicitly exhibited. And so are their possible laboratory
realizations in terms of distant ensemble decomposition.
| [
{
"version": "v1",
"created": "Tue, 2 Mar 1999 14:18:56 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Herbut",
"Fedor",
""
]
] |
quant-ph/9903007 | Jos Uffink | Jos Uffink | How to protect the interpretation of the wave function against
protective measurements | 13 pages, 1 figure | Phys Rev A 60, to appear | 10.1103/PhysRevA.60.3474 | null | quant-ph | null | A new type of procedures, called protective measurements, has been proposed
by Aharonov, Anandan and Vaidman. These authors argue that a protective
measurement allows the determination of arbitrary observables of a single
quantum system and claim that this favors a realistic interpretation of the
quantum state. This paper proves that only observables that commute with the
system's Hamiltonian can be measured protectively. It is argued that this
restriction saves the coherence of alternative interpretations.
| [
{
"version": "v1",
"created": "Tue, 2 Mar 1999 15:34:30 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Uffink",
"Jos",
""
]
] |
quant-ph/9903008 | Yuri I. Manin | Yuri I. Manin | Classical computing, quantum computing, and Shor's factoring algorithm | 27 pp., no figures, amstex | null | null | null | quant-ph math.QA | null | This is an expository talk written for the Bourbaki Seminar. After a brief
introduction, Section 1 discusses in the categorical language the structure of
the classical deterministic computations. Basic notions of complexity icluding
the P/NP problem are reviewed. Section 2 introduces the notion of quantum
parallelism and explains the main issues of quantum computing. Section 3 is
devoted to four quantum subroutines: initialization, quantum computing of
classical Boolean functions, quantum Fourier transform, and Grover's search
algorithm. The central Section 4 explains Shor's factoring algorithm. Section 5
relates Kolmogorov's complexity to the spectral properties of computable
function. Appendix contributes to the prehistory of quantum computing.
| [
{
"version": "v1",
"created": "Tue, 2 Mar 1999 16:27:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Manin",
"Yuri I.",
""
]
] |
quant-ph/9903009 | Saverio Pascazio | Ken Machida, Hiromichi Nakazato, Saverio Pascazio, Helmut Rauch and
Sixia Yu | Reflection and Transmission in a Neutron-Spin Test of the Quantum Zeno
Effect | 26 pages, 6 figures | null | 10.1103/PhysRevA.60.3448 | null | quant-ph | null | The dynamics of a quantum system undergoing frequent "measurements", leading
to the so-called quantum Zeno effect, is examined on the basis of a
neutron-spin experiment recently proposed for its demonstration. When the
spatial degrees of freedom are duely taken into account, neutron-reflection
effects become very important and may lead to an evolution which is totally
different from the ideal case.
| [
{
"version": "v1",
"created": "Tue, 2 Mar 1999 17:52:58 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Machida",
"Ken",
""
],
[
"Nakazato",
"Hiromichi",
""
],
[
"Pascazio",
"Saverio",
""
],
[
"Rauch",
"Helmut",
""
],
[
"Yu",
"Sixia",
""
]
] |
quant-ph/9903010 | Waldemar Puszkarz | Waldemar Puszkarz | On Solutions to the Nonlinear Phase Modification of the Schroedinger
Equation | New organization of the paper, modified, but no changes in the
results, new references added, Latex, 13 pages | null | null | null | quant-ph | null | We present some physically interesting, in general non-stationary,
one-dimensional solutions to the nonlinear phase modification of the
Schr\"{o}dinger equation proposed recently. The solutions include a coherent
state, a phase-modified Gaussian wave packet in the potential of harmonic
oscillator whose strength varies in time, a free Gaussian soliton, and a
similar soliton in the potential of harmonic oscillator comoving with the
soliton. The last of these solutions implies that there exist an energy level
in the spectrum of harmonic oscillator which is not predicted by the linear
theory. The free solitonic solution can be considered a model for a particle
aspect of the wave-particle duality embodied in the quantum theory. The
physical size of this particle is naturally rendered equal to its Compton
wavelength in the subrelativistic framework in which the self-energy of the
soliton is assumed to be equal to its rest-mass energy. The solitonic solutions
exist only for the negative coupling constant for which the Gaussian wave
packets must be larger than some critical finite size if their energy is to be
bounded, i.e., they cannot be point-like objects.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 00:56:17 GMT"
},
{
"version": "v2",
"created": "Fri, 12 Mar 1999 11:21:03 GMT"
},
{
"version": "v3",
"created": "Mon, 17 May 1999 03:55:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Puszkarz",
"Waldemar",
""
]
] |
quant-ph/9903011 | Roman Breslav | R.B.Breslav, G.N.Parfionov and R.R.Zapatrin | Topology measurement within the histories approach | 16 pages, latex | Hadronic J. 22 (1999) 225-239 | null | null | quant-ph | null | An idealised experiment estimating the spacetime topology is considered in
both classical and quantum frameworks. The latter is described in terms of
histories approach to quantum theory. A procedure creating combinatorial models
of topology is suggested. The correspondence between these models and
discretised spacetime models is established.
| [
{
"version": "v1",
"created": "Wed, 3 Mar 1999 06:54:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Breslav",
"R. B.",
""
],
[
"Parfionov",
"G. N.",
""
],
[
"Zapatrin",
"R. R.",
""
]
] |
quant-ph/9903012 | Ignacio Cirac | M. Lewenstein, J. I. Cirac, and S. Karnas | Separability and entanglement in 2xN composite quantum systems | 4 pages, Latex | null | null | null | quant-ph | null | We show that all density operators of 2$\times N$--dimensional quantum
systems that remain invariant after partial transposition with respect to the
first system are separable. Based on this criterion, we derive a sufficient
separability condition for general density operators in such quantum systems.
We also give a simple proof of the separability criterion in $2\times
2$--dimensional systems [A. Peres, Phys. Rev. Lett {\bf 77}, 1413 (1996)]
| [
{
"version": "v1",
"created": "Wed, 3 Mar 1999 08:43:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lewenstein",
"M.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Karnas",
"S.",
""
]
] |
quant-ph/9903013 | Xiao-Guang Wang | Xiao-Guang Wang and Hong-Chen Fu | Negative Binomial States of the Radiation Field and their Excitations
are Nonlinear Coherent States | 10 pages, no figures | Mod.Phys.Lett.B13:617-623,1999 | 10.1142/S0217984999000774 | null | quant-ph | null | We show that the well-known negative binomial states of the radiation field
and their excitations are nonlinear coherent states. Excited nonlinear coherent
state are still nonlinear coherent states with different nonlinear functions.
We finally give exponential form of the nonlinear coherent states and remark
that the binomial states are not nonlinear coherent states.
| [
{
"version": "v1",
"created": "Wed, 3 Mar 1999 09:33:34 GMT"
},
{
"version": "v2",
"created": "Fri, 7 May 1999 15:03:04 GMT"
},
{
"version": "v3",
"created": "Mon, 29 Nov 1999 03:00:02 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wang",
"Xiao-Guang",
""
],
[
"Fu",
"Hong-Chen",
""
]
] |
quant-ph/9903014 | Alex Brodsky | Alex Brodsky and Nicholas Pippenger | Characterizations of 1-Way Quantum Finite Automata | 22 pages | null | null | null | quant-ph | null | The 2-way quantum finite automaton introduced by Kondacs and Watrous can
accept non-regular languages with bounded error in polynomial time. If we
restrict the head of the automaton to moving classically and to moving only in
one direction, the acceptance power of this 1-way quantum finite automaton is
reduced to a proper subset of the regular languages.
In this paper we study two different models of 1-way quantum finite automata.
The first model, termed measure-once quantum finite automata, was introduced by
Moore and Crutchfield, and the second model, termed measure-many quantum finite
automata, was introduced by Kondacs and Watrous.
We characterize the measure-once model when it is restricted to accepting
with bounded error and show that, without that restriction, it can solve the
word problem over the free group. We also show that it can be simulated by a
probabilistic finite automaton and describe an algorithm that determines if two
measure-once automata are equivalent.
We prove several closure properties of the classes of languages accepted by
measure-many automata, including inverse homomorphisms, and provide a new
necessary condition for a language to be accepted by the measure-many model
with bounded error. Finally, we show that piecewise testable languages can be
accepted with bounded error by a measure-many quantum finite automaton, in the
process introducing new construction techniques for quantum automata.
| [
{
"version": "v1",
"created": "Wed, 3 Mar 1999 22:24:52 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Jul 2000 21:56:24 GMT"
},
{
"version": "v3",
"created": "Mon, 30 Oct 2000 20:06:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Brodsky",
"Alex",
""
],
[
"Pippenger",
"Nicholas",
""
]
] |
quant-ph/9903015 | Dipankar Home | Somshubhro Bandyopadhyay, Guruprasad Kar and Anirban Roy | Disentanglement of pure bipartite quantum states by local cloning | 8 pages, Latex, to appear in Phys. Letts. A | Phys.Lett. A258 (1999) 205-209 | 10.1016/S0375-9601(99)00280-7 | null | quant-ph | null | We discuss disentanglement of pure bipartite quantum states within the
framework of the schemes developed for entanglement splitting and broadcasting
of entanglement.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 04:10:46 GMT"
},
{
"version": "v2",
"created": "Sat, 20 Mar 1999 02:43:50 GMT"
},
{
"version": "v3",
"created": "Thu, 29 Apr 1999 06:10:21 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bandyopadhyay",
"Somshubhro",
""
],
[
"Kar",
"Guruprasad",
""
],
[
"Roy",
"Anirban",
""
]
] |
quant-ph/9903016 | Dong Shi Hai | Shi-Hai Dong(IHEP, Beijing, P.R.China) and Zhong-Qi Ma | Levinson's theorem for the Schr\"{o}dinger equation in one dimension | Revtex 11 pages and submitted to Phys. Rev. A | Int.J.Theor.Phys. 39 (2000) 469-481 | 10.1007/s100530070079 | null | quant-ph | null | Levinson's theorem for the one-dimensional Schr\"{o}dinger equation with a
symmetric potential, which decays at infinity faster than $x^{-2}$, is
established by the Sturm-Liouville theorem. The critical case, where the
Schr\"{o}dinger equation has a finite zero-energy solution, is also analyzed.
It is demonstrated that the number of bound states with even (odd) parity
$n_{+}$ ($n_{-}$) is related to the phase shift $\eta_{+}(0)[\eta_{-}(0)]$ of
the scattering states with the same parity at zero momentum as
$\eta_{+}(0)+\pi/2=n_{+}\pi, \eta_{-}(0)=n_{-}\pi$, for the non-critical case,
$\eta_{+}(0)=n_{+}\pi, \eta_{-}(0)-\pi/2=n_{-}\pi$, for the critical case.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 07:03:13 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Dong",
"Shi-Hai",
"",
"IHEP, Beijing, P.R.China"
],
[
"Ma",
"Zhong-Qi",
""
]
] |
quant-ph/9903017 | Holger F. Hofmann | Holger F. Hofmann and Ortwin Hess | Thermal photon statistics in laser light above threshold | 4 pages RevTex | Phys.Rev. A62 (2000) 063807 | 10.1103/PhysRevA.62.063807 | null | quant-ph adap-org cond-mat nlin.AO physics.optics | null | We show that the reduction in photon number fluctuations at laser threshold
often cited as a fundamental laser property does not occur in typical
semiconductor lasers such as the ones commonly used in modern technological
applications today. Indeed, such lasers may still exhibit thermal intensity
fluctuations far above threshold. We therefore conclude that sub-thermal
intensity fluctuations cannot be regarded as a necessary property of laser
light. Rather, one should distinguish betwen a thermal laser regime and a
sub-thermal laser regime.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 09:59:43 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Hofmann",
"Holger F.",
""
],
[
"Hess",
"Ortwin",
""
]
] |
quant-ph/9903018 | Ignacio Cirac | W. D\"ur, J. I. Cirac, and R. Tarrach | Separability and distillability of multiparticle quantum systems | replaced with published version (Phys.Rev.Lett.), in parts rewritten
and clarified | Phys.Rev.Lett.83:3562-3565,1999 | 10.1103/PhysRevLett.83.3562 | null | quant-ph | null | We present a family of 3--qubit states to which any arbitrary state can be
depolarized. We fully classify those states with respect to their separability
and distillability properties. This provides a sufficient condition for
nonseparability and distillability for arbitrary states. We generalize our
results to $N$--particle states.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 16:04:49 GMT"
},
{
"version": "v2",
"created": "Thu, 11 Nov 1999 10:39:13 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Dür",
"W.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Tarrach",
"R.",
""
]
] |
quant-ph/9903019 | Roberto Casadio | R. Casadio and G. Venturi (Dept. of Phys. and INFN, Bologna, Italy) | The accelerated observer with back-reaction effects | 7 pages, LaTeX, no figures | Phys.Lett. A252 (1999) 109-114 | 10.1016/S0375-9601(98)00941-4 | null | quant-ph gr-qc | null | The quantum mechanical evolution of an accelerated extended detector coupled
to a massless scalar field is exhibited and the back-reaction due to emission
or absorption processes computed at first order in the change of the detector's
mass and acceleration. An analogy with black hole evaporation is found and
illustrated.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 13:06:53 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Casadio",
"R.",
"",
"Dept. of Phys. and INFN, Bologna, Italy"
],
[
"Venturi",
"G.",
"",
"Dept. of Phys. and INFN, Bologna, Italy"
]
] |
quant-ph/9903020 | Oscar W. Greenberg | O.W. Greenberg (University of Maryland) and Robert C. Hilborn (Amherst
College) | Quon Statistics for Composite Systems and a Limit on the Violation of
the Pauli Principle for Nucleons and Quarks | 10 pages, Latex, no figures | Phys.Rev.Lett.83:4460,1999 | 10.1103/PhysRevLett.83.4460 | University of Maryland Physics Paper 99-089 | quant-ph hep-ph hep-th nucl-th | null | The quon algebra gives a description of particles, ``quons,'' that are
neither fermions nor bosons. The parameter $q$ attached to a quon labels a
smooth interpolation between bosons, for which $q = +1$, and fermions, for
which $q = -1$. Wigner and Ehrenfest and Oppenheimer showed that a composite
system of identical bosons and fermions is a fermion if it contains an odd
number of fermions and is a boson otherwise. Here we generalize this result to
composite systems of identical quons. We find
$q_{composite}=q_{constituent}^{n^2}$ for a system of $n$ identical quons. This
result reduces to the earlier result for bosons and fermions. Using this
generalization we find bounds on possible violations of the Pauli exclusion
principle for nucleons and quarks based on such bounds for nuclei.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 19:28:36 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Greenberg",
"O. W.",
"",
"University of Maryland"
],
[
"Hilborn",
"Robert C.",
"",
"Amherst\n College"
]
] |
quant-ph/9903021 | null | V.I.Man'ko, G.Marmo | Probability Distributions and Hilbert Spaces: Quantum and Classical
Systems | LATEX,13pages,accepted by Physica Scripta (1999) | null | 10.1238/Physica.Regular.060a00111 | null | quant-ph | null | We use the fact that some linear Hamiltonian systems can be considered as
``finite level'' quantum systems, and the description of quantum mechanics in
terms of probabilities, to associate probability distributions with this
particular class of linear Hamiltonian systems.
| [
{
"version": "v1",
"created": "Thu, 4 Mar 1999 19:43:10 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Man'ko",
"V. I.",
""
],
[
"Marmo",
"G.",
""
]
] |
quant-ph/9903022 | M. Rosenau da Costa | M. Rosenau da Costa, A. O. Caldeira, S. M. Dutra, H. Westfahl Jr | Exact Diagonalization of Two Quantum Models for the Damped Harmonic
Oscillator | 19 pages, 2 figures, ReVTeX | Phys. Rev. A 61, 022107, 2000 | 10.1103/PhysRevA.61.022107 | null | quant-ph | null | The damped harmonic oscillator is a workhorse for the study of dissipation in
quantum mechanics. However, despite its simplicity, this system has given rise
to some approximations whose validity and relation to more refined descriptions
deserve a thorough investigation. In this work, we apply a method that allows
us to diagonalize exactly the dissipative Hamiltonians that are frequently
adopted in the literature. Using this method we derive the conditions of
validity of the rotating-wave approximation (RWA) and show how this approximate
description relates to more general ones. We also show that the existence of
dissipative coherent states is intimately related to the RWA. Finally, through
the evaluation of the dynamics of the damped oscillator, we notice an important
property of the dissipative model that has not been properly accounted for in
previous works; namely, the necessity of new constraints to the application of
the factorizable initial conditions.
| [
{
"version": "v1",
"created": "Fri, 5 Mar 1999 19:57:07 GMT"
},
{
"version": "v2",
"created": "Tue, 1 Aug 2000 15:09:28 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"da Costa",
"M. Rosenau",
""
],
[
"Caldeira",
"A. O.",
""
],
[
"Dutra",
"S. M.",
""
],
[
"Westfahl",
"H.",
"Jr"
]
] |
quant-ph/9903023 | Howard M. Wiseman | H.M. Wiseman and G.E. Toombes | Quantum jumps in a two-level atom | 18 pages, including 8 .eps figures | null | null | null | quant-ph | null | A strongly-driven ($\Omega >> \gamma$) two level atom relaxes towards an
equilibrium state rho which is almost completely mixed. One interpretation of
this state is that it represents an ensemble average, and that an individual
atom is at any time in one of the eigenstates of $\rho$. The theory of Teich
and Mahler [Phys. Rev. A 45, 3300 (1992)] makes this interpretation concrete,
with an individual atom jumping stochastically between the two eigenstates when
a photon is emitted. The dressed atom theory is also supposed to describe the
quantum jumps of an individual atom due to photo-emissions. But the two
pictures are contradictory because the dressed states of the atom are almost
orthogonal to the eigenstates of $\rho$. In this paper we investigate three
ways of measuring the field radiated by the atom, which attempt to reproduce
the simple quantum jump dynamics of the dressed state or Teich and Mahler
models. These are: spectral detection (using optical filters), two-state jumps
(using adaptive homodyne detection) and orthogonal jumps (another adaptive
homodyne scheme). We find that the three schemes closely mimic the jumps of the
dressed state model, with errors of order $(3/4) (\gamma/\Omega)^{2/3}$, $(1/4)
(\gamma/\Omega)^{2}$, and $(3/4) (\gamma/\Omega)^{2}$ respectively. The
significance of this result to the program of environmentally-induced
superselection is discussed.
| [
{
"version": "v1",
"created": "Fri, 5 Mar 1999 06:39:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wiseman",
"H. M.",
""
],
[
"Toombes",
"G. E.",
""
]
] |
quant-ph/9903024 | Peter Horak | Peter Horak and Stephen M. Barnett | Creation of coherence in Bose-Einstein condensates by atom detection | 10 pages, 8 figures (postscript) | J.Phys. B32 (1999) 3421 | 10.1088/0953-4075/32/14/312 | null | quant-ph | null | We investigate the creation of a relative phase between two Bose-Einstein
condensates, initially in number states, by detection of atoms and show how the
system approaches a coherent state. Two very distinct time scales are found:
one for the creation of the interference is of the order of the detection time
for a few single atoms and another, for the preparation of coherent states, of
the order of the detection time for a significant fraction of the total number
of atoms. Approximate analytic solutions are derived and compared with exact
numerical results.
| [
{
"version": "v1",
"created": "Fri, 5 Mar 1999 10:55:42 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Horak",
"Peter",
""
],
[
"Barnett",
"Stephen M.",
""
]
] |
quant-ph/9903025 | Ramchander R. Sastry | Ramchander R. Sastry | Quantum Mechanics of Extended Objects | RevTex, 24 pages, 1 eps and 5 ps figures, format changes | J.Phys. A 33, 8305-8318 (2000) revised version | 10.1088/0305-4470/33/46/311 | null | quant-ph gr-qc hep-th math-ph math.MP nucl-th | null | We propose a quantum mechanics of extended objects that accounts for the
finite extent of a particle defined via its Compton wavelength. The Hilbert
space representation theory of such a quantum mechanics is presented and this
representation is used to demonstrate the quantization of spacetime. The
quantum mechanics of extended objects is then applied to two paradigm examples,
namely, the fuzzy (extended object) harmonic oscillator and the Yukawa
potential. In the second example, we theoretically predict the phenomenological
coupling constant of the $\omega$ meson, which mediates the short range and
repulsive nucleon force, as well as the repulsive core radius.
| [
{
"version": "v1",
"created": "Sun, 7 Mar 1999 14:36:15 GMT"
},
{
"version": "v2",
"created": "Wed, 24 Mar 1999 02:42:30 GMT"
},
{
"version": "v3",
"created": "Mon, 17 May 1999 20:35:52 GMT"
},
{
"version": "v4",
"created": "Thu, 28 Oct 1999 20:40:43 GMT"
},
{
"version": "v5",
"created": "Mon, 1 Nov 1999 23:00:21 GMT"
},
{
"version": "v6",
"created": "Fri, 10 Dec 1999 04:57:54 GMT"
},
{
"version": "v7",
"created": "Sat, 5 Feb 2000 22:43:18 GMT"
},
{
"version": "v8",
"created": "Tue, 9 May 2000 05:09:10 GMT"
},
{
"version": "v9",
"created": "Mon, 3 Jul 2000 16:05:52 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Sastry",
"Ramchander R.",
""
]
] |
quant-ph/9903026 | A. A. Stanislavsky | S.S.Sannikov, A.A.Stanislavsky, M.J.T.F.Cabbolet | Elementary Particles in a New Quantum Scheme | LaTeX, 45 pages | null | null | null | quant-ph | null | Proceeding from the main principles of the non-unitary quantum theory of
relativistic bi-Hamiltonian systems, a system of Lagrangian fields
characterized by a certain dispersion law (mass spectrum of particles),
interactions between them and their coupling constants are constructed. In this
article the mass spectrum formula for ``bare'' fundamental hadrons is
introduced, and an a priori normalization of particle fields is found as well.
Numerical values of some parameters of the present theory are determined.
| [
{
"version": "v1",
"created": "Sat, 6 Mar 1999 13:09:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sannikov",
"S. S.",
""
],
[
"Stanislavsky",
"A. A.",
""
],
[
"Cabbolet",
"M. J. T. F.",
""
]
] |
quant-ph/9903027 | Konrad Banaszek | K. Banaszek, C. Radzewicz, and K. Wodkiewicz (Uniwersytet Warszawski),
and J. S. Krasinski (Oklahoma State University) | Direct measurement of the Wigner function by photon counting | 4 pages, REVTeX | Phys.Rev.A60:674-677,1999 | 10.1103/PhysRevA.60.674 | null | quant-ph | null | We report a direct measurement of the Wigner function characterizing the
quantum state of a light mode. The experimental scheme is based on the
representation of the Wigner function as an expectation value of a displaced
photon number parity operator. This allowed us to scan the phase space
point-by-point, and obtain the complete Wigner function without using any
numerical reconstruction algorithms.
| [
{
"version": "v1",
"created": "Mon, 8 Mar 1999 10:16:18 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Banaszek",
"K.",
"",
"Uniwersytet Warszawski"
],
[
"Radzewicz",
"C.",
"",
"Uniwersytet Warszawski"
],
[
"Wodkiewicz",
"K.",
"",
"Uniwersytet Warszawski"
],
[
"Krasinski",
"J. S.",
"",
"Oklahoma State University"
]
] |
quant-ph/9903028 | Ricardo Moritz Cavalcanti | C. A. A. de Carvalho and R. M. Cavalcanti | Semiclassical Series from Path Integrals | 18 pages, 4 figures. References updated | Trends in Theoretical Physics II (AIP Conference Proceedings 484),
edited by H. Falomir, R. E. Gamboa Saravi, and F. A. Schaposnik (American
Institute of Physics, Woodbury, 1999) pp 256-269 | 10.1063/1.59667 | null | quant-ph cond-mat.stat-mech hep-th | null | We derive the semiclassical series for the partition function in Quantum
Statistical Mechanics (QSM) from its path integral representation. Each term of
the series is obtained explicitly from the (real) minima of the classical
action. The method yields a simple derivation of the exact result for the
harmonic oscillator, and an accurate estimate of ground-state energy and
specific heat for a single-well quartic anharmonic oscillator. As QSM can be
regarded as finite temperature field theory at a point, we make use of Feynman
diagrams to illustrate the non-perturbative character of the series: it
contains all powers of $\hbar$ and graphs with any number of loops; the usual
perturbative series corresponds to a subset of the diagrams of the
semiclassical series. We comment on the application of our results to other
potentials, to correlation functions and to field theories in higher
dimensions.
| [
{
"version": "v1",
"created": "Mon, 8 Mar 1999 16:29:25 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Nov 1999 22:15:53 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"de Carvalho",
"C. A. A.",
""
],
[
"Cavalcanti",
"R. M.",
""
]
] |
quant-ph/9903029 | Enrique Solano | E. Solano, C. L. Cesar, R. L. de Matos Filho, and N. Zagury | Reliable teleportation in trapped ions | 8 Latex pages with five (ps,eps) figures included (EPJ style also
included). Accepted for publication in European Physical Journal D | Eur.Phys.J. D13 (2001) 121 | 10.1007/s100530170293 | null | quant-ph | null | We study a method for the implementation of a reliable teleportation protocol
(theoretically, 100% of success) of internal states in trapped ions. The
generation of the quantum channel (any of four Bell states) may be done
respecting technical limitations on individual addressing and without claiming
the Lamb-Dicke regime. An adequate Bell analyzer, that transforms unitarily the
Bell basis into a completely disentangled one, is considered. Probable sources
of error and fidelity estimations of the teleportation process are studied.
Finally, we discuss experimental issues, proposing a scenario in which the
present scheme could be implemented.
| [
{
"version": "v1",
"created": "Mon, 8 Mar 1999 21:11:15 GMT"
},
{
"version": "v2",
"created": "Mon, 11 Sep 2000 14:08:16 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Solano",
"E.",
""
],
[
"Cesar",
"C. L.",
""
],
[
"Filho",
"R. L. de Matos",
""
],
[
"Zagury",
"N.",
""
]
] |
quant-ph/9903030 | Andrew C. Doherty | A. C. Doherty, S. M. Tan, A. S. Parkins, D. F. Walls (University of
Auckland, New Zealand) | State determination in continuous measurement | 12 pages, 4 figures, Revtex | null | 10.1103/PhysRevA.60.2380 | null | quant-ph | null | The possibility of determining the state of a quantum system after a
continuous measurement of position is discussed in the framework of quantum
trajectory theory. Initial lack of knowledge of the system and external noises
are accounted for by considering the evolution of conditioned density matrices
under a stochastic master equation. It is shown that after a finite time the
state of the system is a pure state and can be inferred from the measurement
record alone. The relation to emerging possibilities for the continuous
experimental observation of single quanta, as for example in cavity quantum
electrodynamics, is discussed.
| [
{
"version": "v1",
"created": "Tue, 9 Mar 1999 02:37:39 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Doherty",
"A. C.",
"",
"University of\n Auckland, New Zealand"
],
[
"Tan",
"S. M.",
"",
"University of\n Auckland, New Zealand"
],
[
"Parkins",
"A. S.",
"",
"University of\n Auckland, New Zealand"
],
[
"Walls",
"D. F.",
"",
"University of\n Auckland, New Zealand"
]
] |
quant-ph/9903031 | Yoel Tikochinski | Yoel Tikochinsky | Comment on ``Consistency, amplitudes and probabilities in quantum
theory'' by A. Caticha | null | null | 10.1088/0305-4470/33/31/314 | null | quant-ph | null | A carefully written paper by A. Caticha [Phys. Rev. A57, 1572 (1998)] applies
consistency arguments to derive the quantum mechanical rules for compounding
probability amplitudes in much the same way as earlier work by the present
author [J. Math. Phys. 29, 398 (1988) and Int. J. Theor. Phys. 27, 543 (1998)].
These works are examined together to find the minimal assumptions needed to
obtain the most general results.
| [
{
"version": "v1",
"created": "Tue, 9 Mar 1999 13:22:27 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Tikochinsky",
"Yoel",
""
]
] |
quant-ph/9903032 | Prague-Guest | M. Dineykhan and R. G. Nazmitdinov | Analytic solutions to the problem of Coulomb and confining potentials | 25 pages (Latex) | Phys.Atom.Nucl. 62 (1999) 138-149; Yad.Fiz. 62 (1999) 143-154 | null | null | quant-ph | null | The oscillator representation method is presented and used to calculate the
energy spectra for a superposition of Coulomb and power-law potentials and for
Coulomb and Yukawa potentials. The method provides an efficient way to obtain
analytic results for arbitrary values of the parameters specifying the
above-type potentials. The calculated energies of the ground and excited states
of the quantum systems in question are found to comply well with exact results.
| [
{
"version": "v1",
"created": "Tue, 9 Mar 1999 15:34:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dineykhan",
"M.",
""
],
[
"Nazmitdinov",
"R. G.",
""
]
] |
quant-ph/9903033 | Dr Dagmar Bruss | D. Bruss, L. Faoro, C. Macchiavello, M. Palma | Quantum entanglement and classical communication through a depolarising
channel | 6 pages, 2 figures; contribution to special issue of JMO on the
physics of quantum information; 2nd version: slight modifications and
improved presentation | J.Mod.Opt. 47 (2000) 325 | 10.1080/09500340008244045 | ITP-UH-12/99 | quant-ph | null | We analyse the role of entanglement for transmission of classical information
through a memoryless depolarising channel. Using the isotropic character of
this channel we prove analytically that the mutual information cannot be
increased by encoding classical bits into entangled states of two qubits.
| [
{
"version": "v1",
"created": "Tue, 9 Mar 1999 15:56:36 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Jun 1999 08:50:44 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Bruss",
"D.",
""
],
[
"Faoro",
"L.",
""
],
[
"Macchiavello",
"C.",
""
],
[
"Palma",
"M.",
""
]
] |
quant-ph/9903034 | Almut Beige | Almut Beige, Gerhard C. Hegerfeldt | Cooperative effects in the light and dark periods of two
dipole-interacting atoms | 16 pages, Latex, 7 Figures | Phys.Rev.A59:2385,1999 | 10.1103/PhysRevA.59.2385 | EFI-99-03 | quant-ph | null | If an atom is able to exhibit macroscopic dark periods, or electron shelving,
then a driven system of two atoms has three types of fluorescence periods
(dark, single and double intensity). We propose to use the average durations of
these fluorescence types as a simple and easily accessible indicator of
cooperative effects. As an example we study two dipole-interacting V systems by
simulation techniques. We show that the durations of the two types of light
periods exhibit marked separation-dependent oscillations and that they vary in
phase with the real part of the dipole-dipole coupling constant.
| [
{
"version": "v1",
"created": "Tue, 9 Mar 1999 20:57:46 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Beige",
"Almut",
""
],
[
"Hegerfeldt",
"Gerhard C.",
""
]
] |
quant-ph/9903035 | Wim van Dam | Harry Buhrman (CWI) and Wim van Dam (CQC and CWI) | Quantum Bounded Query Complexity | 11 pages LaTeX2e, no figures, accepted for CoCo'99 | Proceedings of the 14th Annual IEEE Conference on Computational
Complexity, pp. 149-156 (1999) | 10.1109/CCC.1999.766273 | null | quant-ph cs.CC | null | We combine the classical notions and techniques for bounded query classes
with those developed in quantum computing. We give strong evidence that quantum
queries to an oracle in the class NP does indeed reduce the query complexity of
decision problems. Under traditional complexity assumptions, we obtain an
exponential speedup between the quantum and the classical query complexity of
function classes.
For decision problems and function classes we obtain the following results: o
P_||^NP[2k] is included in EQP_||^NP[k] o P_||^NP[2^(k+1)-2] is included in
EQP^NP[k] o FP_||^NP[2^(k+1)-2] is included in FEQP^NP[2k] o FP_||^NP is
included in FEQP^NP[O(log n)] For sets A that are many-one complete for PSPACE
or EXP we show that FP^A is included in FEQP^A[1]. Sets A that are many-one
complete for PP have the property that FP_||^A is included in FEQP^A[1]. In
general we prove that for any set A there is a set X such that FP^A is included
in FEQP^X[1], establishing that no set is superterse in the quantum setting.
| [
{
"version": "v1",
"created": "Wed, 10 Mar 1999 02:39:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Buhrman",
"Harry",
"",
"CWI"
],
[
"van Dam",
"Wim",
"",
"CQC and CWI"
]
] |
quant-ph/9903036 | Dipankar Home | Dipankar Home and Rajagopal Chattopadhayaya | Determination of When an Outcome is Actualised in a Quantum Measurement
using DNA - Photolyase System | 9 Pages,LaTeX,Revised Communicating author: Rajagopal Chattopadhyay,
[email protected] | null | null | null | quant-ph | null | The biochemical attachment of photolyase to ultraviolet (uv) absorbed DNA
molecules provides a method for registering whether a source has emitted
photons. Here using laws of chemical kinetics and related experimental methods
we argue that the instant after which this information becomes discernible can
be empirically determined by retrodicting from relevant data when the
photolyase binding to uv-absorbed DNA molecules has started occuring. Thus an
empirically investigable twist is provided to the quantum measurement problem.
| [
{
"version": "v1",
"created": "Wed, 10 Mar 1999 07:01:38 GMT"
},
{
"version": "v2",
"created": "Thu, 11 Mar 1999 09:49:19 GMT"
},
{
"version": "v3",
"created": "Tue, 22 Jun 1999 12:58:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Home",
"Dipankar",
""
],
[
"Chattopadhayaya",
"Rajagopal",
""
]
] |
quant-ph/9903037 | Miroljub Dugic | M. Dugic (Faculty of Science, Kragujevac, Yugoslavia) | What is "system" : the arguments from the decoherence theory | 18 (double spaced) pages, no figures | Int.J.Theor.Phys. 45 (2006) 2215-2225 | null | null | quant-ph | null | Within the decoherence theory we investigate the physical background of the
condition of the separability (diagonalizability in noncorrelated basis) of the
interaction Hamiltonian of the composite system, "system plus environment". It
proves that the condition of the separability may serve as a criterion for
defining "system", but so that "system" cannot be defined unless it is
simultaneously defined with its "environment". When extended to a set of the
mutually interacting composite systems, this result implies that the
separability conditions of the local interactions are mutually tied. The task
of defining "system" (and "environment") via investigating the separability of
the Hamiltonian is a sort of the inverse task of the decoherence theory. A
simple example of doing the task is given.
| [
{
"version": "v1",
"created": "Wed, 10 Mar 1999 13:35:33 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dugic",
"M.",
"",
"Faculty of Science, Kragujevac, Yugoslavia"
]
] |
quant-ph/9903038 | Dr. Arun Kumar Pati | Arun Kumar Pati | Quantum superposition of multiple clones and the novel cloning machine | Two column, 5 pages, Latex, some additions, minor changes. Phys. Rev.
Lett. (To appear, 1999) | Phys.Rev.Lett.83:2849-2852,1999 | 10.1103/PhysRevLett.83.2849 | null | quant-ph | null | we envisage a novel quantum cloning machine, which takes an input state and
produces an output state whose success branch can exist in a linear
superposition of multiple copies of the input state and the failure branch
exist in a superposition of composite state independent of the input state. We
prove that unknown non-orthogonal states chosen from a set $\cal S$ can evolve
into a linear superposition of multiple clones by a unitary process if and only
if the states are linearly independent. We derive a bound on the success
probability of the novel cloning machine. We argue that the deterministic and
probabilistic clonings are special cases of our novel cloning machine.
| [
{
"version": "v1",
"created": "Wed, 10 Mar 1999 16:44:39 GMT"
},
{
"version": "v2",
"created": "Sun, 22 Aug 1999 13:56:55 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Pati",
"Arun Kumar",
""
]
] |
quant-ph/9903039 | Joseph R. Buck | J. R. Buck, S. J. van Enk, and Christopher A. Fuchs | Experimental Proposal for Achieving Superadditive Communication
Capacities with a Binary Quantum Alphabet | 7 pages, 5 figures | Phys.Rev.A61:032309,2000 | 10.1103/PhysRevA.61.032309 | null | quant-ph | null | We demonstrate superadditivity in the communication capacity of a binary
alphabet consisting of two nonorthogonal quantum states. For this scheme,
collective decoding is performed two transmissions at a time. This improves
upon the previous schemes of Sasaki et al. [Phys. Rev. A 58, 146 (1998)] where
superadditivity was not achieved until a decoding of three or more
transmissions at a time. This places superadditivity within the regime of a
near-term laboratory demonstration. We propose an experimental test based upon
an alphabet of low photon-number coherent states where the signal decoding is
done with atomic state measurements on a single atom in a high-finesse optical
cavity.
| [
{
"version": "v1",
"created": "Fri, 12 Mar 1999 01:27:36 GMT"
},
{
"version": "v2",
"created": "Tue, 23 Mar 1999 19:35:31 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Buck",
"J. R.",
""
],
[
"van Enk",
"S. J.",
""
],
[
"Fuchs",
"Christopher A.",
""
]
] |
quant-ph/9903040 | Daniel Braun | Daniel Braun, Petr A. Braun and Fritz Haake | Long-lived Quantum Coherence between Macroscopically Distinct States in
Superradiance | 4 pages of revtex | Opt. Comm. {\bf 179}, 195 (2000) | 10.1016/S0030-4018(99)00480-0 | null | quant-ph cond-mat.mes-hall physics.optics | null | The dephasing influence of a dissipative environment reduces linear
superpositions of macroscopically distinct quantum states (sometimes also
called Schr\"odinger cat states) usually almost immediately to a statistical
mixture. This process is called decoherence. Couplings to the environment with
a certain symmetry can lead to slow decoherence. In this Letter we show that
the collective coupling of a large number of two-level atoms to an
electromagnetic field mode in a cavity that leads to the phenomena of
superradiance has such a symmetry, at least approximately. We construct
superpositions of macroscopically distinct quantum states decohering only on a
classical time scale and propose an experiment in which the extraordinarily
slow decoherence should be observable.
| [
{
"version": "v1",
"created": "Thu, 11 Mar 1999 14:23:10 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Braun",
"Daniel",
""
],
[
"Braun",
"Petr A.",
""
],
[
"Haake",
"Fritz",
""
]
] |
quant-ph/9903041 | Daniel Braun | Daniel Braun, Petr A. Braun and Fritz Haake | Slow Decoherence of Superpositions of Macroscopically Distinct States | 8 pages of revtex; to be published in proceedings of the 1998
Bielefeld Conference on 'Decoherence: Theoretical, Experimental, and
Conceptual Problems' | Lect.Notes Phys. 538 (2000) 55-66 | null | null | quant-ph cond-mat.mes-hall physics.optics | null | Linear superpositions of macroscopically distinct quantum states (sometimes
also called Schr\"odinger cat states) are usually almost immediately reduced to
a statistical mixture if exposed to the dephasing influence of a dissipative
environment. Couplings to the environment with a certain symmetry can lead to
slow decoherence, however. We give specific examples of slowly decohering
Schr\"odinger cat states in a realistic quantum optical system and discuss how
they might be constructed experimentally.
| [
{
"version": "v1",
"created": "Thu, 11 Mar 1999 14:55:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Braun",
"Daniel",
""
],
[
"Braun",
"Petr A.",
""
],
[
"Haake",
"Fritz",
""
]
] |
quant-ph/9903042 | Farrokh Vatan | Vwani P. Roychowdhury and Farrokh Vatan | An Almost-Quadratic Lower Bound for Quantum Formula Size | 14 pages, 6 figures | null | null | null | quant-ph cs.CC | null | We show that Nechiporuk's method for proving lower bound for Boolean formulas
can be extended to the quantum case. This leads to an n^2 / log^2 n lower bound
for quantum formulas computing an explicit function. The only known previous
explicit lower bound for quantum formulas (by Yao) states that the majority
function does not have a linear-size quantum formula.
| [
{
"version": "v1",
"created": "Thu, 11 Mar 1999 23:09:24 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Roychowdhury",
"Vwani P.",
""
],
[
"Vatan",
"Farrokh",
""
]
] |
quant-ph/9903043 | T. K. Rai Dastidar | T K Rai Dastidar (Indian Association for the Cultivation of Science,
Calcutta, India) | A Possible Anisotropy in Blackbody Radiation Viewed through Non-uniform
Gaseous Matter | 7 pages, 1 figure. This is a modified version accepted for
publication in Modern Physics Letters A | Mod.Phys.Lett. A14 (1999) 1193-1198 | null | null | quant-ph astro-ph hep-th | null | A non-local gauge symmetry of a complex scalar field, which can be trivially
extended to spinor fields, was demonstrated in a recent paper (Mod.Phys.Lett.
A13, 1265 (1998) ; hep-th/9902020). The corresponding covariant Lagrangian
density yielded a new, non-local Quantum Electrodynamics. In this letter we
show that as a consequence of this new QED, a blackbody radiation viewed
through gaseous matter appears to show a slight deviation from the Planck
formula, and propose an experimental test to check this effect. We also show
that a non-uniformity in this gaseous matter distribution leads to an
(apparent) spatial anisotropy in the blackbody radiation.
| [
{
"version": "v1",
"created": "Fri, 12 Mar 1999 07:56:57 GMT"
},
{
"version": "v2",
"created": "Mon, 7 Jun 1999 04:44:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dastidar",
"T K Rai",
"",
"Indian Association for the Cultivation of Science,\n Calcutta, India"
]
] |
quant-ph/9903044 | Anders Sorensen | Anders Sorensen and Klaus Molmer | Spin-spin interaction and spin-squeezing in an optical lattice | 4 pages, including 4 figures | Phys.Rev.Lett.83:2274-2277,1999 | 10.1103/PhysRevLett.83.2274 | null | quant-ph | null | We show that by displacing two optical lattices with respect to each other,
we may produce interactions similar to the ones describing ferro-magnetism in
condensed matter physics. We also show that particularly simple choices of the
interaction lead to spin-squeezing, which may be used to improve the
sensitivity of atomic clocks. Spin-squeezing is generated even with partially,
and randomly, filled lattices, and our proposal may be implemented with current
technology.
| [
{
"version": "v1",
"created": "Fri, 12 Mar 1999 11:41:49 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Sorensen",
"Anders",
""
],
[
"Molmer",
"Klaus",
""
]
] |
quant-ph/9903045 | Alina Suzko | A.A.Suzko (Joint Institute for Nuclear Research, Dubna, Russia) | Inverse problem and Darboux transformations for two-dimensional
finite-difference Schredinger equation | 12 pages, 1 figure (s_fig.eps), Latex | null | null | ESI-665 | quant-ph | null | A discrete version of the two-dimensional inverse scattering problem is
considered. On this basis, algebraic transformations for the two-dimensional
finite-difference Schredinger equation are elaborated.
| [
{
"version": "v1",
"created": "Fri, 12 Mar 1999 17:34:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Suzko",
"A. A.",
"",
"Joint Institute for Nuclear Research, Dubna, Russia"
]
] |
quant-ph/9903046 | Cristopher Moore | Cristopher Moore | Quantum Circuits: Fanout, Parity, and Counting | null | null | null | null | quant-ph | null | We propose definitions of QAC^0, the quantum analog of the classical class
AC^0 of constant-depth circuits with AND and OR gates of arbitrary fan-in, and
QACC^0[q], where n-ary Mod-q gates are also allowed. We show that it is
possible to make a `cat' state on n qubits in constant depth if and only if we
can construct a parity or Mod-2 gate in constant depth; therefore, any circuit
class that can fan out a qubit to n copies in constant depth also includes
QACC^0[2]. In addition, we prove the somewhat surprising result that parity or
fanout allows us to construct Mod-q gates in constant depth for any q, so
QACC^0[2] = QACC^0. Since ACC^0[p] != ACC^0[q] whenever p and q are mutually
prime, QACC^0[2] is strictly more powerful than its classical counterpart, as
is QAC^0 when fanout is allowed.
| [
{
"version": "v1",
"created": "Sat, 13 Mar 1999 03:59:28 GMT"
},
{
"version": "v2",
"created": "Sun, 14 Mar 1999 00:04:15 GMT"
},
{
"version": "v3",
"created": "Wed, 17 Mar 1999 00:43:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Moore",
"Cristopher",
""
]
] |
quant-ph/9903047 | Yoon-Ho Kim | Yoon-Ho Kim, R. Yu, S.P. Kulik, Y.H. Shih, and Marlan .O. Scully | A Delayed Choice Quantum Eraser | twocolumn, 4pages, submitted to PRL | Phys.Rev.Lett.84:1-5,2000 | 10.1103/PhysRevLett.84.1 | null | quant-ph | null | This paper reports a "delayed choice quantum eraser" experiment proposed by
Scully and Dr\"{u}hl in 1982. The experimental results demonstrated the
possibility of simultaneously observing both particle-like and wave-like
behavior of a quantum via quantum entanglement. The which-path or both-path
information of a quantum can be erased or marked by its entangled twin even
after the registration of the quantum.
| [
{
"version": "v1",
"created": "Sat, 13 Mar 1999 04:37:12 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Kim",
"Yoon-Ho",
""
],
[
"Yu",
"R.",
""
],
[
"Kulik",
"S. P.",
""
],
[
"Shih",
"Y. H.",
""
],
[
"Scully",
"Marlan . O.",
""
]
] |
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