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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
quant-ph/9901013 | Luigi Foschini | Luigi Foschini | Questions on the concept of time | 4 pages, no figures | null | null | null | quant-ph | null | Some notes and questions about the concept of time are exposed. Particular
reference is given to the problem in quantum mechanics, in connection with the
indeterminacy principle.
| [
{
"version": "v1",
"created": "Fri, 8 Jan 1999 10:37:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Foschini",
"Luigi",
""
]
] |
quant-ph/9901014 | Massimiliano F. Sacchi | G. M. D'Ariano, M. F. Sacchi, and P. Kumar | Tomographic measurement of nonclassical radiation states | 5 pages, two columns, 8 eps figures, RevTex | Phys.Rev. A59 (1999) 826-830 | 10.1103/PhysRevA.59.826 | null | quant-ph | null | We propose to experimentally test the nonclassicality of quantum states
through homodyne tomography. For single-mode states we check violations of
inequalities involving the photon-number probability. For two-mode states we
test the nonclassicality by reconstructing some suitable number-operator
functions. The test can be performed with available quantum efficiency of
homodyne detection, by measuring the pertaining quantities on the corresponding
noisy states.
| [
{
"version": "v1",
"created": "Fri, 8 Jan 1999 11:01:15 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"D'Ariano",
"G. M.",
""
],
[
"Sacchi",
"M. F.",
""
],
[
"Kumar",
"P.",
""
]
] |
quant-ph/9901015 | Qiu-Yu Liu | Hong-Yi Fan (USTC, HeFei) and Q.Y. Liu (ICTP, Trieste) | Operator for Describing Polarization States of a Photon | This version (5 pages) will be published in the European Physical
Journal D | Eur.Phys.J. D8 (2000) 399-402 | 10.1007/s100530050050 | null | quant-ph | null | Based on the quantized electromagnetic field described by the
Riemann-Silberstein complex vector $F$, we construct the eigenvector set of $%
F$, which makes up an orthonormal and complete representation. In terms of $% F
$ we then introduce a new operator which can describe the relative ratio of the
left-handed and right-handed polarization states of a polarized photon .In
$F^{\prime}s$ eigenvector basis the operator manifestly exhibits a behaviour
which is similar to a phase difference between two orientations of polarization
of a light beam in classical optics.
| [
{
"version": "v1",
"created": "Fri, 8 Jan 1999 16:11:27 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Sep 1999 17:40:00 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Fan",
"Hong-Yi",
"",
"USTC, HeFei"
],
[
"Liu",
"Q. Y.",
"",
"ICTP, Trieste"
]
] |
quant-ph/9901016 | Jun Yan | Guang-jiong Ni, Jun Yan | Lamb shift calculated by simple noncovariant method | 9 pages, Revtex, 1 Postscript figure | null | null | null | quant-ph | null | The Lamb Shift (LS) of Hydrogenlike atom is evaluated by a simple method of
quantum electrodynamics in noncovariant form, based on the relativistic
stationary Schr\"odinger equation. An induced term proportional to
$\overrightarrow{p}^4$ in the effective Hamiltonian is emphasized. Perturbative
calculation of second order leads to the LS of $ 1S_{1/2}$ state and that of
$2S_{1/2}-2P_{1/2}$ states in H atom with the high accuracy within 0.1%
| [
{
"version": "v1",
"created": "Fri, 8 Jan 1999 18:29:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ni",
"Guang-jiong",
""
],
[
"Yan",
"Jun",
""
]
] |
quant-ph/9901017 | Sharon Jensen | H. Pierre Noyes | Thoughts on Commutation Relations and Measurement Accuracy | LaTex, 8 pages | null | null | SLAC-PUB-7772 | quant-ph | null | We show that measuring the trajectories of charged particles to finite
accuracy leads to the commutation relations needed for the derivation of the
free space Maxwell equations using the {\it discrete ordered calculus} (DOC).
We note that the finite step length derivation of the discrete difference
version of the single particle Dirac equation implies the discrete version of
the p,q commutation relations for a free particle. We speculate that a careful
operational analysis of the change in momenta occurring in a step-wise
continuous solution of the discrete Dirac equation could supply the missing
source-sink terms in the DOC derivation of the Maxwell equations, and lead to a
finite and discrete (``renormalized'') quantum electrodynamics (QED).
| [
{
"version": "v1",
"created": "Fri, 8 Jan 1999 18:52:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Noyes",
"H. Pierre",
""
]
] |
quant-ph/9901018 | Jun Yan | Guang-jiong Ni, Weimin Zhou and Jun Yan | Comparison among Klein-Gordon equation, Dirac equation and Relativistic
Stationary Schrodinger equation | 10 pages, Revtex, 10 Postscript figures | null | null | null | quant-ph | null | A particle is always not pure. It always contains hiding antiparticle
ingredient which is the essence of special relativity. Accordingly, the
Klein-Gordon (KG) equation and Dirac equation are restudied and compared with
the Relativistic Stationary Schr\"odinger Equation (RSSE). When an electron is
bound in a Hydrogenlike atom with pointlike nucleus having charge number $Z$,
the critical value of $Z, Z_c$, equals to 137 in Dirac equation whereas
$Z_c=\sqrt{M/\mu} (137)$ in RSSE with $M$ and $\mu$ being the total mass of
atom and the reduced mass of the electron.
| [
{
"version": "v1",
"created": "Fri, 8 Jan 1999 19:01:24 GMT"
},
{
"version": "v2",
"created": "Fri, 25 Feb 2000 07:43:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ni",
"Guang-jiong",
""
],
[
"Zhou",
"Weimin",
""
],
[
"Yan",
"Jun",
""
]
] |
quant-ph/9901019 | Shuichi Matsumoto | Shoju Kudaka and Shuichi Matsumoto | Uncertainty principle for proper time and mass | 15 pages, accepted for publication in J. Math. Phys | J.Math.Phys. 40 (1999) 1237-1245 | 10.1063/1.532797 | null | quant-ph | null | We review Bohr's reasoning in the Bohr-Einstein debate on the photon box
experiment. The essential point of his reasoning leads us to an uncertainty
relation between the proper time and the rest mass of the clock. It is shown
that this uncertainty relation can be derived if only we take the fundamental
point of view that the proper time should be included as a dynamic variable in
the Lagrangian describing the system of the clock. Some problems and some
positive aspects of our approach are then discussed.
| [
{
"version": "v1",
"created": "Sat, 9 Jan 1999 07:49:30 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kudaka",
"Shoju",
""
],
[
"Matsumoto",
"Shuichi",
""
]
] |
quant-ph/9901020 | Paulo Americo Maia Neto | J. P. F. Mendonca, P. A. Maia Neto and F. I. Takakura | Quantum photon emission from a moving mirror in the nonperturbative
regime | 11 pages, 3 figures. To be published in Optics Communications | null | 10.1016/S0030-4018(98)00658-0 | null | quant-ph | null | We consider the coupling of the electromagnetic vacuum field with an
oscillating perfectly-reflecting mirror in the nonrelativistic approximation.
As a consequence of the frequency modulation associated to the motion of the
mirror, low frequency photons are generated. We calculate the photon emission
rate by following a nonperturbative approach, in which the coupling between the
field sidebands is taken into account. We show that the usual perturbation
theory fails to account correctly for the contribution of TM-polarized vacuum
fluctuations that propagate along directions nearly parallel to the plane
surface of the mirror.
As a result of the modification of the field eigenfunctions, the resonance
frequency for photon emission is shifted from its unperturbed value.
| [
{
"version": "v1",
"created": "Sat, 9 Jan 1999 12:47:34 GMT"
},
{
"version": "v2",
"created": "Mon, 1 Feb 1999 18:12:22 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Mendonca",
"J. P. F.",
""
],
[
"Neto",
"P. A. Maia",
""
],
[
"Takakura",
"F. I.",
""
]
] |
quant-ph/9901021 | Richard Jozsa | Richard Jozsa | Searching in Grover's Algorithm | 8 pages, Latex | null | null | null | quant-ph | null | Grover's algorithm is usually described in terms of the iteration of a
compound operator of the form $Q = - H I_{0} H I_{x_0}$. Although it is quite
straightforward to verify the algebra of the iteration, this gives little
insight into why the algorithm works. What is the significance of the compound
structure of $Q$? Why is there a minus sign? Later it was discovered that $H$
could be replaced by essentially any unitary $U$. What is the freedom involved
here? We give a description of Grover's algorithm which provides some
clarification of these questions.
| [
{
"version": "v1",
"created": "Sat, 9 Jan 1999 21:06:29 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Jozsa",
"Richard",
""
]
] |
quant-ph/9901022 | null | H.Razmi, A.H.Abbassi | The Quantization of Free EM Fields: An Alternative Approach to solve the
Vacuum Catastrophe | 10 pages LaTeX,no figure | null | null | TMU-99-01 | quant-ph astro-ph gr-qc hep-ph hep-th | null | It is shown that the canonical quantum field theory of radiation based on the
field theoretical generalization of a recently proposed [1] commutation
relation between position and momentum operators of massless particles leads to
zero vacuum energy. This may be considered as a step toward the solution of the
cosmological constant problem at least for the electromagnetic (EM) field's
contribution.
| [
{
"version": "v1",
"created": "Sun, 10 Jan 1999 08:19:32 GMT"
}
] | 2012-12-18T00:00:00 | [
[
"Razmi",
"H.",
""
],
[
"Abbassi",
"A. H.",
""
]
] |
quant-ph/9901023 | WD Heiss | W.D. Heiss | Phases of Wave Functions and Level Repulsion | 4 pages Latex, 2 figures encapsulated postscripts (*.epsi) submitted
to The European Physical Journal D | null | 10.1007/s100530050339 | null | quant-ph | null | Avoided level crossings are associated with exceptional points which are the
singularities of the spectrum and eigenfunctions, when they are considered as
functions of a coupling parameter. It is shown that the wave function of {\it
one} state changes sign but not the other, if the exceptional point is
encircled in the complex plane. An experimental setup is suggested where this
peculiar phase change could be observed.
| [
{
"version": "v1",
"created": "Mon, 11 Jan 1999 10:17:19 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Heiss",
"W. D.",
""
]
] |
quant-ph/9901024 | Chau Hoi Fung | H. F. Chau | Quantum-Classical Complexity-Security Tradeoff In Secure Multi-Party
Computation | Greatly expanded and clarified, 10 pages, requires amsfonts | null | 10.1103/PhysRevA.61.032308 | null | quant-ph | null | I construct a secure multi-party scheme to compute a classical function by a
succinct use of a specially designed fault-tolerant random polynomial quantum
error correction code. This scheme is secure provided that (asymptotically)
strictly greater than five-sixths of the players are honest. Moreover, the
security of this scheme follows directly from the theory of quantum error
correcting code, and hence is valid without any computational assumption. I
also discuss the quantum-classical complexity-security tradeoff in secure
multi-party computation schemes and argue why a full-blown quantum code is
necessary in my scheme.
| [
{
"version": "v1",
"created": "Mon, 11 Jan 1999 10:28:20 GMT"
},
{
"version": "v2",
"created": "Mon, 20 Sep 1999 16:14:03 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Chau",
"H. F.",
""
]
] |
quant-ph/9901025 | Daniel Gottesman | Richard Cleve, Daniel Gottesman, and Hoi-Kwong Lo | How to share a quantum secret | 5 pages, REVTeX, submitted to PRL | Phys.Rev.Lett. 83 (1999) 648-651 | 10.1103/PhysRevLett.83.648 | LAUR98-5842 | quant-ph | null | We investigate the concept of quantum secret sharing. In a ((k,n)) threshold
scheme, a secret quantum state is divided into n shares such that any k of
those shares can be used to reconstruct the secret, but any set of k-1 or fewer
shares contains absolutely no information about the secret. We show that the
only constraint on the existence of threshold schemes comes from the quantum
"no-cloning theorem", which requires that n < 2k, and, in all such cases, we
give an efficient construction of a ((k,n)) threshold scheme. We also explore
similarities and differences between quantum secret sharing schemes and quantum
error-correcting codes. One remarkable difference is that, while most existing
quantum codes encode pure states as pure states, quantum secret sharing schemes
must use mixed states in some cases. For example, if k <= n < 2k-1 then any
((k,n)) threshold scheme must distribute information that is globally in a
mixed state.
| [
{
"version": "v1",
"created": "Tue, 12 Jan 1999 00:49:09 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Cleve",
"Richard",
""
],
[
"Gottesman",
"Daniel",
""
],
[
"Lo",
"Hoi-Kwong",
""
]
] |
quant-ph/9901026 | Anirban Roy | G. Kar, A. Roy, S. Ghosh, D. Sarkar | Noncomplemetary Wave-Particle Phenomena Revisited | 11 pages Latex | null | null | null | quant-ph | null | The simultaneous verification of wave and particle property in some recently
suggested experiments has been reviewed in the light of Hilbert space
formalism. In this respect, the recent analysis of biprism experiment [J. L.
Cereceda, Am. J. Phys. 64 (1996) 459] is criticized.
| [
{
"version": "v1",
"created": "Tue, 12 Jan 1999 07:25:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kar",
"G.",
""
],
[
"Roy",
"A.",
""
],
[
"Ghosh",
"S.",
""
],
[
"Sarkar",
"D.",
""
]
] |
quant-ph/9901027 | Armin Uhlmann | Armin Uhlmann | Quantum channels of the Einstein-Podolski-Rosen kind | LATEX, 13 pages. To appear in: Proceedings of the XII Max Born
Symposium FINE DE SIECLE, Wroclaw, September 1998 | Lect.Notes Phys. 539 (2000) 93-108 | null | null | quant-ph | null | Assume the quantum state of a bipartite system is known. The result of local
von Neumann measurements can be described by maps from one subsystem to the
other one. Main properties of these antilinear ''EPR-channel'' maps are shortly
discussed. Talk in honour of Jan Lopuszanski.
| [
{
"version": "v1",
"created": "Wed, 13 Jan 1999 10:10:01 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Uhlmann",
"Armin",
""
]
] |
quant-ph/9901028 | Paolo Facchi | P. Facchi, S. Pascazio and A. Scardicchio | Measurement-induced quantum diffusion | 8 pages | Phys.Rev.Lett. 83 (1999) 61-64 | 10.1103/PhysRevLett.83.61 | BA-TH/99-295 | quant-ph | null | The dynamics of a kicked quantum system undergoing repeated measurements of
momentum is investigated. A diffusive behavior is obtained even when the
dynamics of the classical counterpart is not chaotic. The diffusion coefficient
is explicitly computed for a large class of Hamiltonians and compared to the
classical case.
| [
{
"version": "v1",
"created": "Wed, 13 Jan 1999 16:32:07 GMT"
},
{
"version": "v2",
"created": "Wed, 31 Mar 1999 11:35:35 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Facchi",
"P.",
""
],
[
"Pascazio",
"S.",
""
],
[
"Scardicchio",
"A.",
""
]
] |
quant-ph/9901029 | Peter Hoyer | Mark Ettinger (LANL) and Peter Hoyer (BRICS) | A Quantum Observable for the Graph Isomorphism Problem | 5 pages, no figures | null | null | LA-UR-99-179 | quant-ph | null | Suppose we are given two graphs on $n$ vertices. We define an observable in
the Hilbert space $\Co[(S_n \wr S_2)^m]$ which returns the answer ``yes'' with
certainty if the graphs are isomorphic and ``no'' with probability at least
$1-n!/2^m$ if the graphs are not isomorphic. We do not know if this observable
is efficiently implementable.
| [
{
"version": "v1",
"created": "Wed, 13 Jan 1999 20:35:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ettinger",
"Mark",
"",
"LANL"
],
[
"Hoyer",
"Peter",
"",
"BRICS"
]
] |
quant-ph/9901030 | Matt Visser | Matt Visser (Washington University) | Some general bounds for 1-D scattering | 12 pages, ReV-TeX 3.2 Published: Physical Review A59 (1999) 427--438 | Phys.Rev. A59 (1999) 427-438 | 10.1103/PhysRevA.59.427 | null | quant-ph math-ph math.MP | null | One-dimensional scattering problems are of wide physical interest and are
encountered in many diverse applications. In this article I establish some very
general bounds for reflection and transmission coefficients for one-dimensional
potential scattering. Equivalently, these results may be phrased as general
bounds on the Bogolubov coefficients, or statements about the transfer matrix.
A similar analysis can be provided for the parametric change of frequency of a
harmonic oscillator. A number of specific examples are discussed---in
particular I provide a general proof that sharp step function potentials always
scatter more effectively than the corresponding smoothed potentials. The
analysis also serves to collect together and unify what would otherwise appear
to be quite unrelated results.
| [
{
"version": "v1",
"created": "Thu, 14 Jan 1999 05:29:26 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Visser",
"Matt",
"",
"Washington University"
]
] |
quant-ph/9901031 | Shuichi Matsumoto | Shoju Kudaka and Shuichi Matsumoto | Uncertainty principle for proper time and mass II | 15 pages, LaTex | null | null | null | quant-ph | null | When we quantize a system consisting of a single particle, the proper time
$\tau $ and the rest mass $m$ are usually dealt with as parameters. In the
present article, however, we introduce a new quantization rule by which these
quantities are regarded as operators in addition to the position and the
momentum. Applying this new rule to a scalar particle and to a particle with
spin $ 1/2 $, we analyze the time evolution of the operator $\tau $. In the
former case, the evolution of the proper time perfectly matches several
well-established classical formulae. In the case of the particle with spin 1/2,
our new rule implies that an oscillation appears in the time evolution of the
operator $\tau $. This oscillation is similar to Zitterbewegung which is
well-known in the ordinary Dirac theory. We formulate one physical effect of
this oscillation by considering the interaction with a gravitational field, and
estimate how small it is.
| [
{
"version": "v1",
"created": "Thu, 14 Jan 1999 09:33:29 GMT"
},
{
"version": "v2",
"created": "Wed, 20 Jan 1999 09:28:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kudaka",
"Shoju",
""
],
[
"Matsumoto",
"Shuichi",
""
]
] |
quant-ph/9901032 | Enrique Solano | J. C. Retamal, E. Solano and N. Zagury | Ultracold atoms interacting with a sinusoidal mode of a high-Q cavity | 6 ReVTeX pages and 4 figures, .zip file | Opt.Commun. 154 (1998) 28-34 | 10.1016/S0030-4018(98)00276-4 | null | quant-ph | null | We consider the interaction of two level ultracold atoms resonant with a
sinusoidal mode of the electromagnetic field in a high Q cavity. We found that
well resolved resonances appear in the transmission coefficients even for
actual interaction and cavity parameters. The probability of emission of one
photon and the probability of transmission of an atom, when a number of
coherent states is initially present in the cavity, are discussed. The
interplay between the increasing width of the resonances and multi-peak
steady-state photon-statistics is also studied. Furthermore, we compare our
results with those of a constant field mode.
| [
{
"version": "v1",
"created": "Thu, 14 Jan 1999 17:04:41 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Retamal",
"J. C.",
""
],
[
"Solano",
"E.",
""
],
[
"Zagury",
"N.",
""
]
] |
quant-ph/9901033 | Dr. Arun Kumar Pati | Arun Kumar Pati | Uncertainty relation of Anandan-Aharonov and Intelligent states | Latex, no figures, minor changes, 7 pages | Phys.Lett. A262 (1999) 296-301 | 10.1016/S0375-9601(99)00701-X | null | quant-ph | null | The quantum states which satisfy the equality in the generalised uncertainty
relation are called intelligent states. We prove the existence of intelligent
states for the Anandan-Aharonov uncertainty relation based on the geometry of
the quantum state space for arbitrary parametric evolutions of quantum states
when the initial and final states are non-orthogonal.
| [
{
"version": "v1",
"created": "Thu, 14 Jan 1999 18:10:05 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Nov 1999 18:39:40 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Pati",
"Arun Kumar",
""
]
] |
quant-ph/9901034 | Peter Hoyer | Mark Ettinger (LANL), Peter Hoyer (BRICS) and Emanuel Knill (LANL) | Hidden Subgroup States are Almost Orthogonal | 5 pages, no figures | null | null | null | quant-ph | null | It is well known that quantum computers can efficiently find a hidden
subgroup $H$ of a finite Abelian group $G$. This implies that after only a
polynomial (in $\log |G|$) number of calls to the oracle function, the states
corresponding to different candidate subgroups have exponentially small inner
product. We show that this is true for noncommutative groups also. We present a
quantum algorithm which identifies a hidden subgroup of an arbitrary finite
group $G$ in only a linear (in $\log |G|$) number of calls to the oracle
function. This is exponentially better than the best classical algorithm.
However our quantum algorithm requires an exponential amount of time, as in the
classical case.
| [
{
"version": "v1",
"created": "Thu, 14 Jan 1999 23:48:55 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ettinger",
"Mark",
"",
"LANL"
],
[
"Hoyer",
"Peter",
"",
"BRICS"
],
[
"Knill",
"Emanuel",
"",
"LANL"
]
] |
quant-ph/9901035 | Richard Cleve | Gilles Brassard, Richard Cleve, Alain Tapp | The cost of exactly simulating quantum entanglement with classical
communication | 9 pages, LaTeX, no figures | Phys.Rev.Lett. 83 (1999) 1874-1877 | 10.1103/PhysRevLett.83.1874 | null | quant-ph | null | We investigate the amount of communication that must augment classical local
hidden variable models in order to simulate the behaviour of entangled quantum
systems. We consider the scenario where a bipartite measurement is given from a
set of possibilities and the goal is to obtain exactly the same correlations
that arise when the actual quantum system is measured. We show that, in the
case of a single pair of qubits in a Bell state, a constant number of bits of
communication is always sufficient--regardless of the number of measurements
under consideration. We also show that, in the case of a system of n Bell
states, a constant times 2^n bits of communication are necessary.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 00:51:49 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Brassard",
"Gilles",
""
],
[
"Cleve",
"Richard",
""
],
[
"Tapp",
"Alain",
""
]
] |
quant-ph/9901036 | Dong Shi Hai | Shi-Hai Dong and Zhong-Qi Ma | Exact Solutions to the Schr\"{o}dinger Equation for the Inverse-Power
Potential in Two Dimensions | Latex file 9 pages and submit to Euro. Phys. J. D | null | null | null | quant-ph | null | Utilizing an ${\it ansatz}$ for the eigenfunctions, we arrive at an exact
closed form solution to the Schr\"{o}dinger equation with the inverse-power
potential, $V(r)=ar^{-4}+br^{-3}+cr^{-2}+dr^{-1}$ in two dimensions, where the
parameters of the potential $a, b, c, d$ satisfy a constraint.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 01:51:56 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dong",
"Shi-Hai",
""
],
[
"Ma",
"Zhong-Qi",
""
]
] |
quant-ph/9901037 | Dong Shi Hai | Shi-Hai Dong and Zhong-Qi Ma | The Exact Solution to the Schr\"{o}dinger Equation with the Octic
Potential | Latex file 9 pages and submit to J. P. A | null | null | null | quant-ph | null | The Schr\"{o}dinger equation with the central potential is first studied in
the arbitrary dimensional spaces and obtained an analogy of the two-dimensional
Schr\"{o}dinger equation for the radial wave function through a simple
transformation. As an example, applying an ${\it ansatz}$ to the
eigenfunctions, we then arrive at an exact closed form solution to the modified
two-dimensional Schr\"{o}dinger equation with the octic potential,
$V(r)=ar^2-br^4+cr^6-dr^4+er^{10}$.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 02:10:43 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dong",
"Shi-Hai",
""
],
[
"Ma",
"Zhong-Qi",
""
]
] |
quant-ph/9901038 | Levente Horvath | L. Horvath, B. C. Sanders, B. F. Wielinga | Multiphoton Coincidence Spectroscopy | 6 page, REVTeXs, 6 Postscript figures. The abstract appeared in the
Proceedings of ACOLS98 | J.Opt.B Quant.Semiclass.Opt. 1 (1999) 446-451 | 10.1088/1464-4266/1/4/315 | null | quant-ph | null | We extend the analysis of photon coincidence spectroscopy beyond bichromatic
excitation and two-photon coincidence detection to include multichromatic
excitation and multiphoton coincidence detection. Trichromatic excitation and
three-photon coincidence spectroscopy are studied in detail, and we identify an
observable signature of a triple resonance in an atom-cavity system.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 03:10:43 GMT"
},
{
"version": "v2",
"created": "Tue, 10 Jul 2001 10:08:24 GMT"
}
] | 2009-09-25T00:00:00 | [
[
"Horvath",
"L.",
""
],
[
"Sanders",
"B. C.",
""
],
[
"Wielinga",
"B. F.",
""
]
] |
quant-ph/9901039 | 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. IV. Mixed
states and evolution transport's curvature | 14 standard (11pt, A4) LaTeX 2e pages. The packages AMS-LaTeX and
amsfonts are required. Minor style changes, a problem with the bibliography
is corrected. Continuation of quant-ph/9803083, quant-ph/9803084,
quant-ph/9804062 and quant-ph/9806046. For continuation of the series and
related papers, view http://www.inrne.bas.bg/mathmod/bozhome/ | Int.J.Mod.Phys. A17 (2002) 229-243 | 10.1142/S0217751X02005669 | 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.
The present fourth part of this series is devoted mainly to the fibre bundle
description of mixed quantum states. We show that to the conventional density
operator there corresponds a unique density morphism (along paths) for which
the corresponding equations of motion are derived. It is also investigated the
bundle description of mixed quantum states in the different pictures of motion.
We calculate the curvature of the evolution transport and prove that it is
curvature free iff the values of the Hamiltonian operator at different moments
commute.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 07:23:49 GMT"
},
{
"version": "v2",
"created": "Sat, 20 Feb 1999 14:01:49 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/9901040 | null | J. P. Palao, J. G. Muga, S. Brouard, A. Jadczyk | Barrier traversal times using a phenomenological track formation model | LATEX, 11 pages, 2 ps figures | Phys.Lett. A233 (1997) 227-232 | 10.1016/S0375-9601(97)00466-0 | ULLFIS-980101 | quant-ph | null | A phenomenological model for a measurement of barrier traversal times for
particles is proposed. Two idealized detectors for passage and arrival provide
entrance and exit times for the barrier traversal. The averaged traversal time
is computed over the ensemble of particles detected twice, before and after the
barrier. The Hartman effect can still be found when passage detectors that
conserve the momentum distribution of the incident packet are used.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 15:45:23 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Palao",
"J. P.",
""
],
[
"Muga",
"J. G.",
""
],
[
"Brouard",
"S.",
""
],
[
"Jadczyk",
"A.",
""
]
] |
quant-ph/9901041 | null | J. G. Muga, J. P. Palao, R. Sala | Average local values and local variances in quantum mechanics | 9 pages, no figures, LATEX | Phys.Lett. A238 (1998) 90 | 10.1016/S0375-9601(97)00902-X | ULLFIS980102 | quant-ph | null | Several definitions for the average local value and local variance of a
quantum observable are examined and compared with their classical counterparts.
An explicit way to construct an infinite number of these quantities is
provided. It is found that different classical conditions may be satisfied by
different definitions, but none of the quantum definitions examined is entirely
consistent with all classical requirements.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 16:16:52 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Muga",
"J. G.",
""
],
[
"Palao",
"J. P.",
""
],
[
"Sala",
"R.",
""
]
] |
quant-ph/9901042 | null | R. Sala, J. P. Palao, J, G. Muga | Phase space formalisms of quantum mechanics with singular kernel | 15 pages, no figures, LATEX | Phys.Lett. A231 (1997) 304 | 10.1016/S0375-9601(97)00336-8 | ULLFIS980103 | quant-ph | null | The equivalence of the Rivier-Margenau-Hill and Born-Jordan-Shankara phase
space formalisms to the conventional operator approach of quantum mechanics is
demonstrated. It is shown that in spite of the presence of singular kernels the
mappings relating phase space functions and operators back and forth are
possible.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 16:32:54 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Sala",
"R.",
""
],
[
"Palao",
"J. P.",
""
],
[
"J",
"",
""
],
[
"Muga",
"G.",
""
]
] |
quant-ph/9901043 | Nicolas Gisin | N. Gisin, J. Brendel, J-D. Gautier, B. Gisin, B. Huttner, G. Ribordy,
W. Tittel, H. Zbinden | Quantum cryptography and long distance Bell experiments: How to control
decoherence | To appear in the proceedings of the workshop on "Decoherence"
organised by the ZIF in Bielefeld, October 1998. 6 pages + 5 figures | Lect.Notes Phys. 538 (2000) 191-200 | null | null | quant-ph | null | Several mechanisms that affect one and two photon coherence in optical fibers
and their remedies are discussed. The results are illustrated on quantum
cryptography experiments and on long distance Bell inequality tests.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 17:03:07 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gisin",
"N.",
""
],
[
"Brendel",
"J.",
""
],
[
"Gautier",
"J-D.",
""
],
[
"Gisin",
"B.",
""
],
[
"Huttner",
"B.",
""
],
[
"Ribordy",
"G.",
""
],
[
"Tittel",
"W.",
""
],
[
"Zbinden",
"H.",
""
]
] |
quant-ph/9901044 | Fabrizio Illuminati | Gerd Breitenbach, Fabrizio Illuminati, Stephan Schiller and Jurgen
Mlynek | Broadband detection of squeezed vacuum: A spectrum of quantum states | 11 pages, 5 figures | Europhys.Lett. 44 (1998) 192 | 10.1209/epl/i1998-00456-2 | null | quant-ph | null | We demonstrate the simultaneous quantum state reconstruction of the spectral
modes of the light field emitted by a continuous wave degenerate optical
parametric amplifier. The scheme is based on broadband measurement of the
quantum fluctuations of the electric field quadratures and subsequent Fourier
decomposition into spectral intervals. Applying the standard reconstruction
algorithms to each bandwidth-limited quantum trajectory, a "spectrum" of
density matrices and Wigner functions is obtained. The recorded states show a
smooth transition from the squeezed vacuum to a vacuum state. In the time
domain we evaluated the first order correlation function of the squeezed output
field, showing good agreement with the theory.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 17:31:32 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Breitenbach",
"Gerd",
""
],
[
"Illuminati",
"Fabrizio",
""
],
[
"Schiller",
"Stephan",
""
],
[
"Mlynek",
"Jurgen",
""
]
] |
quant-ph/9901045 | Fabrizio Illuminati | Salvatore De Martino, Silvio De Siena and Fabrizio Illuminati | Inference of Planck action constant by a classical fluctuative postulate
holding for stable microscopic and macroscopic dynamical systems | 14 pages, no figures | Physica A271 (1999) 324-342 | 10.1016/S0378-4371(99)00208-3 | null | quant-ph | null | The possibility is discussed of inferring or simulating some aspects of
quantum dynamics by adding classical statistical fluctuations to classical
mechanics. We introduce a general principle of mechanical stability and derive
a necessary condition for classical chaotic fluctuations to affect confined
dynamical systems, on any scale, ranging from microscopic to macroscopic
domains. As a consequence we obtain, both for microscopic and macroscopic
aggregates, dimensional relations defining the minimum unit of action of
individual constituents, yielding in all cases Planck action constant.
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 17:52:03 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"De Martino",
"Salvatore",
""
],
[
"De Siena",
"Silvio",
""
],
[
"Illuminati",
"Fabrizio",
""
]
] |
quant-ph/9901046 | Jun Yan | Guang-jiong Ni and Hong Guan | Einstein-Podolsky-Rosen Paradox and Antiparticle | 4 pages, no figure, Revtex | null | null | null | quant-ph | null | The original version of Einstein-Podolsky-Rosen (EPR) paradox is discussed to
show the completeness of Quantum Mechanics (QM). The unique solution leads to
the wave function of antiparticle unambiguously, which implies the essential
conformity between QM and Special Relativity (SR).
| [
{
"version": "v1",
"created": "Fri, 15 Jan 1999 23:04:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ni",
"Guang-jiong",
""
],
[
"Guan",
"Hong",
""
]
] |
quant-ph/9901047 | Paolo-Zanardi | Paolo Zanardi (Institute for Scientific Interchange Foundation, and
Unit\`a INFM, Politecnico di Torino) | Computation on a Noiseless Quantum Code and Symmetrization | One result added, to appear in Phys. Rev. A (RC) 4 pages LaTeX, no
figures | Phys. Rev. A 60 (1999) R729 | 10.1103/PhysRevA.60.R729 | null | quant-ph | null | Let ${\cal H}$ be the state-space of a quantum computer coupled with the
environment by a set of error operators spanning a Lie algebra ${\cal L}.$
Suppose ${\cal L}$ admits a noiseless quantum code i.e., a subspace ${\cal
C}\subset{\cal H}$ annihilated by ${\cal L}.$ We show that a universal set of
gates over $\cal C$ is obtained by any generic pair of ${\cal L}$-invariant
gates. Such gates - if not available from the outset - can be obtained by
resorting to a symmetrization with respect to the group generated by ${\cal
L}.$ Any computation can then be performed completely within the coding
decoherence-free subspace.
| [
{
"version": "v1",
"created": "Sat, 16 Jan 1999 17:41:45 GMT"
},
{
"version": "v2",
"created": "Wed, 9 Jun 1999 09:15:00 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Zanardi",
"Paolo",
"",
"Institute for Scientific Interchange Foundation, and\n Unità INFM, Politecnico di Torino"
]
] |
quant-ph/9901048 | De-Horng Lin | De-Hone Lin | Path Integral on Relativistic Spinless Potential Problems | 4 pages, LaTeX file uses sprocl.sty, Talk given at the sixth
International Conference on Path-Integrals from peV to TeV 50 Years from
Feynman's Paper, Florence, Italy, 25-29 August 1998, to appear in the
Proceedings | null | null | null | quant-ph | null | The formulation of the relativistic spinless path integral on the general
affine space is presented. For the one dimensional space, the Duru-Kleinert
(DK) method and the $\delta $-function perturbation technique are applied to
solve the relativistic path integrals of the smooth potential and the Dirichlet
boundary condition problems, respectively.
| [
{
"version": "v1",
"created": "Sun, 17 Jan 1999 02:04:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lin",
"De-Hone",
""
]
] |
quant-ph/9901049 | De-Horng Lin | De-Hone Lin | Quantum Conditions of the Relativistic Potential Problems | 10 pages, ReVTeX, no figures | null | null | null | quant-ph | null | The quantum conditions of the relativistic integrable systems whose classical
motion is multiply periodic are given by considering the single-valuedness of
the linear superposition of the approximate solutions $R_{i}\exp
{\{iS_{i}/\hbar \}}$ with $R_{i}$ and $S_{i}$ being the solutions of the
different branches of the current conservation equation and the relativistic
Hamilton-Jacobian equation, respectively.
| [
{
"version": "v1",
"created": "Sun, 17 Jan 1999 02:05:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lin",
"De-Hone",
""
]
] |
quant-ph/9901050 | De-Horng Lin | De-Hone Lin | Quantization via Classical Orbits | 8 pages, ReVTeX, no figures | null | null | null | quant-ph | null | A systematic method for calculating higher-order corrections of the
relativistic semiclassical fixed-energy amplitude is given. The central scheme
in computing corrections of all orders is related to a time ordering operation
of an operator involving the Van Vleck determinant. This study provides us a
new viewpoint for quantization.
| [
{
"version": "v1",
"created": "Sun, 17 Jan 1999 02:05:50 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lin",
"De-Hone",
""
]
] |
quant-ph/9901051 | De-Horng Lin | De-Hone Lin | Green's Function of the Relativistic Coulomb System via Duru-Kleinert
Method | 10 pages, ReVTeX, no figures | null | null | null | quant-ph | null | In this paper the fixed-energy amplitude (Green's function) of the
relativistic Coulomb system is solved by Duru-Kleinert (DK) method. In the
course of the calculations we observe an equivalence between the relativistic
Coulomb system and a radial oscillator.
| [
{
"version": "v1",
"created": "Sun, 17 Jan 1999 02:06:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Lin",
"De-Hone",
""
]
] |
quant-ph/9901052 | De-Horng Lin | De-Hone Lin | Green's function for the Relativistic Coulomb System via Sum Over
Perturbation Series | 13 pages, ReVTeX, no figures | J.Phys.A31:7577,1998 | 10.1088/0305-4470/31/37/015 | null | quant-ph | null | We evaluate the Green's function of the D-dimensional relativistic Coulomb
system via sum over perturbation series which is obtained by expanding the
exponential containing the potential term $V({\bf x)}$ in the path integral
into a power series. The energy spectra and wave functions are extracted from
the resulting amplitude.
| [
{
"version": "v1",
"created": "Sun, 17 Jan 1999 02:06:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Lin",
"De-Hone",
""
]
] |
quant-ph/9901053 | Vladimir Buzek | V. Buzek, M. Hillery, and R. Werner | Optimal Manipulations with Qubits: Universal NOT Gate | 4 pages, revtex | null | null | null | quant-ph | null | It is not a problem to complement a classical bit, i.e. to change the value
of a bit, a 0 to a 1 and vice versa. This is accomplished by a NOT gate.
Complementing a qubit in an unknown state, however, is another matter. We show
that this operation cannot be done perfectly. We define the Universal-NOT
(U-NOT) gate which out of N identically prepared pure input qubits generates M
output qubits in a state which is as close as possible to the perfect
complement. This gate can be realized by classical estimation and subsequent
re-preparation of complements of the estimated state. Its fidelity is therefore
equal to the fidelity F= (N+1)/(N+2) of optimal estimation, and does not depend
on the required number of outputs. We also show that when some additional a
priori information about the state of input qubit is available, than the
fidelity of the quantum NOT gate can be much better than the fidelity of
estimation.
| [
{
"version": "v1",
"created": "Sun, 17 Jan 1999 11:12:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Buzek",
"V.",
""
],
[
"Hillery",
"M.",
""
],
[
"Werner",
"R.",
""
]
] |
quant-ph/9901054 | Fabrizio Illuminati | Nicola Cufaro Petroni, Salvatore De Martino, Silvio De Siena and
Fabrizio Illuminati | Controlled quantum evolutions | Invited talk, to appear in the Proceedings of the 7th UK Conference
on Mathematical and Conceptual Foundations of Modern Physics; Nottingham (UK)
7-11 September, 1998 | null | null | null | quant-ph | null | We perform a detailed analysis of the non stationary solutions of the
evolution (Fokker-Planck) equations associated to either stationary or non
stationary quantum states by the stochastic mechanics. For the excited
stationary states of quantum systems with singular velocity fields we
explicitely discuss the exact solutions for the HO case. Moreover the
possibility of modifying the original potentials in order to implement
arbitrary evolutions ruled by these equations is discussed with respect to both
possible models for quantum measurements and applications to the control of
particle beams in accelerators.
| [
{
"version": "v1",
"created": "Mon, 18 Jan 1999 14:08:47 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Petroni",
"Nicola Cufaro",
""
],
[
"De Martino",
"Salvatore",
""
],
[
"De Siena",
"Silvio",
""
],
[
"Illuminati",
"Fabrizio",
""
]
] |
quant-ph/9901055 | Dr. Ching-hung Woo | C.H.Woo (University of Maryland) | Consistent-Histories Description of A World of Increasing Entropy | null | null | null | PP99-077 | quant-ph gr-qc hep-th | null | A distinction is made between two kinds of consistent histories: (1) robust
histories consistent by virtue of decoherence, and (2) verifiable histories
consistent through the existence of accessible records. It is events in
verifiable histories which describe amplified quantum fluctuations. If the
consistent-histories formalism is to improve on the Copenhagen interpretation
by providing a self-contained quantum representation of the quasi-classical
world, the appropriate quantum state must track closely all macroscopic
phenomena, and the von Neumann entropy of that quantum state ought to change in
the same direction as the statistical entropy of the macro-world. Since the von
Neumann entropy tends to decrease under successive branchings, the evolution of
an entropy-increasing quasi-classical world is not described by the process of
branchings only: mergings of previously separate histories must also occur. As
a consequence, the number of possible quasi-classical worlds does not have to
grow indefinitely as in the many-world picture.
| [
{
"version": "v1",
"created": "Mon, 18 Jan 1999 17:30:49 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Sep 1999 22:09:48 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Woo",
"C. H.",
"",
"University of Maryland"
]
] |
quant-ph/9901056 | A. Heidmann | Y. Hadjar, P.F. Cohadon, C.G. Aminoff, M. Pinard, A. Heidmann | High-sensitivity optical measurement of mechanical Brownian motion | 4 pages, 4 figures, RevTeX | Europhys.Lett.46:545-551,1999 | 10.1209/epl/i1999-00422-6 | null | quant-ph | null | We describe an experiment in which a laser beam is sent into a high-finesse
optical cavity with a mirror coated on a mechanical resonator. We show that the
reflected light is very sensitive to small mirror displacements. We have
observed the Brownian motion of the resonator with a very high sensitivity.
| [
{
"version": "v1",
"created": "Tue, 19 Jan 1999 09:36:14 GMT"
},
{
"version": "v2",
"created": "Fri, 3 Sep 1999 15:17:30 GMT"
}
] | 2010-12-17T00:00:00 | [
[
"Hadjar",
"Y.",
""
],
[
"Cohadon",
"P. F.",
""
],
[
"Aminoff",
"C. G.",
""
],
[
"Pinard",
"M.",
""
],
[
"Heidmann",
"A.",
""
]
] |
quant-ph/9901057 | A. Heidmann | M. Pinard, Y. Hadjar, A. Heidmann | Effective mass in quantum effects of radiation pressure | 11 pages, 4 figures, RevTeX | Eur. Phys. J. D 7 (1999) 107-116 | 10.1007/s100530050354 | null | quant-ph | null | We study the quantum effects of radiation pressure in a high-finesse cavity
with a mirror coated on a mechanical resonator. We show that the optomechanical
coupling can be described by an effective susceptibility which takes into
account every acoustic modes of the resonator and their coupling to the light.
At low frequency this effective response is similar to a harmonic response with
an effective mass smaller than the total mass of the mirror. For a plano-convex
resonator the effective mass is related to the light spot size and becomes very
small for small optical waists, thus enhancing the quantum effects of
optomechanical coupling.
| [
{
"version": "v1",
"created": "Tue, 19 Jan 1999 18:19:29 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Sep 1999 14:55:24 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Pinard",
"M.",
""
],
[
"Hadjar",
"Y.",
""
],
[
"Heidmann",
"A.",
""
]
] |
quant-ph/9901058 | Andreas Kull | A. Kull (CITA), R. A. Treumann (MPE) | On the Path Integral of the Relativistic Electron | RevTeX, 3 pages including 1 figure; accepted for publication in Int.
J. Theor. Phys | Int.J.Theor.Phys. 38 (1999) 1423-1428 | null | null | quant-ph | null | We revisit the path integral description of the motion of a relativistic
electron. Applying a minor but well motivated conceptional change to Feynman's
chessboard model, we obtain exact solutions of the Dirac equation. The
calculation is performed by means of a particular simple method different from
both the combinatorial approach envisaged by Feynman and its Ising model
correspondence.
| [
{
"version": "v1",
"created": "Tue, 19 Jan 1999 19:15:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kull",
"A.",
"",
"CITA"
],
[
"Treumann",
"R. A.",
"",
"MPE"
]
] |
quant-ph/9901059 | Marty Stock | Edward Farhi, Jeffrey Goldstone, Sam Gutmann, and Michael Sipser | Invariant Quantum Algorithms for Insertion into an Ordered List | 19 pages, LaTeX, amssymb,amsmath packages; email to [email protected] | null | null | MIT-CTP-2815 | quant-ph | null | We consider the problem of inserting one item into a list of N-1 ordered
items. We previously showed that no quantum algorithm could solve this problem
in fewer than log N/(2 log log N) queries, for N large. We transform the
problem into a "translationally invariant" problem and restrict attention to
invariant algorithms. We construct the "greedy" invariant algorithm and show
numerically that it outperforms the best classical algorithm for various N. We
also find invariant algorithms that succeed exactly in fewer queries than is
classically possible, and iterating one of them shows that the insertion
problem can be solved in fewer than 0.53 log N quantum queries for large N
(where log N is the classical lower bound). We don't know whether a o(log N)
algorithm exists.
| [
{
"version": "v1",
"created": "Tue, 19 Jan 1999 21:15:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Farhi",
"Edward",
""
],
[
"Goldstone",
"Jeffrey",
""
],
[
"Gutmann",
"Sam",
""
],
[
"Sipser",
"Michael",
""
]
] |
quant-ph/9901060 | Lewenstein | Maciej Lewenstein and Kazimierz Rzazewski | Quantum Anti-Zeno Effect | 4 pages, 3 figures | null | 10.1103/PhysRevA.61.022105 | ITP-UH-TQO 01.99 | quant-ph | null | We demonstrate that near threshold decay processes may be accelerated by
repeated measurements. Examples include near threshold photodetachment of an
electron from a negative ion, and spontaneous emission in a cavity close to the
cutoff frequency, or in a photon band gap material.
| [
{
"version": "v1",
"created": "Wed, 20 Jan 1999 10:20:03 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Lewenstein",
"Maciej",
""
],
[
"Rzazewski",
"Kazimierz",
""
]
] |
quant-ph/9901061 | Norbert Luetkenhaus | Dagmar Bru\ss (ISI Torino) and Norbert L\"utkenhaus (HIP Helsinki) | Quantum Key Distribution: from Principles to Practicalities | 12 pages, final version, accepted for publication in AAECC | AAECC Vol 10, 383-399 (2000). | null | HIP-1998-72/TH | quant-ph | null | We review the main protocols for key distribution based on principles of
quantum mechanics, describing the general underlying ideas, discussing
implementation requirements and pointing out directions of current experiments.
The issue of security is addressed both from a principal and real-life point of
view.
| [
{
"version": "v1",
"created": "Wed, 20 Jan 1999 13:08:34 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Sep 1999 08:39:26 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bruß",
"Dagmar",
"",
"ISI Torino"
],
[
"Lütkenhaus",
"Norbert",
"",
"HIP Helsinki"
]
] |
quant-ph/9901062 | Andrew Cohen | G.F. Bonini, A.G. Cohen, C. Rebbi and V.A. Rubakov | Tunneling of Bound Systems at Finite Energies: Complex Paths Through
Potential Barriers | 4 pages, revtex with epsfig | null | null | BUHEP-99-3 | quant-ph hep-ph | null | We adapt the semiclassical technique, as used in the context of instanton
transitions in quantum field theory, to the description of tunneling
transmissions at finite energies through potential barriers by complex quantum
mechanical systems. Even for systems initially in their ground state, not
generally describable in semiclassical terms, the transmission probability has
a semiclassical (exponential) form. The calculation of the tunneling exponent
uses analytic continuation of degrees of freedom into a complex phase space as
well as analytic continuation of the classical equations of motion into the
complex time plane. We test this semiclassical technique by comparing its
results with those of a computational investigation of the full quantum
mechanical system, finding excellent agreement.
| [
{
"version": "v1",
"created": "Thu, 21 Jan 1999 16:44:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bonini",
"G. F.",
""
],
[
"Cohen",
"A. G.",
""
],
[
"Rebbi",
"C.",
""
],
[
"Rubakov",
"V. A.",
""
]
] |
quant-ph/9901063 | Nicola Piovella | Rodolfo Bonifacio (Dipartimento di Fisica, Universita' degli Studi di
Milano) | Time as a statistical variable and intrinsic decoherence | 24 pages, e-mail: [email protected]. revised version | Nuovo Cim. B114 (1999) 473-488 | null | null | quant-ph | null | We propose a novel approach to intrinsic decoherence without adding new
assumptions to standard quantum mechanics. We generalize the Liouville equation
just by requiring the dynamical semigroup property of time evolution and
dropping the unitarity requirement. With no approximations and statistical
assumptions we find a generalized Liouville equation which depends on two
characteristic time t1 and t2 and reduces to the usual equation in the limit t1
= t2 -> 0. However, for t1 and t2 arbitrarily small but finite, our equation
can be written as a finite difference equation which predicts state reduction
to the diagonal form in the energy representation. The rate of decoherence
becomes faster at the macroscopic limit as the energy scale of the system
increases. In our approach the evolution time appears, a posteriori, as a
statistical variable with a Poisson-gamma function probability distribution as
if time evolution would take place randomly at average intervals t2 each
evolution having a time width t1. This view point is supported by the
derivation of a generalized Tam Mandelstam inequality. The relation with
previous work by Milburn, with laser and micromaser theory and many
experimental testable examples are described.
| [
{
"version": "v1",
"created": "Fri, 22 Jan 1999 14:55:30 GMT"
},
{
"version": "v2",
"created": "Tue, 26 Jan 1999 14:02:03 GMT"
},
{
"version": "v3",
"created": "Mon, 8 Feb 1999 13:51:12 GMT"
},
{
"version": "v4",
"created": "Tue, 23 Feb 1999 12:12:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bonifacio",
"Rodolfo",
"",
"Dipartimento di Fisica, Universita' degli Studi di\n Milano"
]
] |
quant-ph/9901064 | Konrad Banaszek | Konrad Banaszek (Uniwersytet Warszawski) | Quantum homodyne tomography with a priori constraints | 4 pages, REVTeX, 2 figures | Phys.Rev. A59 (1999) 4797-4800 | 10.1103/PhysRevA.59.4797 | null | quant-ph | null | I present a novel algorithm for reconstructing the Wigner function from
homodyne statistics. The proposed method, based on maximum-likelihood
estimation, is capable of compensating for detection losses in a numerically
stable way.
| [
{
"version": "v1",
"created": "Mon, 25 Jan 1999 10:20:20 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Banaszek",
"Konrad",
"",
"Uniwersytet Warszawski"
]
] |
quant-ph/9901065 | Dr Archan S. Majumdar | D. Home (Bose Institute) and A. S. Majumdar (S.N.Bose Natl. Centr.) | On the importance of the Bohmian approach for interpreting CP-violation
experiments | 7 pages, latex, to appear in Foundations of Physics | Found.Phys. 29 (1999) 721-727 | null | null | quant-ph | null | We argue that the inference of CP violation in experiments involving the
$K^0-\bar{K^0}$ system in weak interactions of particle physics is facilitated
by the assumption of particle trajectories for the decaying particles and the
decay products. A consistent explanation in terms of such trajectories is
naturally incorporated within the Bohmian interpretation of quantum mechanics.
| [
{
"version": "v1",
"created": "Mon, 25 Jan 1999 11:00:15 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Home",
"D.",
"",
"Bose Institute"
],
[
"Majumdar",
"A. S.",
"",
"S.N.Bose Natl. Centr."
]
] |
quant-ph/9901066 | Vladimir Skarzhinsky | Juergen Audretsch and Vladimir Skarzhinsky | Aharonov-Bohm scattering of charged particles and neutral atoms: the
role of absorption | 15 pages, LaTeXfile, 2 figures | null | 10.1103/PhysRevA.60.1854 | Preprint KONS-RGKU-99-01 | quant-ph | null | The Aharonov-Bohm scattering of charged particles by the magnetic field of an
infinitely long and infinitely thin solenoid (magnetic string) in an absorbing
medium is studied. We discuss the partial-wave approach to this problem and
show that standard partial-wave method can be adjusted to this case. The effect
of absorption leads to oscillations of the AB cross section.
Based on this we investigate the scattering of neutral atoms with induced
electric dipole moments by a charge wire of finite radius which is placed in an
uniform magnetic field. The physical realistic and practically important case
that all atoms which collide with the wire are totally absorbed at its surface,
is studied in detail. The dominating terms of the scattering amplitude are
evaluated analytically for different physical constellations. The rest terms
are written in a form suitable for a numerical computation. We show that if the
magnetic field is absent, the absorbing charged wire causes oscillations of the
cross section. In the presence of the magnetic field the cross section
increases and the dominating Aharonov--Bohm peak appears in the forward
direction, suppressing the oscillations.
| [
{
"version": "v1",
"created": "Mon, 25 Jan 1999 11:14:08 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Audretsch",
"Juergen",
""
],
[
"Skarzhinsky",
"Vladimir",
""
]
] |
quant-ph/9901067 | Konrad Banaszek | Konrad Banaszek | Optimal receiver for quantum cryptography with two coherent states | 6 pages, 2 figures. To appear in Phys. Lett. A | Phys.Lett. A253 (1999) 12 | 10.1016/S0375-9601(99)00015-8 | null | quant-ph | null | A setup for discriminating between arbitrary two coherent states of a single
light mode with the highest success rate allowed by quantum mechanics is
presented. Its application to time-multiplexed quantum key distribution is
discussed.
| [
{
"version": "v1",
"created": "Mon, 25 Jan 1999 11:27:46 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Banaszek",
"Konrad",
""
]
] |
quant-ph/9901068 | Christof Zalka | Christof Zalka (T-6 LANL USA) | Could Grover's quantum algorithm help in searching an actual database? | 7 pages, LaTeX | null | 10.1103/PhysRevA.62.052305 | null | quant-ph | null | I investigate whether it would technologically and economically make sense to
build database search engines based on Grover's quantum search algorithm. The
answer is not fully conclusive but in my judgement rather negative.
| [
{
"version": "v1",
"created": "Tue, 26 Jan 1999 00:40:41 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Zalka",
"Christof",
"",
"T-6 LANL USA"
]
] |
quant-ph/9901069 | Vladimir Buzek | Martin Konopka and Vladimir Buzek | Entangling Atoms in Photonic Crystals | 9 pages, revtex, 6 figure | null | 10.1007/s100530050550 | null | quant-ph | null | We propose a method for entangling a system of two-level atoms in photonic
crystals. The atoms are assumed to move in void regions of a photonic crystal.
The interaction between the atoms is mediated either via a defect mode or via
resonant dipole-dipole interaction. We show that these interactions can produce
pure entangled atomic states. We analyze the problem with parameters typical
for currently existing photonic crystals and Rydberg atoms. We show that the
atoms can emerge from photonic crystals in entangled states. Depending on the
linear dimensions of the crystal and on their velocity of the entangled atoms
can be separated by tens of centimeters.
| [
{
"version": "v1",
"created": "Tue, 26 Jan 1999 10:33:13 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Konopka",
"Martin",
""
],
[
"Buzek",
"Vladimir",
""
]
] |
quant-ph/9901070 | Bg Sidharth | B.G. Sidharth | Universe of Fluctuations II | 13 pages, TeX | null | null | null | quant-ph gr-qc hep-th | null | We throw further light on a recently discussed Kerr-Newman type formulation
of Fermions and the related cosmological scheme which predicted an ever
expanding universe, as indeed has subsequently been confirmed. In the spirit of
the correspondence principle, it is shown how the quark picture emerges at the
Compton wavelength and the Big Bang scenario at the Planck length. At the same
time we obtain a theoretical justification for the peculiar characteristics of
the quarks namely their fractional charge, handedness and confinement, as also
the order of magnitude of their masses, all of which were hitherto adhoc
features.
| [
{
"version": "v1",
"created": "Tue, 26 Jan 1999 11:07:50 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sidharth",
"B. G.",
""
]
] |
quant-ph/9901071 | Morton H. Rubin | Morton H. Rubin | Entanglement and State Preparation | 24 pages, 3 figures, submitted to Phys. Rev. A | null | 10.1103/PhysRevA.61.022311 | null | quant-ph | null | When a subset of particles in an entangled state is measured, the state of
the subset of unmeasured particles is determined by the outcome of the
measurement. This first measurement may be thought of as a state preparation
for the remaining particles. In this paper, we examine how the duration of the
first measurement effects the state of the unmeasured subsystem. The state of
the unmeasured subsytem will be a pure or mixed state depending on the nature
of the measurement.
In the case of quantum teleportation we show that there is an eigenvalue
equation which must be satisfied for accurate teleportation. This equation
provides a limitation to the states that can be accurately teleported.
| [
{
"version": "v1",
"created": "Tue, 26 Jan 1999 13:53:46 GMT"
},
{
"version": "v2",
"created": "Wed, 27 Jan 1999 21:02:34 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Rubin",
"Morton H.",
""
]
] |
quant-ph/9901072 | Nicolas Gisin | N. Gisin and S. Popescu | Spin flips and quantum information for anti-parallel spins | null | Physical Review Letters, 82, 432-435, 1999 | 10.1103/PhysRevLett.83.432 | null | quant-ph | null | We consider two different ways to encode quantum information, by parallel or
anti-parallel pairs of spins. We find that there is more information in the
anti-parallel ones. This purely quantum mechanical effect is due to
entanglement, not of the states but occuring in the course of the measuring
process. We also introduce a range of quantum information processing machines,
such as spin-flip and anti-cloning.
| [
{
"version": "v1",
"created": "Tue, 26 Jan 1999 17:20:53 GMT"
}
] | 2013-01-22T00:00:00 | [
[
"Gisin",
"N.",
""
],
[
"Popescu",
"S.",
""
]
] |
quant-ph/9901073 | Joseph Hope | J.J. Hope, G.M. Moy, M.J. Collett and C.M. Savage | The linewidth of a non-Markovian atom laser | 4 pages, 1 encapsulated postscript figure | null | 10.1016/S0030-4018(99)00481-2 | null | quant-ph | null | We present a fully quantum mechanical treatment of a single mode atom laser
including pumping and output coupling. By ignoring atom-atom interactions, we
have solved this model without making the Born-Markov approximation. We find
substantially less gain narrowing than is predicted under that approximation.
| [
{
"version": "v1",
"created": "Wed, 27 Jan 1999 22:34:42 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Hope",
"J. J.",
""
],
[
"Moy",
"G. M.",
""
],
[
"Collett",
"M. J.",
""
],
[
"Savage",
"C. M.",
""
]
] |
quant-ph/9901074 | Jan-Ake Larsson | Jan-{\AA}ke Larsson | Modeling the Singlet State with Local Variables | 15 pages, 13 figures | Phys.Lett. A256 (1999) 245-252 | 10.1016/S0375-9601(99)00236-4 | null | quant-ph | null | A local-variable model yielding the statistics from the singlet state is
presented for the case of inefficient detectors and/or lowered visibility. It
has independent errors and the highest efficiency at perfect visibility is
77.80%, while the highest visibility at perfect detector-efficiency is 63.66%.
Thus, the model cannot be refuted by measurements made to date.
| [
{
"version": "v1",
"created": "Thu, 28 Jan 1999 09:40:00 GMT"
}
] | 2022-03-16T00:00:00 | [
[
"Larsson",
"Jan-Åke",
""
]
] |
quant-ph/9901075 | M. Patra | M. Patra and C. W. J. Beenakker | Excess noise for coherent radiation propagating through amplifying
random media | 8 pages, 6 figures | Phys.Rev. A60 (1999) 4059 | 10.1103/PhysRevA.60.4059 | null | quant-ph cond-mat.mes-hall | null | A general theory is presented for the photodetection statistics of coherent
radiation that has been amplified by a disordered medium. The beating of the
coherent radiation with the spontaneous emission increases the noise above the
shot-noise level. The excess noise is expressed in terms of the transmission
and reflection matrices of the medium, and evaluated using the methods of
random-matrix theory. Inter-mode scattering between $N$ propagating modes
increases the noise figure by up to a factor of $N$, as one approaches the
laser threshold. Results are contrasted with those for an absorbing medium.
| [
{
"version": "v1",
"created": "Thu, 28 Jan 1999 11:13:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Patra",
"M.",
""
],
[
"Beenakker",
"C. W. J.",
""
]
] |
quant-ph/9901076 | Joachim Stolze | Bernd Burghardt and Joachim Stolze (Institut fuer Physik, Universitaet
Dortmund, Germany) | Numerical evaluation of coherent-state path integrals with applications
to time-dependent problems | 4 pages, 1 figure, to appear in the Proceedings of the Conference on
"Path Integrals from peV to TeV", Florence, August, 1998 | null | null | null | quant-ph | null | We study the application of the coherent-state path integral as a numerical
tool for wave-packet propagation. The numerical evaluation of path integrals is
reduced to a matrix-vector multiplication scheme. Together with a
split-operator technique we apply our method to a time-dependent double-well
potential.
| [
{
"version": "v1",
"created": "Thu, 28 Jan 1999 15:40:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Burghardt",
"Bernd",
"",
"Institut fuer Physik, Universitaet\n Dortmund, Germany"
],
[
"Stolze",
"Joachim",
"",
"Institut fuer Physik, Universitaet\n Dortmund, Germany"
]
] |
quant-ph/9901077 | Philip Pearle | Philip Pearle | Collapse Models | 40 pages, to be published in "Open Systems and Measurement in
Relativistic Quantum Theory," F. Petruccione and H. P. Breuer eds. (Springer
Verlag, 1999) | null | 10.1007/BFb0104404 | null | quant-ph | null | This is a review of formalisms and models (nonrelativistic and relativistic)
which modify Schrodinger's equation so that it describes wavefunction collapse
as a dynamical physical process.
| [
{
"version": "v1",
"created": "Fri, 29 Jan 1999 16:45:36 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Pearle",
"Philip",
""
]
] |
quant-ph/9901078 | C. Anastopoulos | Charis Anastopoulos and B. L. Hu | Two - Level Atom - Field Interaction: Exact Master Equations for
Non-Markovian Dynamics, Decoherence and Relaxation | 19 pages, 2 figures, REVTEX. This shortened version without the
finite temperature and coherent state cases, is what will appear in PRA. They
are deleted from the earlier version because of an ambiguity in the
Grassmannian integral which could affect these cases | Phys.Rev.A62:033821,2000 | 10.1103/PhysRevA.62.033821 | umdpp 97-129 | quant-ph | null | We perform a first- principles derivation of the general master equation to
study the non-Markovian dynamics of a two-level atom (2LA) interacting with an
electromagnetic field (EMF). We use the influence functional method which can
incorporate the full backreaction of the field on the atom, while adopting
Grassmannian variables for the 2LA and the coherent state representation for
the EMF. We find exact master equations for the cases of a free quantum field
and a cavity field in the vacuum. In response to the search for mechanisms to
preserve maximal coherence in quantum computations in ion trap prototypes, we
apply these equations to analyse the decoherence of a 2LA in an EMF, and fine
that decoherence time is close to relaxation time. This is at variance to the
claims by authors who studied the same system but used a different coupling
model. We explain the source of difference and argue that, contrary to common
belief, the EMF when resonantly coupled to an atom does not decohere it as
efficiently as a bath does on a quantum Brownian particle. The master-equations
for non-Markovian dynamics derived here is expected to be useful for exploring
new regimes of 2LA-EMF interaction, which is becoming physically important
experimentally.
| [
{
"version": "v1",
"created": "Sat, 30 Jan 1999 01:09:55 GMT"
},
{
"version": "v2",
"created": "Mon, 12 Apr 1999 17:40:50 GMT"
},
{
"version": "v3",
"created": "Mon, 12 Jun 2000 18:37:58 GMT"
}
] | 2011-08-04T00:00:00 | [
[
"Anastopoulos",
"Charis",
""
],
[
"Hu",
"B. L.",
""
]
] |
quant-ph/9902001 | Emil Vasile Prodan | E. Prodan | Transport properties of fermionic systems | 16 pages, no figure, new style + minor corrections | null | null | null | quant-ph | null | We extend the method discovered by A Y Alekseev et al to the case of fermions
in external fields. A general formula for conductance G is proved. In the
(1+1)-D case with symmetry at time reflection, it is shown that: G=e^2/h+o(a^),
where a is the strength of the external field. In (3+1)-D free case, it is
checked that G=n*e^2/h, where n is the number of the filled energetic bands of
the transversal quantization.
| [
{
"version": "v1",
"created": "Mon, 1 Feb 1999 02:10:54 GMT"
},
{
"version": "v2",
"created": "Tue, 2 Feb 1999 05:02:48 GMT"
},
{
"version": "v3",
"created": "Sun, 14 Feb 1999 17:23:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Prodan",
"E.",
""
]
] |
quant-ph/9902002 | Sixia Yu | Liu Yu-Xi and Cao Chang-Qi | Squeezing spectra of the output field by high density exciton laser | 12 pages, no figures | null | 10.1016/S0030-4018(99)00208-4 | null | quant-ph | null | The effect of the non-linear interaction between the high density Wannier
excitons is analysed. We use the Fokker-Planck equation in the positive P
presentation and the corresponding stochastic differential equation to study
the composite system of a single mode cavity field and exciton under classical
field pumping. The small fluctuation approximation is made to get the
quadrature squeezing spectra of the output light field. The conditions for the
squeezing of the either quadrature component of the output light are given.
| [
{
"version": "v1",
"created": "Mon, 1 Feb 1999 03:31:04 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Yu-Xi",
"Liu",
""
],
[
"Chang-Qi",
"Cao",
""
]
] |
quant-ph/9902003 | John Klauder | Bernhard G. Bodmann and John R. Klauder | Path Integral Quantization for a Toroidal Phase Space | 8 pages, LaTeX, no figs., for Proceedings of Bialowieza 98 Workshop | null | null | null | quant-ph | null | A Wiener-regularized path integral is presented as an alternative way to
formulate Berezin-Toeplitz quantization on a toroidal phase space. Essential to
the result is that this quantization prescription for the torus can be
constructed as an induced representation from anti-Wick quantization on its
covering space, the plane. When this construction is expressed in the form of a
Wiener-regularized path integral, symmetrization prescriptions for the
propagator emerge similar to earlier path-integral formulas on
multiply-connected configuration spaces.
| [
{
"version": "v1",
"created": "Mon, 1 Feb 1999 15:55:05 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bodmann",
"Bernhard G.",
""
],
[
"Klauder",
"John R.",
""
]
] |
quant-ph/9902004 | Enrique Solano | E. Solano, R. L. de Matos Filho and N. Zagury | Deterministic Bell states and measurement of the motional state of two
trapped ions | 5 pages with 2 postscript figures included (ReVTeX). To be published
in Physical Review A as a Rapid Communication. Revised version with added
references and minor corrections | Phys.Rev.A59:2539,1999; Erratum-ibid.A61:029903,2000 | 10.1103/PhysRevA.59.2539 10.1103/PhysRevA.61.029903 | null | quant-ph | null | We present a method for the deterministic generation of all the electronic
Bell states of two trapped ions. It involves the combination of a purely
dispersive with a resonant laser excitation of vibronic transitions of the
ions. In contrast to other methods presented up to now, our proposal does not
require differential laser addressing of the individual ions and may be easily
implemented with present available techniques. It is further shown that this
excitation scheme is highly adequate for the complete determination of the
motional state of the ions.
| [
{
"version": "v1",
"created": "Mon, 1 Feb 1999 19:13:47 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Mar 1999 20:21:09 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Solano",
"E.",
""
],
[
"Filho",
"R. L. de Matos",
""
],
[
"Zagury",
"N.",
""
]
] |
quant-ph/9902005 | Michael Werner | M.J. Werner and A. Imamoglu | Photon-photon interactions in cavity electromagnetically induced
transparency | Two atom antibunching results expanded | null | 10.1103/PhysRevA.61.011801 | null | quant-ph | null | Dissipation-free photon-photon interaction at the single photon level is
studied in the context of cavity electromagnetically induced transparency
(EIT). For a single multilevel atom exhibiting EIT in the strong
cavity-coupling regime, the anharmonicity of the atom-cavity system has an
upper bound determined by single atom-photon coupling strength. Photon blockade
is inferred to occur for both single and multi-atom cases from the behaviour of
transition rates between dressed states of the system. Numerical calculations
of the second order coherence function indicate that photon antibunching in
both single and two-atom cases are strong and comparable.
| [
{
"version": "v1",
"created": "Mon, 1 Feb 1999 19:21:27 GMT"
},
{
"version": "v2",
"created": "Thu, 24 Jun 1999 18:02:30 GMT"
},
{
"version": "v3",
"created": "Tue, 12 Oct 1999 17:27:36 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Werner",
"M. J.",
""
],
[
"Imamoglu",
"A.",
""
]
] |
quant-ph/9902006 | Kendra Vant | G. H. Ball, K. M. D. Vant, H. Ammann and N. L. Christensen | A study of quantum decoherence in a system with Kolmogorov-Arnol'd-Moser
tori | 19 pages including 6 figures | null | 10.1088/1464-4266/1/4/301 | null | quant-ph | null | We present an experimental and numerical study of the effects of decoherence
on a quantum system whose classical analogue has Kolmogorov-Arnol'd-Moser (KAM)
tori in its phase space. Atoms are prepared in a caesium magneto-optical trap
at temperatures and densities which necessitate a quantum description. This
real quantum system is coupled to the environment via spontaneous emission. The
degree of coupling is varied and the effects of this coupling on the quantum
coherence of the system are studied. When the classical diffusion through a
partially broken torus is < hbar, diffusion of quantum particles is inhibited.
We find that increasing decoherence via spontaneous emission increases the
transport of quantum particles through the boundary.
| [
{
"version": "v1",
"created": "Tue, 2 Feb 1999 01:25:49 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Ball",
"G. H.",
""
],
[
"Vant",
"K. M. D.",
""
],
[
"Ammann",
"H.",
""
],
[
"Christensen",
"N. L.",
""
]
] |
quant-ph/9902007 | Joerg Main | J. Main, G. Wunner | Semiclassical Calculation of Transition Matrix Elements for Atoms in
External Fields | 4 pages, 2 figures, REVTEX, submitted to Phys. Rev. A (Rapid
Communications) | Phys.Rev. A59 (1999) 2548 | 10.1103/PhysRevA.59.R2548 | null | quant-ph chao-dyn nlin.CD physics.atom-ph | null | Closed orbit theory is generalized to the semiclassical calculation of
cross-correlated recurrence functions for atoms in external fields. The
cross-correlation functions are inverted by a high resolution spectral analyzer
to obtain the semiclassical eigenenergies and transition matrix elements. The
method is demonstrated for dipole transitions of the hydrogen atom in a
magnetic field. This is the first semiclassical calculation of individual
quantum transition strengths from closed orbit theory.
| [
{
"version": "v1",
"created": "Tue, 2 Feb 1999 10:14:37 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Main",
"J.",
""
],
[
"Wunner",
"G.",
""
]
] |
quant-ph/9902008 | Jonathan Halliwell | J. J. Halliwell (Imperial College, London) | Somewhere in the Universe: Where is the Information Stored When
Histories Decohere? | 48 pages, plain Tex. Second revision | Phys. Rev. D 60, 105031 (1999) | 10.1103/PhysRevD.60.105031 | Imperial College preprint TP/98-99/29 | quant-ph gr-qc | null | We investigate the idea that decoherence is connected with the storage of
information about the decohering system somewhere in the universe. The known
connection between decoherence of histories and the existence of records is
extended from the case of pure initial states to mixed states. Records may
still exist but are necessarily imperfect. We formulate an
information-theoretic conjecture about decoherence due to an environment: the
number of bits required to describe a set of decoherent histories is
approximately equal to the number of bits of information thrown away to the
environment in the coarse-graining process. This idea is verified in a simple
model consisting of a particle coupled to an environment that can store only
one bit of information. We explore the decoherence and information storage in
the quantum Brownian motion model. It is shown that the variables that the
environment naturally measures and stores information about are the Fourier
components of the function $x(t)$ (describing the particle trajectory). The
records storing the information about the Fourier modes are the positions and
momenta of the environmental oscillators at the final time. Decoherence is
possible even if there is only one oscillator in the environment. The
information count of the histories and records in the environment add up
according to our conjecture. These results give quantitative content to the
idea that decoherence is related to ``information lost''.
| [
{
"version": "v1",
"created": "Tue, 2 Feb 1999 12:48:16 GMT"
},
{
"version": "v2",
"created": "Tue, 20 Jul 1999 15:49:39 GMT"
},
{
"version": "v3",
"created": "Mon, 26 Jul 1999 12:53:08 GMT"
}
] | 2016-08-25T00:00:00 | [
[
"Halliwell",
"J. J.",
"",
"Imperial College, London"
]
] |
quant-ph/9902009 | Carsten Henkel | Carsten Henkel and Martin Wilkens | Heating of trapped atoms near thermal surfaces | to be published in Europhys. Lett. (7 pages, 3 figures, includes
europhys.sty style file) | Europhys.Lett. 47 (1999) 414-420 | 10.1209/epl/i1999-00404-8 | null | quant-ph | null | We study the electromagnetic coupling and concomitant heating of a particle
in a miniaturized trap close to a solid surface. Two dominant heating
mechanisms are identified: proximity fields generated by thermally excited
currents in the absorbing solid and time-dependent image potentials due to
elastic surface distortions (Rayleigh phonons). Estimates for the lifetime of
the trap ground state are given. Ions are particularly sensitive to electric
proximity fields: for a silver substrate, we find a lifetime below one second
at distances closer than some ten micrometer to the surface. Neutral atoms may
approach the surface more closely: if they have a magnetic moment, a minimum
distance of one micrometer is estimated in tight traps, the heat being
transferred via magnetic proximity fields. For spinless atoms, heat is
transferred by inelastic scattering of virtual photons off surface phonons. The
corresponding lifetime, however, is estimated to be extremely long compared to
the timescale of typical experiments.
| [
{
"version": "v1",
"created": "Tue, 2 Feb 1999 18:31:48 GMT"
},
{
"version": "v2",
"created": "Thu, 11 Feb 1999 16:39:28 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Jul 1999 12:45:31 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Henkel",
"Carsten",
""
],
[
"Wilkens",
"Martin",
""
]
] |
quant-ph/9902010 | Tez Rudolph | Terry Rudolph | Quantum Triangulation and Violation of Conservation of Trouble | 1 page RevTex | null | null | null | quant-ph | null | A scheme is described that allows Alice to communicate to Bob where on earth
she is, even though she doesn't know herself. The situation described shows how
the generalization of a recent result of Gisin and Popescu [quant-ph/9901072]
could be useful.
| [
{
"version": "v1",
"created": "Wed, 3 Feb 1999 23:00:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rudolph",
"Terry",
""
]
] |
quant-ph/9902011 | Dr. Gediminas Juzeliunas | Gediminas Juzeliunas | Comment on "Quantum Theory of Dispersive Electromagnetic Fields" | Submitted to Phys. Rev.A, 5 pages, REVTEX file | null | null | null | quant-ph | null | Recently Drummond and Hillery [Phys. Rev.A 59, 691(1999)] presented a quantum
theory of dispersion based on the analysis of a coupled system of the
electromagnetic field and atoms in the multipolar QED formulation. The theory
has led to the explicit mode-expansions for various field-operators in a
homogeneous medium characterized by an arbitrary number of resonant transitions
with different frequencies. In this Comment, we drawn attention to a similar
multipolar study by Juzeliunas [Phys. Rev.A 53, 3543 (1996); 55, 929 (1997)] on
the field quantization in a discrete molecular (or atomic) medium. A
comparative analysis of the two approaches is carried out, highlighting both
common and distinctive features.
| [
{
"version": "v1",
"created": "Wed, 3 Feb 1999 21:13:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Juzeliunas",
"Gediminas",
""
]
] |
quant-ph/9902012 | Jaroslav Hruby | Jaroslav Hruby | A role of antiquantum bits for superdense coding and quantum computing | null | null | null | null | quant-ph | null | We define an anti-quantum bit state via analogous way as the anti-state in
Particle Physics.We show the quantum information Feymann diagrams for the
teleportations and superdense coding, which preserve the information flow. The
role of information vacuum and anihilation between error information and
anti-information is mentioned for the stability of quantum computing.
| [
{
"version": "v1",
"created": "Wed, 3 Feb 1999 15:38:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hruby",
"Jaroslav",
""
]
] |
quant-ph/9902013 | Massimiliano F. Sacchi | G. M. D'Ariano, M. G. A. Paris and M. F. Sacchi | On the parametric approximation in quantum optics | 19 pages, 9figs, LaTeX with cimento.cls documentclass (included). To
appear on Nuovo Cimento B | Nuovo Cim. B114 (1999) 339-354 | null | null | quant-ph | null | We perform the exact numerical diagonalization of the Hamiltonians that
describe both degenerate and nondegenerate parametric amplifiers, by exploiting
the conservation laws pertaining each device. We clarify the conditions under
which the parametric approximation holds, showing that the most relevant
requirement is the coherence of the pump after the interaction, rather than its
undepletion.
| [
{
"version": "v1",
"created": "Wed, 3 Feb 1999 16:51:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"D'Ariano",
"G. M.",
""
],
[
"Paris",
"M. G. A.",
""
],
[
"Sacchi",
"M. F.",
""
]
] |
quant-ph/9902014 | Michael Steiner | Michael Steiner | Towards Quantifying Non-Local Information Transfer: Finite-Bit
Non-Locality | New version: minor changes. Presented at the Physics of Quantum
Electronics Conference, Jan. 3-7, 1999 | Phys.Lett. A270 (2000) 239-244 | 10.1016/S0375-9601(00)00315-7 | null | quant-ph | null | The advent of Bell's inequalities provoked the possibility that entangled
quantum phenomena is non-local in nature. Since teleportation only requires a
finite amount of classical information, i.e. two bits, the author asks whether
or not it is possible to further characterize the nature of internal
correlation in terms of information. Towards this end, the issue of the amount
of information that is transferred internally and non-locally is addressed.
There are two possibilities: the amount is infinite or the amount is finite. A
partial answer to this problem is given: it is shown that models exist whereby
the amount is finite. The EPR-Bell cosine correlation can be reproduced exactly
using on average 1.48 bits. The issue of simultaneity and the problems it poses
are also examined in this context. Several extensions are suggested.
| [
{
"version": "v1",
"created": "Wed, 3 Feb 1999 17:51:27 GMT"
},
{
"version": "v2",
"created": "Tue, 4 May 1999 14:50:54 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Steiner",
"Michael",
""
]
] |
quant-ph/9902015 | Andrei Kirilyuk | Andrei P. Kirilyuk | Double Solution with Chaos: Dynamic Redundance and Causal Wave-Particle
Duality | 24 pages, PostScript 3.0; Dedicated to Louis de Broglie, the leader
of the causal science of the twentieth century (see also quant-ph/9911107);
contains material from the author's book "Universal Concept of Complexity by
the Dynamic Redundance Paradigm: Causal Randomness, Complete Wave Mechanics,
and the Ultimate Unification of Knowledge" (Kiev, Naukova Dumka, 1997; in
English), see physics/9806002; no change of the essential content in the
revised version | null | null | null | quant-ph chao-dyn gr-qc nlin.CD | null | A system of two interacting, physically real, initially homogeneous fields is
considered as the simplest basis for the world construction in which one of
them, a 'protofield' of electromagnetic nature, is attracted to another
protofield, or medium, responsible for the eventually emerging gravitational
effects. The interaction process is analysed within the generalised 'effective
(optical) potential method' in which we avoid any usual perturbative reduction.
It then appears that for generic system parameters the protofields, instead of
simply 'falling' one onto another and forming a fixed 'bound state', are
engaged in a self-sustained process of nonlinear pulsation, or 'quantum beat',
consisting in unceasing cycles of self-amplified auto-squeeze, or 'collapse'
('reduction'), of a portion of the extended protofields to a small volume
followed by the inverse phase of extension. Centres of consecutive reductions
form the physical 'points' of thus emerging, intrinsically discrete space, and
each of them is 'selected' by the system in a causally random fashion among
many equally possible versions (or 'realisations'). This is a manifestation of
the dynamic redundance forming the unified basis of dynamically complex
(chaotic) behaviour of any real system with interaction (physics/9806002). The
sequence of reduction events constitutes the elementary physical 'clock' of the
world providing it with the unceasing, intrinsically irreversible time flow.
The complex-dynamical quantum beat process in the system of two interacting
protofields is observed as the massive elementary particle (like the electron)
which naturally possesses the property of physically real wave-particle duality
completing the double solution concept of Louis de Broglie (see also
quant-ph/9902016, gr-qc/9906077).
| [
{
"version": "v1",
"created": "Thu, 4 Feb 1999 09:47:38 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Dec 1999 18:18:38 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kirilyuk",
"Andrei P.",
""
]
] |
quant-ph/9902016 | Andrei Kirilyuk | Andrei P. Kirilyuk | Double Solution with Chaos: Completion of de Broglie's Nonlinear Wave
Mechanics and Its Intrinsic Unification with the Causally Extended Relativity | 36 pages, PostScript 3.0; Dedicated to Louis de Broglie, the leader
of the causal science of the twentieth century (see also quant-ph/9911107);
contains material from the author's book "Universal Concept of Complexity by
the Dynamic Redundance Paradigm: Causal Randomness, Complete Wave Mechanics,
and the Ultimate Unification of Knowledge" (Kiev, Naukova Dumka, 1997; in
English), see physics/9806002; explanation of the observed wave properties of
many-particle systems is added in the revised version (section 2, p. 30-32) | null | null | null | quant-ph chao-dyn gr-qc nlin.CD | null | A system of two interacting protofields with generic parameters is unstable
with respect to unceasing cycles of nonlinear squeeze (reduction) to randomly
chosen centres and reverse extension which form the causally probabilistic
process of quantum beat observed as elementary particle (quant-ph/9902015).
Here we show that the emerging wave-particle duality, space, and time lead to
the equations of special relativity and quantum mechanics thus providing their
causal extension and unification. Relativistic inertial mass (energy) is
universally defined as the temporal rate (frequency) of the chaotic quantum
beat process(es). The same complex dynamical processes and mass account for
universal gravitation, since any reduction event in the electromagnetic
protofield involves also the (directly unobservable) gravitational protofield
thus increasing its tension and influencing quantum beat frequencies of other
particles. This complex dynamical mechanism of universal gravitation provides
causal extension of general relativity intrinsically unified with causal
quantum mechanics and special relativity, as well as physical origin and
unification of all the four 'fundamental forces' (also gr-qc/9906077). The
dynamic origin of the Dirac quantization rules is also revealed and used for
the first-principles derivation of the Dirac and Schroedinger equations
describing the same irreducibly complex, internally nonlinear interaction
processes within field-particles and their simplest systems (quant-ph/9511034 -
quant-ph/9511038). The classical, dynamically localised behaviour naturally
emerges as a higher level of complexity appearing as formation of elementary
bound systems (like atoms).
| [
{
"version": "v1",
"created": "Thu, 4 Feb 1999 11:17:42 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Dec 1999 20:18:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kirilyuk",
"Andrei P.",
""
]
] |
quant-ph/9902017 | Christian Grosche | Christian Grosche | Path Integral Solutions for Deformed P"oschl-Teller-like and
Conditionally Solvable Potentials | LaTeX with epsfig | J.Phys. A38 (2005) 2947-2958 | 10.1088/0305-4470/38/13/009 | DESY 99--011 | quant-ph | null | I discuss in this paper the behaviour of the solutions of the so-called
q-hyperbolic potentials, i.e. P"oschl-Teller-like and conditionally solvable
potentials, in terms of the path integral formalism. The differences in
comparison to the usual P"oschl-Teller-like potentials are investigated,
including the discrete energy spectra and the bound state wave-functions.
| [
{
"version": "v1",
"created": "Fri, 5 Feb 1999 09:25:48 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Grosche",
"Christian",
""
]
] |
quant-ph/9902018 | Stefan Teufel | Sheldon Goldstein and Stefan Teufel | Quantum spacetime without observers: ontological clarity and the
conceptual foundations of quantum gravity | 22 pages, to appear in ``Physics meets philosophy at the Planck
scale,'' edited by C. Callender and N. Huggett (Cambridge University Press) | null | null | null | quant-ph gr-qc | null | We explore the possibility of a Bohmian approach to the problem of finding a
quantum theory incorporating gravitational phenomena. The major conceptual
problems of canonical quantum gravity are the problem of time and the problem
of diffeomorphism invariant observables. We find that these problems are
artifacts of the subjectivity and vagueness inherent in the framework of
orthodox quantum theory. When we insist upon ontological clarity---the
distinguishing characteristic of a Bohmian approach---these conceptual problems
vanish. We shall also discuss the implications of a Bohmian perspective for the
significance of the wave function, concluding with unbridled speculation as to
why the universe should be governed by laws so apparently bizarre as those of
quantum mechanics.
| [
{
"version": "v1",
"created": "Fri, 5 Feb 1999 09:42:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Goldstein",
"Sheldon",
""
],
[
"Teufel",
"Stefan",
""
]
] |
quant-ph/9902019 | null | S. Esposito (University of Naples and I.N.F.N.) | On the role of Spin in Quantum Mechanics | latex, 13 pages; to be published in Found. Phys. Lett | Found.Phys.Lett. 12 (1999) 165-177 | null | DSF-98/15, INFN-NA-IV-98/15 | quant-ph hep-ph hep-th | null | From the invariance properties of the Schrodinger equation and the isotropy
of space we show that a generic (non-relativistic) quantum system is endowed
with an ``external'' motion, which can be interpreted as the motion of the
centre of mass, and an ``internal'' one, whose presence disappears in the
classical limit. The latter is caused by the spin of the particle, whatever is
its actual value (different from zero). The quantum potential in the
Schrodinger equation, which is responsible of the quantum effects of the
system, is then completely determined from the properties of the internal
motion, and its ``unusual'' properties have a simple and physical explanation
in the present context. From the impossibility to fix the initial conditions
relevant for the internal motion follows, finally, the need of a probabilistic
interpretation of quantum mechanics.
| [
{
"version": "v1",
"created": "Fri, 5 Feb 1999 09:42:16 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Esposito",
"S.",
"",
"University of Naples and I.N.F.N."
]
] |
quant-ph/9902020 | Ilki Kim | Ilki Kim and Guenter Mahler | Pattern formation in quantum Turing machines | Accepted for publication in Phys.Rev.A, 3 figures, REVTEX file | null | 10.1103/PhysRevA.60.692 | null | quant-ph | null | We investigate the iteration of a sequence of local and pair unitary
transformations, which can be interpreted to result from a Turing-head
(pseudo-spin $S$) rotating along a closed Turing-tape ($M$ additional
pseudo-spins). The dynamical evolution of the Bloch-vector of $S$, which can be
decomposed into $2^{M}$ primitive pure state Turing-head trajectories, gives
rise to fascinating geometrical patterns reflecting the entanglement between
head and tape. These machines thus provide intuitive examples for quantum
parallelism and, at the same time, means for local testing of quantum network
dynamics.
| [
{
"version": "v1",
"created": "Fri, 5 Feb 1999 18:16:41 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kim",
"Ilki",
""
],
[
"Mahler",
"Guenter",
""
]
] |
quant-ph/9902021 | Sunish Menon | Sunish Menon and G. S. Agarwal (Physical Research laboratory) | Probing the Vacuum Induced Coherence in a $\Lambda$-system | 9 pages, 4 postscript files. Submitted for the special issue of
"Laser Physics" on "Lasing without inversion and Interference phenomena in
Atomic systems", Vol 9, #3, 1999 | null | null | null | quant-ph | null | We propose a simple test to demonstrate and detect the presence of vacuum
inducde coherence in a $\Lambda$-system. We show that the probe field
absorption is modulated due to the presence of such a coherence which is
unobservable in fluorescence. We present analytical and numerical results for
the modulated absorption, the cosine and sine components of which display
different types of behavior.
| [
{
"version": "v1",
"created": "Fri, 5 Feb 1999 12:53:27 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Menon",
"Sunish",
"",
"Physical Research laboratory"
],
[
"Agarwal",
"G. S.",
"",
"Physical Research laboratory"
]
] |
quant-ph/9902022 | Noah Linden | Adrian Kent, Noah Linden and Serge Massar | Optimal Entanglement Enhancement for Mixed States | Final version: to appear in Phys. Rev. Lett | Phys.Rev.Lett. 83 (1999) 2656-2659 | 10.1103/PhysRevLett.83.2656 | DAMTP-1999-15, ULB-TH/99-02 | quant-ph | null | We consider the actions of protocols involving local quantum operations and
classical communication (LQCC) on a single system consisting of two separated
qubits. We give a complete description of the orbits of the space of states
under LQCC and characterise the representatives with maximal entanglement of
formation. We thus obtain a LQCC entanglement concentration protocol for a
single given state (pure or mixed) of two qubits which is optimal in the sense
that the protocol produces, with non-zero probability, a state of maximal
possible entanglement of formation. This defines a new entanglement measure,
the maximum extractable entanglement.
| [
{
"version": "v1",
"created": "Fri, 5 Feb 1999 16:43:58 GMT"
},
{
"version": "v2",
"created": "Wed, 1 Sep 1999 13:06:27 GMT"
},
{
"version": "v3",
"created": "Sat, 4 Sep 1999 22:59:24 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Kent",
"Adrian",
""
],
[
"Linden",
"Noah",
""
],
[
"Massar",
"Serge",
""
]
] |
quant-ph/9902023 | Dagmar Bruss | Dagmar Bruss | Entanglement splitting of pure bipartite quantum states | 6 pages, 2 figures, extended version, to be published in Phys. Rev. A | Phys.Rev. A60 (1999) 4344 | 10.1103/PhysRevA.60.4344 | ITP-UH-11/99 | quant-ph | null | The concept of entanglement splitting is introduced by asking whether it is
possible for a party possessing half of a pure bipartite quantum state to
transfer some of his entanglement with the other party to a third party. We
describe the unitary local transformation for symmetric and isotropic splitting
of a singlet into two branches that leads to the highest entanglement of the
output. The capacity of the resulting quantum channels is discussed. Using the
same transformation for less than maximally entangled pure states, the
entanglement of the resulting states is found. We discuss whether they can be
used to do teleportation and to test the Bell inequality. Finally we generalize
to entanglement splitting into more than two branches.
| [
{
"version": "v1",
"created": "Fri, 5 Feb 1999 17:21:01 GMT"
},
{
"version": "v2",
"created": "Tue, 31 Aug 1999 10:06:20 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Bruss",
"Dagmar",
""
]
] |
quant-ph/9902024 | Ilki Kim | Ilki Kim and Guenter Mahler | Moving quantum agents in a finite environment | REVTEX, to appear in Proceedings of Decoherence Workshop, Bielefeld,
1998 | null | null | null | quant-ph | null | We investigate an all-quantum-mechanical spin network, in which a subset of
spins, the $K$ ``moving agents'', are subject to local and pair unitary
transformations controlled by their position with respect to a fixed ring of
$M$ ``environmental''-spins. We demonstrate that a ``flow of coherence''
results between the various subsystems. Despite entanglement between the agents
and between agent and environment, local (non-linear) invariants may persist,
which then show up as fascinating patterns in each agent's Bloch-sphere. Such
patterns disappear, though, if the agents are controlled by different rules.
Geometric aspects thus help to understand the interplay between entanglement
and decoherence.
| [
{
"version": "v1",
"created": "Sat, 6 Feb 1999 18:08:07 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kim",
"Ilki",
""
],
[
"Mahler",
"Guenter",
""
]
] |
quant-ph/9902025 | Kendra Vant | K. M. D. Vant, G. H. Ball, H. Ammann and N. L. Christensen | Experimental evidence for the role of cantori as barriers in a quantum
system | 19 pages including 9 figures, Accepted for publication in Physical
Review E in March 1999 | Phys.Rev. E59 (1999) 2846-2852 | 10.1103/PhysRevE.59.2846 | null | quant-ph | null | We investigate the effect of cantori on momentum diffusion in a quantum
system. Ultracold caesium atoms are subjected to a specifically designed
periodically pulsed standing wave. A cantorus separates two chaotic regions of
the classical phase space. Diffusion through the cantorus is classically
predicted. Quantum diffusion is only significant when the classical phase-space
area escaping through the cantorus per period greatly exceeds Planck's
constant. Experimental data and a quantum analysis confirm that the cantori act
as barriers.
| [
{
"version": "v1",
"created": "Mon, 8 Feb 1999 00:34:14 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Vant",
"K. M. D.",
""
],
[
"Ball",
"G. H.",
""
],
[
"Ammann",
"H.",
""
],
[
"Christensen",
"N. L.",
""
]
] |
quant-ph/9902026 | Roberto Floreanini | F. Benatti and R. Floreanini | Complete positivity and neutron interferometry | 12 pages, plain TeX | Phys.Lett. B451 (1999) 422-429 | 10.1016/S0370-2693(99)00177-X | null | quant-ph hep-ph hep-th nucl-th | null | We analyze the dynamics of neutron beams in interferometry experiments using
quantum dynamical semigroups. We show that these experiments could provide
stringent limits on the non-standard, dissipative terms appearing in the
extended evolution equations.
| [
{
"version": "v1",
"created": "Mon, 8 Feb 1999 11:11:47 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Benatti",
"F.",
""
],
[
"Floreanini",
"R.",
""
]
] |
quant-ph/9902027 | Castagnoli Giuseppe | Giuseppe Castagnoli (Information Communication Technology Dept.,
Genova, Italy) | Non-Mechanism in Quantum Oracle Computing | 9 text pages, 3 figures in one additional ps file, manuscript of the
presentation to be held at the SILFS Workshop on Logic and Quantum
Computation, Cesena, Italy, February 16, 1999 | null | null | null | quant-ph | null | A typical oracle problem is finding which software program is installed on a
computer, by running the computer and testing its input-output behaviour. The
program is randomly chosen from a set of programs known to the problem solver.
As well known, some oracle problems are solved more efficiently by using
quantum algorithms; this naturally implies changing the computer to quantum,
while the choice of the software program remains sharp. In order to highlight
the non-mechanistic origin of this higher efficiency, also the uncertainty
about which program is installed must be represented in a quantum way.
| [
{
"version": "v1",
"created": "Mon, 8 Feb 1999 16:25:13 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Castagnoli",
"Giuseppe",
"",
"Information Communication Technology Dept.,\n Genova, Italy"
]
] |
quant-ph/9902028 | Bg Sidharth | B.G. Sidharth | The Universe of Chaos and Quanta | 18 pages, TeX | Chaos Solitons Fractals 11 (2000) 1269-1278 | 10.1016/S0960-0779(99)00036-3 | null | quant-ph | null | In recent papers it was shown that stochastic processes in the universe as a
whole lead to discrete space time at Compton scales as also non-relativistic
Quantum Mechanics. In this paper, we deduce the Dirac equation and thence a
unified formulation of quarks and leptons. In the process several puzzling
empirical results and coincidences are shown to be a consequence of the theory.
These include the discreteness of the charge, handedness of quarks, their
fractional charge, confinement and masses and the handedness of neutrinos, the
so called accidental relation that the classical Kerr- Newman metric describes,
the field of an electron including the purely quantum mechanical gyromagnetic
ratio g=2, as also the many large number coincidences made famous by Dirac and
Weinberg's mysterious empirical formula that relates the pion mass to the
Hubble Constant. A cosmology based on fluctuations related to the above
stochastic space-time discretization, consistent with latest observations is
also seen to follow.
| [
{
"version": "v1",
"created": "Mon, 8 Feb 1999 13:28:10 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Sidharth",
"B. G.",
""
]
] |
quant-ph/9902029 | Nicola Piovella | Rodolfo Bonifacio | Time as a statistical variable and intrinsic decoherence | 11 pages, e-mail: [email protected]. revised version
Proceedings AIP R:CP461 of the workshop "Misteries and Puzzles of Quantum
mechanics", Gargnano (ITALY) | null | 10.1063/1.57868 | null | quant-ph | null | We propose a novel approach to intrinsic decoherence without adding new
assumptions to standard Quantum Mechanics. We generalize the Liouville equation
just by requiring the dynamical semigroup property of time evolution and
dropping the unitarity requirement. With no approximations and specific
statistical assumptions we find a generalized Liouville equation which depends
on two characteristic time t1 and t2 and reduces to the usual equation in the
limit t1 = t2 --> 0. However, for t1 and t2 arbitrarily small but finite, our
equation can be written as a finite difference equation which predicts state
reduction to the diagonal form in the energy representation. The rate of
decoherence becomes faster at the macroscopic limit as the energy scale of the
system increases. In our approach the evolution time appears, a posteriori, as
a statistical variable as if time evolution would take place randomly at
average intervals t2, each evolution having a time width t1. A generalized Tam
Mandelstam inequality is derived. The relation with previous work by Milburn is
discussed. The agreement with recent experiments on damped Rabi oscillations is
described.
| [
{
"version": "v1",
"created": "Mon, 8 Feb 1999 14:14:17 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Feb 1999 15:09:26 GMT"
},
{
"version": "v3",
"created": "Tue, 23 Feb 1999 12:13:40 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Bonifacio",
"Rodolfo",
""
]
] |
quant-ph/9902030 | Peter van Loock | P. van Loock, Samuel L. Braunstein, and H. J. Kimble | Broadband teleportation | 27 pages, 7 figures, revised version for publication, Physical Review
A (August 2000); major changes, in parts rewritten | Phys. Rev. A 62, 022309 (2000) | 10.1103/PhysRevA.62.022309 | null | quant-ph | null | Quantum teleportation of an unknown broadband electromagnetic field is
investigated. The continuous-variable teleportation protocol by Braunstein and
Kimble [Phys. Rev. Lett. {\bf 80}, 869 (1998)] for teleporting the quantum
state of a single mode of the electromagnetic field is generalized for the case
of a multimode field with finite bandwith. We discuss criteria for
continuous-variable teleportation with various sets of input states and apply
them to the teleportation of broadband fields. We first consider as a set of
input fields (from which an independent state preparer draws the inputs to be
teleported) arbitrary pure Gaussian states with unknown coherent amplitude
(squeezed or coherent states). This set of input states, further restricted to
an alphabet of coherent states, was used in the experiment by Furusawa {\it et
al.} [Science {\bf 282}, 706 (1998)]. It requires unit-gain teleportation for
optimizing the teleportation fidelity. In our broadband scheme, the excess
noise added through unit-gain teleportation due to the finite degree of the
squeezed-state entanglement is just twice the (entanglement) source's squeezing
spectrum for its ``quiet quadrature.'' The teleportation of one half of an
entangled state (two-mode squeezed vacuum state), i.e., ``entanglement
swapping,'' and its verification are optimized under a certain nonunit gain
condition. We will also give a broadband description of this
continuous-variable entanglement swapping based on the single-mode scheme by
van Loock and Braunstein [Phys. Rev. A {\bf 61}, 10302 (2000)]
| [
{
"version": "v1",
"created": "Mon, 8 Feb 1999 16:03:56 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Jun 2000 13:16:30 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"van Loock",
"P.",
""
],
[
"Braunstein",
"Samuel L.",
""
],
[
"Kimble",
"H. J.",
""
]
] |
quant-ph/9902031 | Tetsufumi Tanamoto | Tetsufumi Tanamoto (Toshiba Corporation) | Quantum gates by coupled asymmetric quantum dots and controlled-NOT-gate
operation | LaTeX, 7 pages, 5 figures, revised content, to appear in Phys. Rev. A | Phys.Rev.A61:022305,2000 | 10.1103/PhysRevA.61.022305 | null | quant-ph | null | A quantum computer based on an asymmetric coupled dot system has been
proposed and shown to operate as the controlled-NOT-gate. The basic idea is (1)
the electron is localized in one of the asymmetric coupled dots. (2)The
electron transfer takes place from one dot to the other when the energy-levels
of the coupled dots are set close. (3)The Coulomb interaction between the
coupled dots mutually affects the energy levels of the other coupled dots. The
decoherence time of the quantum computation and the measurement time are
estimated. The proposed system can be realized by developing the technology of
the single-electron memory using Si nanocrystals and the direct combination of
the quantum circuit and the conventional circuit is possible.
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 05:27:35 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Oct 1999 03:00:14 GMT"
}
] | 2008-12-18T00:00:00 | [
[
"Tanamoto",
"Tetsufumi",
"",
"Toshiba Corporation"
]
] |
quant-ph/9902032 | Michael Jack | M. W. Jack, M. J. Collett and D. F. Walls | A non-Markovian quantum trajectory approach to radiation into structured
continuum | null | null | 10.1088/1464-4266/1/4/316 | null | quant-ph | null | We present a non-Markovian quantum trajectory method for treating atoms
radiating into a reservoir with a non-flat density of states. The results of an
example numerical simulation of the case where the free space modes of the
reservoir are altered by the presence of a cavity are presented and compared
with those of an extended system approach.
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 05:50:11 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Jack",
"M. W.",
""
],
[
"Collett",
"M. J.",
""
],
[
"Walls",
"D. F.",
""
]
] |
quant-ph/9902033 | Guifre Vidal Bonafont | Guifre Vidal | Entanglement of pure states for a single copy | Revtex, 4 pages, no figures. Minor changes. Appendix removed | Phys.Rev.Lett. 83 (1999) 1046-1049 | 10.1103/PhysRevLett.83.1046 | null | quant-ph | null | An optimal local conversion strategy between any two pure states of a
bipartite system is presented. It is optimal in that the probability of success
is the largest achievable if the parties which share the system, and which can
communicate classically, are only allowed to act locally on it. The study of
optimal local conversions sheds some light on the entanglement of a single copy
of a pure state. We propose a quantification of such an entanglement by means
of a finite minimal set of new measures from which the optimal probability of
conversion follows.
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 11:44:01 GMT"
},
{
"version": "v2",
"created": "Fri, 26 Mar 1999 08:19:06 GMT"
}
] | 2009-10-31T00:00:00 | [
[
"Vidal",
"Guifre",
""
]
] |
quant-ph/9902034 | Victor Red'kov | V.M. Red'kov | On intrinsic structure of wave function of fermion triplet in external
monopole field | 30 pages, Latex 209 | null | null | null | quant-ph | null | Using the Weyl-Tetrode-Fock spinor formalism, the fermion triplet in the 't
Hooft-Polyakov monopole field is examined all over again. Spherical solutions
corresponding to the total conserved momentum J =l + S + T are constructed. The
angular dependence is expressed in terms of the Wigner's functions. The radial
system of 12 equations decomposes into two sub-systems by diagonalizing some
complicated inversion operator. The case of minimal j = 1/2 is considered
separately. A more detailed analysis is accomplished for the case of simplest
monopole field: namely, the one produced by putting the Dirac potential into
the non-Abelian scheme. Now a discrete operation diagonalized contains an
additional complex parameter A. The same parameter enters wave functions. This
quantity can manifest itself at matrix elements. In particular, there have been
analyzed the N(A)-parity selection rules: those depending on the A. As shown,
the A-freedom is a consequence of the existence of additional symmetry of the
relevant Hamiltonian. The wave functions exhibit else one kind of freedom:
B-freedom associated in turn with its own symmetry of the Hamiltonian. There
has been examined both A and B-transformations relating functions associated
with different A and B.
| [
{
"version": "v1",
"created": "Tue, 9 Feb 1999 14:21:40 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Red'kov",
"V. M.",
""
]
] |
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