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6.09k
| versions
list | update_date
timestamp[s] | authors_parsed
list |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
quant-ph/9904077
|
Gui Lu Long
|
Gui Lu Long, Wei Lin Zhang, Yan Song Li and Li Niu
|
Arbitrary phase rotation of the marked state can not be used for
Grover's quantum search algorithm
|
5 pages, 5 figures
|
Commun.Theor.Phys. 32 (1999) 335-338
|
10.1088/0253-6102/32/3/335
| null |
quant-ph
| null |
A misunderstanding that an arbitrary phase rotation of the marked state
together with the inversion about average operation in Grover's search
algorithm can be used to construct a (less efficient) quantum search algorithm
is cleared. The $\pi$ rotation of the phase of the marked state is not only the
choice for efficiency, but also vital in Grover's quantum search algorithm. The
results also show that Grover's quantum search algorithm is robust.
|
[
{
"version": "v1",
"created": "Wed, 21 Apr 1999 22:09:50 GMT"
}
] | 2018-01-17T00:00:00 |
[
[
"Long",
"Gui Lu",
""
],
[
"Zhang",
"Wei Lin",
""
],
[
"Li",
"Yan Song",
""
],
[
"Niu",
"Li",
""
]
] |
quant-ph/9904078
|
Dominic Mayers
|
Dominic Mayers, Louis Salvail and Yoshie Chiba-Kohno
|
Unconditionally Secure Quantum Coin Tossing
|
7 pages Revtex format It is known to be impossible. There was no
claimed proof in the paper. It is just a bad intuition
| null | null | null |
quant-ph
| null |
In coin tossing two remote participants want to share a uniformly distributed
random bit. At the least in the quantum version, each participant test whether
or not the other has attempted to create a bias on this bit. It is requested
that, for b = 0,1, the probability that Alice gets bit b and pass the test is
smaller than 1/2 whatever she does, and similarly for Bob. If the bound 1/2
holds perfectly against any of the two participants, the task realised is
called an exact coin tossing. If the bound is actually $1/2 + \xi$ where the
bias $\xi$ vanishes when a security parameter m defined by the protocol
increases, the task realised is a (non exact) coin tossing. It is found here
that exact coin tossing is impossible. At the same time, an unconditionally
secure quantum protocol that realises a (non exact) coin tossing is proposed.
The protocol executes m biased quantum coin tossing procedures at the same
time. It executes the first round in each of these m procedures sequentially,
then the second rounds are executed, and so on until the end of the n
procedures. Each procedure requires 4n particles where $n \in O(\lg m)$. The
final bit x is the parity of the m random bits. The information about each of
these m bits is announced a little bit at a time which implies that the
principle used against bit commitment does not apply. The bias on x is smaller
than $1/m$. The result is discussed in the light of the impossibility result
for exact coin tossing.
|
[
{
"version": "v1",
"created": "Thu, 22 Apr 1999 22:43:38 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Feb 2018 01:24:47 GMT"
}
] | 2018-02-28T00:00:00 |
[
[
"Mayers",
"Dominic",
""
],
[
"Salvail",
"Louis",
""
],
[
"Chiba-Kohno",
"Yoshie",
""
]
] |
quant-ph/9904079
|
Ronald de Wolf
|
Andris Ambainis (UC Berkeley) and Ronald de Wolf (CWI and U of
Amsterdam)
|
Average-Case Quantum Query Complexity
|
14 pages, LaTeX. Some parts rewritten. This version to appear in the
Journal of Physics A
| null | null | null |
quant-ph cs.CC
| null |
We compare classical and quantum query complexities of total Boolean
functions. It is known that for worst-case complexity, the gap between quantum
and classical can be at most polynomial. We show that for average-case
complexity under the uniform distribution, quantum algorithms can be
exponentially faster than classical algorithms. Under non-uniform distributions
the gap can even be super-exponential. We also prove some general bounds for
average-case complexity and show that the average-case quantum complexity of
MAJORITY under the uniform distribution is nearly quadratically better than the
classical complexity.
|
[
{
"version": "v1",
"created": "Fri, 23 Apr 1999 10:46:02 GMT"
},
{
"version": "v2",
"created": "Thu, 11 Nov 1999 09:48:25 GMT"
},
{
"version": "v3",
"created": "Mon, 2 Jul 2001 10:18:23 GMT"
}
] | 2009-09-25T00:00:00 |
[
[
"Ambainis",
"Andris",
"",
"UC Berkeley"
],
[
"de Wolf",
"Ronald",
"",
"CWI and U of\n Amsterdam"
]
] |
quant-ph/9904080
|
Piotr Garbaczewski
|
Piotr Garbaczewski
|
Noise perturbations in the Brownian motion and quantum dynamics
|
Phys. Lett. A, (1999), in press
|
Phys.Lett. A257 (1999) 31-36
|
10.1016/S0375-9601(99)00283-2
| null |
quant-ph chao-dyn cond-mat nlin.CD
| null |
The third Newton law for mean velocity fields is utilised to generate
anomalous (enhanced) or non-dispersive diffusion-type processes which, in
particular, can be interpreted as a probabilistic counterpart of the
Schr\"{o}dinger picture quantum dynamics.
|
[
{
"version": "v1",
"created": "Fri, 23 Apr 1999 13:22:24 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Garbaczewski",
"Piotr",
""
]
] |
quant-ph/9904081
|
Ulrich Mohrhoff
|
Ulrich Mohrhoff
|
Quantum mechanics and elements of reality
|
24 pages, plain TeX
| null | null |
SAAPS-99041
|
quant-ph
| null |
It is widely accepted that a Born probability of 1 is sufficient for the
existence of a corresponding element of reality. Recently Vaidman has extended
this idea to the ABL probabilities of the time-symmetrized version of quantum
mechanics originated by Aharonov, Bergmann, and Lebowitz. Several authors have
objected to Vaidman's time-symmetrized elements of reality without casting
doubt on the widely accepted sufficiency condition for `ordinary' elements of
reality. In this paper I show that while the proper truth condition for a
quantum counterfactual is an ABL probability of 1, neither a Born probability
of 1 nor an ABL probability of 1 is sufficient for the existence of an element
of reality. The reason this is so is that the contingent properties of
quantum-mechanical systems are extrinsic. To obtain this result, I need to
discuss objective probabilities, retroactive causality, and the objectivity or
otherwise of the psychological arrow of time. One consequence of the extrinsic
nature of quantum-mechanical properties is that quantum mechanics presupposes
property-defining actual events (or states of affairs) and therefore cannot be
called upon to account for their occurrence (existence). Neither these events
nor the correlations between them are capable of explanation, the former
because they are causal primaries, the latter because they are fundamental:
there are no underlying causal processes. Causal connections are something we
project onto the statistical correlations, and this works only to the extent
that statistical variations can be ignored. There are nevertheless important
conclusions to be drawn from the quantum-mechanical correlations, such as the
spatial nonseparability of the world.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 03:00:20 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Mohrhoff",
"Ulrich",
""
]
] |
quant-ph/9904082
|
Paolo Facchi
|
P. Facchi and S. Pascazio
|
Berry phase due to quantum measurements
|
6 pages, 2 figures. Contribution to the Sixth Central-European
Workshop on Quantum Optics, Chudobin near Olomouc, Czech Republic, April-May
1999
|
Acta Phys.Slov. 49 (1999) 671-676
| null | null |
quant-ph
| null |
The usual, "static" version of the quantum Zeno effect consists in the
hindrance of the evolution of a quantum systems due to repeated measurements.
There is however a "dynamic" version of the same phenomenon, first discussed by
von Neumann in 1932 and subsequently explored by Aharonov and Anandan, in which
a system is forced to follow a given trajectory. A Berry phase appears if such
a trajectory is a closed loop in the projective Hilbert space. A specific
example involving neutron spin is considered and a similar situation with
photon polarization is investigated.
|
[
{
"version": "v1",
"created": "Sat, 24 Apr 1999 10:08:07 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Facchi",
"P.",
""
],
[
"Pascazio",
"S.",
""
]
] |
quant-ph/9904083
|
Sayan Kar
|
Sayan Kar and Avinash Khare
|
Classical and quantum mechanics of a particle on a rotating loop
|
30 pages, RevTex, 7 figures
|
Am.J.Phys. 68 (2000) 1128-1133
|
10.1119/1.1286427
|
IOP Preprint, Physics Dept. and CTS, IITKgp Preprint
|
quant-ph
| null |
The toy model of a particle on a vertical rotating circle in the presence of
uniform gravitational/ magnetic fields is explored in detail. After an analysis
of the classical mechanics of the problem we then discuss the quantum mechanics
from both exact and semi--classical standpoints. Exact solutions of the
Schrodinger equation are obtained in some cases by diverse methods. Instantons,
bounces are constructed and semi-classical, leading order tunneling
amplitudes/decay rates are written down. We also investigate qualitatively the
nature of small oscillations about the kink/bounce solutions. Finally, the
connections of these toy examples with field theoretic and statistical
mechanical models of relevance are pointed out.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 04:41:59 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Kar",
"Sayan",
""
],
[
"Khare",
"Avinash",
""
]
] |
quant-ph/9904084
|
Sergei Kozyrev
|
L.Accardi, S.V.Kozyrev, I.V.Volovich
|
Non-Exponential Decay for Polaron Model
|
Latex, 10 pages
|
Phys.Lett. A260 (1999) 31-38
|
10.1016/S0375-9601(99)00510-1
|
SMI-26-04-99
|
quant-ph
| null |
A model of particle interacting with quantum field is considered. The model
includes as particular cases the polaron model and non-relativistic quantum
electrodynamics. We compute matrix elements of the evolution operator in the
stochastic approximation and show that depending on the state of the particle
one can get the non-exponential decay with the rate t^{-3/2}. In the process of
computation a new algebra of commutational relations that can be considered as
an operator deformation of quantum Boltzmann commutation relations is used.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 09:46:51 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Accardi",
"L.",
""
],
[
"Kozyrev",
"S. V.",
""
],
[
"Volovich",
"I. V.",
""
]
] |
quant-ph/9904085
|
Antonio Vidiella-Barranco
|
A.F. Gomes, J.A. Roversi, and A. Vidiella-Barranco (Universidade
Estadual de Campinas, Brazil)
|
Transfer of coherence from atoms to mixed field states in a two-photon
lossless micromaser
|
20 pages, 8 figures, to appear in Journal of Modern Optics
|
J.Mod.Opt. 46 (1999) 1421
|
10.1080/09500349908231344
| null |
quant-ph physics.atom-ph
| null |
We propose a two-photon micromaser-based scheme for the generation of a
nonclassical state from a mixed state. We conclude that a faster, as well as a
higher degree of field purity is achieved in comparison to one-photon
processes. We investigate the statistical properties of the resulting field
states, for initial thermal and (phase-diffused) coherent states.
Quasiprobabilities are employed to characterize the state of the generated
fields.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 14:43:57 GMT"
}
] | 2016-02-16T00:00:00 |
[
[
"Gomes",
"A. F.",
"",
"Universidade\n Estadual de Campinas, Brazil"
],
[
"Roversi",
"J. A.",
"",
"Universidade\n Estadual de Campinas, Brazil"
],
[
"Vidiella-Barranco",
"A.",
"",
"Universidade\n Estadual de Campinas, Brazil"
]
] |
quant-ph/9904086
|
Angelo Mariano
|
P. Facchi, A. Mariano, S. Pascazio
|
Wigner function and coherence properties of cold and thermal neutrons
|
6 pages, 3 figures. Contribution to the Sixth Central-European
Workshop on Quantum Optics, Chudobin near Olomouc, Czech Republic, April-May
1999
|
Acta Phys.Slov. 49 (1999) 677-682
| null | null |
quant-ph
| null |
We analyze the coherence properties of a cold or a thermal neutron by
utilizing the Wigner quasidistribution function. We look in particular at a
recent experiment performed by Badurek {\em et al.}, in which a polarized
neutron crosses a magnetic field that is orthogonal to its spin, producing
highly non-classical states. The quantal coherence is extremely sensitive to
the field fluctuation at high neutron momenta. A "decoherence parameter" is
introduced in order to get quantitative estimates of the losses of coherence.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 10:01:20 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Facchi",
"P.",
""
],
[
"Mariano",
"A.",
""
],
[
"Pascazio",
"S.",
""
]
] |
quant-ph/9904087
|
Sunish Menon
|
G. S. Agarwal
|
Control of Decoherence and Relaxation by Frequency Modulation of Heat
Bath
|
5 text pages plus 3 figures. Submitted for publication in Phys. Rev.
Lett
| null |
10.1103/PhysRevA.61.013809
| null |
quant-ph
| null |
We demonstrate in a very general fashion, considerable slowing down of
decoherence and relaxation by fast frequency modulation of the system heat bath
coupling. The slowing occurs as the decoherence rates are now determined by the
spectral components of bath correlations which are shifted due to fast
modulation. We present several examples including the slowing down of the
heating of a trapped ion, where the system - bath interaction is not
necessarily Markovian.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 10:50:42 GMT"
}
] | 2021-05-26T00:00:00 |
[
[
"Agarwal",
"G. S.",
""
]
] |
quant-ph/9904088
|
A. K. Rajagopal
|
Sumiyoshi Abe(1) and A. K. Rajagopal(2) ((1)College of Science and
Technology, Nihon University, Funabashi, Chiba, Japan (2)Naval Research
Laboratory, Washington D.C., U.S.A)
|
Quantum entanglement inferred by the principle of maximum Tsallis
entropy
|
15 pages, 1 figure
|
Phys.Rev. A60 (1999) 3461
|
10.1103/PhysRevA.60.3461
| null |
quant-ph cond-mat.stat-mech
| null |
The problem of quantum state inference and the concept of quantum
entanglement are studied using a non-additive measure in the form of Tsallis
entropy indexed by the positive parameter q. The maximum entropy principle
associated with this entropy along with its thermodynamic interpretation are
discussed in detail for the Einstein-Podolosky-Rosen pair of two spin-1/2
particles. Given the data on the Bell-Clauser-Horne-Shimony-Holt observable,
the analytic expression is given for the inferred quantum entangled state. It
is shown that for q greater than unity, indicating the sub-additive feature of
the Tsalls entropy, the entangled region is small and enlarges as one goes into
super-additive regime where q is less than unity. It is also shown that quantum
entanglement can be quantified by the generalized Kullback-Leibler entropy.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 12:08:11 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Abe",
"Sumiyoshi",
""
],
[
"Rajagopal",
"A. K.",
""
]
] |
quant-ph/9904089
|
Konrad Banaszek
|
K. Banaszek, C. Radzewicz, K. Wodkiewicz, J. S. Krasinski
|
Determination of the Wigner function from photon statistics
|
4 pages LaTeX, contribution to proceedings of 6th central-european
workshop on quantum optics; see also
http://www.fuw.edu.pl/~kbanasz/QOLab/ExpWigner/
|
Acta Phys.Slov. 49 (1999) 643-646
| null | null |
quant-ph
| null |
We present an experimental realisation of the direct scheme for measuring the
Wigner function of a single quantized light mode. In this method, the Wigner
function is determined as the expectation value of the photon number parity
operator for the phase space displaced quantum state.
|
[
{
"version": "v1",
"created": "Mon, 26 Apr 1999 14:07:52 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Apr 1999 07:42:23 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Banaszek",
"K.",
""
],
[
"Radzewicz",
"C.",
""
],
[
"Wodkiewicz",
"K.",
""
],
[
"Krasinski",
"J. S.",
""
]
] |
quant-ph/9904090
|
Boris F. Samsonov
|
Boris F. Samsonov
|
Coherent States for Transparent Potentials
| null |
J.Phys.A33:591-605,2000
|
10.1088/0305-4470/33/3/312
| null |
quant-ph
| null |
Darboux transformation operators that produce multisoliton potentials are
analyzed as operators acting in a Hilbert space. Isometric correspondence
between Hilbert spaces of states of a free particle and a particle moving in a
soliton potential is established. It is shown that the Darboux transformation
operator is unbounded but closed and can not realize an isometric mapping
between Hilbert spaces. A quasispectral representation of such an operator in
terms of continuum bases is obtained. Different types of coherent states of a
multisoliton potential are introduced. Measures that realize the resolution of
the identity operator in terms of the projectors on the coherent states vectors
are calculated. It is shown that when these states are related with free
particle coherent states by a bounded symmetry operator the measure is defined
by ordinary functions and in the case of a semibounded symmetry operator the
measure is defined by a generalized function.
|
[
{
"version": "v1",
"created": "Tue, 27 Apr 1999 03:17:21 GMT"
}
] | 2008-11-26T00:00:00 |
[
[
"Samsonov",
"Boris F.",
""
]
] |
quant-ph/9904091
|
Hoi-Kwong Lo
|
Hoi-Kwong Lo (Hewlett-Packard Labs, Bristol)
|
A simple proof of the unconditional security of quantum key distribution
|
13 pages, extended abstract. Comments will be appreciated
|
J.Phys.A34:6957-6968,2001
|
10.1088/0305-4470/34/35/321
| null |
quant-ph cs.CR
| null |
Quantum key distribution is the most well-known application of quantum
cryptography. Previous proposed proofs of security of quantum key distribution
contain various technical subtleties. Here, a conceptually simpler proof of
security of quantum key distribution is presented. The new insight is the
invariance of the error rate of a teleportation channel: We show that the error
rate of a teleportation channel is independent of the signals being
transmitted. This is because the non-trivial error patterns are permuted under
teleportation. This new insight is combined with the recently proposed quantum
to classical reduction theorem. Our result shows that assuming that Alice and
Bob have fault-tolerant quantum computers, quantum key distribution can be made
unconditionally secure over arbitrarily long distances even against the most
general type of eavesdropping attacks and in the presence of all types of
noises.
|
[
{
"version": "v1",
"created": "Tue, 27 Apr 1999 08:49:27 GMT"
}
] | 2008-11-26T00:00:00 |
[
[
"Lo",
"Hoi-Kwong",
"",
"Hewlett-Packard Labs, Bristol"
]
] |
quant-ph/9904092
|
Michal Horodecki
|
Pawel Horodecki, Michal Horodecki and Ryszard Horodecki
|
Binding entanglement channels
|
RevTeX, 5 pages, submitted to special issue of J. Mod. Opt
|
J.Mod.Opt. 47 (2000) 347-354
|
10.1080/09500340008244047
| null |
quant-ph
| null |
We define the binding entanglement channel as the quantum channel through
which quantum information cannot be reliably transmitted, but which can be used
to share bound entanglement. We provide a characterization of such class of
channels. We also show that any bound entangled state can be used to
construction of the map corresponding the binding entanglement channel.
|
[
{
"version": "v1",
"created": "Tue, 27 Apr 1999 16:14:53 GMT"
}
] | 2015-06-26T00:00:00 |
[
[
"Horodecki",
"Pawel",
""
],
[
"Horodecki",
"Michal",
""
],
[
"Horodecki",
"Ryszard",
""
]
] |
quant-ph/9904093
|
Ashwin Nayak
|
Ashwin Nayak
|
Optimal lower bounds for quantum automata and random access codes
|
8 pages, 1 figure, Latex2e. Extensive modifications have been made to
increase clarity. To appear in FOCS'99
| null | null | null |
quant-ph cs.CC
| null |
Consider the finite regular language L_n = {w0 : w \in {0,1}^*, |w| \le n}.
It was shown by Ambainis, Nayak, Ta-Shma and Vazirani that while this language
is accepted by a deterministic finite automaton of size O(n), any one-way
quantum finite automaton (QFA) for it has size 2^{Omega(n/log n)}. This was
based on the fact that the evolution of a QFA is required to be reversible.
When arbitrary intermediate measurements are allowed, this intuition breaks
down. Nonetheless, we show a 2^{Omega(n)} lower bound for such QFA for L_n,
thus also improving the previous bound. The improved bound is obtained by
simple entropy arguments based on Holevo's theorem. This method also allows us
to obtain an asymptotically optimal (1-H(p))n bound for the dense quantum codes
(random access codes) introduced by Ambainis et al. We then turn to Holevo's
theorem, and show that in typical situations, it may be replaced by a tighter
and more transparent in-probability bound.
|
[
{
"version": "v1",
"created": "Tue, 27 Apr 1999 23:59:48 GMT"
},
{
"version": "v2",
"created": "Wed, 28 Apr 1999 00:00:48 GMT"
},
{
"version": "v3",
"created": "Tue, 7 Sep 1999 23:04:01 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Nayak",
"Ashwin",
""
]
] |
quant-ph/9904094
|
Thomas Thiemann
|
A. Ashtekar, D. Marolf, J. Mour\~ao, T. Thiemann
|
Constructing Hamiltonian quantum theories from path integrals in a
diffeomorphism invariant context
|
Plain Latex, 25 p., references added, abstract and title changed
(originally :``Osterwalder Schrader Reconstruction and Diffeomorphism
Invariance''), introduction extended, one appendix with illustrative model
added, accepted by Class. Quantum Grav
|
Class.Quant.Grav. 17 (2000) 4919-4940
|
10.1088/0264-9381/17/23/310
|
AEI-109
|
quant-ph gr-qc hep-th
| null |
Osterwalder and Schrader introduced a procedure to obtain a (Lorentzian)
Hamiltonian quantum theory starting from a measure on the space of (Euclidean)
histories of a scalar quantum field. In this paper, we extend that construction
to more general theories which do not refer to any background, space-time
metric (and in which the space of histories does not admit a natural linear
structure). Examples include certain gauge theories, topological field theories
and relativistic gravitational theories. The treatment is self-contained in the
sense that an a priori knowledge of the Osterwalder-Schrader theorem is not
assumed.
|
[
{
"version": "v1",
"created": "Wed, 28 Apr 1999 06:24:43 GMT"
},
{
"version": "v2",
"created": "Fri, 1 Dec 2000 17:18:12 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Ashtekar",
"A.",
""
],
[
"Marolf",
"D.",
""
],
[
"Mourão",
"J.",
""
],
[
"Thiemann",
"T.",
""
]
] |
quant-ph/9904095
|
Stefan Weigert
|
Stefan Weigert
|
A Discrete Phase-Space Calculus for Quantum Spins based on a
Reconstruction Method using Coherent States
|
Latex2e, 9 pages
| null | null | null |
quant-ph
| null |
To reconstruct a mixed or pure quantum state of a spin s is possible through
coherent states: its density matrix is fixed by the probabilities to measure
the value s along 4s(s+1) appropriately chosen directions in space. Thus, after
inverting the experimental data, the statistical operator is parametrized
entirely by expectation values. On this basis, a symbolic calculus for quantum
spins is developed, the `expectation-value representation.' It resembles the
Moyal representation for SU(2) but two important differences exist. On the one
hand, the symbols take values on a discrete set of points in phase space only.
On the other hand, no quasi-probabilities - that is, phase-space distributions
with negative values - are encountered in this approach.
|
[
{
"version": "v1",
"created": "Wed, 28 Apr 1999 12:23:39 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Weigert",
"Stefan",
""
]
] |
quant-ph/9904096
|
Atac Imamoglu
|
A. Imamoglu, D. D. Awschalom, G. Burkard, D. P. DiVincenzo, D. Loss,
M. Sherwin, A. Small
|
Quantum information processing using quantum dot spins and cavity-QED
|
Revised version including a method to realize parallel two-qubit
operations
| null | null | null |
quant-ph cond-mat.mes-hall
| null |
The electronic spin degrees of freedom in semiconductors typically have
decoherence times that are several orders of magnitude longer than other
relevant timescales. A solid-state quantum computer based on localized electron
spins as qubits is therefore of potential interest. Here, a scheme that
realizes controlled interactions between two distant quantum dot spins is
proposed. The effective long-range interaction is mediated by the vacuum field
of a high finesse microcavity. By using conduction-band-hole Raman transitions
induced by classical laser fields and the cavity-mode, parallel controlled-not
operations and arbitrary single qubit rotations can be realized. Optical
techniques can also be used to measure the spin-state of each quantum dot.
|
[
{
"version": "v1",
"created": "Wed, 28 Apr 1999 18:03:53 GMT"
},
{
"version": "v2",
"created": "Thu, 15 Jul 1999 19:07:05 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Imamoglu",
"A.",
""
],
[
"Awschalom",
"D. D.",
""
],
[
"Burkard",
"G.",
""
],
[
"DiVincenzo",
"D. P.",
""
],
[
"Loss",
"D.",
""
],
[
"Sherwin",
"M.",
""
],
[
"Small",
"A.",
""
]
] |
quant-ph/9904097
|
Constantin Brif
|
C. Brif and A. Mann
|
Testing Bell's inequality with two-level atoms via population
spectroscopy
|
4 pages, REVTeX, no figures. More info on
http://www.ligo.caltech.edu/~cbrif/science.html
|
Europhys.Lett.49:1-7,2000
|
10.1209/epl/i2000-00111-0
| null |
quant-ph
| null |
We propose a feasible experimental scheme, employing methods of population
spectroscopy with two-level atoms, for a test of Bell's inequality for massive
particles. The correlation function measured in this scheme is the joint atomic
$Q$ function. An inequality imposed by local realism is violated by any
entangled state of a pair of atoms.
|
[
{
"version": "v1",
"created": "Wed, 28 Apr 1999 19:48:06 GMT"
}
] | 2010-12-17T00:00:00 |
[
[
"Brif",
"C.",
""
],
[
"Mann",
"A.",
""
]
] |
quant-ph/9904098
|
Aephraim M. Steinberg
|
A. M. Steinberg (Univ. of Toronto)
|
On energy transfer by detection of a tunneling atom
|
5 pages, 2 figures
|
J.KoreanPhys.Soc.35:122-126,1999
| null | null |
quant-ph
| null |
We are in the process of building an experiment to study the tunneling of
laser-cooled Rubidium atoms through an optical barrier. A particularly thorny
set of questions arises when one considers the possibility of observing a
tunneling particle while it is in the ``forbidden'' region. In earlier work, we
have discussed how one might probe a tunneling atom ``weakly,'' so as to
prevent collapse. Here we make some observations about the implications of a
more traditional quantum measurement. Considerations of energy conservation
suggest that attempts to observe tunneling atoms will enhance inelastic
scattering, but not in a way which can be directly observed. It is possible
that attempts to make such measurements may lead to experimentally realizable
``observationally assisted barrier penetration.''
|
[
{
"version": "v1",
"created": "Wed, 28 Apr 1999 21:52:19 GMT"
}
] | 2008-11-26T00:00:00 |
[
[
"Steinberg",
"A. M.",
"",
"Univ. of Toronto"
]
] |
quant-ph/9904099
|
Michael Werner
|
M.J. Werner
|
Quantum soliton generation using an interferometer
|
7 pages, 3 figures
|
Phys.Rev.Lett. 81 (1998) 4132-4135
|
10.1103/PhysRevLett.81.4132
| null |
quant-ph
| null |
For the first time a method for realizing macroscopic quantum optical
solitons is presented. Simultaneous photon-number and momentum squeezing is
predicted using soliton propagation in an interferometer. Extraction of soliton
pulses closer to true quantum solitons than their coherent counterparts from
mode-locked lasers is possible. Moreover, it is a general method of reducing
photon-number fluctuations below the shot-noise level for non-soliton pulses as
well. It is anticipated that similar reductions in particle fluctuations could
occur for other forms of interfering bosonic fields whenever self-interaction
nonlinearities exist, for example, interacting ultracold atoms.
|
[
{
"version": "v1",
"created": "Wed, 28 Apr 1999 23:04:31 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Werner",
"M. J.",
""
]
] |
quant-ph/9904100
|
Debbie Leung
|
Debbie W. Leung (1,2), Isaac L. Chuang (2), Fumiko Yamaguchi (1) and
Yoshihisa Yamamoto (1,3) ((1) Stanford University (2) IBM Almaden Research
Center (3) NTT Basic Research Laboratories)
|
Efficient implementation of selective recoupling in heteronuclear spin
systems using Hadamard matrices
|
7 pages, 4 figures, mypsfig2, revtex, submitted April 27, 1999
|
Phys.Rev.A61:042310,2000
|
10.1103/PhysRevA.61.042310
| null |
quant-ph
| null |
We present an efficient scheme which couples any designated pair of spins in
heteronuclear spin systems. The scheme is based on the existence of Hadamard
matrices. For a system of $n$ spins with pairwise coupling, the scheme
concatenates $cn$ intervals of system evolution and uses at most $c n^2$ pulses
where $c \approx 1$. Our results demonstrate that, in many systems, selective
recoupling is possible with linear overhead, contrary to common speculation
that exponential effort is always required.
|
[
{
"version": "v1",
"created": "Wed, 28 Apr 1999 23:57:39 GMT"
}
] | 2008-12-18T00:00:00 |
[
[
"Leung",
"Debbie W.",
""
],
[
"Chuang",
"Isaac L.",
""
],
[
"Yamaguchi",
"Fumiko",
""
],
[
"Yamamoto",
"Yoshihisa",
""
]
] |
quant-ph/9904101
|
Paul Slater
|
Paul B. Slater (University of California)
|
Hall Normalization Constants for the Bures Volumes of the n-State
Quantum Systems
|
14 pages, LaTeX, 6 postscript figures. Revised version to appear in
J. Phys. A. We make a few slight changes from the previous version, but also
add a subsection (III G) in which several variations of the basic problem are
newly studied. Rather strong evidence is adduced that the Hall constants are
related to partial sums of denominators of the even-indexed Bernoulli
numbers, although a general formula is still lacking
|
J.Phys.A32:8231-8246,1999
|
10.1088/0305-4470/32/47/303
| null |
quant-ph math-ph math.MP
| null |
We report the results of certain integrations of quantum-theoretic interest,
relying, in this regard, upon recently developed parameterizations of Boya et
al of the n x n density matrices, in terms of squared components of the unit
(n-1)-sphere and the n x n unitary matrices. Firstly, we express the normalized
volume elements of the Bures (minimal monotone) metric for n = 2 and 3,
obtaining thereby "Bures prior probability distributions" over the two- and
three-state systems. Then, as an essential first step in extending these
results to n > 3, we determine that the "Hall normalization constant" (C_{n})
for the marginal Bures prior probability distribution over the
(n-1)-dimensional simplex of the n eigenvalues of the n x n density matrices
is, for n = 4, equal to 71680/pi^2. Since we also find that C_{3} = 35/pi, it
follows that C_{4} is simply equal to 2^{11} C_{3}/pi. (C_{2} itself is known
to equal 2/pi.) The constant C_{5} is also found. It too is associated with a
remarkably simple decompositon, involving the product of the eight consecutive
prime numbers from 2 to 23.
We also preliminarily investigate several cases, n > 5, with the use of
quasi-Monte Carlo integration. We hope that the various analyses reported will
prove useful in deriving a general formula (which evidence suggests will
involve the Bernoulli numbers) for the Hall normalization constant for
arbitrary n. This would have diverse applications, including quantum inference
and universal quantum coding.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 20:15:42 GMT"
},
{
"version": "v2",
"created": "Fri, 7 May 1999 20:23:30 GMT"
},
{
"version": "v3",
"created": "Sat, 8 May 1999 20:45:38 GMT"
},
{
"version": "v4",
"created": "Thu, 1 Jul 1999 17:25:42 GMT"
},
{
"version": "v5",
"created": "Thu, 7 Oct 1999 20:19:24 GMT"
}
] | 2016-09-08T00:00:00 |
[
[
"Slater",
"Paul B.",
"",
"University of California"
]
] |
quant-ph/9904102
|
Adrian Alscher
|
Adrian Alscher and Hermann Grabert
|
Semiclassical dynamics of a spin-1/2 in an arbitrary magnetic field
|
16 pages, submitted to Journal of Physics A
|
J.Phys.A32:4907-4919,1999
|
10.1088/0305-4470/32/26/309
| null |
quant-ph math-ph math.MP
| null |
The spin coherent state path integral describing the dynamics of a
spin-1/2-system in a magnetic field of arbitrary time-dependence is considered.
Defining the path integral as the limit of a Wiener regularized expression, the
semiclassical approximation leads to a continuous minimal action path with
jumps at the endpoints. The resulting semiclassical propagator is shown to
coincide with the exact quantum mechanical propagator. A non-linear
transformation of the angle variables allows for a determination of the
semiclassical path and the jumps without solving a boundary-value problem. The
semiclassical spin dynamics is thus readily amenable to numerical methods.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 18:17:12 GMT"
}
] | 2008-11-26T00:00:00 |
[
[
"Alscher",
"Adrian",
""
],
[
"Grabert",
"Hermann",
""
]
] |
quant-ph/9904103
|
Adrian Alscher
|
Joachim Hainz and Hermann Grabert
|
Centrifugal terms in the WKB approximation and semiclassical
quantization of hydrogen
|
5 pages, to appear in Phys. Rev. A
| null |
10.1103/PhysRevA.60.1698
| null |
quant-ph physics.atom-ph
| null |
A systematic semiclassical expansion of the hydrogen problem about the
classical Kepler problem is shown to yield remarkably accurate results. Ad hoc
changes of the centrifugal term, such as the standard Langer modification where
the factor l(l+1) is replaced by (l+1/2)^2, are avoided. The semiclassical
energy levels are shown to be exact to first order in $\hbar$ with all higher
order contributions vanishing. The wave functions and dipole matrix elements
are also discussed.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 18:31:41 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Apr 1999 09:17:49 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Hainz",
"Joachim",
""
],
[
"Grabert",
"Hermann",
""
]
] |
quant-ph/9904104
|
Michael Werner
|
M. J. Werner and S. R. Friberg
|
Phase transitions and the internal noise structure of nonlinear
Schr\"odi nger equation solitons
|
10 pages, 5 figures
|
Phys.Rev.Lett. 79 (1997) 4143-4146
|
10.1103/PhysRevLett.79.4143
| null |
quant-ph
| null |
We predict phase-transitions in the quantum noise characteristics of systems
described by the quantum nonlinear Schr\"odinger equation, showing them to be
related to the solitonic field transition at half the fundamental soliton
amplitude. These phase-transitions are robust with respect to Raman noise and
scattering losses. We also describe the rich internal quantum noise structure
of the solitonic fields in the vicinity of the phase-transition. For optical
coherent quantum solitons, this leads to the prediction that eliminating the
peak side-band noise due to the electronic nonlinearity of silica fiber by
spectral filtering leads to the optimal photon-number noise reduction of a
fundamental soliton.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 19:17:29 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Werner",
"M. J.",
""
],
[
"Friberg",
"S. R.",
""
]
] |
quant-ph/9904105
|
Gennady Berman
|
G.P. Berman, G.D. Doolen, and V.I. Tsifrinovich
|
Quantum Computation as a Dynamical Process
|
13 pages, 1 column, no figures
|
Comput.Phys.Commun.127:91-99,2000
|
10.1016/S0010-4655(00)00031-X
| null |
quant-ph
| null |
In this paper, we discuss the dynamical issues of quantum computation. We
demonstrate that fast wave function oscillations can affect the performance of
Shor's quantum algorithm by destroying required quantum interference. We also
show that this destructive effect can be routinely avoided by using
resonant-pulse techniques. We discuss the dynamics of resonant pulse
implementations of quantum logic gates in Ising spin systems. We also discuss
the influence of non-resonant excitations. We calculate the range of parameters
where undesirable non-resonant effects can be minimized. Finally, we describe
the ``$2\pi k$-method'' which avoids the detrimental deflection of non-resonant
qubits.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 20:30:11 GMT"
}
] | 2011-04-15T00:00:00 |
[
[
"Berman",
"G. P.",
""
],
[
"Doolen",
"G. D.",
""
],
[
"Tsifrinovich",
"V. I.",
""
]
] |
quant-ph/9904106
|
Dan Solomon
|
Dan Solomon
|
Mathematical Inconsistencies in Dirac Field Theory
|
44 pages
| null | null | null |
quant-ph
| null |
If a mathematical theory contains incompatible postulates then it is likely
that the theory will produce theorems or results that are contradictory. It
will be shown that this is the case with Dirac field theory. An example of such
a contradiction is the problem asociated with evaluating the Schwinger term. It
is generally known that different ways of evaluating this quantity yield
different results. It will be shown that the reason for this is that Dirac
field theory is mathematically inconsistent, i.e., it contains incompatible
assumptions or postulates. The generally accepted definition of the vacuum
state must be modified in order to create a consistent theory.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 20:35:51 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Solomon",
"Dan",
""
]
] |
quant-ph/9904107
|
Yaoyun Shi
|
Yaoyun Shi (Princeton University)
|
Lower bounds of quantum black-box complexity and degree of approximation
polynomials by influence of Boolean variables
|
12 pages, LaTex, minor changes
|
IPL, 75(1-2):79--83, July 2000.
| null | null |
quant-ph
| null |
We prove that, to compute a Boolean function $f$ on $N$ variables with error
probability $\epsilon$, any quantum black-box algorithm has to query at least
$\frac{1 - 2\sqrt{\epsilon}}{2} \rho_f N = \frac{1 - 2\sqrt{\epsilon}}{2}
\bar{S}_f$ times, where $\rho_f$ is the average influence of variables in $f$,
and $\bar{S}_f$ is the average sensitivity. It's interesting to contrast this
result with the known lower bound of $\Omega (\sqrt{S_f})$, where $S_f$ is the
sensitivity of $f$. This lower bound is tight for some functions. We also show
for any polynomial $\tilde{f}$ that approximates $f$ with error probability
$\epsilon$, $deg(\tilde{f}) \ge 1/4 (1 - \frac{3 \epsilon}{1 + \epsilon})^2
\rho_f N$. This bound can be better than previous known lower bound of
$\Omega(\sqrt{BS_f})$ for some functions. Our technique may be of intest
itself: we apply Fourier analysis to functions mapping $\{0, 1\}^N$ to unit
vectors in a Hilbert space. From this viewpoint, the state of the quantum
computer at step $t$ can be written as $\sum_{s\in \{0, 1\}^N, |s| \le t}
\hat{\phi}_s (-1)^ {s \cdot x}$, which is handy for lower bound analysis.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 21:25:48 GMT"
},
{
"version": "v2",
"created": "Sat, 8 May 1999 00:56:34 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Shi",
"Yaoyun",
"",
"Princeton University"
]
] |
quant-ph/9904108
|
Wim van Dam
|
Wim van Dam (1,2) and Frederic Magniez (3) and Michele Mosca (2,4) and
Miklos Santha (3,5) ((1) CWI Amsterdam (2) CQC Oxford (3) LRI Paris Sud (4) U
of Waterloo (5) CNRS)
|
Self-Testing of Universal and Fault-Tolerant Sets of Quantum Gates
|
LaTeX2e, 14 pages, no figures, usepackage{a4wide,amssymb,amsmath};
major changes (Feb 2000), results expanded to 2-qubit gates. To appear in
Proceedings of the 32nd Annual ACM Symposium on Theory of Computing
|
Proceedings of the 32nd Annual ACM Symposium on Theory of
Computing (STOC2000), pages 688-696
|
10.1145/335305.335402
| null |
quant-ph cs.OH
| null |
We consider the design of self-testers for quantum gates. A self-tester for
the gates F_1,...,F_m is a classical procedure that, given any gates
G_1,...,G_m, decides with high probability if each G_i is close to F_i. This
decision has to rely only on measuring in the computational basis the effect of
iterating the gates on the classical states. It turns out that instead of
individual gates, we can only design procedures for families of gates. To
achieve our goal we borrow some elegant ideas of the theory of program testing:
we characterize the gate families by specific properties, we develop a theory
of robustness for them, and show that they lead to self-testers. In particular
we prove that the universal and fault-tolerant set of gates consisting of a
Hadamard gate, a c-NOT gate, and a phase rotation gate of angle pi/4 is
self-testable.
|
[
{
"version": "v1",
"created": "Thu, 29 Apr 1999 22:06:49 GMT"
},
{
"version": "v2",
"created": "Sun, 13 Feb 2000 21:09:33 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"van Dam",
"Wim",
""
],
[
"Magniez",
"Frederic",
""
],
[
"Mosca",
"Michele",
""
],
[
"Santha",
"Miklos",
""
]
] |
quant-ph/9904109
|
Ruediger Schack
|
R. Schack (Royal Holloway, University of London), C. M. Caves
(University of New Mexico)
|
Explicit product ensembles for separable quantum states
|
15 pages, no figures
|
J.Mod.Opt. 47 (2000) 387-399
|
10.1080/09500340008244050
| null |
quant-ph
| null |
We present a general method for constructing pure-product-state
representations for density operators of $N$ quantum bits. If such a
representation has nonnegative expansion coefficients, it provides an explicit
separable ensemble for the density operator. We derive the condition for
separability of a mixture of the Greenberger-Horne-Zeilinger state with the
maximally mixed state.
|
[
{
"version": "v1",
"created": "Fri, 30 Apr 1999 14:29:56 GMT"
},
{
"version": "v2",
"created": "Wed, 19 May 1999 08:32:48 GMT"
}
] | 2015-06-26T00:00:00 |
[
[
"Schack",
"R.",
"",
"Royal Holloway, University of London"
],
[
"Caves",
"C. M.",
"",
"University of New Mexico"
]
] |
quant-ph/9904110
|
M. Czachor
|
Marek Czachor, Maciej Kuna, Sergiej B. Leble, and Jan Naudts
|
Nonlinear von Neumann-type equations
|
To be published in "New insights in quantum mechanics", H.D. Doebner,
S.T. Ali, M. Keyl, and R.F. Werner, eds. (World Scientific, 1999); 3 eps
figures, style goslar.cls included
| null | null | null |
quant-ph nlin.SI solv-int
| null |
We review some recent developments in the theory of nonlinear von Neumann
equations. We distinguish between the von Neumann equation (which can be
nonlinear) and the Liouville equation (which should be linear). Explicit
examples illustrate the technique of binary Darboux integration of nonlinear
density matrix equations and special attention is payed to the problem of how
to find physically nontrivial `self-scattering' solutions.
|
[
{
"version": "v1",
"created": "Fri, 30 Apr 1999 18:07:14 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Czachor",
"Marek",
""
],
[
"Kuna",
"Maciej",
""
],
[
"Leble",
"Sergiej B.",
""
],
[
"Naudts",
"Jan",
""
]
] |
quant-ph/9905001
|
Chiao
|
Raymond Y. Chiao and Jack Boyce (Dept. of Physics, University of
California, Berkeley, California)
|
Bogoliubov dispersion relation and the possibility of superfluidity for
weakly-interacting photons in a 2D photon fluid
|
11 pages, 4 figures, REVTEX style, to be published in PRA, Nov. 1,
1999
| null |
10.1103/PhysRevA.60.4114
| null |
quant-ph cond-mat
| null |
The Bogoliubov dispersion relation for the elementary excitations of the
weakly-interacting Bose gas is shown to hold for the case of the
weakly-interacting photon gas (the ``photon fluid'') in a nonlinear Fabry-Perot
cavity. This relation, which is also derived by means of a linearized
fluctuation analysis in classical nonlinear optics, implies the possibility of
a new superfluid state of light. The theory underlying an experiment in
progress to measure this dispersion relation is described, and another
experiment to test the prediction of the superfluidity of this state of light
is proposed.
|
[
{
"version": "v1",
"created": "Sat, 1 May 1999 00:38:57 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Jul 1999 01:24:05 GMT"
},
{
"version": "v3",
"created": "Tue, 12 Oct 1999 02:12:56 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Chiao",
"Raymond Y.",
"",
"Dept. of Physics, University of\n California, Berkeley, California"
],
[
"Boyce",
"Jack",
"",
"Dept. of Physics, University of\n California, Berkeley, California"
]
] |
quant-ph/9905002
|
E. D. Davis
|
E. D. Davis, G. I. Ghandour
|
Implications of invariance of the Hamiltonian under canonical
transformations in phase space
|
REVTeX v3.1, 13 pages
|
J.Phys.A35:5875-5891,2002
|
10.1088/0305-4470/35/28/307
| null |
quant-ph
| null |
We observe that, within the effective generating function formalism for the
implementation of canonical transformations within wave mechanics, non-trivial
canonical transformations which leave invariant the form of the Hamilton
function of the classical analogue of a quantum system manifest themselves in
an integral equation for its stationary state eigenfunctions. We restrict
ourselves to that subclass of these dynamical symmetries for which the
corresponding effective generating functions are necessaarily free of quantum
corrections. We demonstrate that infinite families of such transformations
exist for a variety of familiar conservative systems of one degree of freedom.
We show how the geometry of the canonical transformations and the symmetry of
the effective generating function can be exploited to pin down the precise form
of the integral equations for stationary state eigenfunctions. We recover
several integral equations found in the literature on standard special
functions of mathematical physics. We end with a brief discussion (relevant to
string theory) of the generalization to scalar field theories in 1+1
dimensions.
|
[
{
"version": "v1",
"created": "Mon, 3 May 1999 11:52:13 GMT"
}
] | 2008-11-26T00:00:00 |
[
[
"Davis",
"E. D.",
""
],
[
"Ghandour",
"G. I.",
""
]
] |
quant-ph/9905003
|
David Marcus Appleby
|
D. M. Appleby
|
Generic Bohmian Trajectories of an Isolated Particle
|
16 pages, 5 figures, AMS-latex. Argument condensed. No changes to
content
|
Found.Phys.29:1863-1916,1999
|
10.1023/A:1018842401049
|
QMW-PH-99-06
|
quant-ph
| null |
The generic Bohmian trajectories are calculated for an isolated particle in
an approximate energy eigenstate, for an arbitrary one-dimensional potential
well. It is shown, that the necessary and sufficient condition for there to be
a negligible probability of the trajectory deviating significantly from the
classical trajectory at any stage in the motion is, that the state be a
narrowly localised wave packet. The properties of the Bohmian trajectories are
discussed in relationship to the theory of retrodictively optimal simultaneous
measurements of position and momentum which was presented in several previous
papers. It is shown that the Bohmian velocity at x is the expectation value of
the velocity which would be observed at x, if one were to make a retrodictively
optimal simultaneous measurement of x and p, in the limit as the error in the
measurement of x tends to zero. This explains the tendency of the Bohmian
particle to behave in a highly non-classical manner. It also explains why the
trajectories in the interpretation recently proposed by Garcia de Polavieja
tend to be much more nearly classical in the limit of large quantum number. The
implications for other trajectory interpretations are considered.
|
[
{
"version": "v1",
"created": "Mon, 3 May 1999 23:20:05 GMT"
},
{
"version": "v2",
"created": "Sun, 8 Aug 1999 22:46:25 GMT"
}
] | 2014-11-18T00:00:00 |
[
[
"Appleby",
"D. M.",
""
]
] |
quant-ph/9905004
|
H. Dieter Zeh
|
H. D. Zeh
|
The Meaning of Decoherence
|
25 pages, Latex, needs Springer macro cl2emult. Version to be
published. An error in the comments regarding the relation between Bloch
vectors and Wigner functions has been eliminated (see Footnote 3)
|
Lect.Notes Phys. 538 (2000) 19-42
| null | null |
quant-ph cond-mat math-ph math.MP physics.atom-ph physics.chem-ph
| null |
The conceptual and dynamical aspects of decoherence are analyzed, while their
consequences are discussed for several fundamental applications. This
mechanism, which is based on a universal Schr\"odinger equation, is furthermore
compared with the phenomenological description of open systems in terms of
`quantum dynamical maps'.
|
[
{
"version": "v1",
"created": "Tue, 4 May 1999 14:27:20 GMT"
},
{
"version": "v2",
"created": "Tue, 29 Jun 1999 13:27:22 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Zeh",
"H. D.",
""
]
] |
quant-ph/9905005
|
Liu Yuxi
|
Chang-qi Cao, Liu Yu-Xi and Hui Cao
|
The exact solution for the superfluorescence of low density Frenkel
excitons in double and triple lattice-layers
|
10 pages no figure. submitted to Phys. Rev. B
| null | null | null |
quant-ph
| null |
In low density regime, the fluorescence of Frenkel exitons in crystal slab
can be studied without the aid of rotating wave and Mackoffian approximation.
The equations for the case of double and triple lattice-layers are now solved
exactly to give the eigen decay rates, frequency shifts and the statistical
properties of the fields.
|
[
{
"version": "v1",
"created": "Tue, 4 May 1999 05:18:01 GMT"
},
{
"version": "v2",
"created": "Thu, 6 May 1999 01:40:35 GMT"
},
{
"version": "v3",
"created": "Wed, 26 Jan 2000 03:13:27 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Cao",
"Chang-qi",
""
],
[
"Yu-Xi",
"Liu",
""
],
[
"Cao",
"Hui",
""
]
] |
quant-ph/9905006
|
Ting Yu
|
Ting Yu, Lajos Diosi, Nicolas Gisin, and Walter T. Strunz
|
Post-Markov master equation for the dynamics of open quantum systems
|
7 pages, 2 figures, RevTex
|
Phys.Lett. A265 (2000) 331-336
|
10.1016/S0375-9601(00)00014-1
| null |
quant-ph cond-mat.stat-mech
| null |
A systematic first-order correction to the standard Markov master equation
for open quantum systems interacting with a bosonic bath is presented. It
extends the Markov Lindblad master equation to the more general case of
non-Markovian evolution. The meaning and applications of our `post'-Markov
master equation are illustrated with several examples, including a damped
two-level atom, the spin-boson model and the quantum Brownian motion model.
Limitations of the Markov approximation, the problem of positivity violation
and initial slips are also discussed.
|
[
{
"version": "v1",
"created": "Tue, 4 May 1999 09:20:36 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Yu",
"Ting",
""
],
[
"Diosi",
"Lajos",
""
],
[
"Gisin",
"Nicolas",
""
],
[
"Strunz",
"Walter T.",
""
]
] |
quant-ph/9905007
|
Stefan Scheel
|
Stefan Scheel, Ludwig Knoell, Dirk-Gunnar Welsch
|
Spontaneous decay in the presence of absorbing dielectric bodies
|
10 pages LaTeX, 8 Postscript figures, contribution to proceedings of
the 6th central-european workshop on quantum optics (adacta.sty included)
| null | null | null |
quant-ph
| null |
We present a formalism for studying the influence of dispersive and absorbing
dielectric bodies on a radiating atom in the framework of quantization of the
phenomenological Maxwell equations for given complex permittivities of the
bodies. In Markov approximation, the rate of spontaneous decay and the line
shift associated with it can then be related to the complex permittivities and
geometries of the bodies via the dyadic Green function of the classical
boundary value problem of electrodynamics -- a result which is in agreement
with second-order calculations for microscopic model systems. The theory is
applied to an atom near a planar interface as well as to an atom in a spherical
cavity. The latter, also known as the real-cavity model for spontaneous decay
of an excited atom embedded in a dielectric, is compared with the
virtual-cavity model. Connections with other approaches are mentioned and the
results are compared.
|
[
{
"version": "v1",
"created": "Tue, 4 May 1999 10:22:24 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Scheel",
"Stefan",
""
],
[
"Knoell",
"Ludwig",
""
],
[
"Welsch",
"Dirk-Gunnar",
""
]
] |
quant-ph/9905008
|
Jonathan A. Jones
|
J. A. Jones and E. Knill
|
Efficient Refocussing of One Spin and Two Spin Interactions for NMR
Quantum Computation
|
4 pages, RevTeX, including 4 LaTeX figures
|
J.Magn.Resonance 141 (1999) 322-325
|
10.1006/jmre.1999.1890
|
JAJQP-99-01
|
quant-ph
| null |
The use of spin echoes to refocus one spin interactions (chemical shifts) and
two spin interactions (spin-spin couplings) plays a central role in both
conventional NMR experiments and NMR quantum computation. Here we describe
schemes for efficient refocussing of such interactions in both fully and
partially coupled spin systems.
|
[
{
"version": "v1",
"created": "Tue, 4 May 1999 10:40:16 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Jones",
"J. A.",
""
],
[
"Knill",
"E.",
""
]
] |
quant-ph/9905009
|
Richard J. Hughes
|
Richard J. Hughes, William T. Buttler, Paul G. Kwiat, Steve K.
Lamoreaux, George L. Morgan, Jane E. Nordholt and C. G. Peterson
|
Practical quantum cryptography for secure free-space communications
|
12 pages, 4 figures
| null |
10.1117/12.346170
|
LA-UR-99-737
|
quant-ph
| null |
Quantum cryptography is an emerging technology in which two parties may
simultaneously generate shared, secret cryptographic key material using the
transmission of quantum states of light. The security of these transmissions is
based on the inviolability of the laws of quantum mechanics and
information-theoretically secure post-processing methods. An adversary can
neither successfully tap the quantum transmissions, nor evade detection, owing
to Heisenberg's uncertainty principle. In this paper we describe the theory of
quantum cryptography, and the most recent results from our experimental
free-space system with which we have demonstrated for the first time the
feasibility of quantum key generation over a point-to-point outdoor atmospheric
path in daylight. We achieved a transmission distance of 0.5 km, which was
limited only by the length of the test range. Our results provide strong
evidence that cryptographic key material could be generated on demand between a
ground station and a satellite (or between two satellites), allowing a
satellite to be securely re-keyed on orbit. We present a feasibility analysis
of surface-to-satellite quantum key generation.
|
[
{
"version": "v1",
"created": "Tue, 4 May 1999 17:43:37 GMT"
}
] | 2015-06-26T00:00:00 |
[
[
"Hughes",
"Richard J.",
""
],
[
"Buttler",
"William T.",
""
],
[
"Kwiat",
"Paul G.",
""
],
[
"Lamoreaux",
"Steve K.",
""
],
[
"Morgan",
"George L.",
""
],
[
"Nordholt",
"Jane E.",
""
],
[
"Peterson",
"C. G.",
""
]
] |
quant-ph/9905010
|
Dr P. K. Panigrahi
|
V. Sunilkumar, B. A. Bambah, P. K. Panigrahi and V. Srinivasan
|
Coherent States for the Deformed Algebras
|
11 pages, REVTeX
| null | null | null |
quant-ph hep-th math-ph math.MP
| null |
We provide a unified approach for finding the coherent states of various
deformed algebras, including quadratic, Higgs and q-deformed algebras, which
are relevant for many physical problems. For the non-compact cases, coherent
states, which are the eigenstates of the respective annihilation operators, are
constructed by finding the canonical conjugates of these operators. We give a
general procedure to map these deformed algebras to appropriate Lie algebras.
Generalized coherent states, in the Perelomov sense, follow from this
construction.
|
[
{
"version": "v1",
"created": "Wed, 5 May 1999 04:22:56 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Sunilkumar",
"V.",
""
],
[
"Bambah",
"B. A.",
""
],
[
"Panigrahi",
"P. K.",
""
],
[
"Srinivasan",
"V.",
""
]
] |
quant-ph/9905011
|
Dr P. K. Panigrahi
|
N. Gurappa, Prasanta K. Panigrahi and T. Soloman Raju
|
Quantum equivalent of the Bertrand's theorem
|
11 pages, REVTeX
|
Mod.Phys.Lett.A15:1851-1858,2000
|
10.1142/S0217732300002255
| null |
quant-ph
| null |
A procedure for constructing bound state potentials is given. We show that,
under the natural conditions imposed on a radial eigenvalue problem, the only
special cases of the general central potential, which are exactly solvable and
have infinite number of energy eigenvalues, are the Coulomb and harmonic
oscillator potentials.
|
[
{
"version": "v1",
"created": "Wed, 5 May 1999 05:12:32 GMT"
}
] | 2011-07-19T00:00:00 |
[
[
"Gurappa",
"N.",
""
],
[
"Panigrahi",
"Prasanta K.",
""
],
[
"Raju",
"T. Soloman",
""
]
] |
quant-ph/9905012
|
Habatwa Vincent Mweene
|
Habatwa Vincent Mweene (Physics Department, University of Zambia)
|
Derivation of Spin Vectors and Operators From First Principles
|
LaTeX, 30 pages, submitted to "Foundations of Physics." Replaced to
thoroughly revise notation and improve some sections
| null | null |
UNZAPHYS-001
|
quant-ph
| null |
The interpretation of quantum mechanics due to Lande' is applied to the
connection between wave mechanics and matrix mechanics. The connection between
the differential eigenvalue equation and the matrix eigenvalue equation for an
operator is elucidated. In particular, we show that the elements of a matrix
vector state are probability amplitudes with a structure rather than being mere
constants. We obtain the most general expressions for the probability
amplitudes for the description of spin-1/2 measurements. As a result, we derive
spin-1/2 operators and vectors from first principles. The procedure used is
analogous to that by which orbital angular momentum wavefunctions and operators
are transformed to matrix mechanics vectors and matrices. The most generalized
forms of the spin operators and their eigenvectors for spin-1/2 are derived and
shown to reduce to the Pauli spin matrices and vectors in an appropriate limit.
|
[
{
"version": "v1",
"created": "Wed, 5 May 1999 11:44:49 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Jun 2000 23:29:58 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Mweene",
"Habatwa Vincent",
"",
"Physics Department, University of Zambia"
]
] |
quant-ph/9905013
|
Tommaso Calarco
|
T. Calarco (1,2), E.A. Hinds (3), D. Jaksch (1), J. Schmiedmayer (4),
J.I. Cirac (1), and P. Zoller (1) ((1) Institut fuer Theoretische Physik,
Universitaet Innsbruck, Innsbruck, Austria (2) ECT*, Villa Tambosi,
Villazzano (Trento), Italy (3) Sussex Centre for Optical and Atomic Physics,
Brighton, United Kingdom (4) Institut fuer Experimentalphysik, universitaet
Innsbruck, Innsbruck, Austria)
|
Quantum gates with neutral atoms: Controlling collisional interactions
in time dependent traps
|
10 pages, 3 figures
|
Phys. Rev. A 61, 022304 (2000)
|
10.1103/PhysRevA.61.022304
| null |
quant-ph
| null |
We theoretically study specific schemes for performing a fundamental
two-qubit quantum gate via controlled atomic collisions by switching
microscopic potentials. In particular we calculate the fidelity of a gate
operation for a configuration where a potential barrier between two atoms is
instantaneously removed and restored after a certain time. Possible
implementations could be based on microtraps created by magnetic and electric
fields, or potentials induced by laser light.
|
[
{
"version": "v1",
"created": "Wed, 5 May 1999 16:09:05 GMT"
},
{
"version": "v2",
"created": "Thu, 20 May 1999 10:48:11 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Calarco",
"T.",
""
],
[
"Hinds",
"E. A.",
""
],
[
"Jaksch",
"D.",
""
],
[
"Schmiedmayer",
"J.",
""
],
[
"Cirac",
"J. I.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/9905014
|
A. M. Lisewski
|
A.M. Lisewski
|
On the classical hydrodynamic limit of quantum field theories
|
minor changes, 9 pages, no figures, uses revtex
| null | null | null |
quant-ph
| null |
We discuss the transition from a quantum to a classical domain for a model
where a separation into environment and system is explicitely not given.
Utilizing the coarse graining procedure for free quantum fields we also apply
the projection method and the Hamiltonian principle to study possible cases of
emergent classicality. General conditions for classical dynamics are given.
Eventually, they lead to the equations of motion for a perfect classical fluid.
|
[
{
"version": "v1",
"created": "Wed, 5 May 1999 20:14:47 GMT"
},
{
"version": "v2",
"created": "Wed, 30 Jun 1999 12:53:58 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Lisewski",
"A. M.",
""
]
] |
quant-ph/9905015
|
'Andrey V. Novikov-Borodin'
|
Andrey V. Novikov-Borodin (Institute for Nuclear Research of Russian
Academy of Sciences, Moscow, Russia)
|
Wave Function Interpretation and Quantum Mechanics Equations
|
5 pages, LaTeX
| null | null | null |
quant-ph
| null |
The quantum mechanics description of a physical object stretched in space and
stable in time from the relativistic space-time properties point of view,
introduced in special theory of relativity, is considered and analysed. The
mathematical model of physical objects is proposed. This model gives a
possibility to unite a description of corpuscular and wave properties of real
physical objects, i.e. fields and particles. There are substantiated an
approach and a mathematical pattern which give a possibility to describe
physical object not only in causal, but also in absolute remote fields of the
Minkowski space. Applying the proposed approach to the microcosm description,
one can get the equations that in passage to the limit transfer to such quantum
mechanics equations as Schrodinger, Klein-Gordon-Fock and in particular case -
the wave equation. The event nature of the received equations is discussed. It
is shown that all mentioned equations reflect the space-time relativistic
properties during the description of the invariant and non-invariant physics
object characteristics.
|
[
{
"version": "v1",
"created": "Wed, 5 May 1999 22:31:54 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Novikov-Borodin",
"Andrey V.",
"",
"Institute for Nuclear Research of Russian\n Academy of Sciences, Moscow, Russia"
]
] |
quant-ph/9905016
|
Marcis Auzinsh
|
M. Auzinsh, R. Damburg (Dept. of Physics, University of Latvia)
|
A simple formula for ground state energy of a two-electron atom
|
LaTeX 5 pages, 1 figure, 1 table
|
Latv.J.Phys.Tech.Sci. 5 (1999) 22
| null | null |
quant-ph physics.atom-ph physics.ed-ph
| null |
A simple expression for a ground state energy for a two-electron atom is
derived. For this, assumption based upon the Niels Bohr ''old'' quantum
mechanics idea about electron correlation in a two-electron atom is exploited.
Results are compared with experimental data and theoretical results based on a
variation approach.
|
[
{
"version": "v1",
"created": "Thu, 6 May 1999 10:19:32 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Auzinsh",
"M.",
"",
"Dept. of Physics, University of Latvia"
],
[
"Damburg",
"R.",
"",
"Dept. of Physics, University of Latvia"
]
] |
quant-ph/9905017
|
Paolo Facchi
|
P. Facchi and S. Pascazio
|
Temporal behavior and quantum Zeno time of an excited state of the
hydrogen atom
|
11 pages
|
Phys.Lett. A241 (1998) 139-144
|
10.1016/S0375-9601(98)00144-3
| null |
quant-ph
| null |
The quantum "Zeno" time of the 2P-1S transition of the hydrogen atom is
computed and found to be approximately 3.59 10^{-15}s (the lifetime is
approximately 1.595 10^{-9}s). The temporal behavior of this system is analyzed
in a purely quantum field theoretical framework and is compared to the
exponential decay law.
|
[
{
"version": "v1",
"created": "Thu, 6 May 1999 15:10:32 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Facchi",
"P.",
""
],
[
"Pascazio",
"S.",
""
]
] |
quant-ph/9905018
|
Nicolas Gisin
|
N. Gisin and B. Gisin
|
A local hidden variable model of quantum correlation exploiting the
detection loophole
|
6 pages + 1 figure. A software producing data violating Bell
inequality between two classical computers can be downloaded from
http://www.gapoptique.unige.ch/News/BellSoft.asp
|
Phys.Lett. A260 (1999) 323-327
|
10.1016/S0375-9601(99)00519-8
| null |
quant-ph
| null |
A local hidden variable model exploiting the detection loophole to reproduce
exactly the quantum correlation of the singlet state is presented. The model is
shown to be compatible with both the CHSH and the CH Bell inequalities.
Moreover, it bears the same rotational symmetry as spins. The reason why the
model can reproduce the quantum correlation without violating the Bell theorem
is that in the model the efficiency of the detectors depends on the local
hidden variable. On average the detector efficiency is limited to 75%.
|
[
{
"version": "v1",
"created": "Thu, 6 May 1999 15:53:58 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Gisin",
"N.",
""
],
[
"Gisin",
"B.",
""
]
] |
quant-ph/9905019
|
Theor. Phys. Group
|
Qiong-gui Lin
|
Quantum-mechanical model for particles carrying electric charge and
magnetic flux in two dimensions
|
12 pages, REVTeX, no figure
|
Phys.Rev. A59 (1999) 3228-3235
|
10.1103/PhysRevA.59.3228
| null |
quant-ph hep-th
| null |
We propose a simple quantum mechanical equation for $n$ particles in two
dimensions, each particle carrying electric charge and magnetic flux. Such
particles appear in (2+1)-dimensional Chern-Simons field theories as charged
vortex soliton solutions, where the ratio of charge to flux is a constant
independent of the specific solution. As an approximation, the charge-flux
interaction is described here by the Aharonov-Bohm potential, and the
charge-charge interaction by the Coulomb one. The equation for two particles,
one with charge and flux ($q, \Phi/Z$) and the other with ($-Zq, -\Phi$) where
$Z$ is a pure number is studied in detail. The bound state problem is solved
exactly for arbitrary $q$ and $\Phi$ when $Z>0$. The scattering problem is
exactly solved in parabolic coordinates in special cases when $q\Phi/2\pi\hbar
c$ takes integers or half integers. In both cases the cross sections obtained
are rather different from that for pure Coulomb scattering.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 10:20:21 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Lin",
"Qiong-gui",
""
]
] |
quant-ph/9905020
|
Miloslav Znojil
|
Miloslav Znojil
|
PT -symmetric harmonic oscillators
|
9 pages, submitted to Phys. Lett. A
|
Phys.Lett. A259 (1999) 220-223
|
10.1016/S0375-9601(99)00429-6
| null |
quant-ph
| null |
Within the framework of the recently proposed formalism using non-hermitean
Hamiltonians constrained merely by their PT invariance we describe a new
exactly solvable family of the harmonic-oscillator-like potentials with
non-equidistant spectrum. Our one-dimensional superposition of the harmonic x^2
with the centrifugal-like G/x^2 is regularized by a purely imaginary shift of
$x$.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 12:48:33 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Znojil",
"Miloslav",
""
]
] |
quant-ph/9905021
|
Dan Solomon
|
Dan Solomon
|
Gauge invariance and the vacuum state
|
32 pages
|
Can.J.Phys. 76 (1998) 111-127
|
10.1139/cjp-76-2-111
| null |
quant-ph
| null |
Quantum field theory is assumed to be gauge invariant. It is shown that for a
Dirac field the assumption of gauge invariance impacts on the way the vacuum
state is defined. It is shown that the conventional definition of the vacuum
state must be modified to take into account the requirements of gauge
invariance.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 14:13:14 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Solomon",
"Dan",
""
]
] |
quant-ph/9905022
|
Fumiaki Morikoshi
|
Fumiaki Morikoshi
|
Entanglement measure and distance
|
3 pages, REVTeX
| null | null |
EPHOU-99-006
|
quant-ph
| null |
Recently a new entanglemenet dilution scheme has been constructed by Lo and
Popescu. This paper points out that this result has a deep implication that the
entanglement measure for bipartite pure states is independent of the distance
between entangled two systems.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 14:28:13 GMT"
},
{
"version": "v2",
"created": "Thu, 8 Jul 1999 08:10:18 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Morikoshi",
"Fumiaki",
""
]
] |
quant-ph/9905023
|
Inigo L. Egusquiza
|
I. L. Egusquiza and J. G. Muga
|
Free motion time-of-arrival operator and probability distribution
|
10 a4 pages, no figures
|
Phys.Rev.A61:012104,1999
|
10.1103/PhysRevA.61.012104
|
EHU-FT/9901
|
quant-ph
| null |
We reappraise and clarify the contradictory statements found in the
literature concerning the time-of-arrival operator introduced by Aharonov and
Bohm in Phys. Rev. {\bf 122}, 1649 (1961). We use Naimark's dilation theorem to
reproduce the generalized decomposition of unity (or POVM) from any
self-adjoint extension of the operator, emphasizing a natural one, which arises
from the analogy with the momentum operator on the half-line. General time
operators are set within a unifying perspective. It is shown that they are not
in general related to the time of arrival, even though they may have the same
form.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 14:30:19 GMT"
}
] | 2008-12-18T00:00:00 |
[
[
"Egusquiza",
"I. L.",
""
],
[
"Muga",
"J. G.",
""
]
] |
quant-ph/9905024
|
Lucien Hardy
|
Lucien Hardy and David D. Song
|
No Signalling and Probabilistic Quantum Cloning
|
5 pages
|
Phys.Lett. A259 (1999) 331-333
|
10.1016/S0375-9601(99)00448-X
| null |
quant-ph
| null |
We show that the condition of no faster-than-light signalling restricts the
number of quantum states that can be cloned in a given Hilbert space. This
condition leads to the constraints on a probabilistic quantum cloning machine
(PQCM) recently found by Duan and Guo.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 14:35:11 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Hardy",
"Lucien",
""
],
[
"Song",
"David D.",
""
]
] |
quant-ph/9905025
|
Mikhail Lukin
|
M.D.Lukin and P.R.Hemmer
|
Coherent Control of Atom-Atom Interactions and Entanglement using
Optical Fields
| null | null | null | null |
quant-ph
| null |
Two-photon optical transitions combined with long-range dipole-dipole
interactions can be used for the coherent manipulation of collective metastable
states composed of different atoms. We show that it is possible to induce
optical resonances accompanied by the generation of entangled superpositions of
the atomic states. Resonances of this kind can be used to implement quantum
logic gates using optically excited single atoms (impurities) in the condensed
phase.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 14:54:38 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Lukin",
"M. D.",
""
],
[
"Hemmer",
"P. R.",
""
]
] |
quant-ph/9905026
|
Rusins Freivalds
|
Andris Ambainis, Richard Bonner, Rusins Freivalds, Marats Golovkins,
Marek Karpinski
|
Quantum finite multitape automata
|
14 pages, LaTeX
| null | null | null |
quant-ph cs.CC cs.FL
| null |
Quantum finite automata were introduced by C.Moore, J.P. Crutchfield, and by
A.Kondacs and J.Watrous. This notion is not a generalization of the
deterministic finite automata. Moreover, it was proved that not all regular
languages can be recognized by quantum finite automata. A.Ambainis and
R.Freivalds proved that for some languages quantum finite automata may be
exponentially more concise rather than both deterministic and probabilistic
finite automata. In this paper we introduce the notion of quantum finite
multitape automata and prove that there is a language recognized by a quantum
finite automaton but not by a deterministic or probabilistic finite automata.
This is the first result on a problem which can be solved by a quantum computer
but not by a deterministic or probabilistic computer. Additionally we discover
unexpected probabilistic automata recognizing complicated languages.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 15:05:45 GMT"
}
] | 2011-06-14T00:00:00 |
[
[
"Ambainis",
"Andris",
""
],
[
"Bonner",
"Richard",
""
],
[
"Freivalds",
"Rusins",
""
],
[
"Golovkins",
"Marats",
""
],
[
"Karpinski",
"Marek",
""
]
] |
quant-ph/9905027
|
Eric Dennis
|
Eric Dennis
|
Toward fault-tolerant quantum computation without concatenation
|
12 pages, 2 figures, replaced: new stuff on error models, numerical
example for concatenation criteria
|
Phys.Rev.A63:052314,2001
|
10.1103/PhysRevA.63.052314
| null |
quant-ph
| null |
It has been known that quantum error correction via concatenated codes can be
done with exponentially small failure rate if the error rate for physical
qubits is below a certain accuracy threshold. Other, unconcatenated codes with
their own attractive features-improved accuracy threshold, local
operations-have also been studied. By iteratively distilling a certain
two-qubit entangled state it is shown how to perform an encoded Toffoli gate,
important for universal computation, on CSS codes that are either
unconcatenated or, for a range of very large block sizes, singly concatenated.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 18:48:08 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Jul 2000 02:51:10 GMT"
}
] | 2008-12-18T00:00:00 |
[
[
"Dennis",
"Eric",
""
]
] |
quant-ph/9905028
|
Richard J. Nelson
|
Richard J. Nelson, David G. Cory, and Seth Lloyd
|
Experimental Demonstration of Greenberger-Horne-Zeilinger Correlations
Using Nuclear Magnetic Resonance
|
Latex2.09, 8 pages, 1 eps figure
| null |
10.1103/PhysRevA.61.022106
| null |
quant-ph
| null |
The Greenberger-Horne-Zeilinger (GHZ) effect provides an example of quantum
correlations that cannot be explained by classical local hidden variables. This
paper reports on the experimental realization of GHZ correlations using nuclear
magnetic resonance (NMR). The NMR experiment differs from the originally
proposed GHZ experiment in several ways: it is performed on mixed states rather
than pure states; and instead of being widely separated, the spins on which it
is performed are all located in the same molecule. As a result, the NMR version
of the GHZ experiment cannot entirely rule out classical local hidden
variables. It nonetheless provides an unambiguous demonstration of the
"paradoxical" GHZ correlations, and shows that any classical hidden variables
must communicate by non-standard and previously undetected forces. The NMR
demonstration of GHZ correlations shows the power of NMR quantum information
processing techniques for demonstrating fundamental effects in quantum
mechanics.
|
[
{
"version": "v1",
"created": "Fri, 7 May 1999 21:28:47 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Nelson",
"Richard J.",
""
],
[
"Cory",
"David G.",
""
],
[
"Lloyd",
"Seth",
""
]
] |
quant-ph/9905029
|
Xiao-Guang Wang
|
Xiao-Guang Wang
|
Phase properties of hypergeometric states and negative hypergeometric
states
|
7 pages, 4 figures
|
J.Opt.BQuant.Semiclass.Opt.2:29-32,2000
|
10.1088/1464-4266/2/1/305
| null |
quant-ph
| null |
We show that the three quantum states (P$\acute{o}$lya states, the
generalized non-classical states related to Hahn polynomials and negative
hypergeometric states) introduced recently as intermediates states which
interpolate between the binomial states and negative binomial states are
essentially identical. By using the Hermitial-phase-operator formalism, the
phase properties of the hypergeometric states and negative hypergeometric
states are studied in detail. We find that the number of peaks of phase
probability distribution is one for the hypergeometric states and $M$ for the
negative hypergeometric states.
|
[
{
"version": "v1",
"created": "Sat, 8 May 1999 05:33:16 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Wang",
"Xiao-Guang",
""
]
] |
quant-ph/9905030
|
Brett D. Altschul
|
Martin S. Altschul and Brett D. Altschul
|
A Realizable, Non-Null Schroedinger's Cat Experiment
|
17 pages, 9 figures, RevTeX
| null | null | null |
quant-ph
| null |
Working from the Schroedinger's Cat paradigm, a series of experiments are
constructed. The Bedford-Wang experiment is examined, and the ambiguity in its
meaning is addressed. We eliminate this ambiguity by abandoning the idea of the
triggering event, replacing the two-state system with a mirror that undergoes
wave packet spreading. This creates an experimentally testable version of a
modified Schroedinger's Cat experiment for which a null result is not the
obvious outcome.
|
[
{
"version": "v1",
"created": "Mon, 10 May 1999 01:15:36 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Altschul",
"Martin S.",
""
],
[
"Altschul",
"Brett D.",
""
]
] |
quant-ph/9905031
|
A. C. de la Torre
|
A. C. de la Torre (Univ. Nac. de Mar del Plata, Argentina)
|
A one-dimensional lattice model for a quantum mechanical free particle
|
8 pages. Revtex
|
Eur. Phys. J. D8, 165-168, 2000.
|
10.1007/s100530050022
| null |
quant-ph
| null |
Two types of particles, A and B with their corresponding antiparticles, are
defined in a one dimensional cyclic lattice with an odd number of sites. In
each step of time evolution, each particle acts as a source for the
polarization field of the other type of particle with nonlocal action but with
an effect decreasing with the distance: A -->...\bar{B} B \bar{B} B \bar{B} ...
; B --> A \bar{A} A \bar{A} A ... . It is shown that the combined distribution
of these particles obeys the time evolution of a free particle as given by
quantum mechanics.
|
[
{
"version": "v1",
"created": "Mon, 10 May 1999 12:12:09 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"de la Torre",
"A. C.",
"",
"Univ. Nac. de Mar del Plata, Argentina"
]
] |
quant-ph/9905032
|
A. C. de la Torre
|
A. C. de la Torre and A. Daleo (Univ. Nac. Mar del Plata)
|
Quantum Mechanics as a Classical Field Theory
|
14 pages. revtex
| null | null | null |
quant-ph
| null |
The formalism of quantum mechanics is presented in a way that its
interpretation as a classical field theory is emphasized. Two coupled real
fields are defined with given equations of motion. Densities and currents
associated to the fields are found with their corresponding conserved
quantities. The behavior of these quantities under a galilean transformation
suggest the association of the fields with a quantum mechanical free particle.
An external potential is introduced in the Lagrange formalism. The description
is equivalent to the conventional Schr\"odinger equation treatment of a
particle. We discuss the attempts to build an interpretation of quantum
mechanics based on this scheme. The fields become the primary onthology of the
theory and the particles appear as emergent properties of the fields. These
interpretations face serious problems for systems with many degrees of freedom.
|
[
{
"version": "v1",
"created": "Mon, 10 May 1999 15:23:32 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"de la Torre",
"A. C.",
"",
"Univ. Nac. Mar del Plata"
],
[
"Daleo",
"A.",
"",
"Univ. Nac. Mar del Plata"
]
] |
quant-ph/9905033
|
Brau Fabian
|
F. Brau (Univ. of Mons-Hainaut)
|
Minimal Length Uncertainty Relation and Hydrogen Atom
|
7 pages, REVTeX
|
J.Phys.A32:7691-7696,1999
|
10.1088/0305-4470/32/44/308
|
UMH-PNT-99-12
|
quant-ph
| null |
We propose a new approach to calculate perturbatively the effects of a
particular deformed Heisenberg algebra on energy spectrum. We use this method
to calculate the harmonic oscillator spectrum and find that corrections are in
agreement with a previous calculation. Then, we apply this approach to obtain
the hydrogen atom spectrum and we find that splittings of degenerate energy
levels appear. Comparison with experimental data yields an interesting upper
bound for the deformation parameter of the Heisenberg algebra.
|
[
{
"version": "v1",
"created": "Mon, 10 May 1999 15:29:16 GMT"
}
] | 2008-11-26T00:00:00 |
[
[
"Brau",
"F.",
"",
"Univ. of Mons-Hainaut"
]
] |
quant-ph/9905034
|
Matt Visser
|
Stefano Liberati (SISSA, Trieste), Matt Visser (Washington University,
St Louis), Francesco Belgiorno (Milano), Dennis Sciama (SISSA, ICTP, Trieste;
Oxford)
|
Sonoluminescence as a QED vacuum effect. II: Finite Volume Effects
|
23 pages, LaTeX 209, ReV-TeX 3.2, five figures
|
Phys.Rev. D61 (2000) 085024
|
10.1103/PhysRevD.61.085024
| null |
quant-ph cond-mat hep-th
| null |
In a companion paper [quant-ph/9904013] we have investigated several
variations of Schwinger's proposed mechanism for sonoluminescence. We
demonstrated that any realistic version of Schwinger's mechanism must depend on
extremely rapid (femtosecond) changes in refractive index, and discussed ways
in which this might be physically plausible. To keep that discussion tractable,
the technical computations in that paper were limited to the case of a
homogeneous dielectric medium. In this paper we investigate the additional
complications introduced by finite-volume effects. The basic physical scenario
remains the same, but we now deal with finite spherical bubbles, and so must
decompose the electromagnetic field into Spherical Harmonics and Bessel
functions. We demonstrate how to set up the formalism for calculating Bogolubov
coefficients in the sudden approximation, and show that we qualitatively retain
the results previously obtained using the homogeneous-dielectric (infinite
volume) approximation.
|
[
{
"version": "v1",
"created": "Mon, 10 May 1999 17:02:34 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Liberati",
"Stefano",
"",
"SISSA, Trieste"
],
[
"Visser",
"Matt",
"",
"Washington University,\n St Louis"
],
[
"Belgiorno",
"Francesco",
"",
"Milano"
],
[
"Sciama",
"Dennis",
"",
"SISSA, ICTP, Trieste;\n Oxford"
]
] |
quant-ph/9905035
|
Emerson Silva Guerra
|
J. C. Retamal and E. S. Guerra
|
A protocol to preserve quantum coherence in cavity QED
|
4 pages
| null | null | null |
quant-ph
| null |
We consider the problem of quantum decoherence in cavity QED devices and
investigate the possibility to preserve a Schroedinger cat as a coherent
superposition along the time.
|
[
{
"version": "v1",
"created": "Mon, 10 May 1999 19:52:33 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Retamal",
"J. C.",
""
],
[
"Guerra",
"E. S.",
""
]
] |
quant-ph/9905036
|
Subhasis Ghosh
|
Sibasish Ghosh, Somshubhro Bandyopadhyay, Anirban Roy, Debasis Sarkar,
Guruprasad Kar
|
Optimal Universal Disentangling Machine for Two Qubit Quantum States
|
15 pages, 2 eps figures, 1 section added, 1 eps figure added, minor
corrections, 2 reference numbers corrected
|
Phys.Rev.A61:052301,2000
|
10.1103/PhysRevA.61.052301
| null |
quant-ph
| null |
We derive the optimal curve satisfied by the reduction factors, in the case
of universal disentangling machine which uses only local operations.
Impossibility of constructing a better disentangling machine, by using
non-local operations, is discussed.
|
[
{
"version": "v1",
"created": "Tue, 11 May 1999 10:10:49 GMT"
},
{
"version": "v2",
"created": "Tue, 18 May 1999 10:08:26 GMT"
},
{
"version": "v3",
"created": "Wed, 13 Oct 1999 09:16:51 GMT"
},
{
"version": "v4",
"created": "Thu, 14 Oct 1999 09:40:16 GMT"
}
] | 2009-09-25T00:00:00 |
[
[
"Ghosh",
"Sibasish",
""
],
[
"Bandyopadhyay",
"Somshubhro",
""
],
[
"Roy",
"Anirban",
""
],
[
"Sarkar",
"Debasis",
""
],
[
"Kar",
"Guruprasad",
""
]
] |
quant-ph/9905037
|
Jan Myrheim
|
Jan Myrheim
|
Quantum mechanics on a real Hilbert space
|
13 pages, LaTeX, no figures
| null | null | null |
quant-ph hep-th
| null |
The complex Hilbert space of standard quantum mechanics may be treated as a
real Hilbert space. The pure states of the complex theory become mixed states
in the real formulation. It is then possible to generalize standard quantum
mechanics, keeping the same set of physical states, but admitting more general
observables. The standard time reversal operator involves complex conjugation,
in this sense it goes beyond the complex theory and may serve as an example to
motivate the generalization. Another example is unconventional canonical
quantization such that the harmonic oscillator of angular frequency $\omega$
has any given finite or infinite set of discrete energy eigenvalues, limited
below by $\hbar\omega/2$.
|
[
{
"version": "v1",
"created": "Tue, 11 May 1999 15:16:00 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Myrheim",
"Jan",
""
]
] |
quant-ph/9905038
|
Abel Camacho Quintana
|
Abel Camacho Quintana (Astrophysikalisches Institut Potsdam)
|
Gravity-Induced Interference and Continuous Quantum Measurements
|
Accepted for publication in Physics Letters A, 12 pages, no figures
|
Phys.Lett. A256 (1999) 339
|
10.1016/S0375-9601(99)00267-4
| null |
quant-ph gr-qc
| null |
Gravity-induced quantum interference is a remarkable effect that has already
been confirmed experimentally, and it is a phenomenon in which quantum
mechanics and gravity play simultaneously an important role. Additionally, a
generalized version of this interference experiment could offer the possibility
to confront against measurement outputs one of the formalisms that claim to
give an explanation to the so called quantum measurement problem, namely the
restricted path integral formalism. In this work we will analyze a possible
extension of Colella, Overhauser, and Werner experiment and find that in the
context of the restricted path integral formalism we obtain new interference
terms that could be measured in an extended version of this experimental
construction. These new terms not only show, as in the first experiment, that
at the quantum level gravity is not a purely geometric effect, it still depends
on mass, but also show that interference does depend on some parameters that
appear in the restricted path integral formalism, thus offering the possibility
to have a testing framework for its theoretical predictions.
|
[
{
"version": "v1",
"created": "Tue, 11 May 1999 14:26:40 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Quintana",
"Abel Camacho",
"",
"Astrophysikalisches Institut Potsdam"
]
] |
quant-ph/9905039
|
Yoon-Ho Kim
|
Yoon-Ho Kim and Yanhua Shih
|
Experimental realization of Popper's Experiment: Violation of the
Uncertainty Principle?
|
6 pages, twocolumn. Revised. To appear in Foundations of Physics
|
Found.Phys. 29 (1999) 1849
| null | null |
quant-ph
| null |
An entangled pair of photons (1 and 2) are emitted to opposite directions. A
narrow slit is placed in the path of photon 1 to provide precise knowledge of
its position on the $y$ axis and this also determines the precise $y$ position
of its twin, photon 2, due to quantum entanglement. Is photon 2 going to
experience a greater uncertainty in momentum, i.e., a greater $\Delta p_{y}$,
due to the precise knowledge of its position $y$? The experimental data shows
$\Delta y\Delta p_{y}<\hbar $ for photon 2. Can this recent realization of the
historical thought experiment of Karl Popper signal a violation of the
uncertainty principle?
|
[
{
"version": "v1",
"created": "Tue, 11 May 1999 15:00:06 GMT"
},
{
"version": "v2",
"created": "Tue, 19 Oct 1999 18:57:15 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Kim",
"Yoon-Ho",
""
],
[
"Shih",
"Yanhua",
""
]
] |
quant-ph/9905040
|
Constantin Brif
|
C. Brif and A. Mann
|
Quantum statistical properties of the radiation field in a cavity with a
movable mirror
|
REVTeX, 9 pages, 5 figures. More info on
http://www.ligo.caltech.edu/~cbrif/science.html
|
J.Opt.B Quant.Semiclass.Opt. 2 (2000) 53-61
|
10.1088/1464-4266/2/1/309
| null |
quant-ph
| null |
A quantum system composed of a cavity radiation field interacting with a
movable mirror is considered and quantum statistical properties of the field
are studied. Such a system can serve in principle as an idealized meter for
detection of a weak classical force coupled to the mirror which is modelled by
a quantum harmonic oscillator. It is shown that the standard quantum limit on
the measurement of the mirror position arises naturally from the properties of
the system during its dynamical evolution. However, the force detection
sensitivity of the system falls short of the corresponding standard quantum
limit. We also study the effect of the nonlinear interaction between the moving
mirror and the radiation pressure on the quadrature fluctuations of the
initially coherent cavity field.
|
[
{
"version": "v1",
"created": "Tue, 11 May 1999 20:15:50 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Brif",
"C.",
""
],
[
"Mann",
"A.",
""
]
] |
quant-ph/9905041
|
Lieven Vandersypen
|
Lieven M.K. Vandersypen (1 and 2), Costantino S. Yannoni (2), Mark H.
Sherwood (2), Isaac L. Chuang (2) ((1) Solid State and Photonics Laboratory,
Stanford University (2) IBM Almaden Research Center)
|
Realization of logically labeled effective pure states for bulk quantum
computation
|
PRL 83, 3085 (1999). Small changes made to improve readability and
remove ambiguities
|
Phys.Rev.Lett.83:3085,1999
|
10.1103/PhysRevLett.83.3085
| null |
quant-ph
| null |
We report the first use of "logical labeling" to perform a quantum
computation with a room-temperature bulk system. This method entails the
selection of a subsystem which behaves as if it were at zero temperature -
except for a decrease in signal strength - conditioned upon the state of the
remaining system. No averaging over differently prepared molecules is required.
In order to test this concept, we execute a quantum search algorithm in a
subspace of two nuclear spins, labeled by a third spin, using solution nuclear
magnetic resonance (NMR), and employing a novel choice of reference frame to
uncouple nuclei.
|
[
{
"version": "v1",
"created": "Wed, 12 May 1999 07:01:51 GMT"
},
{
"version": "v2",
"created": "Wed, 13 Oct 1999 02:16:03 GMT"
}
] | 2009-01-23T00:00:00 |
[
[
"Vandersypen",
"Lieven M. K.",
"",
"1 and 2"
],
[
"Yannoni",
"Costantino S.",
""
],
[
"Sherwood",
"Mark H.",
""
],
[
"Chuang",
"Isaac L.",
""
]
] |
quant-ph/9905042
|
Robert Clifton
|
Hans Halvorson (Depts. of Mathematics and Philosophy, University of
Pittsburgh), Rob Clifton (Depts. of Philosophy and History and Philosophy of
Science, University of Pittsburgh)
|
Maximal Beable Subalgebras of Quantum-Mechanical Observables
|
46 pages, AMS-LaTeX, Submitted to The Journal of Functional Analysis
|
Int.J.Theor.Phys. 38 (1999) 2441-2484
| null | null |
quant-ph math-ph math.MP math.OA
| null |
Given a state on an algebra of bounded quantum-mechanical observables (the
self-adjoint part of a C*-algebra), we investigate those subalgebras that are
maximal with respect to the property that the given state's restriction to the
subalgebra is a mixture of dispersion-free states---what we call maximal
"beable" subalgebras (borrowing a terminology due to J. S. Bell). We also
extend our investigation to the theory of algebras of unbounded observables (as
developed by R. Kadison), and show how our results articulate a solid
mathematical foundation for central tenets of the orthodox Copenhagen
interpretation of quantum theory (such as the joint indeterminacy of
canonically conjugate observables, and Bohr's defense of the completeness of
quantum theory against the argument of Einstein, Podolsky, and Rosen).
|
[
{
"version": "v1",
"created": "Thu, 13 May 1999 16:55:44 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Halvorson",
"Hans",
"",
"Depts. of Mathematics and Philosophy, University of\n Pittsburgh"
],
[
"Clifton",
"Rob",
"",
"Depts. of Philosophy and History and Philosophy of\n Science, University of Pittsburgh"
]
] |
quant-ph/9905043
|
Alexandre M. Zagoskin
|
Alexandre Blais and Alexandre M. Zagoskin
|
Operation of universal gates in a DXD superconducting solid state
quantum computer
|
4 pages, 2 figures
|
Physical Review A, v.61, 042308 (2000)
|
10.1103/PhysRevA.61.042308
| null |
quant-ph cond-mat.mes-hall cond-mat.other cond-mat.supr-con cs.GL
| null |
We demonstrate that complete set of gates can be realized in a DXD
superconducting solid state quantum computer (quamputer), thereby proving its
universality.
|
[
{
"version": "v1",
"created": "Thu, 13 May 1999 21:44:55 GMT"
},
{
"version": "v2",
"created": "Fri, 7 Apr 2000 23:42:37 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Blais",
"Alexandre",
""
],
[
"Zagoskin",
"Alexandre M.",
""
]
] |
quant-ph/9905044
|
Jun Yan
|
Guang-jiong Ni, Weimin Zhou and Jun Yan
|
Klein paradox and antiparticle
|
4 pages, no figures, revtex
| null | null | null |
quant-ph
| null |
The Klein paradox of Klein-Gordon (KG) equation is discussed to show that KG
equation is self-consistent even at one-particle level and the wave function
for antiparticle is uniquely determined by the reasonable explanation of Klein
paradox. No concept of ``hole'' is needed.
|
[
{
"version": "v1",
"created": "Thu, 13 May 1999 20:57:53 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Ni",
"Guang-jiong",
""
],
[
"Zhou",
"Weimin",
""
],
[
"Yan",
"Jun",
""
]
] |
quant-ph/9905045
|
Timothy F. Havel
|
S. S. Somaroo, C. H. Tseng, T. F. Havel, R. Laflamme, D. G. Cory
|
Quantum Simulations on a Quantum Computer
|
4 pages, 2 figures (\documentstyle[prl,aps,epsfig,amscd]{revtex}); to
appear in Phys. Rev. Lett
|
Phys.Rev.Lett.82:5381-5384,1999
|
10.1103/PhysRevLett.82.5381
| null |
quant-ph
| null |
We present a general scheme for performing a simulation of the dynamics of
one quantum system using another. This scheme is used to experimentally
simulate the dynamics of truncated quantum harmonic and anharmonic oscillators
using nuclear magnetic resonance. We believe this to be the first explicit
physical realization of such a simulation.
|
[
{
"version": "v1",
"created": "Thu, 13 May 1999 22:29:09 GMT"
}
] | 2009-01-23T00:00:00 |
[
[
"Somaroo",
"S. S.",
""
],
[
"Tseng",
"C. H.",
""
],
[
"Havel",
"T. F.",
""
],
[
"Laflamme",
"R.",
""
],
[
"Cory",
"D. G.",
""
]
] |
quant-ph/9905046
|
Waldemar Puszkarz
|
Waldemar Puszkarz
|
Non-separability without Non-separability in Nonlinear Quantum Mechanics
|
Latex, 13 pages
| null | null | null |
quant-ph
| null |
We show an example of benign non-separability in an apparently separable
system consisting of $n$ free non-correlated quantum particles, solitonic
solutions to the nonlinear phase modification of the Schr\"{o}dinger equation
proposed recently. The non-separability manifests itself in the wave function
of a single particle being influenced by the very presence of other particles.
In the simplest case of identical particles, it is the number of particles that
affects the wave function of each particle and, in particular, the width of its
Gaussian probability density. As a result, this width, a local property, is
directly linked to the mass of the entire Universe in a very Machian manner. In
the realistic limit of large $n$ if the width in question is to be microscopic,
the coupling constant must be very small resulting in an ``almost linear''
theory. This provides a model explanation of why the linearity of quantum
mechanics can be accepted with such a high degree of certainty even if the more
fundamental underlying theory could be nonlinear. We also demonstrate that when
such non-correlated solitons are coupled to harmonic oscilators they lead to a
faster-than-light nonlocal telegraph since changing the frequency of one
oscillator affects instantaneously the probability density of particles
associated with other oscillators. This effect can be alleviated by fine-tuning
the parameters of the solution. Exclusion rules of a novel kind that we term
supersuperselection rules also emerge from these solutions. They are similar to
the mass and the univalence superselection rules in linear quantum mechanics.
The effects in question and the exclusion rules do not appear if a weakly
separable extension to $n$-particles is employed.
|
[
{
"version": "v1",
"created": "Fri, 14 May 1999 08:15:27 GMT"
},
{
"version": "v2",
"created": "Mon, 17 May 1999 03:28:00 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Puszkarz",
"Waldemar",
""
]
] |
quant-ph/9905047
|
Laboratory of nanophysics
|
Yu. Lozovik, A. Filinov
|
Transmission time of wave packets through tunneling barriers
|
23 pages, 5 figures
|
J.Exp.Theor.Phys. 88 (1999) 1026-1035; Zh.Eksp.Teor.Fiz. 115
(1999) 1872-1889
|
10.1134/1.558886
|
ISAN-99-20
|
quant-ph
| null |
The transmission of wave packets through tunneling barriers is studied in
detail by the method of quantum molecular dynamics. The distribution function
of the times describing the arrival of a tunneling packet in front of and
behind a barrier and the momentum distribution function of the packet are
calculated. The behavior of the average coordinate of a packet, the average
momentum, and their variances is investigated. It is found that under the
barrier a part of the packet is reflected and a Gaussian barrier increases the
average momentum of the transmitted packet and its variance in momentum space.
|
[
{
"version": "v1",
"created": "Fri, 14 May 1999 10:28:05 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Lozovik",
"Yu.",
""
],
[
"Filinov",
"A.",
""
]
] |
quant-ph/9905048
|
DE MARTINI Francesco
|
F.A. Bovino, F. De Martini, V. Mussi
|
Quantum Superposition of Parametrically Amplified Multiphoton Pure
States whitin a Decoherence-Free Schroedinger-Cat Structure
|
25 pages, 5 figures, submitted to Phys. Rev. A
| null | null | null |
quant-ph
| null |
The new process of quantum-injection into an optical parametric amplifier
operating in entangled configuration is adopted to amplify into a large
dimensionality spin 1/2 Hilbert space the quantum entanglement and
superposition properties of the photon-couples generated by parametric
down-conversion. The structure of the Wigner function and of the field's
correlation functions shows a decoherence-free, multiphoton Schroedinger-cat
behaviour of the emitted field which is largely detectable against the
squeezed-vacuum noise. Furthermore, owing to its entanglement character, the
system is found to exhibit multi-particle quantum nonseparability and Bell-type
nonlocality properties. These relevant quantum features are analyzed for
several travelling-wave optical configurations implying different input
quantum-injection schemes
|
[
{
"version": "v1",
"created": "Fri, 14 May 1999 11:52:51 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Bovino",
"F. A.",
""
],
[
"De Martini",
"F.",
""
],
[
"Mussi",
"V.",
""
]
] |
quant-ph/9905049
|
Gabriel Drobny
|
B. Hladky, G. Drobny (Institute of Physics, Bratislava), V. Buzek
|
Quantum synthesis of arbitrary unitary operators
|
6 RevTeX pages with 3 figures, submitted to Phys.Rev.A, see also
http://nic.savba.sk/sav/inst/fyzi/qo/
| null |
10.1103/PhysRevA.61.022102
| null |
quant-ph
| null |
Nature provides us with a restricted set of microscopic interactions. The
question is whether we can synthesize out of these fundamental interactions an
arbitrary unitary operator. In this paper we present a constructive algorithm
for realization of any unitary operator which acts on a (truncated) Hilbert
space of a single bosonic mode. In particular, we consider a physical
implementation of unitary transformations acting on 1-dimensional vibrational
states of a trapped ion. As an example we present an algorithm which realizes
the discrete Fourier transform.
|
[
{
"version": "v1",
"created": "Fri, 14 May 1999 16:54:02 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Hladky",
"B.",
"",
"Institute of Physics, Bratislava"
],
[
"Drobny",
"G.",
"",
"Institute of Physics, Bratislava"
],
[
"Buzek",
"V.",
""
]
] |
quant-ph/9905050
|
Steve Simon
|
Steven H. Simon and P. M. Platzman (Bell Labs)
|
Fundamental Limit on ``Interaction Free'' Measurements
| null | null |
10.1103/PhysRevA.61.052103
|
BL-SHS-99005
|
quant-ph
| null |
In ``interaction free'' measurements, one typically wants to detect the
presence of an object without touching it with even a single photon. One often
imagines a bomb whose trigger is an extremely sensitive measuring device whose
presence we would like to detect without triggering it. We point out that all
such measuring devices have a maximum sensitivity set by the uncertainty
principle, and thus can only determine whether a measurement is ``interaction
free'' to within a finite minimum resolution. We further discuss exactly what
can be achieved with the proposed ``interaction free'' measurement schemes.
|
[
{
"version": "v1",
"created": "Fri, 14 May 1999 19:52:14 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Simon",
"Steven H.",
"",
"Bell Labs"
],
[
"Platzman",
"P. M.",
"",
"Bell Labs"
]
] |
quant-ph/9905051
|
Kendra Vant
|
G Ball, K Vant and N Christensen
|
A Numerical Investigation of the Effects of Classical Phase Space
Structure on a Quantum System
|
15 pages, 22 figures
|
Phys.Rev.E61:1299-1311,2000
|
10.1103/PhysRevE.61.1299
| null |
quant-ph
| null |
We present a detailed numerical study of a chaotic classical system and its
quantum counterpart. The system is a special case of a kicked rotor and for
certain parameter values possesses cantori dividing chaotic regions of the
classical phase space. We investigate the diffusion of particles through a
cantorus; classical diffusion is observed but quantum diffusion is only
significant when the classical phase space area escaping through the cantorus
per kicking period greatly exceeds Planck's constant. A quantum analysis
confirms that the cantori act as barriers. We numerically estimate the
classical phase space flux through the cantorus per kick and relate this
quantity to the behaviour of the quantum system. We introduce decoherence via
environmental interactions with the quantum system and observe the subsequent
increase in the transport of quantum particles through the boundary.
|
[
{
"version": "v1",
"created": "Mon, 17 May 1999 01:48:11 GMT"
}
] | 2008-12-18T00:00:00 |
[
[
"Ball",
"G",
""
],
[
"Vant",
"K",
""
],
[
"Christensen",
"N",
""
]
] |
quant-ph/9905052
|
DE MARTINI Francesco
|
E. De Angelis, F. De Martini and P. Mataloni
|
Bose-Einstein Partition Statistics of Photons Emitted from a
Superradiant Active Microcavity
|
9 pages, 3 figures, submitted to Phys. Rev. Lett
| null | null | null |
quant-ph
| null |
We report the results of the first investigation on the superradiant temporal
and spatial quantum dynamics of two dipoles excited in a planar symmetrical
microcavity by a controlled femtosecond two-pulse excitation. A superradiant
enhancement of the time decay of the dipole excitation for a decreasing
inter-dipole transverse distance R has been found. Furthermore, the photon
partition statistics of the emitted field is found to exhibit a striking
quantum behaviour for R<lc, the transverse extension of the single allowed
microcavity mode.
|
[
{
"version": "v1",
"created": "Mon, 17 May 1999 13:29:20 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"De Angelis",
"E.",
""
],
[
"De Martini",
"F.",
""
],
[
"Mataloni",
"P.",
""
]
] |
quant-ph/9905053
|
Henry Stapp
|
Henry P. Stapp
|
Quantum Ontologies and Mind-Matter Synthesis
|
69 pages. Invited contribution to Xth Max Born Symposium: "Quantum
Future". Published in "Quantum Future", eds. P. Blanchard and A. Jadczyk,
Springer-Verlag, 1999, ISBN 3-540-65218-3. LBNL 40722
| null |
10.1007/BFb0105346
| null |
quant-ph
| null |
Aspects of a quantum mechanical theory of a world containing efficacious
mental aspects that are closely tied to brains, but that are not identical to
brains.
|
[
{
"version": "v1",
"created": "Mon, 17 May 1999 20:07:09 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Stapp",
"Henry P.",
""
]
] |
quant-ph/9905054
|
Henry Stapp
|
Henry P. Stapp
|
Attention, Intention, and Will in Quantum Physics
|
Invited contribution to the Volition Issue of J. Conscious Studies,
July 1999. LBNL-42650
| null | null | null |
quant-ph
| null |
The need for a self-observing quantum system to pose questions leads to a
tripartite quantum process involving a Schroedinger process that is local
deterministic, a Heisenberg process that poses the question, and a Dirac
process that picks the answer. In the classical limit where Planck's constant
is set to zero these three processes reduce to one single deterministic
classical process: the fine structure wherein lies the effect of mind upon
matter is obliterated.
|
[
{
"version": "v1",
"created": "Mon, 17 May 1999 20:25:12 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Stapp",
"Henry P.",
""
]
] |
quant-ph/9905055
|
Henry Stapp
|
Henry P. Stapp
|
Nonlocality, Counterfactual, and Consistent Histories
|
Version submitted today to Physical Review A. The Conclusions section
is shortened to a brief description of the conclusion: The paper develops a
version of modal logic that stays completely within the framework provided by
quantum principles, and then proves, within the framework of quantum
thinking, and in particular without invoking "hidden variables", a Bell-type
nonlocality result
| null | null | null |
quant-ph
| null |
The paper develops a version of modal logic that stays completely within the
framework provided by quantum principles, and then proves, within the framework
of quantum thinking, and in particular without invoking "hidden variables", a
Bell-type nonlocality result.
|
[
{
"version": "v1",
"created": "Mon, 17 May 1999 20:39:17 GMT"
},
{
"version": "v2",
"created": "Tue, 8 Jun 1999 21:22:14 GMT"
},
{
"version": "v3",
"created": "Tue, 15 Jun 1999 17:16:13 GMT"
},
{
"version": "v4",
"created": "Mon, 16 Aug 1999 02:25:51 GMT"
},
{
"version": "v5",
"created": "Fri, 18 Feb 2000 19:23:32 GMT"
},
{
"version": "v6",
"created": "Tue, 27 Jun 2000 21:32:52 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Stapp",
"Henry P.",
""
]
] |
quant-ph/9905056
|
Gregoire Ribordy
|
Gregoire Ribordy, Jean-Daniel Gautier, Nicolas Gisin, Olivier
Guinnard, Hugo Zbinden
|
Fast and User-friendly Quantum Key Distribution
|
21 pages, 6 figures, added reference
| null |
10.1080/09500340008244057
| null |
quant-ph
| null |
Some guidelines for the comparison of different quantum key distribution
experiments are proposed. An improved 'plug & play' interferometric system
allowing fast key exchange is then introduced. Self-alignment and compensation
of birefringence remain. Original electronics implementing the BB84 protocol
and allowing user-friendly operation is presented. Key creation with 0.1 photon
per pulse at a rate of 486 Hz with a 5.4% QBER - corresponding to a net rate of
210Hz - over a 23 Km installed cable was performed.
|
[
{
"version": "v1",
"created": "Tue, 18 May 1999 15:08:11 GMT"
},
{
"version": "v2",
"created": "Fri, 30 Jul 1999 13:26:56 GMT"
}
] | 2015-06-26T00:00:00 |
[
[
"Ribordy",
"Gregoire",
""
],
[
"Gautier",
"Jean-Daniel",
""
],
[
"Gisin",
"Nicolas",
""
],
[
"Guinnard",
"Olivier",
""
],
[
"Zbinden",
"Hugo",
""
]
] |
quant-ph/9905057
|
Konstantin B. Korotchenko
|
K.B. Korotchenko
|
The test particle motion equations metrical form in a potential field
|
4 pages
|
Sov.Phys.J. 12 (1983) 55-58
| null | null |
quant-ph hep-th math-ph math.MP
| null |
It is shown in the present work that the three-dimensional trajectories of an
electrical test particle in potential fields may be regarded as geodesic lines
lying on isotropic surfaces of some four-dimensional configurational space, the
connection of which has tortion, while the transference is nonmetric.
|
[
{
"version": "v1",
"created": "Wed, 19 May 1999 08:33:57 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Korotchenko",
"K. B.",
""
]
] |
quant-ph/9905058
|
Michal Horodecki
|
Michal Horodecki
|
Optimal compression for mixed signal states
|
RevTeX, 5 pages, improvement of the proof (changes in the formula
(16))
|
Phys. Rev. A, 61, 052309 (2000)
|
10.1103/PhysRevA.61.052309
| null |
quant-ph
| null |
We consider the problem of the optimal compression rate in the case of the
source producing mixed signal states within the {\it visible} scheme (where
Alice, who is to compress the signal, can know the identities of the produced
states). We show that a simple strategy based on replacing the signal states
with their {\it extensions} gives {\it optimal} compression. As a result we
obtain a considerable simplification of the formula for optimal compression
rate within visible scheme.
|
[
{
"version": "v1",
"created": "Wed, 19 May 1999 13:46:35 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Dec 1999 13:52:57 GMT"
},
{
"version": "v3",
"created": "Wed, 30 Aug 2000 15:57:54 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Horodecki",
"Michal",
""
]
] |
quant-ph/9905059
|
Helmut Kroger
|
H. Jirari, H. Kr\"oger, X.Q. Luo, and K.J.M. Moriarty
|
Monte Carlo Hamiltonian
|
LaTeX file (text) + 9 PS files (figures + tables)
|
Phys.Lett. A258 (1999) 6-14
|
10.1016/S0375-9601(99)00304-7
| null |
quant-ph hep-lat
| null |
We construct an effective Hamiltonian via Monte Carlo from a given action.
This Hamiltonian describes physics in the low energy regime. We test it by
computing spectrum, wave functions and thermodynamical observables (average
energy and specific heat) for the free system and the harmonic oscillator. The
method is shown to work also for other local potentials.
|
[
{
"version": "v1",
"created": "Wed, 19 May 1999 19:58:58 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Jirari",
"H.",
""
],
[
"Kröger",
"H.",
""
],
[
"Luo",
"X. Q.",
""
],
[
"Moriarty",
"K. J. M.",
""
]
] |
quant-ph/9905060
|
Adan Cabello
|
Adan Cabello
|
Quantum correlations are not contained in the initial state
|
REVTeX, 4 pages, 1 figure
|
Phys.Rev.A60:877,1999
|
10.1103/PhysRevA.60.877
| null |
quant-ph
| null |
Two proofs are presented which show that quantum mechanics is incompatible
with the following assumption: all possible correlations between subsystems of
an individual isolated composite quantum system are contained in the initial
quantum state of the whole system, although just a subset of them is revealed
by the actual experiment.
|
[
{
"version": "v1",
"created": "Wed, 19 May 1999 20:40:06 GMT"
}
] | 2009-09-25T00:00:00 |
[
[
"Cabello",
"Adan",
""
]
] |
quant-ph/9905061
|
Marco Pravia
|
M. A. Pravia, E. Fortunato, Y. Weinstein, M. D. Price, G. Teklemariam,
R. J. Nelson, Y. Sharf, S. Somaroo, C. H. Tseng, T. F. Havel, D. G. Cory
|
Observations of Quantum Dynamics by Solution-State NMR Spectroscopy
|
17 pages, 9 figures
|
Concepts Magn.Res. 11 (1999) 225-238
| null | null |
quant-ph
| null |
NMR is emerging as a valuable testbed for the investigation of foundational
questions in quantum mechanics. The present paper outlines the preparation of a
class of mixed states, called pseudo-pure states, that emulate pure quantum
states in the highly mixed environment typically used to describe
solution-state NMR samples. It also describes the NMR observation of spinor
behavior in spin 1/2 nuclei, the simulation of wave function collapse using a
magnetic field gradient, the creation of entangled (or Bell) pseudo-pure
states, and a brief discussion of quantum computing logic gates, including the
Quantum Fourier Transform. These experiments show that liquid-state NMR can be
used to demonstrate quantum dynamics at a level suitable for laboratory
exercises.
|
[
{
"version": "v1",
"created": "Thu, 20 May 1999 01:01:26 GMT"
},
{
"version": "v2",
"created": "Fri, 18 Jun 1999 22:53:16 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Pravia",
"M. A.",
""
],
[
"Fortunato",
"E.",
""
],
[
"Weinstein",
"Y.",
""
],
[
"Price",
"M. D.",
""
],
[
"Teklemariam",
"G.",
""
],
[
"Nelson",
"R. J.",
""
],
[
"Sharf",
"Y.",
""
],
[
"Somaroo",
"S.",
""
],
[
"Tseng",
"C. H.",
""
],
[
"Havel",
"T. F.",
""
],
[
"Cory",
"D. G.",
""
]
] |
quant-ph/9905062
|
Nicolas Gisin
|
N. Gisin
|
Bell inequality for arbitrary many settings of the analyzers
|
3 pages, 1 figure
|
Phys.Lett. A260 (1999) 1-3
|
10.1016/S0375-9601(99)00428-4
| null |
quant-ph
| null |
A generalization of the CHSH-Bell inequality to arbitrary many settings is
presented. The singlet state of two spin $\half$ violates this inequality for
all numbers of setting. In the limit of arbitrarily large number of settings,
the violation tends to the finite ratio $4/\pi \approx 1.27$.
|
[
{
"version": "v1",
"created": "Thu, 20 May 1999 07:59:23 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Gisin",
"N.",
""
]
] |
quant-ph/9905063
|
Stanley A. Bruce
|
S. Bruce and J. Diaz-Valdes
|
An approximation to the Lamb shift and hyperfine splitting as nonlinear
effective Coulomb-like interactions in the Dirac equation
| null | null | null | null |
quant-ph
| null |
The Dirac equation for the Coulomb problem is restated by incorporating a
nonlinear effective interaction into the Dirac Hamiltonian: one keeps the $1/r$
dependence for the Coulomb field, but the coupling constant is modified by a
factor depending on the n (principal quantum number) power of the mean value of
the Hamiltonian. In this simple context we study the Lamb shift and the
hyperfine splitting of the s-levels of hydrogenic atoms. We discuss to what
extent the corresponding calculations fit the energy splittings to the
appropriate order in the fine structure constant.
|
[
{
"version": "v1",
"created": "Thu, 20 May 1999 15:41:14 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Bruce",
"S.",
""
],
[
"Diaz-Valdes",
"J.",
""
]
] |
quant-ph/9905064
|
Seth Lloyd
|
Seth Lloyd, Jean-Jacques E. Slotine
|
Quantum feedback with weak measurements
|
11 pages, TeX, replaced to incorporate suggestions of Asher Peres
| null |
10.1103/PhysRevA.62.012307
| null |
quant-ph
| null |
The problem of feedback control of quantum systems by means of weak
measurements is investigated in detail. When weak measurements are made on a
set of identical quantum systems, the single-system density matrix can be
determined to a high degree of accuracy while affecting each system only
slightly. If this information is fed back into the systems by coherent
operations, the single-system density matrix can be made to undergo an
arbitrary nonlinear dynamics, including for example a dynamics governed by a
nonlinear Schr\"odinger equation. We investigate the implications of such
nonlinear quantum dynamics for various problems in quantum control and quantum
information theory, including quantum computation. The nonlinear dynamics
induced by weak quantum feedback could be used to create a novel form of
quantum chaos in which the time evolution of the single-system wave function
depends sensitively on initial conditions.
|
[
{
"version": "v1",
"created": "Thu, 20 May 1999 15:55:21 GMT"
},
{
"version": "v2",
"created": "Sun, 5 Dec 1999 21:52:56 GMT"
}
] | 2009-10-31T00:00:00 |
[
[
"Lloyd",
"Seth",
""
],
[
"Slotine",
"Jean-Jacques E.",
""
]
] |
quant-ph/9905065
|
Robert Clifton
|
Rob Clifton (Depts. of Philosophy and History and Philosophy of
Science, University of Pittsburgh), Bradley Monton (Dept. of Philosophy
Princeton University)
|
Losing Your Marbles in Wavefunction Collapse Theories
|
30 pages, LaTeX, To be published in the December 1999 issue of The
British Journal for Philosophy of Science
| null | null | null |
quant-ph
| null |
Peter Lewis ([1997]) has recently argued that the wavefunction collapse
theory of GRW (Ghirardi, Rimini, and Weber [1986]) can only solve the problem
of wavefunction tails at the expense of predicting that arithmetic does not
apply to ordinary macroscopic objects. More specifically, Lewis argues that the
GRW theory must violate the enumeration principle: that `if marble 1 is in the
box and marble 2 is in the box and so on through marble $n$, then all $n$
marbles are in the box' ([1997], p. 321). Ghirardi and Bassi ([1999]) have
replied that it is meaningless to say that the enumeration principle is
violated because the wavefunction Lewis uses to exhibit the violation cannot
persist, according to the GRW theory, for more than a split second ([1999], p.
709). On the contrary, we argue that Lewis's argument survives Ghirardi and
Bassi's criticism unscathed. We then go on to show that, while the enumeration
principle can fail in the GRW theory, the theory itself guarantees that the
principle can never be empirically falsified, leaving the applicability of
arithmetical reasoning to both micro- and macroscopic objects intact.
|
[
{
"version": "v1",
"created": "Thu, 20 May 1999 19:23:26 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Clifton",
"Rob",
"",
"Depts. of Philosophy and History and Philosophy of\n Science, University of Pittsburgh"
],
[
"Monton",
"Bradley",
"",
"Dept. of Philosophy\n Princeton University"
]
] |
quant-ph/9905066
|
Hayashi Masahito
|
Fuminori Sakaguchi (Fukui University), Masahito Hayashi (Kyoto
University)
|
su(1,1) coherent states and a normal extension of su(1,1) annihilation
operator: squeezed states and the simultaneous measurement of Q^{-1}P+PQ^{-1}
and Q^{-2}
|
LaTeX2e. 13 pages
| null | null | null |
quant-ph
| null |
The the over-complete eigenvector system of the operator Q^{-1}P (Q:position,
P:momentum) which consists of the squeezed states |0; s, t > with various s and
t are investigated from the viewpoint of the annihilation and creation
relations related to the algebra su(1,1). We derive a positive operator-valued
measure(POVM) for the simultaneous measurement between the self-adjoint and
anti-self-adjoint parts of PQ^{-1}.
|
[
{
"version": "v1",
"created": "Fri, 21 May 1999 07:43:02 GMT"
}
] | 2007-05-23T00:00:00 |
[
[
"Sakaguchi",
"Fuminori",
"",
"Fukui University"
],
[
"Hayashi",
"Masahito",
"",
"Kyoto\n University"
]
] |
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