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quant-ph/0703217 | Laurent Chusseau | Jacques Arnaud (CEM2), Laurent Chusseau (CEM2), Fabrice Philippe
(LIRMM) | Semi-classical theory of quiet lasers. Short version | Submitted to European Journal of Physics | null | null | null | quant-ph | null | This article is the shorten version of quant-phys/0610106 with a supplemented
theory and new results concerning a single-electron laser driven by a
constant-potentiel battery. "Quiet (or sub-Poissonian) oscillators generate a
number of dissipation events whose variance is less than the mean. It was shown
in 1984 by Golubev and Sokolov that lasers driven by regular pumps are quiet in
that sense. We consider in the present paper two oscillators that should
exhibit in principle the same property. First, a reflex klystron, a vacuum tube
operating in the microwave range of frequency. Second a laser involving a
single electron permanently interacting with the field. It is unnecessary to
quantize the optical field, that is, the theory is semi-classical, yet exact.
As an example, the battery-driven one-electron laser delivers a detected noise
of 7/8 of the shot-noise level, and is therefore sub-Poissonian. Our
calculations are related to resonance-fluorescence treatments but with a
different physical interpretation. Previous theories considering excited-state
atoms regularly-injected in low-loss resonators, on the other hand, do require
light quantization. The theory presented here is restricted to above-threshold
stationary single-mode oscillators. The paper is written in such a way that
readers should be able to follow it without having to refer to quantum-optics
texts."
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 07:48:56 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Arnaud",
"Jacques",
"",
"CEM2"
],
[
"Chusseau",
"Laurent",
"",
"CEM2"
],
[
"Philippe",
"Fabrice",
"",
"LIRMM"
]
] |
quant-ph/0703218 | Marcin Paw{\l}owski | Marcin Pawlowski | Comment on: Disproof of Bell's Theorem by Clifford Algebra Valued Local
Variables | 1 page, no figures | null | null | null | quant-ph | null | We ''save'' Bell's Theorem by showing a flaw in Christian's argument.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 10:00:46 GMT"
},
{
"version": "v2",
"created": "Sun, 25 Mar 2007 09:55:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Pawlowski",
"Marcin",
""
]
] |
quant-ph/0703219 | Yunchung Na | Y.C. Neil Na, Shoko Utsunomiya, Lin Tian and Yoshihisa Yamamoto | Strongly Correlated Polaritons in a Two-Dimensional Array of Photonic
Crystal Microcavities | 14 pages, 5 figures | Phys. Rev. A 77, 031803(R) (2008) | 10.1103/PhysRevA.77.031803 | null | quant-ph cond-mat.other | null | We propose a practical scheme to observe the polaritonic quantum phase
transition (QPT) from the superfluid (SF) to Bose-glass (BG) to Mott-insulator
(MI) states. The system consists of a two-dimensional array of photonic crystal
microcavities doped with substitutional donor/acceptor impurities. Using
realistic parameters, we show that such strongly correlated polaritonic systems
can be constructed using the state-of-art semiconductor technology.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 11:04:24 GMT"
},
{
"version": "v2",
"created": "Mon, 26 Mar 2007 18:48:44 GMT"
},
{
"version": "v3",
"created": "Wed, 4 Apr 2007 05:54:26 GMT"
},
{
"version": "v4",
"created": "Fri, 12 Oct 2007 16:41:21 GMT"
}
] | 2013-05-29T00:00:00 | [
[
"Na",
"Y. C. Neil",
""
],
[
"Utsunomiya",
"Shoko",
""
],
[
"Tian",
"Lin",
""
],
[
"Yamamoto",
"Yoshihisa",
""
]
] |
quant-ph/0703220 | William E. Baylis | R. Cabrera, C. Rangan, W. E. Baylis | Overcoming the su(2^n) sufficient condition for the coherent control of
n-qubit systems | 13 pp., 2 figures | null | 10.1103/PhysRevA.76.033401 | null | quant-ph | null | We study quantum systems with even numbers N of levels that are completely
state-controlled by unitary transformations generated by Lie algebras
isomorphic to sp(N) of dimension N(N+1)/2. These Lie algebras are smaller than
the respective su(N) with dimension N^2-1. We show that this reduction
constrains the Hamiltonian to have symmetric energy levels. An example of such
a system is an n-qubit system. Using a geometric representation for the quantum
wave function of a finite system, we present an explicit example that shows a
two-qubit system can be controlled by the elements of the Lie algebra sp(4)
(isomorphic to spin(5) and so(5)) with dimension ten rather than su(4) with
dimension fifteen. These results enable one to envision more efficient
algorithms for the design of fields for quantum-state engineering, and they
provide more insight into the fundamental structure of quantum control.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 13:58:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Cabrera",
"R.",
""
],
[
"Rangan",
"C.",
""
],
[
"Baylis",
"W. E.",
""
]
] |
quant-ph/0703221 | Andr\'as Vukics | Andr\'as Vukics, Christoph Maschler, and Helmut Ritsch | Microscopic physics of quantum self-organisation of optical lattices in
cavities | 14 pages 6 figures | New J. Phys. 9 (2007) 255 | 10.1088/1367-2630/9/8/255 | null | quant-ph | null | We study quantum particles at zero temperature in an optical lattice coupled
to a resonant cavity mode. The cavity field substantially modifies the particle
dynamics in the lattice, and for strong particle-field coupling leads to a
quantum phase with only every second site occupied. We study the growth of this
new order out of a homogeneous initial distribution for few particles as the
microscopic physics underlying a quantum phase transition. Simulations reveal
that the growth dynamics crucially depends on the initial quantum many-body
state of the particles and can be monitored via the cavity fluorescence.
Studying the relaxation time of the ordering reveals inhibited tunnelling,
which indicates that the effective mass of the particles is increased by the
interaction with the cavity field. However, the relaxation becomes very quick
for large coupling.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 14:04:53 GMT"
},
{
"version": "v2",
"created": "Mon, 26 Mar 2007 10:10:33 GMT"
}
] | 2007-09-04T00:00:00 | [
[
"Vukics",
"András",
""
],
[
"Maschler",
"Christoph",
""
],
[
"Ritsch",
"Helmut",
""
]
] |
quant-ph/0703222 | Riccardo Franco | R. Franco | Quantum mechanics, Bayes' theorem and the conjunction fallacy | 11 pages | null | null | null | quant-ph | null | In the present article we consider the conjunction fallacy, a well known
cognitive heuristic experimentally tested in cognitive science, which occurs
for intuitive judgments in situations of bounded rationality. We show that the
quantum formalism can be used to describe in a very simple way this fallacy in
terms of interference effect. We evidence that the quantum formalism leads
quite naturally to violations of Bayes' rule when considering the probability
of the conjunction of two events. Thus we suggest that in cognitive science the
formalism of quantum mechanics can be used to describe a \textit{quantum
regime}, the bounded-rationality regime, where the cognitive heuristics are
valid.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 14:32:20 GMT"
},
{
"version": "v2",
"created": "Thu, 17 May 2007 07:01:34 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Franco",
"R.",
""
]
] |
quant-ph/0703223 | Renato Portugal | Carlos Magno M. Cosme and Renato Portugal | Quantum algorithm for the hidden subgroup problem on a class of
semidirect product groups | 5 pages, no figures | null | null | null | quant-ph | null | We present efficient quantum algorithms for the hidden subgroup problem (HSP)
on the semidirect product of cyclic groups $\Z_{p^r}\rtimes_{\phi}\Z_{p^2}$,
where $p$ is any odd prime number and $r$ is any integer such that $r>4$. We
also address the HSP in the group $\Z_{N}\rtimes_{\phi}\Z_{p^2}$, where $N$ is
an integer with a special prime factorization. These quantum algorithms are
exponentially faster than any classical algorithm for the same purpose.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 16:55:58 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Apr 2007 14:39:02 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Cosme",
"Carlos Magno M.",
""
],
[
"Portugal",
"Renato",
""
]
] |
quant-ph/0703224 | B. M. Garraway | B.J.Dalton and B.M.Garraway | Cascade atom in high-Q cavity: The spectrum for non-Markovian decay | 29 pages, 14 figures; v2: very minor correction to two equations,
thicker lines in some figures | J. Mod. Opt. 54, 2049 (2007). | 10.1080/09500340701352557 | null | quant-ph | null | The spontaneous emission spectrum for a three level cascade configuration
atom in a single mode high-Q cavity coupled to a zero temperature reservoir of
continuum external modes is determined from the atom-cavity mode master
equation using the quantum regression theorem. Initially the atom is in its
upper state and the cavity mode empty of photons. Following Glauber, the
spectrum is defined via the response of a detector atom. Spectra are calculated
for the detector located inside the cavity (case A), outside the cavity end
mirror (Case B-end emission), or placed for emission out the side of the cavity
(Case C). The spectra for case A and case B are found to be essentially the
same. In all the cases the predicted lineshapes are free of instrumental
effects and only due to cavity decay. Spectra are presented for intermediate
and strong coupling regime situations (where both atomic transitions are
resonant with the cavity frequency), for cases of non-zero cavity detuning, and
for cases where the two atomic transition frequencies differ. The spectral
features for Cases B(A) and C are qualitatively similar, with six spectral
peaks for resonance cases and eight for detuned cases. These general features
of the spectra can be understood via the dressed atom model. However, Case B
and C spectra differ in detail, with the latter exhibiting a deep spectral hole
at the cavity frequency due to quantum interference effects.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 18:29:06 GMT"
},
{
"version": "v2",
"created": "Sun, 8 Jul 2007 08:13:11 GMT"
}
] | 2017-08-23T00:00:00 | [
[
"Dalton",
"B. J.",
""
],
[
"Garraway",
"B. M.",
""
]
] |
quant-ph/0703225 | Jens Eisert | J. Eisert, T. Tyc, T. Rudolph, B.C. Sanders | Gaussian quantum marginal problem | 18 pages, 1 figure, material added, references updated, except from
figure identical with version to appear in Commun. Math. Phys | Commun. Math. Phys. 280, 263 (2008) | 10.1007/s00220-008-0442-4 | null | quant-ph math-ph math.MP | null | The quantum marginal problem asks what local spectra are consistent with a
given spectrum of a joint state of a composite quantum system. This setting,
also referred to as the question of the compatibility of local spectra, has
several applications in quantum information theory. Here, we introduce the
analogue of this statement for Gaussian states for any number of modes, and
solve it in generality, for pure and mixed states, both concerning necessary
and sufficient conditions. Formally, our result can be viewed as an analogue of
the Sing-Thompson Theorem (respectively Horn's Lemma), characterizing the
relationship between main diagonal elements and singular values of a complex
matrix: We find necessary and sufficient conditions for vectors (d1, ..., dn)
and (c1, ..., cn) to be the symplectic eigenvalues and symplectic main diagonal
elements of a strictly positive real matrix, respectively. More physically
speaking, this result determines what local temperatures or entropies are
consistent with a pure or mixed Gaussian state of several modes. We find that
this result implies a solution to the problem of sharing of entanglement in
pure Gaussian states and allows for estimating the global entropy of
non-Gaussian states based on local measurements. Implications to the actual
preparation of multi-mode continuous-variable entangled states are discussed.
We compare the findings with the marginal problem for qubits, the solution of
which for pure states has a strikingly similar and in fact simple form.
| [
{
"version": "v1",
"created": "Sun, 25 Mar 2007 11:15:53 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 10:13:36 GMT"
}
] | 2008-11-22T00:00:00 | [
[
"Eisert",
"J.",
""
],
[
"Tyc",
"T.",
""
],
[
"Rudolph",
"T.",
""
],
[
"Sanders",
"B. C.",
""
]
] |
quant-ph/0703226 | Gordon N. Fleming | Gordon N. Fleming | Correlation coefficients and the Robertson-Schroedinger uncertainty
relations | 15 pages, 1 figure | null | null | PSU/TH/254 | quant-ph | null | Calling the quantity; 2delta(A)delta(B)/|<[A, B]>|, with non-zero
denominator, the uncertainty product ratio or UPR for the pair of observables,
(A, B), it is shown that any non-zero correlation coefficient between two
observables raises, above unity, the lower bound of the UPR for each member of
an infinite collection of pairs of incompatible observables. Conversely, any
UPR is subject to lower bounds above unity determined by each of an infinite
collection of correlation coefficients. This result generalizes the well known
Schroedinger strengthening of the Robertson uncertainty relations (with the
former expressed in terms of the correlation coefficient rather than the
anticommutator) where the UPR and the correlation coefficient both involve the
same pair of observables. Two, independent, derivations of the result are
presented to clarify its origins and some examples of its use are examined.
| [
{
"version": "v1",
"created": "Fri, 23 Mar 2007 20:42:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Fleming",
"Gordon N.",
""
]
] |
quant-ph/0703227 | Dagomir Kaszlikowski | Anushya Chandran, Dagomir Kaszlikowski, Aditi Sen De, Ujjwal Sen, and
Vlatko Vedral | Regional versus Global Entanglement in Resonating-Valence-Bond states | 4 pages, no figures, RevTeX4; v2: improved result in the multiparty
case, presentation improved (5 pages, one figure); v3: further changes in
presentation, results unchanged, published version | Phys. Rev. Lett. 99, 170502 (2007) | 10.1103/PhysRevLett.99.170502 | null | quant-ph cond-mat.str-el | null | We investigate the entanglement properties of resonating-valence-bond states
on two and higher dimensional lattices, which play a significant role in our
understanding of various many-body systems. We show that these states are
genuinely multipartite entangled, while there is only a negligible amount of
two-site entanglement. We comment on possible physical implications of our
findings.
| [
{
"version": "v1",
"created": "Sat, 24 Mar 2007 01:00:13 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Apr 2007 13:07:50 GMT"
},
{
"version": "v3",
"created": "Fri, 4 Jan 2008 17:15:20 GMT"
}
] | 2009-10-20T00:00:00 | [
[
"Chandran",
"Anushya",
""
],
[
"Kaszlikowski",
"Dagomir",
""
],
[
"De",
"Aditi Sen",
""
],
[
"Sen",
"Ujjwal",
""
],
[
"Vedral",
"Vlatko",
""
]
] |
quant-ph/0703228 | Jianming Cai | Jian-Ming Cai, Zheng-Wei Zhou, Ye-Fei Yuan, Guang-Can Guo | Quantum Decoherence Modulated by Special Relativity | null | Phys. Rev. A 76, 042101 (2007) | 10.1103/PhysRevA.76.042101 | null | quant-ph | null | By investigating the evolution of a moving spin-1/2 Dirac electron coupled
with a background magnetic noise, we demonstrate that the effects of special
relativity will significantly modify the decoherence properties of the spin
state. The dephasing could be much suppressed, and for a sufficiently long time
the decoherence even seems to halt. This interesting phenomenon stems from the
dressed environment induced by special relativity.
| [
{
"version": "v1",
"created": "Sat, 24 Mar 2007 07:52:23 GMT"
},
{
"version": "v2",
"created": "Wed, 3 Oct 2007 11:40:09 GMT"
}
] | 2007-10-03T00:00:00 | [
[
"Cai",
"Jian-Ming",
""
],
[
"Zhou",
"Zheng-Wei",
""
],
[
"Yuan",
"Ye-Fei",
""
],
[
"Guo",
"Guang-Can",
""
]
] |
quant-ph/0703229 | Paulo Maia Neto | Robson B. Rodrigues, Paulo A. Maia Neto, Astrid Lambrecht and Serge
Reynaud | The lateral Casimir force beyond the proximity force approximation: a
nontrivial interplay between geometry and quantum vacuum | 10 pages, 7 figures. Accepted version with minor amendments. To
appear in Physical Review A | Phys. Rev. A 75, 062108 (2007) | 10.1103/PhysRevA.75.062108 | null | quant-ph hep-th | null | The lateral Casimir force between two corrugated metallic plates makes
possible a study of the nontrivial interplay of geometry and Casimir effect
appearing beyond the regime of validity of the Proximity Force Approximation
(PFA). Quantitative evaluations can be obtained by using scattering theory in a
perturbative expansion valid when the corrugation amplitudes are smaller than
the three other length scales: the mean separation distance $L$ of the plates,
the corrugation period $\lambda_\C$ and the plasma wavelength $\lambda_\P$.
Within this perturbative expansion, evaluations are obtained for arbitrary
relative values of $L$, $\lambda_\C$ and $\lambda_\P$ while limiting cases,
some of them already known, are recovered when these values obey some specific
orderings. The consequence of these results for comparison with existing
experiments is discussed in the end of the paper.
| [
{
"version": "v1",
"created": "Sat, 24 Mar 2007 11:32:20 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Apr 2007 13:50:02 GMT"
}
] | 2007-06-18T00:00:00 | [
[
"Rodrigues",
"Robson B.",
""
],
[
"Neto",
"Paulo A. Maia",
""
],
[
"Lambrecht",
"Astrid",
""
],
[
"Reynaud",
"Serge",
""
]
] |
quant-ph/0703230 | Panos Aliferis | Panos Aliferis | Level Reduction and the Quantum Threshold Theorem | 125 pages, Ph.D. thesis, Caltech, 2007; pdf file fixed | null | null | CALT-68-2641 | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The quantum threshold theorem shows that a noisy quantum computer can
accurately and efficiently simulate any ideal quantum computation provided that
noise is weakly correlated and its strength is below a critical value known as
the quantum accuracy threshold. This thesis provides a simpler and more
transparent non-inductive proof of this theorem based on the concept of level
reduction. This concept is also used in proving the quantum threshold theorem
for coherent and leakage noise and for quantum computation by measurements. In
addition, the proof provides a methodology which allows us to establish
improved rigorous lower bounds on the value of the quantum accuracy threshold.
| [
{
"version": "v1",
"created": "Sun, 25 Mar 2007 22:43:01 GMT"
},
{
"version": "v2",
"created": "Mon, 11 Jul 2011 20:04:49 GMT"
}
] | 2011-07-13T00:00:00 | [
[
"Aliferis",
"Panos",
""
]
] |
quant-ph/0703231 | Avinatan Hassidim | M. Ben-Or, Avinatan Hassidim | Quantum Search in an Ordered List via Adaptive Learning | 10 pages no figures | null | null | null | quant-ph | null | We use a Bayesian approach to optimally solve problems in noisy binary
search. We deal with two variants:
1. Each comparison can be erroneous with some probability $1 - p$. 2. At each
stage $k$ comparisons can be performed in parallel and a noisy answer is
returned
We present a (classic) algorithm which optimally solves both variants
together, up to an additive term of O(\log \log(n)), and prove matching
information theoretic lower bounds. We use the algorithm to improve the results
of Farhi et al \cite{FGGS99} presenting a quantum (error free) search algorithm
in an ordered list of expected complexity less than (\log_2n) / 3.
| [
{
"version": "v1",
"created": "Sat, 24 Mar 2007 21:34:56 GMT"
},
{
"version": "v2",
"created": "Fri, 9 Nov 2007 11:00:48 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Ben-Or",
"M.",
""
],
[
"Hassidim",
"Avinatan",
""
]
] |
quant-ph/0703232 | Italo Vecchi | Italo Vecchi | Electrino bubbles and relational entanglement | Corrected typos, improved presentation | null | null | null | quant-ph | null | We argue that the phenomena exhibited by bubbles forming around free
electrons in liquid helium and examined by Maris in his controversial 2000
paper point to the experimental relevance of relational entanglement. An
experiment to verify/disprove the relevant argument is suggested.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 13:03:02 GMT"
},
{
"version": "v2",
"created": "Sun, 19 Aug 2007 20:27:39 GMT"
}
] | 2007-08-19T00:00:00 | [
[
"Vecchi",
"Italo",
""
]
] |
quant-ph/0703233 | Xian-Ting Liang | Xian-Ting Liang | Decoherence and relaxation of a qubit coupled to an Ohmic bath directly
and via an intermediate harmonic oscillator | 9 pages, 6 figures | Chem. Phys. Lett. 449 (2007) 296-303 | 10.1016/j.cplett.2007.10.074 | null | quant-ph | null | Using the numerical path integral method we investigate the decoherence and
relaxation of qubits coupled to an Ohmic bath directly and via an intermediate
harmonic oscillator (IHO). Here, we suppose the oscillation frequencies of the
bath modes are higher than the IHO's. When we choose suitable parameters the
qubits in the two models may have almost same decoherence and relaxation times.
However, the decoherence and relaxation times of the qubit in the
qubit-IHO-bath model can be modulated through changing the coupling
coefficients of the qubit-IHO and IHO-bath and the oscillation frequency of the
IHO.
| [
{
"version": "v1",
"created": "Sun, 25 Mar 2007 14:25:49 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Jun 2007 08:53:00 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Dec 2007 08:09:19 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Liang",
"Xian-Ting",
""
]
] |
quant-ph/0703234 | Cem Yuce | C. Yuce, A. Kilic and A. Coruh | Inverted Oscillator | 4 pages | Phys. Scr. 74 114 (2006) | 10.1088/0031-8949/74/1/014 | null | quant-ph | null | The inverted harmonic oscillator problem is investigated quantum
mechanically. The exact wave function for the confined inverted oscillator is
obtained and it is shown that the associated energy eigenvalues are discrete
and it is given as a linear function of the quantum number $n$.
| [
{
"version": "v1",
"created": "Sun, 25 Mar 2007 18:14:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yuce",
"C.",
""
],
[
"Kilic",
"A.",
""
],
[
"Coruh",
"A.",
""
]
] |
quant-ph/0703235 | Cem Yuce | C. Yuce | Complex Spectrum of a Spontaneously Unbroken PT Symmetric Hamiltonian | 4 pages, no figures | null | null | null | quant-ph | null | It is believed that unbroken PT symmetry is sufficient to guarantee that the
spectrum of a non-Hermitian Hamiltonian is real. We prove that this is not
true. We study a Hamiltonian with complex spectrum for which PT symmetry is not
spontaneously broken.
| [
{
"version": "v1",
"created": "Sun, 25 Mar 2007 15:13:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Yuce",
"C.",
""
]
] |
quant-ph/0703236 | Simone Severini | Nitin Saxena, Simone Severini, Igor Shparlinski | Parameters of Integral Circulant Graphs and Periodic Quantum Dynamics | 12 pages | null | null | null | quant-ph | null | The intention of the paper is to move a step towards a classification of
network topologies that exhibit periodic quantum dynamics. We show that the
evolution of a quantum system, whose hamiltonian is identical to the adjacency
matrix of a circulant graph, is periodic if and only if all eigenvalues of the
graph are integers (that is, the graph is integral). Motivated by this
observation, we focus on relevant properties of integral circulant graphs.
Specifically, we bound the number of vertices of integral circulant graphs in
terms of their degree, characterize bipartiteness and give exact bounds for
their diameter. Additionally, we prove that circulant graphs with odd order do
not allow perfect state transfer.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 09:37:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Saxena",
"Nitin",
""
],
[
"Severini",
"Simone",
""
],
[
"Shparlinski",
"Igor",
""
]
] |
quant-ph/0703237 | Robert Spalek | Robert Spalek (UC Berkeley) | The Multiplicative Quantum Adversary | 15 pages, v2: removed an incorrect claim, v3: cleaned up, commented
better, added stronger bound for OR | null | null | null | quant-ph | null | We present a new variant of the quantum adversary method. All adversary
methods give lower bounds on the quantum query complexity of a function by
bounding the change of a progress function caused by one query. All previous
variants upper-bound the_difference_ of the progress function, whereas our new
variant upper-bounds the_ratio_ and that is why we coin it the multiplicative
adversary. The new method generalizes to all functions the new quantum
lower-bound method by Ambainis [Amb05, ASW06] based on the analysis of
eigenspaces of the density matrix. We prove a strong direct product theorem for
all functions that have a multiplicative adversary lower bound.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 19:08:19 GMT"
},
{
"version": "v2",
"created": "Wed, 28 Mar 2007 19:42:39 GMT"
},
{
"version": "v3",
"created": "Wed, 25 Apr 2007 20:45:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Spalek",
"Robert",
"",
"UC Berkeley"
]
] |
quant-ph/0703238 | Peter Rohde | Peter P Rohde | Improving the fidelity of single photon preparation from conditional
down-conversion via asymmetric multiport detection | 2 pages | null | null | null | quant-ph | null | We discuss the conditional preparation of single photons via parametric
down-conversion. This technique is commonly used as a single photon source in
modern quantum optics experiments. A significant problem facing this technique
is the inability of present day photo-detectors to resolve photon number. This
results in mixing with higher photon number terms. To overcome this several
techniques have been proposed, including multi-port detection and time-division
multiplexing. These techniques help approximate number resolving detection even
when using non-number resolving detectors. In this paper we focus on 2-port
detection, the simplest such scheme. We show that by making the 2-port device
asymmetric the fidelity of prepared photons can be improved.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 01:00:39 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Rohde",
"Peter P",
""
]
] |
quant-ph/0703239 | Xiao-Jie Hao | Guo-Ping Guo, Xiao-Jie Hao, Tao Tu, Zhi-Cheng Zhu, and Guang-Can Guo | Eliminating interactions between non-neighboring qubits in the
preparation of cluster states in quantum molecules | 5 pages, 4 figures, 2 tables | European Journal of Physics B, 61, 141-146 (2008) | 10.1140/epjb/e2008-00053-9 | null | quant-ph | null | We propose a scheme to eliminate the effect of non-nearest-neighbor qubits in
preparing cluster state with double-dot molecules. As the interaction
Hamiltonians between qubits are Ising-model and mutually commute, we can get
positive and negative effective interactions between qubits to cancel the
effect of non-nearest-neighbor qubits by properly changing the electron charge
states of each quantum dot molecule. The total time for the present multi-step
cluster state preparation scheme is only doubled for one-dimensional qubit
chain and tripled for two-dimensional qubit array comparing with the time of
previous protocol leaving out the non-nearest-neighbor interactions.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 01:26:08 GMT"
},
{
"version": "v2",
"created": "Thu, 24 Apr 2008 08:34:08 GMT"
}
] | 2008-04-24T00:00:00 | [
[
"Guo",
"Guo-Ping",
""
],
[
"Hao",
"Xiao-Jie",
""
],
[
"Tu",
"Tao",
""
],
[
"Zhu",
"Zhi-Cheng",
""
],
[
"Guo",
"Guang-Can",
""
]
] |
quant-ph/0703240 | Hermann Kampermann | R.G. Unanyan, H. Kampermann, D. Bruss | A Decomposition of Separable Werner States | 7 pages, 1 figures | J. Phys. A, 40: F483 (2007) | 10.1088/1751-8113/40/24/F07 | null | quant-ph | null | We derive an integral convex combination of product states for a range of
separable Werner states. Our method consists of expanding the sought-after
local density operators in terms of Wigner operators. For dimension d=2, our
decomposition holds for the whole separable range of Werner states, while for
d>2 it is valid for a subset of separable Werner states. We illustrate the
general method with the explicit examples d=2 and d=3.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 11:36:38 GMT"
}
] | 2008-09-03T00:00:00 | [
[
"Unanyan",
"R. G.",
""
],
[
"Kampermann",
"H.",
""
],
[
"Bruss",
"D.",
""
]
] |
quant-ph/0703241 | Aloisio Vaglica | A. Vaglica and G. Vetri | Irreversible decay of nonlocal entanglement via a reservoir of a single
degree of freedom | 6 pages, 4 figures, improved presentation, v2: title changed,
references added, accepted for publication in Phys. Rev. A (Fundamental
concepts) | null | 10.1103/PhysRevA.75.062120 | null | quant-ph | null | Recently, it has been realized that nonlocal disentanglement may take a
finite time as opposite to the asymptotic decay of local coherences. We find in
this paper that a sudden irreversible death of entanglement takes place in a
two atom optical Stern-Gerlach model. In particular, the one degree non
dissipative environment here considered suddenly destroys the initial
entanglement of any Bell's states $\ket{\phi^{\pm}}$ superposition.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 12:09:50 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Jun 2007 13:58:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Vaglica",
"A.",
""
],
[
"Vetri",
"G.",
""
]
] |
quant-ph/0703242 | Martin Ostermeyer | Martin Ostermeyer, Nino Walenta | On the implementation of a deterministic secure coding protocol using
polarization entangled photons | 12 pages, 2 figures | Optics Communications 281 4540 - 4544 (2008) | 10.1016/j.optcom.2008.04.068 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We demonstrate a prototype-implementation of deterministic information
encoding for quantum key distribution (QKD) following the ping-pong coding
protocol [K. Bostroem, T. Felbinger, Phys. Rev. Lett. 89 (2002) 187902-1]. Due
to the deterministic nature of this protocol the need for post-processing the
key is distinctly reduced compared to non-deterministic protocols. In the
course of our implementation we analyze the practicability of the protocol and
discuss some security aspects of information transfer in such a deterministic
scheme.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 12:17:41 GMT"
},
{
"version": "v2",
"created": "Mon, 21 Jul 2008 08:54:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ostermeyer",
"Martin",
""
],
[
"Walenta",
"Nino",
""
]
] |
quant-ph/0703243 | Jan Naudts | Jan Naudts and Tobias Verhulst | Ensemble averaged entanglement of two-particle states in Fock space | 19 pages Latex, changed title, references added in the conclusions | null | 10.1103/PhysRevA.75.062104 | null | quant-ph | null | Recent results, extending the Schmidt decomposition theorem to wavefunctions
of identical particles, are reviewed. They are used to give a definition of
reduced density operators in the case of two identical particles. Next, a
method is discussed to calculate time averaged entanglement. It is applied to a
pair of identical electrons in an otherwise empty band of the Hubbard model,
and to a pair of bosons in the the Bose-Hubbard model with infinite range
hopping. The effect of degeneracy of the spectrum of the Hamiltonian on the
average entanglement is emphasised.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 14:23:44 GMT"
},
{
"version": "v2",
"created": "Tue, 3 Apr 2007 08:14:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Naudts",
"Jan",
""
],
[
"Verhulst",
"Tobias",
""
]
] |
quant-ph/0703244 | Joy Christian | Joy Christian (Perimeter and Oxford) | Disproof of Bell's Theorem: Reply to Critics | 12 pages; One more response added: See also arXiv:quant-ph/0703179
and arXiv:0707.1333 | null | null | null | quant-ph | null | This is a collection of my responses to the criticisms of my argument against
the impossibility proof of John Bell, which aims to undermine any conceivable
local realistic completion of quantum mechanics. I plan to periodically update
this preprint instead of creating a new one for each response.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 19:15:54 GMT"
},
{
"version": "v10",
"created": "Wed, 19 Dec 2007 23:42:42 GMT"
},
{
"version": "v11",
"created": "Tue, 1 Jan 2008 09:13:27 GMT"
},
{
"version": "v12",
"created": "Thu, 3 Jan 2008 17:25:07 GMT"
},
{
"version": "v2",
"created": "Mon, 2 Apr 2007 13:16:01 GMT"
},
{
"version": "v3",
"created": "Thu, 12 Jul 2007 19:06:05 GMT"
},
{
"version": "v4",
"created": "Wed, 18 Jul 2007 19:15:18 GMT"
},
{
"version": "v5",
"created": "Wed, 15 Aug 2007 19:10:17 GMT"
},
{
"version": "v6",
"created": "Mon, 20 Aug 2007 18:52:10 GMT"
},
{
"version": "v7",
"created": "Thu, 13 Dec 2007 10:29:12 GMT"
},
{
"version": "v8",
"created": "Fri, 14 Dec 2007 20:44:38 GMT"
},
{
"version": "v9",
"created": "Mon, 17 Dec 2007 21:19:46 GMT"
}
] | 2008-01-03T00:00:00 | [
[
"Christian",
"Joy",
"",
"Perimeter and Oxford"
]
] |
quant-ph/0703245 | Farrukh Mukhamedov M. | Nasir Ganikhodjaev, Farrukh Mukhamedov | On Entropy Transmission for Quantum Channels | 11 pages. Applied Math. & Inform. Sciences (in accepted) | Appl. Math. & Inform. Sci} 1 (2007), 3, 12 pages | null | null | quant-ph | null | In this paper a notion of entropy transmission of quantum channels is
introduced as a natural extension of Ohya's entropy. Here by quantum channel is
meant unital completely positive mappings (ucp) of $B(H)$ into itself, where
$H$ is an infinite dimensional Hilbert space. Using a representation theorem of
ucp mapping we associate to every ucp map a uniquely determined state, and
prove that entropy of ucp map is less then Ohya's entropy of the associated
state.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 17:28:59 GMT"
},
{
"version": "v2",
"created": "Thu, 31 May 2007 16:36:04 GMT"
}
] | 2007-11-21T00:00:00 | [
[
"Ganikhodjaev",
"Nasir",
""
],
[
"Mukhamedov",
"Farrukh",
""
]
] |
quant-ph/0703246 | Gilad Gour | Gilad Gour | How many ebits can be unlocked with one classical bit? | 3 pages, Brief Report, Comments are Welcome | Physical Review A 75, 054301 (2007). | 10.1103/PhysRevA.75.054301 | null | quant-ph | null | We find an upper bound on the rate at which entanglement can be unlocked by
classical bits. In particular, we show that for quantum information sources
that are specified by ensambles of pure bipartite states, one classical bit can
unlock at most one ebit.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 18:17:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gour",
"Gilad",
""
]
] |
quant-ph/0703247 | Hui Jing | H. Jing, J. Cheng, and P. Meystre | Coherent atom-trimer conversion in a repulsive Bose-Einstein condensate | 3 figures | null | 10.1103/PhysRevLett.99.133002 | null | quant-ph | null | We show that the use of a generalized atom-molecule dark state permits the
enhanced coherent creation of triatomic molecules in a repulsive atomic
Bose-Einstein condensate, with further enhancement being possible in the case
of heteronuclear trimers via the constructive interference between two chemical
reaction channels.
| [
{
"version": "v1",
"created": "Mon, 26 Mar 2007 20:41:13 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jing",
"H.",
""
],
[
"Cheng",
"J.",
""
],
[
"Meystre",
"P.",
""
]
] |
quant-ph/0703248 | Lev Kaplan | S. A. Fulling, L. Kaplan, and J. H. Wilson | Vacuum Energy and Repulsive Casimir Forces in Quantum Star Graphs | 7 pages, 5 figures; REVTeX | Phys. Rev. A 76, 012118 (2007) | 10.1103/PhysRevA.76.012118 | null | quant-ph nlin.CD | null | Casimir pistons are models in which finite Casimir forces can be calculated
without any suspect renormalizations. It has been suggested that such forces
are always attractive, but we present several counterexamples, notably a simple
type of quantum graph in which the sign of the force depends upon the number of
edges. We also show that Casimir forces in quantum graphs can be reliably
computed by summing over the classical orbits, and study the rate of
convergence of the periodic orbit expansion. In generic situations where no
analytic expression is available, the sign and approximate magnitude of Casimir
forces can often be obtained using only the shortest classical orbits.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 02:07:25 GMT"
}
] | 2008-02-18T00:00:00 | [
[
"Fulling",
"S. A.",
""
],
[
"Kaplan",
"L.",
""
],
[
"Wilson",
"J. H.",
""
]
] |
quant-ph/0703249 | Isabel Sainz | Isabel Sainz Abascal and Gunnar Bj\"ork | Bipartite entanglement measure based on covariances | We have changed a preprint reference for the correspondent published | Phys. Rev. A 75, 062317 (2007) | null | null | quant-ph | null | We propose an entanglement measure for two qudits based on the covariances of
a set of generators of the su(N) algebra. In particular, we represent this
measure in terms of the mutually unbiased projectors for N prime. For pure
states this measure quantify entanglement, we obtain an explicit expression
which relates it to the concurrence hierarchy, specifically the I-concurrence
and the 3-concurrence. For mixed states we propose a separability criterion.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 08:30:15 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Apr 2007 11:41:53 GMT"
},
{
"version": "v3",
"created": "Mon, 18 Jun 2007 09:52:03 GMT"
}
] | 2007-06-18T00:00:00 | [
[
"Abascal",
"Isabel Sainz",
""
],
[
"Björk",
"Gunnar",
""
]
] |
quant-ph/0703250 | Rustem Shakhmuratov | R. N. Shakhmuratov, A. A. Kalachev, and J. Odeurs | Instantaneous processing of "slow light": amplitude-duration control,
storage, and splitting | 9 pages, 1 figure, submitted to PRL on 18, December, 2006 | null | 10.1103/PhysRevA.76.031802 | null | quant-ph | null | Nonadiabatic change of the control field or of the low-frequency coherence
allows for an almost instantaneous change of the signal field propagating in a
thick resonant absorber where electromagnetically induced transparency is
realized. This finding is applied for the storage and retrieval of the signal,
for the creation of a signal copy and separation of this copy from the original
pulse without its destruction.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 13:14:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Shakhmuratov",
"R. N.",
""
],
[
"Kalachev",
"A. A.",
""
],
[
"Odeurs",
"J.",
""
]
] |
quant-ph/0703251 | Alexandre Matzkin | A. Matzkin | Classical statistical distributions can violate Bell-type inequalities | v3: Extended version. To be published in J. Phys. A | J. Phys. A: Math. Theor. 41, 085303, 2008. | 10.1088/1751-8113/41/8/085303 | null | quant-ph | null | We investigate two-particle phase-space distributions in classical mechanics
characterized by a well-defined value of the total angular momentum. We
construct phase-space averages of observables related to the projection of the
particles' angular momenta along axes with different orientations. It is shown
that for certain observables, the correlation function violates Bell's
inequality. The key to the violation resides in choosing observables impeding
the realization of the counterfactual event that plays a prominent role in the
derivation of the inequalities. This situation can have statistical (detection
related) or dynamical (interaction related) underpinnings, but non-locality
does not play any role.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 17:03:36 GMT"
},
{
"version": "v2",
"created": "Mon, 9 Apr 2007 10:17:15 GMT"
},
{
"version": "v3",
"created": "Fri, 18 Jan 2008 11:34:04 GMT"
}
] | 2008-02-12T00:00:00 | [
[
"Matzkin",
"A.",
""
]
] |
quant-ph/0703252 | Qin Wang | Qin Wang, Xiang-Bin Wang, Gunnar Bjork, Anders Karlsson | Improved practical decoy state method in quantum key distribution with
parametric down conversion source | 8 pages, 3 figures | null | 10.1103/PhysRevA.75.012312 | null | quant-ph | null | In this paper, a new decoy-state scheme for quantum key distribution with
parametric down-conversion source is proposed. We use both three-intensity
decoy states and their triggered and nontriggered components to estimate the
fraction of single-photon counts and quantum bit-error rate of single-photon,
and then deduce a more accurate value of key generation rate. The final key
rate over transmission distance is simulated, which shows that we can obtain a
higher key rate than that of the existing methods, including our own earlier
work.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 17:07:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wang",
"Qin",
""
],
[
"Wang",
"Xiang-Bin",
""
],
[
"Bjork",
"Gunnar",
""
],
[
"Karlsson",
"Anders",
""
]
] |
quant-ph/0703253 | Sebastien Sauge | S. Sauge, M. Swillo, S. Albert-Seifried, G. B. Xavier, J. Waldeback,
M. Tengner, D. Ljunggren, A. Karlsson | Narrowband polarization-entangled photon pairs distributed over a WDM
link for qubit networks | 8 pages, 4 figures | Opt. Express 15, 6926-6933 (2007) | 10.1364/OE.15.006926 | null | quant-ph | null | We present a bright, narrowband, portable, quasi-phase-matched two-crystal
source generating polarization-entangled photon pairs at 809 nm and 1555 nm at
a maximum rate of 1.2 10^6 s-1 THz-1 mW-1 after coupling to single-mode fiber.
The quantum channel at 1555 nm and the synchronization signal gating the single
photon detector are multiplexed in the same optical fiber of length 27 km by
means of wavelength division multiplexers (WDM) having 100 GHz (0.8 nm) spacing
between channels. This implementation makes quantum communication applications
compatible with current high-speed optical networks.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 18:16:53 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Sep 2007 13:13:03 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Sep 2007 14:41:54 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sauge",
"S.",
""
],
[
"Swillo",
"M.",
""
],
[
"Albert-Seifried",
"S.",
""
],
[
"Xavier",
"G. B.",
""
],
[
"Waldeback",
"J.",
""
],
[
"Tengner",
"M.",
""
],
[
"Ljunggren",
"D.",
""
],
[
"Karlsson",
"A.",
""
]
] |
quant-ph/0703254 | Andreas Fring | Paulo E.G. Assis and Andreas Fring | The quantum brachistochrone problem for non-Hermitian Hamiltonians | 7 pages Latex, 2 figures | J.Phys.A41:244002,2008 | 10.1088/1751-8113/41/24/244002 | null | quant-ph hep-th math-ph math.MP | null | Recently Bender, Brody, Jones and Meister found that in the quantum
brachistochrone problem the passage time needed for the evolution of certain
initial states into specified final states can be made arbitrarily small, when
the time-evolution operator is taken to be non-Hermitian but PT-symmetric. Here
we demonstrate that such phenomena can also be obtained for non-Hermitian
Hamiltonians for which PT-symmetry is completely broken, i.e. dissipative
systems. We observe that the effect of a tunable passage time can be achieved
by projecting between orthogonal eigenstates by means of a time-evolution
operator associated to a non-Hermitian Hamiltonian. It is not essential that
this Hamiltonian is PT-symmetric.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 18:47:20 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Oct 2007 16:38:48 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Assis",
"Paulo E. G.",
""
],
[
"Fring",
"Andreas",
""
]
] |
quant-ph/0703255 | Robert Thew | Nicolas Gisin and Rob Thew | Quantum Communication | Submitted version, 8 pg (2 cols) 5 figs | Nature Photonics, vol 1, No. 3, pp165-171 (2007) | 10.1038/nphoton.2007.22 | null | quant-ph | null | Quantum communication, and indeed quantum information in general, has changed
the way we think about quantum physics. In 1984 and 1991, the first protocol
for quantum cryptography and the first application of quantum non-locality,
respectively, attracted a diverse field of researchers in theoretical and
experimental physics, mathematics and computer science. Since then we have seen
a fundamental shift in how we understand information when it is encoded in
quantum systems. We review the current state of research and future directions
in this new field of science with special emphasis on quantum key distribution
and quantum networks.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 20:10:10 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Gisin",
"Nicolas",
""
],
[
"Thew",
"Rob",
""
]
] |
quant-ph/0703256 | Dmitri Maslov | D. Maslov, S. M. Falconer, and M. Mosca | Quantum Circuit Placement | 15 pages, 4 figures. Improved theory and software implementation, new
experimental results | IEEE Transactions on Computer-Aided Design of Integrated Circuits
and Systems 27(4):752-763, April 2008 | 10.1109/TCAD.2008.917562 | null | quant-ph | null | We study the problem of the practical realization of an abstract quantum
circuit when executed on quantum hardware. By practical, we mean adapting the
circuit to particulars of the physical environment which restricts/complicates
the establishment of certain direct interactions between qubits. This is a
quantum version of the classical circuit placement problem. We study the
theoretical aspects of the problem and also present empirical results that
match the best known solutions that have been developed by experimentalists.
Finally, we discuss the efficiency of the approach and scalability of its
implementation with regards to the future development of quantum hardware.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 20:56:53 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Mar 2008 18:07:37 GMT"
}
] | 2008-03-27T00:00:00 | [
[
"Maslov",
"D.",
""
],
[
"Falconer",
"S. M.",
""
],
[
"Mosca",
"M.",
""
]
] |
quant-ph/0703257 | Dan Solomon | Dan Solomon | Space-like energy momentum in quantum electrodynamics | 9 pages | null | null | null | quant-ph | null | A common assumption in quantum field theory is that the energy-momentum
4-vector of any quantum state must be time-like. However it has been recently
shown [4] that this is not the case for a Dirac-Maxwell field in the coulomb
gauge. Here we will present a proof that is simpler then the proof of Ref. [4]
that there must exist quantum states which are space-like for a Dirac-Maxwell
field in the coulomb gauge.
| [
{
"version": "v1",
"created": "Tue, 27 Mar 2007 21:30:38 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Solomon",
"Dan",
""
]
] |
quant-ph/0703258 | Jesse Fern | Jesse Fern | Correctable noise of Quantum Error Correcting Codes under adaptive
concatenation | 5 pages, no figures, RevTex4, minor changes, similar to final
publication version | Phys. Rev. A 77, 010301(R) (2008) | 10.1103/PhysRevA.77.010301 | null | quant-ph | null | We examine the transformation of noise under a quantum error correcting code
(QECC) concatenated repeatedly with itself, by analyzing the effects of a
quantum channel after each level of concatenation using recovery operators that
are optimally adapted to use error syndrome information from the previous
levels of the code. We use the Shannon entropy of these channels to estimate
the thresholds of correctable noise for QECCs and find considerable
improvements under this adaptive concatenation. Similar methods could be used
to increase quantum fault tolerant thresholds.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 01:43:25 GMT"
},
{
"version": "v2",
"created": "Tue, 14 Aug 2007 17:28:27 GMT"
},
{
"version": "v3",
"created": "Wed, 27 Feb 2008 01:04:07 GMT"
}
] | 2008-02-27T00:00:00 | [
[
"Fern",
"Jesse",
""
]
] |
quant-ph/0703259 | Evgeny Shchukin | E. Shchukin | Bell inequalities, classical cryptography and fractals | 26 pages, 7 figures | null | null | null | quant-ph | null | The relation between the boolean functions and Bell inequalities for qubits
is analyzed. The connection between the maximal quantum violation of a Bell
inequality and the nonlinearity of the corresponding boolean function is
discussed. A visualization scheme of boolean functions is proposed. An attempt
to classify Bell inequalities for qubits is made, a weaker result
(classification with respect to Jevons group) is obtained. The fractal
structure of the classification is shown. All constructs are illustrated by
Mathematica code.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 05:07:02 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Apr 2007 18:12:04 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Shchukin",
"E.",
""
]
] |
quant-ph/0703260 | Sandro Sozzo | Claudio Garola, Sandro Sozzo | Reinterpreting Quantum Probabilities in a Realistic and Local Framework:
The Modified BCHSH Inequalities | 34 pages, revision of footnote 8, minor changes in the terminology,
standard Latex | null | null | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Most physicists uphold that the tests of the Bell inequalities (BI) performed
up to now confirm the predictions of standard quantum mechanics (SQM) and
refute local realism. But some scholars criticize this conviction, defending
local realism in various ways. We present here a new viewpoint based on an
improved version of the extended semantic realism (ESR) model that has been
recently worked out by one of the authors. The ESR model embodies the
mathematical formalism of SQM into a more general framework in which not only
local realism but also objectivity of physical properties holds, and the
probabilities of SQM are reinterpreted as conditional instead of absolute.
Hence the ESR model provides some predictions that are formally identical to
those of SQM but have a different physical interpretation, and further
predictions that differ also formally from those of SQM. In particular, we show
here that the BI introduced by Clauser, Horne, Shimony and Holt (BCHSH
inequalities) must be replaced by modified BCHSH inequalities. These depend on
detection probabilities which may be such that the new inequalities are never
violated by the conditional expectation values predicted by the model. The
condition that no violation occurs implies the existence of upper bounds on
detection probabilities, which makes the ESR model falsifiable. These results
admit an intuitive explanation in terms of unfair sampling but basically differ
from the seemingly similar results obtained by other approaches in which the
efficiency problem is discussed in order to vindicate some kind of local
realism.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 13:36:02 GMT"
},
{
"version": "v2",
"created": "Fri, 8 Jun 2007 15:23:24 GMT"
},
{
"version": "v3",
"created": "Wed, 25 Jul 2007 13:22:20 GMT"
},
{
"version": "v4",
"created": "Fri, 23 Nov 2007 08:42:36 GMT"
},
{
"version": "v5",
"created": "Fri, 4 Jul 2008 12:30:05 GMT"
}
] | 2008-07-04T00:00:00 | [
[
"Garola",
"Claudio",
""
],
[
"Sozzo",
"Sandro",
""
]
] |
quant-ph/0703261 | Gian Paolo Beretta | Gian Paolo Beretta | Quantum thermodynamic Carnot and Otto-like cycles for a two-level system | RevTex4, 4 pages, 1 figure | EPL, 99, 20005 (2012) | 10.1209/0295-5075/99/20005 | null | quant-ph | null | From the thermodynamic equilibrium properties of a two-level system with
variable energy-level gap $\Delta$, and a careful distinction between the Gibbs
relation $dE = T dS + (E/\Delta) d\Delta$ and the energy balance equation $dE =
\delta Q^\leftarrow - \delta W^\to$, we infer some important aspects of the
second law of thermodynamics and, contrary to a recent suggestion based on the
analysis of an Otto-like thermodynamic cycle between two values of $\Delta$ of
a spin-1/2 system, we show that a quantum thermodynamic Carnot cycle, with the
celebrated optimal efficiency $1 - (T_{low}/T_{high})$, is possible in
principle with no need of an infinite number of infinitesimal processes,
provided we cycle smoothly over at least three (in general four) values of
$\Delta$, and we change $\Delta$ not only along the isoentropics, but also
along the isotherms, e.g., by use of the recently suggested maser-laser tandem
technique. We derive general bounds to the net-work to high-temperature-heat
ratio for a Carnot cycle and for the 'inscribed' Otto-like cycle, and represent
these cycles on useful thermodynamic diagrams.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 15:08:57 GMT"
}
] | 2014-01-22T00:00:00 | [
[
"Beretta",
"Gian Paolo",
""
]
] |
quant-ph/0703262 | David Leonard | David Leonard and Paul Mansfield | Solving the Anharmonic Oscillator: Tuning the Boundary Condition | 10 pages, 4 figures. V3 contains minor changes made before final
publication | J.Phys.A40:10291-10300,2007 | 10.1088/1751-8113/40/33/020 | null | quant-ph hep-th | null | We outline a remarkably efficient method for generating solutions to quantum
anharmonic oscillators with an x^{2M} potential. We solve the Schroedinger
equation in terms of a free parameter which is then tuned to give the correct
boundary condition by generating a power series expansion of the wavefunction
in x and applying a modified Borel resummation technique to obtain the large x
behaviour. The process allows us to calculate energy eigenvalues to an
arbitrary level of accuracy. High degrees of precision are achieved even with
modest computing power. Our technique extends to all levels of excitation and
produces the correct solution to the double well oscillators even though they
are dominated by non-perturbative effects.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 14:53:20 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Apr 2007 16:11:18 GMT"
},
{
"version": "v3",
"created": "Thu, 9 Aug 2007 13:55:13 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Leonard",
"David",
""
],
[
"Mansfield",
"Paul",
""
]
] |
quant-ph/0703263 | Angel S. Sanz | D. Gerbasi, A. S. Sanz, P. S. Christopher, M. Shapiro, P. Brumer | Overlapping resonances in the control of intramolecular vibrational
redistribution | 10 pages, 7 figures | J. Chem. Phys. 126, 124307 (2007) | 10.1063/1.2710791 | null | quant-ph | null | Coherent control of bound state processes via the interfering overlapping
resonances scenario [Christopher et al., J. Chem. Phys. 123, 064313 (2006)] is
developed to control intramolecular vibrational redistribution (IVR). The
approach is applied to the flow of population between bonds in a model of
chaotic OCS vibrational dynamics, showing the ability to significantly alter
the extent and rate of IVR by varying quantum interference contributions.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 17:35:11 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gerbasi",
"D.",
""
],
[
"Sanz",
"A. S.",
""
],
[
"Christopher",
"P. S.",
""
],
[
"Shapiro",
"M.",
""
],
[
"Brumer",
"P.",
""
]
] |
quant-ph/0703264 | John Preskill | Panos Aliferis, Daniel Gottesman, John Preskill | Accuracy threshold for postselected quantum computation | 54 pages, 26 figures, uses qic.sty. (v2): minor revisions | Quant. Inf. Comput. 8 (2008) 181-244 | null | CALT-68-2616 | quant-ph | null | We prove an accuracy threshold theorem for fault-tolerant quantum computation
based on error detection and postselection. Our proof provides a rigorous
foundation for the scheme suggested by Knill, in which preparation circuits for
ancilla states are protected by a concatenated error-detecting code and the
preparation is aborted if an error is detected. The proof applies to
independent stochastic noise but (in contrast to proofs of the quantum accuracy
threshold theorem based on concatenated error-correcting codes) not to
strongly-correlated adversarial noise. Our rigorously established lower bound
on the accuracy threshold, 1.04 \times 10^{-3}, is well below Knill's numerical
estimates.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 20:19:39 GMT"
},
{
"version": "v2",
"created": "Mon, 17 Sep 2007 21:17:30 GMT"
}
] | 2008-02-27T00:00:00 | [
[
"Aliferis",
"Panos",
""
],
[
"Gottesman",
"Daniel",
""
],
[
"Preskill",
"John",
""
]
] |
quant-ph/0703265 | Andrei Faraon | Andrei Faraon, Dirk Englund, Ilya Fushman, Nick Stoltz, Pierre
Petroff, Jelena Vuckovic | Local Quantum Dot Tuning on Photonic Crystal Chips | null | null | 10.1063/1.2742789 | null | quant-ph | null | Quantum networks based on InGaAs quantum dots embedded in photonic crystal
devices rely on QDs being in resonance with each other and with the cavities
they are embedded in. We developed a new technique based on temperature tuning
to spectrally align different quantum dots located on the same chip. The
technique allows for up to 1.8nm reversible on-chip quantum dot tuning.
| [
{
"version": "v1",
"created": "Wed, 28 Mar 2007 22:46:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Faraon",
"Andrei",
""
],
[
"Englund",
"Dirk",
""
],
[
"Fushman",
"Ilya",
""
],
[
"Stoltz",
"Nick",
""
],
[
"Petroff",
"Pierre",
""
],
[
"Vuckovic",
"Jelena",
""
]
] |
quant-ph/0703266 | Gennadi Sardanashvily | L.Mangiarotti and G.Sardanashvily | Quantum mechanics with respect to different reference frames | 16 pages | J. Math. Phys. v.48 (2007) 082104 | 10.1063/1.2769147 | null | quant-ph math-ph math.MP | null | Geometric (Schrodinger) quantization of nonrelativistic mechanics with
respect to different reference frames is considered. In classical
nonrelativistic mechanics, a reference frame is represented by a connection on
a configuration space fibered over a time axis. Under quantization, it yields a
connection on the quantum algebra of Schrodinger operators. The operators of
energy with respect to different reference frames are examined.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 06:14:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Mangiarotti",
"L.",
""
],
[
"Sardanashvily",
"G.",
""
]
] |
quant-ph/0703267 | Ebrahim Karimi | Mohammad R. Setare, Ebrahim Karimi | Algebraic approach to the Hulthen potential | 8 Pages, 1 Table | Int. J. Theor. Phys. 46, 1381 (2007). | 10.1007/s10773-006-9276-z | null | quant-ph | null | In this paper the energy eigenvalues and the corresponding eigenfunctions are
calculated for Hulthen potential. Then we obtain the ladder operators and show
that these operators satisfy SU(2) commutation relation.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 08:48:08 GMT"
}
] | 2009-08-30T00:00:00 | [
[
"Setare",
"Mohammad R.",
""
],
[
"Karimi",
"Ebrahim",
""
]
] |
quant-ph/0703268 | Lluis Masanes | Lluis Masanes, Yeong-Cherng Liang, Andrew C. Doherty | All bipartite entangled states display some hidden nonlocality | 5 pages, 1 figure | Physical Review Letters, vol 100, art. 090403 (2008) | 10.1103/PhysRevLett.100.090403 | null | quant-ph | null | We show that a violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality
can be demonstrated in a certain kind of Bell experiment for all bipartite
entangled states. Our protocol allows local filtering measurements and involves
shared ancilla states that do not themselves violate CHSH. Our result follows
from two main steps. We first provide a simple characterization of the states
that violate the CHSH-inequality after local filtering operations in terms of
witness-like operators. Second, we prove that for each entangled state
$\sigma$, there exists another state $\rho$ not violating CHSH, such that
$\rho\otimes\sigma$ violates CHSH. Hence, in this scenario, $\sigma$ cannot be
substituted by classical correlations without changing the statistics of the
experiment; we say that $\sigma$ is not simulable by classical correlations and
our result is that entanglement is equivalent to non-simulability.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 10:05:08 GMT"
}
] | 2008-03-06T00:00:00 | [
[
"Masanes",
"Lluis",
""
],
[
"Liang",
"Yeong-Cherng",
""
],
[
"Doherty",
"Andrew C.",
""
]
] |
quant-ph/0703269 | Mykola Stetsko | M. M. Stetsko | Corrections to the ns-levels of hydrogen atom in deformed space with
minimal length | 9 pages, 1 figure | Phys. Rev. A 74, 062105, 2006 | 10.1103/PhysRevA.74.062105 | null | quant-ph | null | We investigated the hydrogen atom problem with deformed Heisenberg algebra
leading to the existence of minimal length. Using modified perturbation theory
developed in our previous work [M. M. Stetsko and V. M. Tkachuk, Phys. Rev. A
74, 012101 (2006)] we calculated the corrections to the arbitrary s-levels for
hydrogen atom. We received a simple relation for the estimation of minimal
length. We also compared the estimation of minimal length obtained here with
the results obtained in the preceding investigations.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 10:43:36 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Stetsko",
"M. M.",
""
]
] |
quant-ph/0703270 | Thomas Coudreau | P\'erola Milman (MPQ), Wilfried Maineult (MPQ), Samuel Guibal (MPQ),
Luca Guidoni (MPQ), Beno\^it Dou\c{c}ot (LPTHE), Lev Ioffe, Thomas Coudreau
(MPQ) | Topologically decoherence-protected qubits with trapped ions | 4 pages | Physical Review Letters 99, 2 (13/07/2007) 020503 | 10.1103/PhysRevLett.99.020503 | null | quant-ph cond-mat.other | null | We show that trapped ions can be used to simulate a highly symmetrical
Hamiltonian with eingenstates naturally protected against local sources of
decoherence. This Hamiltonian involves long range coupling between particles
and provides a more efficient protection than nearest neighbor models discussed
in previous works. Our results open the perspective of experimentally realizing
in controlled atomic systems, complex entangled states with decoherence times
up to nine orders of magnitude longer than isolated quantum systems.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 11:53:41 GMT"
},
{
"version": "v2",
"created": "Sun, 15 Jul 2007 16:40:11 GMT"
}
] | 2007-07-15T00:00:00 | [
[
"Milman",
"Pérola",
"",
"MPQ"
],
[
"Maineult",
"Wilfried",
"",
"MPQ"
],
[
"Guibal",
"Samuel",
"",
"MPQ"
],
[
"Guidoni",
"Luca",
"",
"MPQ"
],
[
"Douçot",
"Benoît",
"",
"LPTHE"
],
[
"Ioffe",
"Lev",
"",
"MPQ"
],
[
"Coudreau",
"Thomas",
"",
"MPQ"
]
] |
quant-ph/0703271 | Alexandre Matzkin | A. Matzkin | A local model violating Bell's inequalities | This preprint is now replaced by arXiv:0808.2420 | null | null | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A model for two entangled systems in an EPR setting is shown to reproduce the
quantum-mechanical outcomes and expectation values. Each system is represented
by a small sphere containing a point-like particle embedded in a field. A
quantum state appears as an equivalence class of several possible
particle-field configurations. Contrarily to Bell-type hidden variables models,
the fields account for the non-commutative aspects of the measurements and deny
the simultaneous reality of incompatible physical quantities, thereby allowing
to escape EPR's "completeness or locality" dilemma.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 13:23:41 GMT"
},
{
"version": "v2",
"created": "Mon, 9 Apr 2007 18:25:50 GMT"
},
{
"version": "v3",
"created": "Wed, 14 Jan 2009 20:06:33 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Matzkin",
"A.",
""
]
] |
quant-ph/0703272 | Hector Bombin | H. Bombin, M.A. Martin-Delgado | Optimal Resources for Topological 2D Stabilizer Codes: Comparative Study | revtex, 6 pages, 7 figures | Phys. Rev. A 76, 012305 (2007) | 10.1103/PhysRevA.76.012305 | null | quant-ph cond-mat.str-el | null | We study the resources needed to construct topological 2D stabilizer codes as
a way to estimate in part their efficiency and this leads us to perform a
comparative study of surface codes and color codes. This study clarifies the
similarities and differences between these two types of stabilizer codes. We
compute the error correcting rate $C:=n/d^2$ for surface codes $C_s$ and color
codes $C_c$ in several instances. On the torus, typical values are $C_s=2$ and
$C_c=3/2$, but we find that the optimal values are $C_s=1$ and $C_c=9/8$. For
planar codes, a typical value is $C_s=2$, while we find that the optimal values
are $C_s=1$ and $C_c=3/4$. In general, a color code encodes twice as much
logical qubits as a surface code does.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 13:47:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bombin",
"H.",
""
],
[
"Martin-Delgado",
"M. A.",
""
]
] |
quant-ph/0703273 | Andrzej Dragan | Andrzej Dragan and Pawel Zin | Interference of Fock states in a single measurement | 4 pages | null | 10.1103/PhysRevA.76.042124 | null | quant-ph | null | We study analytically the structure of an arbitrary order correlation
function for a pair of Fock states and prove without any approximations that in
a single measurement of particle positions interference effects must occur as
experimentally observed with Bose-Einstein condensates. We also show that the
noise level present in the statistics is slightly lower than for a respective
measurement of phase states.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 17:05:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dragan",
"Andrzej",
""
],
[
"Zin",
"Pawel",
""
]
] |
quant-ph/0703274 | Daniel A. Lidar | R.L. Kosut, A. Shabani, D.A. Lidar | Robust Quantum Error Correction via Convex Optimization | 4 pages, including 3 figures. v2: new examples | Phys. Rev. Lett. 100, 020502 (2008) | 10.1103/PhysRevLett.100.020502 | null | quant-ph | null | We present a semidefinite program optimization approach to quantum error
correction that yields codes and recovery procedures that are robust against
significant variations in the noise channel. Our approach allows us to optimize
the encoding, recovery, or both, and is amenable to approximations that
significantly improve computational cost while retaining fidelity. We
illustrate our theory numerically for optimized 5-qubit codes, using the
standard [5,1,3] code as a benchmark. Our optimized encoding and recovery
yields fidelities that are uniformly higher by 1-2 orders of magnitude against
random unitary weight-2 errors compared to the [5,1,3] code with standard
recovery. We observe similar improvement for a 4-qubit decoherence-free
subspace code.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 20:03:45 GMT"
},
{
"version": "v2",
"created": "Tue, 18 Sep 2007 17:01:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kosut",
"R. L.",
""
],
[
"Shabani",
"A.",
""
],
[
"Lidar",
"D. A.",
""
]
] |
quant-ph/0703275 | Jaroslav Hruby | Jaroslav Hruby | Supersymmetry and quantum games | QIP 07 | null | null | null | quant-ph | null | In this paper we show the connection between the supersymmetry and quantum
games.
| [
{
"version": "v1",
"created": "Thu, 29 Mar 2007 22:39:25 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Hruby",
"Jaroslav",
""
]
] |
quant-ph/0703276 | Rafael Sorkin | Rafael D. Sorkin (Perimeter Institute and Syracuse University) | An exercise in "anhomomorphic logic" | plainTeX, 14 pages, no figures. To appear in a special volume of {\it
Journal of Physics}, edited by L. Diosi, H-T Elze, and G. Vitiello. Most
current version is available at
http://www.physics.syr.edu/~sorkin/some.papers/ (or wherever my home-page may
be) | J.Phys.Conf.Ser.67:012018,2007 | 10.1088/1742-6596/67/1/012018 | null | quant-ph gr-qc hep-th | null | A classical logic exhibits a threefold inner structure comprising an algebra
of propositions `A', a space of ``truth values'' `V', and a distinguished
family of mappings `phi' from propositions to truth values. Classically A is a
Boolean algebra, V=Z_2, and the admissible maps phi:A-->Z_2 are {\it
homomorphisms}. If one admits a larger set of maps, one obtains an
anhomomorphic logic that seems better suited to quantal reality (and the needs
of quantum gravity). I explain these ideas and illustrate them with three
simple examples.
| [
{
"version": "v1",
"created": "Fri, 30 Mar 2007 02:00:59 GMT"
},
{
"version": "v2",
"created": "Sat, 31 Mar 2007 21:22:19 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Sorkin",
"Rafael D.",
"",
"Perimeter Institute and Syracuse University"
]
] |
quant-ph/0703277 | Gerardo Adesso | Gerardo Adesso and Fabrizio Illuminati | Strong Monogamy of Bipartite and Genuine Multipartite Entanglement: The
Gaussian Case | 4 pages, 2 figures. Final version, published in PRL | Phys. Rev. Lett. 99, 150501 (2007) | 10.1103/PhysRevLett.99.150501 | null | quant-ph cond-mat.stat-mech hep-th math-ph math.MP | null | We demonstrate the existence of general constraints on distributed quantum
correlations, which impose a trade-off on bipartite and multipartite
entanglement at once. For all N-mode Gaussian states under permutation
invariance, we establish exactly a monogamy inequality, stronger than the
traditional one, that by recursion defines a proper measure of genuine
N-partite entanglement. Strong monogamy holds as well for subsystems of
arbitrary size, and the emerging multipartite entanglement measure is found to
be scale invariant. We unveil its operational connection with the optimal
fidelity of continuous variable teleportation networks.
| [
{
"version": "v1",
"created": "Fri, 30 Mar 2007 12:34:49 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Apr 2007 16:58:16 GMT"
},
{
"version": "v3",
"created": "Sat, 25 Aug 2007 07:45:00 GMT"
},
{
"version": "v4",
"created": "Tue, 9 Oct 2007 16:00:44 GMT"
}
] | 2007-10-09T00:00:00 | [
[
"Adesso",
"Gerardo",
""
],
[
"Illuminati",
"Fabrizio",
""
]
] |
quant-ph/0703278 | Matthew Elliott | Matthew B. Elliott, Bryan Eastin, and Carlton M. Caves | Graphical description of the action of Clifford operators on stabilizer
states | 14 pages, 8 figures. Version 2 contains significant changes.
Submitted to PRA | Phys. Rev. A 77, 042307 (2008) | 10.1103/PhysRevA.77.042307 | null | quant-ph | null | We introduce a graphical representation of stabilizer states and translate
the action of Clifford operators on stabilizer states into graph operations on
the corresponding stabilizer-state graphs. Our stabilizer graphs are
constructed of solid and hollow nodes, with (undirected) edges between nodes
and with loops and signs attached to individual nodes. We find that local
Clifford transformations are completely described in terms of local
complementation on nodes and along edges, loop complementation, and change of
node type or sign. Additionally, we show that a small set of equivalence rules
generates all graphs corresponding to a given stabilizer state; we do this by
constructing an efficient procedure for testing the equality of any two
stabilizer graphs.
| [
{
"version": "v1",
"created": "Fri, 30 Mar 2007 18:43:39 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 15:26:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Elliott",
"Matthew B.",
""
],
[
"Eastin",
"Bryan",
""
],
[
"Caves",
"Carlton M.",
""
]
] |
quant-ph/9412001 | Guenter Schrade | G. Schrade, V.M. Akulin, W.P. Schleich, and V.I. Man'ko | Photon Statistics of a Two-Mode Squeezed Vacuum | LATEX, 6 pages, Contribution to the third International Workshop on
Squeezed States and Uncertainty Relations, Baltimore, August 1993 | Phys.Rev.A48:2398-2406,1993 | 10.1103/PhysRevA.48.2398 | null | quant-ph | null | We investigate the general case of the photon distribution of a two-mode
squeezed vacuum and show that the distribution of photons among the two modes
depends on four parameters: two squeezing parameters, the relative phase
between the two oscillators and their spatial orientation. The distribution of
the total number of photons depends only on the two squeezing parameters. We
derive analytical expressions and present pictures for both distributions.
| [
{
"version": "v1",
"created": "Wed, 21 Dec 1994 09:22:43 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Schrade",
"G.",
""
],
[
"Akulin",
"V. M.",
""
],
[
"Schleich",
"W. P.",
""
],
[
"Man'ko",
"V. I.",
""
]
] |
quant-ph/9412002 | Michael R. Gallis | Michael R. Gallis | The Emergence of Classicality via Decoherence: Beyond the
Caldeira-Legget Environment | LaTeX, 5 pages, (to appear in Proceedings of the 4th Drexel Symposium
on Quantum Nonintegrability) | null | null | null | quant-ph | null | Maximally predictive states, as defined in recent work by Zurek, Habib and
Paz, are studied for more elaborate environment models than a linear coupling.
An environment model which includes spatial correlations in the noise is
considered in the non-dissipative regime. The Caldeira-Leggett model is also
reconsidered in the context of an averaging procedure which produces a
completely positive form for the quantum master equation. In both cases, the
maximally predictive states for the harmonic oscillator are the coherent
states, which is the same result found by Zurek,Habib and Paz for the
Caldeira-Legget environment.
| [
{
"version": "v1",
"created": "Thu, 22 Dec 1994 18:15:00 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Gallis",
"Michael R.",
""
]
] |
quant-ph/9412003 | Ulf Danielsson | Ulf H. Danielsson (Institute for Theoretical Physics, Uppsala
University) | String Theory, Black Holes and Klein's Lemma | 17 pages, Latex | null | null | UUITP-20/94 | quant-ph | null | This is a writeup of a talk given at the Oskar Klein Centenery Symposium,
Stockholm, September 19-21, 1994. It is an essay on the black hole information
paradox and its connection with thermodynamics and the foundations of quantum
mechanics.
| [
{
"version": "v1",
"created": "Fri, 23 Dec 1994 13:39:50 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Danielsson",
"Ulf H.",
"",
"Institute for Theoretical Physics, Uppsala\n University"
]
] |
quant-ph/9412004 | Karl Svozil | C. Calude, D. I. Campbell, K. Svozil and D. \c{S}tef\u{a}necu | Strong Determinism vs. Computability | 13 pages, LaTeX | The Foundational Debate. Complexity and Constructivity in
Mathematics and Physics. Vienna Circle Institute Yearbook, Vol. 3, ed. by
Werner DePauli Schimanovich, Eckehart Koehler and Friedrich Stadler (Kluwer,
Dordrecht, Boston, London, 1995), p. 115-131. | null | null | quant-ph chao-dyn nlin.CD | null | Are minds subject to laws of physics? Are the laws of physics computable? Are
conscious thought processes computable? Currently there is little agreement as
to what are the right answers to these questions. Penrose goes one step further
and asserts that: {\it a radical new theory is indeed needed, and I am
suggesting, moreover, that this theory, when it is found, will be of an
essentially non-computational character.} The aim of this paper is three fold:
1) to examine the incompatibility between the hypothesis of strong determinism
and computability, 2) to give new examples of uncomputable physical laws, and
3) to discuss the relevance of G\"odel's Incompleteness Theorem in refuting the
claim that an algorithmic theory---like strong AI---can provide an adequate
theory of mind. Finally, we question the adequacy of the theory of computation
to discuss physical laws and thought processes.
| [
{
"version": "v1",
"created": "Fri, 23 Dec 1994 17:45:06 GMT"
}
] | 2010-03-17T00:00:00 | [
[
"Calude",
"C.",
""
],
[
"Campbell",
"D. I.",
""
],
[
"Svozil",
"K.",
""
],
[
"Ştefănecu",
"D.",
""
]
] |
quant-ph/9412005 | null | Zhong-Qi Ma (CCAST and Institute of High Energy Physics, Beijing) | On the Stronger Statement of Levinson's Theorem for the Dirac Equation | null | null | null | null | quant-ph | null | Recently a stronger statement of Levinson's theorem for the Dirac equation
was presented, where the limits of the phase shifts at $E=\pm M$ are related to
the numbers of nodes of radial functions at the same energies, respectively.
However, in this letter we show that this statement has to be modified because
the limits of the phase shifts may be negative for the Dirac equation.
| [
{
"version": "v1",
"created": "Mon, 26 Dec 1994 14:46:37 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ma",
"Zhong-Qi",
"",
"CCAST and Institute of High Energy Physics, Beijing"
]
] |
quant-ph/9412006 | Asher Peres | Michael Kernaghan and Asher Peres | Kochen-Specker theorem for 8-dimensional space | LaTeX 8 pages | Phys.Lett. A198 (1995) 1-5 | 10.1016/0375-9601(95)00012-R | null | quant-ph | null | A Kochen-Specker contradiction is produced with 36 vectors in a real
8-dimensional Hilbert space. These vectors can be combined into 30 distinct
projection operators (14 of rank 2, and 16 of rank 1). A state-specific variant
of this contradiction requires only 13 vectors, a remarkably low number for 8
dimensions.
| [
{
"version": "v1",
"created": "Mon, 26 Dec 1994 07:21:13 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Kernaghan",
"Michael",
""
],
[
"Peres",
"Asher",
""
]
] |
quant-ph/9412007 | Asher Peres | Ofir E. Alon, Nimrod Moiseyev, and Asher Peres | Infinite matrices may violate the associative law | final version in J. Phys. A28 (1995) 1765-1770 | J.Phys. A28 (1995) 1765-1770 | 10.1088/0305-4470/28/6/027 | null | quant-ph | null | The momentum operator for a particle in a box is represented by an infinite
order Hermitian matrix $P$. Its square $P^2$ is well defined (and diagonal),
but its cube $P^3$ is ill defined, because $P P^2\neq P^2 P$. Truncating these
matrices to a finite order restores the associative law, but leads to other
curious results.
| [
{
"version": "v1",
"created": "Mon, 26 Dec 1994 11:30:51 GMT"
},
{
"version": "v2",
"created": "Thu, 10 Sep 1998 13:48:25 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Alon",
"Ofir E.",
""
],
[
"Moiseyev",
"Nimrod",
""
],
[
"Peres",
"Asher",
""
]
] |
quant-ph/9412008 | null | M. Khorrami | A general formulation of discrete-time quantum mechanics, restrictions
on the action and the relation of unitarity to the existence theorem for
initial-value problems | 13 pages, TeX | Annals Phys. 244 (1995) 101-111 | 10.1006/aphy.1995.1108 | IPM-94-073, TUDP 94-3, IASBS 94-7 | quant-ph | null | A general formlulation for discrete-time quantum mechanics, based on
Feynman's method in ordinary quantum mechanics, is presented. It is shown that
the ambiguities present in ordinary quantum mechanics (due to noncommutativity
of the operators), are no longer present here. Then the criteria for the
unitarity of the evolution operator is examined. It is shown that the unitarity
of the evolution operator puts restrictions on the form of the action, and also
implies the existence of a solution for the classical initial-value problem.
| [
{
"version": "v1",
"created": "Wed, 28 Dec 1994 08:16:58 GMT"
}
] | 2015-06-26T00:00:00 | [
[
"Khorrami",
"M.",
""
]
] |
quant-ph/9412009 | Wolfgang Scherer | Wolfgang Scherer | Superconvergent Perturbation Method in Quantum Mechanics | 11 pages, LaTeX | Phys.Rev.Lett.74:1495-1499,1995 | 10.1103/PhysRevLett.74.1495 | ASI-TPA/17/94 | quant-ph | null | An analogue of Kolmogorov's superconvergent perturbation theory in classical
mechanics is constructed for self adjoint operators. It is different from the
usual Rayleigh--Schr\"odinger perturbation theory and yields expansions for
eigenvalues and eigenvectors in terms of functions of the perturbation
parameter.
| [
{
"version": "v1",
"created": "Fri, 30 Dec 1994 12:31:04 GMT"
}
] | 2009-01-23T00:00:00 | [
[
"Scherer",
"Wolfgang",
""
]
] |
quant-ph/9412010 | Wolfgang Scherer | Wolfgang Scherer | Quantum Averaging I: Poincar\'e--von Zeipel is Rayleigh--Schr\"odinger | 12 pages, LaTeX, to appear in Journ. Phys. A | J.Phys. A27 (1994) 8231-8246 | 10.1088/0305-4470/27/24/028 | ASI-TPA/16/94 | quant-ph | null | An exact analogue of the method of averaging in classical mechanics is
constructed for self--adjoint operators. It is shown to be completely
equivalent to the usual Rayleigh--Schr\"odinger perturbation theory but gives
the sums over intermediate states in closed form expressions. The anharmonic
oscillator and the Henon--Heiles system are treated as examples to illustrate
the quantum averaging method.
| [
{
"version": "v1",
"created": "Fri, 30 Dec 1994 12:54:24 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Scherer",
"Wolfgang",
""
]
] |
quant-ph/9412011 | Arvind | Arvind, B. Dutta, N. Mukunda and R. Simon | Two Mode Quantum Systems: Invariant Classification of Squeezing
Transformations and Squeezed States | Revtex 37 pages, Latex figures included | Phys. Rev. A 52, 1609 (1995) | 10.1103/PhysRevA.52.1609 | null | quant-ph | null | A general analysis of squeezing transformations for two mode systems is given
based on the four dimensional real symplectic group $Sp(4,\Re)\/$. Within the
framework of the unitary metaplectic representation of this group, a
distinction between compact photon number conserving and noncompact photon
number nonconserving squeezing transformations is made. We exploit the
$Sp(4,\Re)-SO(3,2)\/$ local isomorphism and the $U(2)\/$ invariant squeezing
criterion to divide the set of all squeezing transformations into a two
parameter family of distinct equivalence classes with representative elements
chosen for each class. Familiar two mode squeezing transformations in the
literature are recognized in our framework and seen to form a set of measure
zero. Examples of squeezed coherent and thermal states are worked out. The need
to extend the heterodyne detection scheme to encompass all of $U(2)\/$ is
emphasized, and known experimental situations where all $U(2)\/$ elements can
be reproduced are briefly described.
| [
{
"version": "v1",
"created": "Sat, 31 Dec 1994 10:18:28 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Arvind",
"",
""
],
[
"Dutta",
"B.",
""
],
[
"Mukunda",
"N.",
""
],
[
"Simon",
"R.",
""
]
] |
quant-ph/9412012 | Daniel C. Galehouse | Daniel C. Galehouse | Quantization Failure in Unified Field Theories | 10 pages, latex/revtex, no figures | null | null | QFUFT-6.0-12/26/94 | quant-ph gr-qc | null | Studies of geometrical theories suggest that fundmental problems of
quantization arise from the disparate usage of displacement operators. These
may be the source of a concealed inconsistency in the accepted formalism of
quantum physics. General relativity and related theories cannot be quantized by
the classical procedure. It is necessary to avoid the construction of
differential equations by operators applied algebraically. For such theories,
Von Neumann's theorem concerning hidden variables is avoided. A specified
alternative class of gravitational-quantum-electrodynamic theories is possible.
| [
{
"version": "v1",
"created": "Sun, 1 Jan 1995 05:47:55 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Galehouse",
"Daniel C.",
""
]
] |
quant-ph/9501001 | null | Lajos Diosi and B. Lukacs | Critique of proposed limit to space--time measurement, based on Wigner's
clocks and mirrors | 5 pages, LaTex, field "Author:" corrected | Europhys.Lett.34:479-481,1996 | 10.1209/epl/i1996-00482-6 | null | quant-ph | null | Based on a relation between inertial time intervals and the Riemannian
curvature, we show that space--time uncertainty derived by Ng and van Dam
implies absurd uncertainties of the Riemannian curvature.
| [
{
"version": "v1",
"created": "Wed, 4 Jan 1995 12:17:00 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Jan 1995 13:06:00 GMT"
},
{
"version": "v3",
"created": "Fri, 6 Jan 1995 12:26:00 GMT"
}
] | 2010-12-17T00:00:00 | [
[
"Diosi",
"Lajos",
""
],
[
"Lukacs",
"B.",
""
]
] |
quant-ph/9501002 | Lev Vaidman | Y. Aharonov and L. Vaidman | RESOLUTION OF A ``RETRODICTION PARADOX'' | 4 pages | null | null | TAUP 2213-94 | quant-ph | null | It is shown that the ``retrodiction paradox'' recently introduced by Peres
arises not because of the fallacy of the time-symmetric approach as he claimed,
but due to an inappropriate usage of retrodiction.
| [
{
"version": "v1",
"created": "Wed, 4 Jan 1995 14:38:37 GMT"
},
{
"version": "v2",
"created": "Tue, 7 Mar 1995 09:02:45 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Aharonov",
"Y.",
""
],
[
"Vaidman",
"L.",
""
]
] |
quant-ph/9501003 | Lev Vaidman | L. Vaidman | NONLOCALITY OF A SINGLE PHOTON REVISITED AGAIN | 5 pages, LaTeX | Phys.Rev.Lett. 75 (1995) 2063 | 10.1103/PhysRevLett.75.2063 | TAUP 2214-94 | quant-ph | null | Comment on L. Hardy, Phys. Rev. Lett. {\bf 73}, 2279 (1994). It is argued
that the experiment proposed by Hardy should not be considered as a single
photon experiment.
| [
{
"version": "v1",
"created": "Wed, 4 Jan 1995 14:41:43 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Vaidman",
"L.",
""
]
] |
quant-ph/9501004 | null | Claus Kiefer | Irreversibility in quantum field theory | 7 pages, LATEX, Contribution to the Clausthal-Symposium (August 1994) | null | null | Freiburg THEP-95/2 | quant-ph hep-th | null | It is shown how the programme of decoherence can be applied in the context of
quantum field theory. To illustrate the role of gauge invariance, we first
discuss the charge superselection rule in quantum electrodynamics in some
detail. We then present an example where macroscopic electromagnetic fields are
``measured" through interaction with charges and thereby rendered classical.
| [
{
"version": "v1",
"created": "Wed, 4 Jan 1995 15:02:52 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Kiefer",
"Claus",
""
]
] |
quant-ph/9501005 | Asher Peres | Asher Peres | Reply to the comment of Y. Aharonov and L. Vaidman on ``Time asymmetry
in quantum mechanics: a retrodiction paradox'' | final version in Physics Letters A 203 (1995) 150 | null | 10.1016/0375-9601(95)00395-J | null | quant-ph | null | In the standard physical interpretation of quantum theory, prediction and
retrodiction are not symmetric. The opposite assertion by some authors results
from their use of non-standard interpretations of the theory.
| [
{
"version": "v1",
"created": "Thu, 5 Jan 1995 16:00:03 GMT"
},
{
"version": "v2",
"created": "Thu, 24 Sep 1998 13:29:21 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Peres",
"Asher",
""
]
] |
quant-ph/9501006 | Lev Vaidman | Y. Aharonov, S. Popsecu, and L. Vaidman | CAUSALITY, MEMORY ERASING AND DELAYED CHOICE EXPERIMENTS | 4 pages, LaTeX | null | 10.1103/PhysRevA.52.4984 | TAUP 2223-95 | quant-ph | null | Comment on [R.L. Ingraham, Phys. Rev. A 50, 4502 (1994)]. Ingraham suggested
``a delayed-choice experiment with partial, controllable memory erasing''. It
is shown that he cannot be right since his predictions contradict relativistic
causality. A subtle quantum effect which was overlooked by Ingraham is
explained.
| [
{
"version": "v1",
"created": "Sun, 8 Jan 1995 15:57:50 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Aharonov",
"Y.",
""
],
[
"Popsecu",
"S.",
""
],
[
"Vaidman",
"L.",
""
]
] |
quant-ph/9501007 | Marek Czachor | Marek Czachor | Nonlinear Schroedinger equation and two-level atoms | null | null | 10.1103/PhysRevA.53.1310 | null | quant-ph | null | General features of nonlinear quantum mechanics are discussed in the context
of applications to two-level atoms.
| [
{
"version": "v1",
"created": "Mon, 9 Jan 1995 00:01:40 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Czachor",
"Marek",
""
]
] |
quant-ph/9501008 | Marek Czachor | Marek Czachor | Triple bracket generalization of quantum mechanics | null | null | null | null | quant-ph | null | An extension of the Liouville-von Neumann dynamics to a Nambu-type dynamics
is proposed. The resulting theory is the first version of nonlinear QM which is
free from internal inconsistencies.
| [
{
"version": "v1",
"created": "Mon, 9 Jan 1995 00:14:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Czachor",
"Marek",
""
]
] |
quant-ph/9501009 | null | Lajos Diosi | Selective continuous quantum measurements: Restricted path integrals and
wave equations | 5 pages, LaTex | null | null | null | quant-ph | null | We discuss both the restricted path integral (RPI) and the wave equation (WE)
techniques in the theory of continuous quantum measurements. We intend to make
Mensky's fresh review complete by transforming his "effective" WE with complex
Hamiltonian into Ito-differential equations.
| [
{
"version": "v1",
"created": "Tue, 10 Jan 1995 15:51:00 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Diosi",
"Lajos",
""
]
] |
quant-ph/9501010 | null | S. De Martino, S. De Siena and F. Illuminati | Dymanics of Generalized Coherent States | 8 pages, plain latex, no figures | Mod.Phys.Lett. B9 (1995) 823 | 10.1142/S0217984995000772 | DFPD 94/TH/66, December 1994 | quant-ph cond-mat hep-th | null | We show that generalized coherent states follow Schr\"{o}dinger dynamics in
time-dependent potentials. The normalized wave-packets follow a classical
evolution without spreading; in turn, the Schr\"{o}dinger potential depends on
the state through the classical trajectory. This feedback mechanism with
continuous dynamical re-adjustement allows the packets to remain coherent
indefinetely.
| [
{
"version": "v1",
"created": "Tue, 10 Jan 1995 13:35:36 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"De Martino",
"S.",
""
],
[
"De Siena",
"S.",
""
],
[
"Illuminati",
"F.",
""
]
] |
quant-ph/9501011 | Benni Reznik | B. Reznik and Y. Aharonov | On a Time Symmetric Formulation of Quantum Mechanics | LaTex, 44 pages, 4 figures included. Figure captions and related text
in sections 3.1, 4.2 are revised. A paragraph in pages 9-10 about non-generic
two-states is clarified. Footnotes added | Phys. Rev. A 52, 2538 (1995). | 10.1103/PhysRevA.52.2538 | TP-94-010, TAUP-2200-94 | quant-ph hep-th | null | We explore further the suggestion to describe a pre- and post-selected system
by a two-state, which is determined by two conditions. Starting with a formal
definition of a two-state Hilbert space and basic operations, we systematically
recast the basics of quantum mechanics - dynamics, observables, and measurement
theory - in terms of two-states as the elementary quantities. We find a simple
and suggestive formulation, that ``unifies'' two complementary observables:
probabilistic observables and non-probabilistic `weak' observables.
Probabilities are relevant for measurements in the `strong coupling regime'.
They are given by the absolute square of a two-amplitude (a projection of a
two-state). Non-probabilistic observables are observed in sufficiently `weak'
measurements, and are given by linear combinations of the two-amplitude. As a
sub-class they include the `weak values' of hermitian operators. We show that
in the intermediate regime, one may observe a mixing of probabilities and weak
values. A consequence of the suggested formalism and measurement theory, is
that the problem of non-locality and Lorentz non-covariance, of the usual
prescription with a `reduction', may be eliminated. We exemplify this point for
the EPR experiment and for a system under successive observations.
| [
{
"version": "v1",
"created": "Fri, 13 Jan 1995 03:11:48 GMT"
},
{
"version": "v2",
"created": "Thu, 11 May 1995 01:16:34 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Reznik",
"B.",
""
],
[
"Aharonov",
"Y.",
""
]
] |
quant-ph/9501012 | null | Murray Peshkin (Argonne), H. J. Lipkin (Weizmann) | Topology, Locality, and Aharonov-Bohm Effect with Neutrons | 9 pages | Phys.Rev.Lett. 74 (1995) 2847-2850 | 10.1103/PhysRevLett.74.2847 | PHY-7841-TH-94 (Argonne), WIS-94/31/July-PH (Weizmann) | quant-ph hep-th | null | Recent neutron interferometry experiments have been interpreted as
demonstrating a new topological phenomenon similar in principle to the usual
Aharonov-Bohm (AB) effect, but with the neutron's magnetic moment replacing the
electron's charge. We show that the new phenomenon, called Scalar AB (SAB)
effect, follows from an ordinary local interaction, contrary to the usual AB
effect, and we argue that the SAB effect is not a topological effect by any
useful definition. We find that SAB actually measures an apparently novel spin
autocorrelation whose operator equations of motion contain the local torque in
the magnetic field. We note that the same remarks apply to the Aharonov-Casher
effect.
| [
{
"version": "v1",
"created": "Fri, 13 Jan 1995 16:56:00 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Peshkin",
"Murray",
"",
"Argonne"
],
[
"Lipkin",
"H. J.",
"",
"Weizmann"
]
] |
quant-ph/9501013 | Aephraim Steinberg | Aephraim M. Steinberg, Raymond Y. Chiao | Sub-femtosecond determination of transmission delay times for a
dielectric mirror (photonic bandgap) as a function of angle of incidence | 5 pages and 5 figures | null | 10.1103/PhysRevA.51.3525 | null | quant-ph | null | Using a two-photon interference technique, we measure the delay for
single-photon wavepackets to be transmitted through a multilayer dielectric
mirror, which functions as a ``photonic bandgap'' medium. By varying the angle
of incidence, we are able to confirm the behavior predicted by the group delay
(stationary phase approximation), including a variation of the delay time from
superluminal to subluminal as the band edge is tuned towards to the wavelength
of our photons. The agreement with theory is better than 0.5 femtoseconds (less
than one quarter of an optical period) except at large angles of incidence. The
source of the remaining discrepancy is not yet fully understood.
| [
{
"version": "v1",
"created": "Mon, 16 Jan 1995 11:11:10 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Steinberg",
"Aephraim M.",
""
],
[
"Chiao",
"Raymond Y.",
""
]
] |
quant-ph/9501014 | Zvi Schreiber | Zvi Schreiber | The Nine Lives of Schroedinger's Cat | LaTeX + 2 PostScript figures. Uses amstex and epsf.sty. Imperial
College MSc dissertation | null | null | null | quant-ph | null | This MSc dissertation surveys nine interpretations of non-relativistic
quantum mechanics. Extensive references are given. The interpretations covered
are: the orthodox interpretation, Bohr's interpretation, the idea that the mind
causes collapse, hidden variables, the many-worlds interpretation, the
many-minds interpretation, Bohm's interpretation and two interpretations based
on decoherent histories.
| [
{
"version": "v1",
"created": "Mon, 16 Jan 1995 08:13:25 GMT"
},
{
"version": "v2",
"created": "Tue, 17 Jan 1995 09:55:49 GMT"
},
{
"version": "v3",
"created": "Thu, 19 Jan 1995 14:54:13 GMT"
},
{
"version": "v4",
"created": "Thu, 26 Jan 1995 21:32:11 GMT"
},
{
"version": "v5",
"created": "Fri, 27 Jan 1995 14:14:43 GMT"
}
] | 2008-02-03T00:00:00 | [
[
"Schreiber",
"Zvi",
""
]
] |
quant-ph/9501015 | Aephraim Steinberg | Aephraim M. Steinberg | How much time does a tunneling particle spend in the barrier region? | 5 pages; no figures | Phys.Rev.Lett.74:2405-2409,1995 | 10.1103/PhysRevLett.74.2405 | null | quant-ph | null | The question in the title may be answered by considering the outcome of a
``weak measurement'' in the sense of Aharonov et al. Various properties of the
resulting time are discussed, including its close relation to the Larmor times.
It is a universal description of a broad class of measurement interactions, and
its physical implications are unambiguous.
| [
{
"version": "v1",
"created": "Tue, 17 Jan 1995 20:01:22 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Steinberg",
"Aephraim M.",
""
]
] |
quant-ph/9501016 | Aephraim Steinberg | Raymond Y. Chiao, Paul G. Kwiat, Aephraim M. Steinberg | Quantum Nonlocality in Two-Photon Experiments at Berkeley | 16 pages including 24 figures | null | 10.1088/1355-5111/7/3/006 | null | quant-ph | null | We review some of our experiments performed over the past few years on
two-photon interference. These include a test of Bell's inequalities, a study
of the complementarity principle, an application of EPR correlations for
dispersion-free time-measurements, and an experiment to demonstrate the
superluminal nature of the tunneling process. The nonlocal character of the
quantum world is brought out clearly by these experiments. As we explain,
however, quantum nonlocality is not inconsistent with Einstein causality.
| [
{
"version": "v1",
"created": "Wed, 18 Jan 1995 13:16:57 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Chiao",
"Raymond Y.",
""
],
[
"Kwiat",
"Paul G.",
""
],
[
"Steinberg",
"Aephraim M.",
""
]
] |
quant-ph/9501017 | Marek Czachor | M. Czachor and A. Posiewnik | What happens to spin during the SO(3)->SE(2) contraction? (On spin and
extended structures in quantum mechanics) | 6 pages, REVTeX | null | null | null | quant-ph | null | It is shown that the spin operator can be described by an algebra which is in
between so(3) and e(2). Relativistic version of the singlet state for two Dirac
electrons is discussed. It is shown that a measure of massless particle's
extension can be naturally constructed and that this measure corresponds at the
classical level to the radius of the Robinson congruence.
| [
{
"version": "v1",
"created": "Wed, 18 Jan 1995 23:51:59 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Czachor",
"M.",
""
],
[
"Posiewnik",
"A.",
""
]
] |
quant-ph/9501018 | null | N.Brunner, K.Svozil and M.Baaz | Effective Quantum Observables | TeX-file, 32 pages | NuovoCim.B110:1397-1414,1995 | 10.1007/BF02849839 | null | quant-ph | null | Thought experiments about the physical nature of set theoretical
counterexamples to the axiom of choice motivate the investigation of peculiar
constructions, e.g. an infinite dimensional Hilbert space with a modular
quantum logic. Applying a concept due to BENIOFF, we identify the intrinsically
effective Hamiltonians with those observables of quantum theory which may
coexist with a failure of the axiom of choice. Here a self adjoint operator is
intrinsically effective, iff the Schroedinger equation of its generated
semigroup is soluble by means of eigenfunction series expansions.
| [
{
"version": "v1",
"created": "Mon, 23 Jan 1995 11:45:36 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Brunner",
"N.",
""
],
[
"Svozil",
"K.",
""
],
[
"Baaz",
"M.",
""
]
] |
quant-ph/9501019 | Asher Peres | Asher Peres | Nonlocal effects in Fock space | final version in PRL 74 (1995) 4571; 76 (1996) 2205 (erratum) | Phys.Rev.Lett. 74 (1995) 4571; Erratum-ibid. 76 (1996) 2205 | 10.1103/PhysRevLett.74.4571 | null | quant-ph | null | If a physical system contains a single particle, and if two distant detectors
test the presence of linear superpositions of one-particle and vacuum states, a
violation of classical locality can occur. It is due to the creation of a
two-particle component by the detecting process itself.
| [
{
"version": "v1",
"created": "Wed, 25 Jan 1995 07:52:34 GMT"
},
{
"version": "v2",
"created": "Wed, 16 Sep 1998 12:20:01 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Peres",
"Asher",
""
]
] |
quant-ph/9501020 | Sandu Popescu | Sandu Popescu | An optical method for teleportation | minor changes and a reference added | null | null | null | quant-ph | null | A teleportation method using standard present day optical technology is
presented.
| [
{
"version": "v1",
"created": "Thu, 26 Jan 1995 14:11:15 GMT"
},
{
"version": "v2",
"created": "Sun, 29 Jan 1995 15:19:26 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Popescu",
"Sandu",
""
]
] |
quant-ph/9501021 | null | A. Venugopalan, Deepak Kumar and R. Ghosh | Effect of Decoherence on Bell's Inequality for an EPR Pair | 5 pages, revtex, no figures | null | null | SPS-JNU preprint | quant-ph | null | According to Bell's theorem, the degree of correlation between spatially
separated measurements on a quantum system is limited by certain inequalities
if one assumes the condition of locality. Quantum mechanics predicts that this
limit can be exceeded, making it nonlocal. We analyse the effect of an
environment modelled by a fluctuating magnetic field on the quantum
correlations in an EPR singlet as seen in the Bell inequality. We show that in
an EPR setup, the system goes from the usual 'violation' of Bell inequality to
a 'non-violation' for times larger than a characteristic time scale which is
related to the parameters of the fluctuating field. We also look at these
inequalities as a function of the spatial separation between the EPR pair.
| [
{
"version": "v1",
"created": "Fri, 27 Jan 1995 16:52:58 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Venugopalan",
"A.",
""
],
[
"Kumar",
"Deepak",
""
],
[
"Ghosh",
"R.",
""
]
] |
quant-ph/9501022 | null | A. Venugopalan, Deepak Kumar and R. Ghosh | Analysis of the Stern-Gerlach Measurement | 6 pages, revtex, 3 post script figures available on request | null | null | SPS-JNU preprint | quant-ph | null | A dynamical model for the collapse of the wave function in a quantum
measurement process is proposed by considering the interaction of a quantum
system (spin-1/2) with a macroscopic quantum apparatus interacting with an
environment in a dissipative manner. The dissipative interaction leads to
decoherence in the superposition states of the apparatus, making its behaviour
classical in the sense that the density matrix becomes diagonal with time.
Since the apparatus is also interacting with the system, the probabilities of
the diagonal density matrix are determined by the state vector of the system.
We consider a Stern-Gerlach type model, where a spin- 1/2 particle is in an
inhomogeneous magnetic field, the whole set up being in contact with a large
environment. Here we find that the density matrix of the combined system and
apparatus becomes diagonal and the momentum of the particle becomes correlated
with a spin operator, selected by the choice of the system-apparatus
interaction. This allows for a measurement of spin via a momentum measurement
on the particle with associated probabilities in accordance with quantum
principles.
| [
{
"version": "v1",
"created": "Fri, 27 Jan 1995 16:51:09 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Venugopalan",
"A.",
""
],
[
"Kumar",
"Deepak",
""
],
[
"Ghosh",
"R.",
""
]
] |
quant-ph/9501023 | Benni Reznik | B. Reznik | Interaction with a pre and post selected environment and recoherence | 17 pages, Latex. | null | null | TP-001-95 | quant-ph gr-qc hep-th | null | The interaction of an open system $\s$ with a pre- and post-selected
environment is studied. In general, under such circumstances $\s$ can not be
described in terms of a density matrix, {\it even when $\s$ in not
post-selected}. However, a simple description in terms of a two-state (TS) is
always available. The two-state of $\s$ evolves in time from an initially
`pure' TS to a `mixed' TS and back to a final `pure' TS. This generic process
is governed by a modified Liouville equation, which is derived. For a sub-class
of observables, which can still be described by an ordinary density matrix,
this evolution generates recoherence to a final pure state. In some cases
post-selection can even suppress any decoherence.
| [
{
"version": "v1",
"created": "Tue, 31 Jan 1995 00:16:40 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Reznik",
"B.",
""
]
] |
quant-ph/9502001 | null | T. Calarco, R. Onofrio | Optimal Measurements of Magnetic Flux in Superconducting Circuits and
Macroscopic Quantum Mechanics | 11 pages (no figures), to be published in Physics Letters A | Phys. Lett. A 198 (1995) 279 | 10.1016/0375-9601(94)01020-U | DFPD 95/GP/01 | quant-ph | null | A model of repeated quantum measurements of magnetic flux in superconducting
circuits manifesting tunneling is discussed. The perturbation due to the
previous measurements of magnetic flux is always present unless quantum
nondemolition measurements are performed. By replacing the classical notion of
noninvasivity with this condition, temporal Bell-like inequalities allows one
to test the observability at the macroscopic level of the conflict between
realism and quantum theory.
| [
{
"version": "v1",
"created": "Wed, 1 Feb 1995 11:11:32 GMT"
}
] | 2009-10-28T00:00:00 | [
[
"Calarco",
"T.",
""
],
[
"Onofrio",
"R.",
""
]
] |
quant-ph/9502002 | Satoshi Uchiyama | S. Uchiyama (Hokkaido University) | Cannot Local Reality Exist in the EPR-Bohm Gedankenexperiment ? | 13 pages, phyzzx, six figures available upon request. | null | 10.1007/BF02055508 | EPHOU-94-006 | quant-ph | null | We model measuring processes of a single spin-1/2 object and of a pair of
spin-1/2 objects in the EPR-Bohm state by systems of differential equations.
Our model is a local model with hidden-variables of the EPR-Bohm
Gedankenexperiment. Although there is no dynamical interaction between a pair
of spin-1/2 objects, the model can reproduce approximately the
quantum-mechanical correlations by the coincidence counting. Hence the Bell
inequality is violated. This result supports the idea that the coincidence
counting is the source of the non-locality in the EPR-Bohm Gedankenexperiment.
| [
{
"version": "v1",
"created": "Thu, 2 Feb 1995 06:24:32 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Uchiyama",
"S.",
"",
"Hokkaido University"
]
] |
quant-ph/9502003 | Aephraim M. Steinberg | Aephraim M. Steinberg | Conditional probabilities in quantum theory, and the tunneling time
controversy | 11 pages, latex, 4 postscript figures separate (one w/ 3 parts) | Phys.Rev.A52:32-42,1995 | 10.1103/PhysRevA.52.32 | null | quant-ph | null | It is argued that there is a sensible way to define conditional probabilities
in quantum mechanics, assuming only Bayes's theorem and standard quantum
theory. These probabilities are equivalent to the ``weak measurement''
predictions due to Aharonov {\it et al.}, and hence describe the outcomes of
real measurements made on subensembles. In particular, this approach is used to
address the question of the history of a particle which has tunnelled across a
barrier. A {\it gedankenexperiment} is presented to demonstrate the physically
testable implications of the results of these calculations, along with graphs
of the time-evolution of the conditional probability distribution for a
tunneling particle and for one undergoing allowed transmission. Numerical
results are also presented for the effects of loss in a bandgap medium on
transmission and on reflection, as a function of the position of the lossy
region; such loss should provide a feasible, though indirect, test of the
present conclusions. It is argued that the effects of loss on the pulse {\it
delay time} are related to the imaginary value of the momentum of a tunneling
particle, and it is suggested that this might help explain a small discrepancy
in an earlier experiment.
| [
{
"version": "v1",
"created": "Thu, 2 Feb 1995 22:17:17 GMT"
}
] | 2016-09-08T00:00:00 | [
[
"Steinberg",
"Aephraim M.",
""
]
] |
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