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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
quant-ph/0703017 | V. Ravishankar | Shanthanu Bhardwaj and V. Ravishankar | A complete characterization of mixed state entanglement using
probability density functions | four pages, four figures | null | null | null | quant-ph cond-mat.other hep-th | null | We propose that the entanglement of mixed states is characterised properly in
terms of a probability density function $\mathcal{P}(\mathcal{E})$. There is a
need for such a measure since the prevalent measures (such as
\textit{concurrence} and \textit{negativity}) are rough benchmarks, and not
monotones of each other. Considering the specific case of two qubit mixed
states, we provide an explicit construction of $\mathcal{P}(\mathcal{E})$ and
show that it is characterised by a set of parameters, of which concurrence is
but one particular combination. $\mathcal{P}(\mathcal{E})$ is manifestly
invariant under $SU(2) \times SU(2)$ transformations. It can, in fact,
reconstruct the state up to local operations
- with the specification of at most four additional parameters. Finally the
new measure resolves the controversy regarding the role of entanglement in
quantum computation in NMR systems.
| [
{
"version": "v1",
"created": "Fri, 2 Mar 2007 11:55:10 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Apr 2007 11:58:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Bhardwaj",
"Shanthanu",
""
],
[
"Ravishankar",
"V.",
""
]
] |
quant-ph/0703018 | Mafalda Almeida | Mafalda L. Almeida, Stefano Pironio, Jonathan Barrett, Geza Toth,
Antonio Acin | Noise robustness of the nonlocality of entangled quantum states | 5 pages, no figures. It contains only minor changes, published
version | Phys. Rev. Lett. 99, 040403 (2007) | 10.1103/PhysRevLett.99.040403 | null | quant-ph | null | We study the nonlocal properties of states resulting from the mixture of an
arbitrary entangled state rho of two d-dimensional systems and completely
depolarized noise, with respective weights p and 1-p. We first construct a
local model for the case in which rho is maximally entangled and p at or below
a certain bound. We then extend the model to arbitrary rho. Our results provide
bounds on the resistance to noise of the nonlocal correlations of entangled
states. For projective measurements, the critical value of the noise parameter
p for which the state becomes local is at least asymptotically log(d) larger
than the critical value for separability.
| [
{
"version": "v1",
"created": "Fri, 2 Mar 2007 14:26:52 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 10:50:55 GMT"
}
] | 2007-08-02T00:00:00 | [
[
"Almeida",
"Mafalda L.",
""
],
[
"Pironio",
"Stefano",
""
],
[
"Barrett",
"Jonathan",
""
],
[
"Toth",
"Geza",
""
],
[
"Acin",
"Antonio",
""
]
] |
quant-ph/0703019 | Guo-Feng Zhang Dr | Guo-Feng Zhang | Thermal entanglement and teleportation in a two-qubit Heisenberg chain
with Dzyaloshinski-Moriya anisotropic antisymmetric interaction | 1 tex;5eps. accepted by Physical Review A | Physical Review A 75, 034304 (2007) | 10.1103/PhysRevA.75.034302 | null | quant-ph | null | Thermal entanglement of a two-qubit Heisenberg chain in presence of the
Dzyaloshinski-Moriya (DM) anisotropic antisymmetric interaction and
entanglement teleportation when using two independent Heisenberg chains as
quantum channel are investigated. It is found that the DM interaction can
excite the entanglement and teleportation fidelity. The output entanglement
increases linearly with increasing value of input one, its dependences on the
temperature, DM interaction and spin coupling constant are given in detail.
Entanglement teleportation will be better realized via antiferromagnetic spin
chain when the DM interaction is turned off and the temperature is low.
However, the introduction of DM interaction can cause the ferromagnetic spin
chain to be a better quantum channel for teleportation. A minimal entanglement
of the thermal state in the model is needed to realize the entanglement
teleportation regardless of antiferromagnetic or ferromagnetic spin chains.
| [
{
"version": "v1",
"created": "Fri, 2 Mar 2007 15:18:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhang",
"Guo-Feng",
""
]
] |
quant-ph/0703020 | Dennis Dieks | Dennis Dieks | Probability in modal interpretations of quantum mechanics | null | null | null | null | quant-ph | null | Modal interpretations have the ambition to construe quantum mechanics as an
objective, man-independent description of physical reality. Their second
leading idea is probabilism: quantum mechanics does not completely fix physical
reality but yields probabilities. In working out these ideas an important motif
is to stay close to the standard formalism of quantum mechanics and to refrain
from introducing new structure by hand. In this paper we explain how this
programme can be made concrete. In particular, we show that the Born
probability rule, and sets of definite-valued observables to which the Born
probabilities pertain, can be uniquely defined from the quantum state and
Hilbert space structure. We discuss the status of probability in modal
interpretations, and to this end we make a comparison with many-worlds
alternatives. An overall point that we stress is that the modal ideas define a
general framework and research programme rather than one definite and finished
interpretation.
| [
{
"version": "v1",
"created": "Fri, 2 Mar 2007 15:38:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Dieks",
"Dennis",
""
]
] |
quant-ph/0703021 | Dennis Dieks | Dennis Dieks and Marijn Versteegh | Identical Quantum Particles and Weak Discernibility | null | null | 10.1007/s10701-008-9243-z | null | quant-ph | null | We examine a recent argument that ``identical'' quantum particles with an
anti-symmetric state (fermions) are weakly discernible objects, just like
irreflexively related ordinary objects in situations with perfect symmetry
(Black's spheres, for example). We conclude that the argument uses a silent
premise that is not justified in the quantum case.
| [
{
"version": "v1",
"created": "Fri, 2 Mar 2007 15:44:16 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dieks",
"Dennis",
""
],
[
"Versteegh",
"Marijn",
""
]
] |
quant-ph/0703022 | C\'esar Rodr\'iguez | C\'esar A. Rodr\'iguez-Rosario, Kavan Modi, Aik-meng Kuah, Anil Shaji,
E. C. G. Sudarshan | Completely Positive Maps and Classical Correlations | 4 pages, 1 figure | J. Phys. A: Math. Theor. 41 (2008) 205301 | 10.1088/1751-8113/41/20/205301 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We expand the set of initial states of a system and its environment that are
known to guarantee completely positive reduced dynamics for the system when the
combined state evolves unitarily. We characterize the correlations in the
initial state in terms of its quantum discord [H. Ollivier and W. H. Zurek,
Phys. Rev. Lett. 88, 017901 (2001)]. We prove that initial states that have
only classical correlations lead to completely positive reduced dynamics. The
induced maps can be not completely positive when quantum correlations
including, but not limited to, entanglement are present. We outline the
implications of our results to quantum process tomography experiments.
| [
{
"version": "v1",
"created": "Fri, 2 Mar 2007 21:13:25 GMT"
},
{
"version": "v2",
"created": "Fri, 23 Mar 2007 18:39:14 GMT"
},
{
"version": "v3",
"created": "Mon, 2 Apr 2007 19:39:54 GMT"
},
{
"version": "v4",
"created": "Thu, 29 Oct 2009 09:01:59 GMT"
}
] | 2009-10-29T00:00:00 | [
[
"Rodríguez-Rosario",
"César A.",
""
],
[
"Modi",
"Kavan",
""
],
[
"Kuah",
"Aik-meng",
""
],
[
"Shaji",
"Anil",
""
],
[
"Sudarshan",
"E. C. G.",
""
]
] |
quant-ph/0703023 | Daniel A. Lidar | Joseph Geraci and Daniel A. Lidar | On the Exact Evaluation of Certain Instances of the Potts Partition
Function by Quantum Computers | null | Comm. Math. Phys. 279, 735 (2008) | 10.1007/s00220-008-0438-0 | null | quant-ph | null | We present an efficient quantum algorithm for the exact evaluation of either
the fully ferromagnetic or anti-ferromagnetic q-state Potts partition function
Z for a family of graphs related to irreducible cyclic codes. This problem is
related to the evaluation of the Jones and Tutte polynomials. We consider the
connection between the weight enumerator polynomial from coding theory and Z
and exploit the fact that there exists a quantum algorithm for efficiently
estimating Gauss sums in order to obtain the weight enumerator for a certain
class of linear codes. In this way we demonstrate that for a certain class of
sparse graphs, which we call Irreducible Cyclic Cocycle Code (ICCC_\epsilon)
graphs, quantum computers provide a polynomial speed up in the difference
between the number of edges and vertices of the graph, and an exponential speed
up in q, over the best classical algorithms known to date.
| [
{
"version": "v1",
"created": "Sat, 3 Mar 2007 02:12:26 GMT"
}
] | 2008-09-27T00:00:00 | [
[
"Geraci",
"Joseph",
""
],
[
"Lidar",
"Daniel A.",
""
]
] |
quant-ph/0703024 | Narumi Ohkawa | Narumi Ohkawa | Entangled Causal Relation in Measurement by Two Measurement Devices
Moving Mutually | 6 pages, 4 figures | null | null | null | quant-ph | null | I want to show situations in which causal relation of two events is entangled
and similar to time paradox, without employing time machines. Such situations
will be obtained in measurement by two measurement devices moving mutually.
According to the concept of the collapse of wave packet and the relativity of
simultaneity, the causal relation of two measurements can be entangled.
| [
{
"version": "v1",
"created": "Sat, 3 Mar 2007 02:25:31 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ohkawa",
"Narumi",
""
]
] |
quant-ph/0703025 | Andrew Scott | Aidan Roy, A. J. Scott | Weighted complex projective 2-designs from bases: optimal state
determination by orthogonal measurements | 28 pages, to appear in J. Math. Phys | J. Math. Phys. 48, 072110 (2007) | 10.1063/1.2748617 | null | quant-ph math.CO | null | We introduce the problem of constructing weighted complex projective
2-designs from the union of a family of orthonormal bases. If the weight
remains constant across elements of the same basis, then such designs can be
interpreted as generalizations of complete sets of mutually unbiased bases,
being equivalent whenever the design is composed of d+1 bases in dimension d.
We show that, for the purpose of quantum state determination, these designs
specify an optimal collection of orthogonal measurements. Using highly
nonlinear functions on abelian groups, we construct explicit examples from d+2
orthonormal bases whenever d+1 is a prime power, covering dimensions d=6, 10,
and 12, for example, where no complete sets of mutually unbiased bases have
thus far been found.
| [
{
"version": "v1",
"created": "Sat, 3 Mar 2007 03:36:42 GMT"
},
{
"version": "v2",
"created": "Thu, 17 May 2007 01:39:39 GMT"
}
] | 2007-07-31T00:00:00 | [
[
"Roy",
"Aidan",
""
],
[
"Scott",
"A. J.",
""
]
] |
quant-ph/0703026 | Shao-Ming Fei | Sergio Albeverio, Laura Cattaneo, Shao-Ming Fei and Xiao-Hong Wang | Addendum to "Multipartite states under local unitary transformations" | 5 pages | Rep. Math. Phys. 58(2006)223-226 | null | null | quant-ph | null | In previous work the authors introduced a notion of generic states and
obtained criteria for local equivalence of them. Here they introduce the
concept of CHG states maintaining the criteria of local equivalence. This fact
allows the authors to halve the number of invariants necessary to characterize
the equivalence classes under local unitary transformations for the set of
tripartite states whose partial trace with respect to one of the subsystems
belongs to the class of CHG mixed states.
| [
{
"version": "v1",
"created": "Sat, 3 Mar 2007 08:54:53 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Albeverio",
"Sergio",
""
],
[
"Cattaneo",
"Laura",
""
],
[
"Fei",
"Shao-Ming",
""
],
[
"Wang",
"Xiao-Hong",
""
]
] |
quant-ph/0703027 | Ian Durham | Ian T. Durham | Are entropic Bell inequalities implied by the second law? | Yes. Extensively expanded and updated based upon feedback received on
previous version. (10 pages; presented at the 2007 Mearch Meeting of the APS
under the title "Entanglement and the second law") | null | null | null | quant-ph | null | Bell's inequalities, in the form given by Cerf and Adami, are derived from
the combination of the second law of thermodynamics and the Markov postulate.
Violations of these inequalities are discussed in terms of the mixing
characteristics of the density operators. A quantum mechanical bound for a
system of three qubits, two of which are entangled, is found and is shown to
lead to strong subadditivity in one case. Finally, in interpreting the results,
the role the uncertainty relations play in the definition of entropy and the
second law is discussed, demonstrating a link to Bell's inequalities.
Additionally the second law is shown to be dependent on the type of measurement
in quantum systems. Specifically, a more general statement of the second law
appropriate to both quantum and classical systems is suggested.
| [
{
"version": "v1",
"created": "Sat, 3 Mar 2007 18:35:05 GMT"
},
{
"version": "v2",
"created": "Sat, 31 Mar 2007 21:03:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Durham",
"Ian T.",
""
]
] |
quant-ph/0703028 | Andreia Mendonca Saguia | A. Saguia, M. S. Sarandy, B. Boechat, M. A. Continentino | Entanglement Entropy in Random Quantum Spin-S Chains | 5 pages, 4 figures | Phys. Rev. A 75, 052329 (2007) | 10.1103/PhysRevA.75.052329 | null | quant-ph cond-mat.dis-nn | null | We discuss the scaling of entanglement entropy in the random singlet phase
(RSP) of disordered quantum magnetic chains of general spin-S. Through an
analysis of the general structure of the RSP, we show that the entanglement
entropy scales logarithmically with the size of a block and we provide a closed
expression for this scaling. This result is applicable for arbitrary quantum
spin chains in the RSP, being dependent only on the magnitude S of the spin.
Remarkably, the logarithmic scaling holds for the disordered chain even if the
pure chain with no disorder does not exhibit conformal invariance, as is the
case for Heisenberg integer spin chains. Our conclusions are supported by
explicit evaluations of the entanglement entropy for random spin-1 and spin-3/2
chains using an asymptotically exact real-space renormalization group approach.
| [
{
"version": "v1",
"created": "Sat, 3 Mar 2007 18:44:40 GMT"
},
{
"version": "v2",
"created": "Sun, 17 Jun 2007 18:11:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Saguia",
"A.",
""
],
[
"Sarandy",
"M. S.",
""
],
[
"Boechat",
"B.",
""
],
[
"Continentino",
"M. A.",
""
]
] |
quant-ph/0703029 | Liang Jiang | L. Jiang, J. M. Taylor, A. S. S{\o}rensen, M. D. Lukin | Scalable Quantum Networks based on Few-Qubit Registers | 4 pages, 3 figures (new figures 1 and 3) | Int. J. Quanum Inform. 08, 93 (2010) | 10.1142/S0219749910006058 | null | quant-ph | null | We describe and analyze a hybrid approach to scalable quantum computation
based on an optically connected network of few-qubit quantum registers. We show
that probabilistically connected five-qubit quantum registers suffice for
deterministic, fault-tolerant quantum computation even when state preparation,
measurement, and entanglement generation all have substantial errors. We
discuss requirements for achieving fault-tolerant operation for two specific
implementations of our approach.
| [
{
"version": "v1",
"created": "Sun, 4 Mar 2007 03:21:59 GMT"
},
{
"version": "v2",
"created": "Tue, 6 Nov 2007 04:27:49 GMT"
}
] | 2013-02-26T00:00:00 | [
[
"Jiang",
"L.",
""
],
[
"Taylor",
"J. M.",
""
],
[
"Sørensen",
"A. S.",
""
],
[
"Lukin",
"M. D.",
""
]
] |
quant-ph/0703030 | Quesne Christiane | C. Quesne | Abrupt termination of a quantum channel and exactly solvable
position-dependent mass models in three dimensions | 8 pages, no figure | null | null | ULB/229/CQ/07/1 | quant-ph | null | We consider a particle with a position-dependent mass, moving in a
three-dimensional semi-infinite parallelepipedal or cylindrical channel under
the influence of some hyperbolic potential. We show that the lack of uniformity
in the environment generates an infinite number of bound states.
| [
{
"version": "v1",
"created": "Sun, 4 Mar 2007 08:54:37 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Quesne",
"C.",
""
]
] |
quant-ph/0703031 | Andrea Micheli | A. Micheli, G. Pupillo, H. P. B\"uchler, and P. Zoller | Cold polar molecules in 2D traps: Tailoring interactions with external
fields for novel quantum phases | 28 pages, 15 figures | Phys. Rev. A 76, 043604 (2007) | 10.1103/PhysRevA.76.043604 | null | quant-ph | null | We discuss techniques to engineer effective long-range interactions between
polar molecules using external static electric and microwave fields. We
consider a setup where molecules are trapped in a two-dimensional pancake
geometry by a far-off-resonance optical trap, which ensures the stability of
the dipolar collisions. We detail how to modify the shape and the strength of
the long-range part of interaction potentials, which can be utilized to realize
interesting quantum phases in the context of cold molecular gases.
| [
{
"version": "v1",
"created": "Sun, 4 Mar 2007 17:16:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Micheli",
"A.",
""
],
[
"Pupillo",
"G.",
""
],
[
"Büchler",
"H. P.",
""
],
[
"Zoller",
"P.",
""
]
] |
quant-ph/0703032 | A. F. Kracklauer | A. F. Kracklauer | State visibility in Q-bit space | 3 pages RevTeX | null | null | null | quant-ph | null | We study by comparison the structure of singlet type states in Q-bit space in
the light of quantum and classical paradigms. It is shown that only the
classical paradigm implies a variation in the visibility of correlation
coefficients, that has been observed in fact in experiments. We conclude that
Q-bit space in not a appropriate venue for an EPR test of quantum completeness.
| [
{
"version": "v1",
"created": "Sun, 4 Mar 2007 19:13:49 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Kracklauer",
"A. F.",
""
]
] |
quant-ph/0703033 | Guoming Wang | Guoming Wang, Mingsheng Ying | Multipartite unlockable bound entanglement in the stabilizer formalism | 7 pages, no figure | Physical Review A 75, 052332 (2007) | 10.1103/PhysRevA.75.052332 | null | quant-ph | null | We find an interesting relationship between multipartite bound entangled
states and the stabilizer formalism. We prove that if a set of commuting
operators from the generalized Pauli group on $n$ qudits satisfy certain
constraints, then the maximally mixed state over the subspace stabilized by
them is an unlockable bound entangled state. Moreover, the properties of this
state, such as symmetry under permutations of parties, undistillability and
unlockability, can be easily explained from the stabilizer formalism without
tedious calculation. In particular, the four-qubit Smolin state and its recent
generalization to even number of qubits can be viewed as special examples of
our results. Finally, we extend our results to arbitrary multipartite systems
in which the dimensions of all parties may be different.
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 12:54:50 GMT"
},
{
"version": "v2",
"created": "Sun, 11 Mar 2007 10:17:31 GMT"
},
{
"version": "v3",
"created": "Thu, 31 May 2007 06:30:05 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wang",
"Guoming",
""
],
[
"Ying",
"Mingsheng",
""
]
] |
quant-ph/0703034 | Ramazan Sever | Ozlem Yesiltas and Ramazan sever | Exact Solutions of Schrodinger Equation for a Ring-Shaped Potential | 12 pages | null | null | null | quant-ph | null | The exact solutions of Schrodinger equation are obtained for a noncentral
potential which is a ring-shaped potential. The energy eigenvalues and
corresponding eigenfunctions are obtained for any angular momentum l.
Nikiforov-Uvarov method is used in the computations.
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 07:11:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Yesiltas",
"Ozlem",
""
],
[
"sever",
"Ramazan",
""
]
] |
quant-ph/0703035 | Ulrich Mohrhoff | Ulrich Mohrhoff | Objective probability and quantum fuzziness | 21 pages, no graphics, inspired by "Subjective probability and
quantum certainty" (quant-ph/0608190 v2) | Found. Phys. 39/2 (2009) 137-155 | 10.1007/s10701-008-9266-5 | SAICE090201 | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper offers a critique of the Bayesian interpretation of quantum
mechanics with particular focus on a paper by Caves, Fuchs, and Schack
containing a critique of the "objective preparations view" or OPV. It also aims
to carry the discussion beyond the hardened positions of Bayesians and
proponents of the OPV. Several claims made by Caves et al. are rebutted,
including the claim that different pure states may legitimately be assigned to
the same system at the same time, and the claim that the quantum nature of a
preparation device cannot legitimately be ignored. Both Bayesians and
proponents of the OPV regard the time dependence of a quantum state as the
continuous dependence on time of an evolving state of some kind. This leads to
a false dilemma: quantum states are either objective states of nature or
subjective states of belief. In reality they are neither. The present paper
views the aforesaid dependence as a dependence on the time of the measurement
to whose possible outcomes the quantum state serves to assign probabilities.
This makes it possible to recognize the full implications of the only testable
feature of the theory, viz., the probabilities it assigns to measurement
outcomes...
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 08:34:10 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Feb 2009 03:04:49 GMT"
}
] | 2009-02-04T00:00:00 | [
[
"Mohrhoff",
"Ulrich",
""
]
] |
quant-ph/0703036 | Serge Massar | Serge Massar | Uncertainty Relations for Positive Operator Valued Measures | 5 pages, minor modifications and clarifications | Phys. Rev. A 76, 042114 (2007) | 10.1103/PhysRevA.76.042114 | null | quant-ph | null | How much unavoidable randomness is generated by a Positive Operator Valued
Measure (POVM)? We address this question using two complementary approaches.
First we study the variance of a real variable associated to the POVM outcomes.
In this context we introduce an uncertainty operator which measures how much
additional noise is introduced by carrying out a POVM rather than a von Neumann
measurement. We illustrate this first approach by studying the variances of
joint estimates of \sigma_x and \sigma_z for spin 1/2 particles. We show that
for unbiased measurements the sum of these variances is lower bounded by 1. In
our second approach we study the entropy of the POVM outcomes. In particular we
try to establish lower bounds on the entropy of the POVM outcomes. We
illustrate this second approach by examples.
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 10:45:36 GMT"
},
{
"version": "v2",
"created": "Sat, 25 Aug 2007 11:52:12 GMT"
}
] | 2011-06-03T00:00:00 | [
[
"Massar",
"Serge",
""
]
] |
quant-ph/0703037 | Annalisa Marzuoli | Silvano Garnerone, Annalisa Marzuoli and Mario Rasetti | Efficient quantum processing of 3-manifold topological invariants | 39 pages, 22 figures, accepted for publication in Advances in
Theoretical and Mathematical Physics | Adv.Theor.Math.Phys.13:6,2009 | null | null | quant-ph gr-qc | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A quantum algorithm for approximating efficiently 3--manifold topological
invariants in the framework of SU(2) Chern-Simons-Witten (CSW) topological
quantum field theory at finite values of the coupling constant k is provided.
The model of computation adopted is the q-deformed spin network model viewed as
a quantum recognizer in the sense of Wiesner and Crutchfield, where each basic
unitary transition function can be efficiently processed by a standard quantum
circuit.
This achievement is an extension of the algorithm for approximating
polynomial invariants of colored oriented links found in Refs 2,3. Thus all the
significant quantities - partition functions and observables - of quantum CSW
theory can be processed efficiently on a quantum computer, reflecting the
intrinsic, field-theoretic solvability of such theory at finite k.
The paper is supplemented by a critical overview of the basic conceptual
tools underlying the construction of quantum invariants of links and
3-manifolds and connections with algorithmic questions that arise in geometry
and quantum gravity models are discussed.
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 15:27:54 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Aug 2009 01:23:21 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Garnerone",
"Silvano",
""
],
[
"Marzuoli",
"Annalisa",
""
],
[
"Rasetti",
"Mario",
""
]
] |
quant-ph/0703038 | Jeffrey Tollaksen Dr. | Jeff Tollaksen | Robust Weak Measurements on Finite Samples | null | J. Phys. Conf. Ser. (2007); Third Feynmann Festival (University of
Maryland, College Park, August 2006), Guest Editors: H. Brandt, Y.S. Kim, and
M.A. Man'ko. | 10.1088/1742-6596/70/1/012015 | null | quant-ph | null | A new weak measurement procedure is introduced for finite samples which
yields accurate weak values that are outside the range of eigenvalues and which
do not require an exponentially rare ensemble. This procedure provides a unique
advantage in the amplification of small non-random signals by minimizing
uncertainties in determining the weak value and by minimizing sample size. This
procedure can also extend the strength of the coupling between the system and
measuring device to a new regime.
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 15:52:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tollaksen",
"Jeff",
""
]
] |
quant-ph/0703039 | W. M. Stuckey | W.M. Stuckey | Implications for a spatially discrete transition amplitude in the
twin-slit experiment | Revised to reflect referee comments | null | null | null | quant-ph | null | A discrete path integral formalism is used to obtain the transition amplitude
between 'sources' (slits and detector) in the twin-slit experiment of quantum
mechanics. This method explicates the normally tacit construct of dynamic
entities with temporal duration. The resulting amplitude is compared to that of
Schrodinger dynamics in order to relate 'source' dynamics and spatial
separation. The implied metric embodies non-separability, in stark contrast to
the metric of general relativity. Thus, this approach may have implications for
quantum gravity.
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 15:55:25 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Apr 2007 16:00:23 GMT"
},
{
"version": "v3",
"created": "Wed, 12 Dec 2007 19:06:50 GMT"
}
] | 2007-12-12T00:00:00 | [
[
"Stuckey",
"W. M.",
""
]
] |
quant-ph/0703040 | Antonio Negretti | Antonio Negretti, Uffe V. Poulsen, Klaus Molmer | Quantum Superposition State Production by Continuous Observations and
Feedback | RevTex4, 4 pages, 2 figures. Published in Phys. Rev. Lett. with
higher quality figures. The first part of the manuscript, regarding the Fock
state generator, has been removed | Phys. Rev. Lett. 99, 223601 (2007) | 10.1103/PhysRevLett.99.223601 | null | quant-ph | null | We present a protocol for generation of superpositions of states with
distinguishable field amplitudes in an optical cavity by quantum nondemolition
photon number measurements and coherent feeding of the cavity.
| [
{
"version": "v1",
"created": "Mon, 5 Mar 2007 18:53:23 GMT"
},
{
"version": "v2",
"created": "Tue, 6 Mar 2007 16:31:21 GMT"
},
{
"version": "v3",
"created": "Tue, 27 Nov 2007 09:02:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Negretti",
"Antonio",
""
],
[
"Poulsen",
"Uffe V.",
""
],
[
"Molmer",
"Klaus",
""
]
] |
quant-ph/0703041 | Paul Davies | P.C.W. Davies | The Implications of a Cosmological Information Bound for Complexity,
Quantum Information and the Nature of Physical Law | Chapter for a book celebrating the work of Gregory Chaitin:
"Randomness & Complexity, from Leibniz to Chaitin," edited by C.S. Calude,
World Scientific, Singapore, 2007 (to appear) | null | null | null | quant-ph | null | The finite age of the universe and the existence of cosmological horizons
provides a strong argument that the observable universe represents a finite
causal region with finite material and informational resources. A similar
conclusion follows from the holographic principle. In this paper I address the
question of whether the cosmological information bound has implications for
fundamental physics. Orthodox physics is based on Platonism: the laws are
treated as infinitely precise, perfect, immutable mathematical relationships
that transcend the physical universe and remain totally unchanged by physical
processes, however extreme. If instead the laws of physics are regarded as akin
to computer software, with the physical universe as the corresponding hardware,
then the finite computational capacity of the universe imposes a fundamental
limit on the precision of the laws and the specifiability of physical states.
That limit depends on the age of the universe. I examine how the imprecision of
the laws impacts on the evolution of highly entangled states and on the problem
of dark energy.
| [
{
"version": "v1",
"created": "Tue, 6 Mar 2007 00:04:23 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Davies",
"P. C. W.",
""
]
] |
quant-ph/0703042 | Ramazan Sever | Sameer M. Ikhdair and Ramazan Sever | Exact solutions of the pseudo-Coulomb potential plus ring-shaped
potential in the D-dimensional Schrodinger equation by the Nikiforov-Uvarov
method | 15 pages | Chinese J. Phys. 46, 291(2008) | null | null | quant-ph | null | We present analytically the exact energy bound-states solutions of the
Schrodinger equation in D-dimensions for an alternative (often used)
pseudo-Coulomb potential-plus- ring-shaped potential of the form $V(r)=-%
\frac{a}{r}+\frac{b}{r^{2}}+\frac{\beta \cos ^{2}\theta}{r^{2}\sin ^{2}\theta
}+c$ by means of the conventional Nikiforov-Uvarov method. We give a clear
recipe of how to obtain an explicit solution to the radial and angular parts of
the wave functions in terms of orthogonal polynomials. The total energy of the
system is different from the pseudo-Coulomb potential because of the
contribution of the angular part. The general results obtained in this work can
be reduced to the standard forms given in literature.
| [
{
"version": "v1",
"created": "Tue, 6 Mar 2007 06:28:16 GMT"
}
] | 2008-07-15T00:00:00 | [
[
"Ikhdair",
"Sameer M.",
""
],
[
"Sever",
"Ramazan",
""
]
] |
quant-ph/0703043 | Faisal El-Orany Dr. | Faisal A. A. El-Orany, S. Abdel-Khalek, M. Abdel-Aty, M. R. B.
Wahiddin | Entanglement in the bimodal Jaynes-Cummings model with the two-mode
squeezed vacuum state | 12 pages, 4 figures | null | 10.1007/s10773-007-9549-1 | null | quant-ph | null | In this paper, we study the interaction between the two-level atom and a
bimodal cavity field, namely, two-mode Jaynes-Cummings model when the atom and
the modes are initially in the atomic superposition state and two-mode squeezed
vacuum state, respectively. For this system we investigate the atomic
inversion, linear entropy and atomic Wehrl entropy. We show that there is a
connection between all these quantities. Also we prove that the atomic Wehrl
entropy exhibits behaviors similar to those of the linear entropy and the von
Neumann entropy. Moreover, we show that the bipartite exhibits periodical
disentanglement and derive the explicit forms of the states of the atom and the
modes at these values of the interaction times.
| [
{
"version": "v1",
"created": "Tue, 6 Mar 2007 16:02:50 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"El-Orany",
"Faisal A. A.",
""
],
[
"Abdel-Khalek",
"S.",
""
],
[
"Abdel-Aty",
"M.",
""
],
[
"Wahiddin",
"M. R. B.",
""
]
] |
quant-ph/0703044 | Luigi Amico | Luigi Amico, Rosario Fazio, Andreas Osterloh, and Vlatko Vedral | Entanglement in Many-Body Systems | 61 pages, 29 figures | Rev.Mod.Phys.80:517-576,2008 | 10.1103//RevModPhys.80.517 | null | quant-ph cond-mat.stat-mech hep-th | null | The recent interest in aspects common to quantum information and condensed
matter has prompted a prosperous activity at the border of these disciplines
that were far distant until few years ago. Numerous interesting questions have
been addressed so far. Here we review an important part of this field, the
properties of the entanglement in many-body systems. We discuss the zero and
finite temperature properties of entanglement in interacting spin, fermionic
and bosonic model systems. Both bipartite and multipartite entanglement will be
considered. At equilibrium we emphasize on how entanglement is connected to the
phase diagram of the underlying model. The behavior of entanglement can be
related, via certain witnesses, to thermodynamic quantities thus offering
interesting possibilities for an experimental test. Out of equilibrium we
discuss how to generate and manipulate entangled states by means of many-body
Hamiltonians.
| [
{
"version": "v1",
"created": "Tue, 6 Mar 2007 17:21:43 GMT"
},
{
"version": "v2",
"created": "Thu, 15 Nov 2007 19:13:56 GMT"
},
{
"version": "v3",
"created": "Fri, 9 May 2008 18:02:40 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Amico",
"Luigi",
""
],
[
"Fazio",
"Rosario",
""
],
[
"Osterloh",
"Andreas",
""
],
[
"Vedral",
"Vlatko",
""
]
] |
quant-ph/0703045 | Jens Eisert | K. Kieling, D. Gross, J. Eisert | Cluster state preparation using gates operating at arbitrary success
probabilities | 7 pages, 9 figures, contribution to special issue of New J. Phys. on
"Measurement-Based Quantum Information Processing". Replaced with published
version | New J. Phys. 9, 200 (2007) | 10.1088/1367-2630/9/6/200 | null | quant-ph | null | Several physical architectures allow for measurement-based quantum computing
using sequential preparation of cluster states by means of probabilistic
quantum gates. In such an approach, the order in which partial resources are
combined to form the final cluster state turns out to be crucially important.
We determine the influence of this classical decision process on the expected
size of the final cluster. Extending earlier work, we consider different
quantum gates operating at various probabilites of success. For finite
resources, we employ a computer algebra system to obtain the provably optimal
classical control strategy and derive symbolic results for the expected final
size of the cluster. We identify two regimes: When the success probability of
the elementary gates is high, the influence of the classical control strategy
is found to be negligible. In that case, other figures of merit become more
relevant. In contrast, for small probabilities of success, the choice of an
appropriate strategy is crucial.
| [
{
"version": "v1",
"created": "Tue, 6 Mar 2007 21:47:33 GMT"
},
{
"version": "v2",
"created": "Wed, 4 Jul 2007 09:29:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Kieling",
"K.",
""
],
[
"Gross",
"D.",
""
],
[
"Eisert",
"J.",
""
]
] |
quant-ph/0703046 | Simon Pierre Desrosiers | Simon Pierre Desrosiers | Entropic security in Quantum Cryptography | 12 pages | null | null | null | quant-ph | null | We present two new definitions of security for quantum ciphers which are
inspired by the definition of entropic security and entropic
indistinguishability defined by Dodis and Smith. We prove the equivalence of
these two new definitions. We also propose a generalization of a cipher
described by Dodis and Smith and show that it can actually encrypt n qubits
using less than n bits of key under reasonable conditions and yet be secure in
an information theoretic setting. This cipher also totally closes the gap
between the key requirement of quantum ciphers and classical ciphers.
| [
{
"version": "v1",
"created": "Tue, 6 Mar 2007 22:24:57 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 20:28:07 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Desrosiers",
"Simon Pierre",
""
]
] |
quant-ph/0703047 | Alberto Carlini | A. Carlini, A. Hosoya, T. Koike and Y. Okudaira | Quantum Brachistochrone for Mixed States | 8 pages, 3 figures | J. Phys. A: Math. Theor. 41 (2008), 045303 | 10.1088/1751-8113/41/4/045303 | null | quant-ph | null | We present a general formalism based on the variational principle for finding
the time-optimal quantum evolution of mixed states governed by a master
equation, when the Hamiltonian and the Lindblad operators are subject to
certain constraints. The problem reduces to solving first a fundamental
equation (the {\it quantum brachistochrone}) for the Hamiltonian, which can be
written down once the constraints are specified, and then solving the
constraints and the master equation for the Lindblad and the density operators.
As an application of our formalism, we study a simple one-qubit model where the
optimal Lindblad operators control decoherence and can be simulated by a
tunable coupling with an ancillary qubit. It is found that the evolution
through mixed states can be more efficient than the unitary evolution between
given pure states. We also discuss the mixed state evolution as a finite time
unitary evolution of the system plus an environment followed by a single
measurement. For the simplest choice of the constraints, the optimal duration
time for the evolution is an exponentially decreasing function of the
environment's degrees of freedom.
| [
{
"version": "v1",
"created": "Tue, 6 Mar 2007 23:33:19 GMT"
}
] | 2014-12-01T00:00:00 | [
[
"Carlini",
"A.",
""
],
[
"Hosoya",
"A.",
""
],
[
"Koike",
"T.",
""
],
[
"Okudaira",
"Y.",
""
]
] |
quant-ph/0703048 | Hannu Wichterich | Hannu Wichterich, Markus J. Henrich, Heinz-Peter Breuer, Jochen
Gemmer, Mathias Michel | Modeling heat transport through completely positive maps | 7 pages, 2 figures | Phys. Rev. E 76, 031115 (2007) | 10.1103/PhysRevE.76.031115 | null | quant-ph | null | We investigate heat transport in a spin-1/2 Heisenberg chain, coupled locally
to independent thermal baths of different temperature. The analysis is carried
out within the framework of the theory of open systems by means of appropriate
quantum master equations. The standard microscopic derivation of the
weak-coupling Lindblad equation in the secular approximation is considered, and
shown to be inadequate for the description of stationary nonequilibrium
properties like a non-vanishing energy current. Furthermore, we derive an
alternative master equation that is capable to describe a stationary energy
current and, at the same time, leads to a completely positive dynamical map.
This paves the way for efficient numerical investigations of heat transport in
larger systems based on Monte Carlo wave function techniques.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 16:34:45 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Jun 2007 08:08:59 GMT"
},
{
"version": "v3",
"created": "Thu, 27 Sep 2007 10:34:21 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wichterich",
"Hannu",
""
],
[
"Henrich",
"Markus J.",
""
],
[
"Breuer",
"Heinz-Peter",
""
],
[
"Gemmer",
"Jochen",
""
],
[
"Michel",
"Mathias",
""
]
] |
quant-ph/0703049 | Xuexi Yi | X. X. Yi, W. Wang | Geometric phases induced in auxiliary qubits by many-body systems near
its critical points | null | Phys. Rev. A 75, 032103 (2007) | 10.1103/PhysRevA.75.032103 | null | quant-ph | null | The geometric phase induced in an auxiliary qubit by a many-body system is
calculated and discussed. Two kinds of coupling between the auxiliary qubit and
the many-body system are considered, which lead to dephasing and dissipation in
the qubit, respectively. As an example, we consider the XY spin-chain
dephasingly couple to a qubit, the geometric phase induced in the qubit is
presented and discussed. The results show that the geometric phase might be
used to signal the critical points of the many-body system, and it tends to
zero with the parameters of the many-body system going away from the critical
points.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 05:21:52 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yi",
"X. X.",
""
],
[
"Wang",
"W.",
""
]
] |
quant-ph/0703050 | Satoshi Morita | Satoshi Morita | Faster annealing schedules for quantum annealing | 10 pages, 5 figures, minor corrections | J. Phys. Soc. Jpn. 76 (2007) 104001 | 10.1143/JPSJ.76.104001 | null | quant-ph cond-mat.dis-nn | null | New annealing schedules for quantum annealing are proposed based on the
adiabatic theorem. These schedules exhibit faster decrease of the excitation
probability than a linear schedule. To derive this conclusion, the asymptotic
form of the excitation probability for quantum annealing is explicitly obtained
in the limit of long annealing time. Its first-order term, which is inversely
proportional to the square of the annealing time, is shown to be determined
only by the information at the initial and final times. Our annealing schedules
make it possible to drop this term, thus leading to a higher order (smaller)
excitation probability. We verify these results by solving numerically the
time-dependent Schrodinger equation for small size systems
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 07:45:03 GMT"
},
{
"version": "v2",
"created": "Fri, 5 Oct 2007 06:00:35 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Morita",
"Satoshi",
""
]
] |
quant-ph/0703051 | Jean-Claude Garreau | Carlos Renato De Carvalho (IF-UFRJ), Emerson S. Guerra (DF-UFRRJ),
Ginette Jalbert (IF-UFRJ), Jean Claude Garreau (PhLAM, CERLA) | Nonprobabilistic teleportation of field state via cavity QED | null | Journal of Physics B: Atomic, Molecular and Optical Physics 40
(05/03/2007) 1271-1282 | 10.1088/0953-4075/40/6/017 | null | quant-ph | null | In this article we discuss a teleportation scheme of coherent states of
cavity field. The experimental realization proposed makes use of cavity quatum
electrodynamics involving the interaction of Rydberg atoms with micromaser and
Ramsey cavities. In our scheme the Ramsey cavities and the atoms play the role
of auxiliary systems used to teleport the state from a micromaser cavity to
another. We show that, even if the correct atomic detection fails in the first
trials, one can succeed in teleportating the cavity field state if the proper
measurement occurs in a later atom.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 09:18:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"De Carvalho",
"Carlos Renato",
"",
"IF-UFRJ"
],
[
"Guerra",
"Emerson S.",
"",
"DF-UFRRJ"
],
[
"Jalbert",
"Ginette",
"",
"IF-UFRJ"
],
[
"Garreau",
"Jean Claude",
"",
"PhLAM, CERLA"
]
] |
quant-ph/0703052 | Luca Sapienza | Luca Sapienza (MPQ), Raffaele Colombelli (IEF), Angela Vasanelli
(MPQ), Cristiano Ciuti (MPQ), Christophe Manquest (MPQ), Ulf Gennser (LPN),
Carlo Sirtori (MPQ) | Photovoltaic Probe of Cavity Polaritons in a Quantum Cascade Structure | submitted to Applied Physics Letters | Applied Physics Letters 90, 201101 (2007) | 10.1063/1.2739308 | null | quant-ph cond-mat.other | null | The strong coupling between an intersubband excitation in a quantum cascade
structure and a photonic mode of a planar microcavity has been detected by
angle-resolved photovoltaic measurements. A typical anticrossing behavior, with
a vacuum-field Rabi splitting of 16 meV at 78K, has been measured, for an
intersubband transition at 163 meV. These results show that the strong coupling
regime between photons and intersubband excitations can be engineered in a
quantum cascade opto-electronic device. They also demonstrate the possibility
to perform angle-resolved mid-infrared photodetection and to develop active
devices based on intersubband cavity polaritons.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 11:09:17 GMT"
}
] | 2016-01-22T00:00:00 | [
[
"Sapienza",
"Luca",
"",
"MPQ"
],
[
"Colombelli",
"Raffaele",
"",
"IEF"
],
[
"Vasanelli",
"Angela",
"",
"MPQ"
],
[
"Ciuti",
"Cristiano",
"",
"MPQ"
],
[
"Manquest",
"Christophe",
"",
"MPQ"
],
[
"Gennser",
"Ulf",
"",
"LPN"
],
[
"Sirtori",
"Carlo",
"",
"MPQ"
]
] |
quant-ph/0703053 | Konstantin Feldman E | K.E.Feldman | Boundary Effects in Non-Uniform Spin Chains | 13 pages, to appear in International Journal of Information & Systems
Sciences | null | null | null | quant-ph cond-mat.other math-ph math.MP | null | We give an explicit comparison of eigenvalues and eigenvectors of XY
Hamiltonians of an open linear spin-1/2 chain and a closed spin-1/2 ring with
periodic in space coefficients. It is shown that the Hamiltonian of a
k-periodic chain with nk-1 sites has (n-1)k multiplicity one eigenvalues which
are eigenvalues of multiplicity two for a Hamiltonian of a k-periodic ring with
2kn sites. For the corresponding eigenvectors in the case of a chain an
explicit expression in terms of eigenvectors of the ring Hamiltonian is given.
The remaining k-1 eigenvalues of the chain Hamiltonian and 2k eigenvalues of
the ring Hamiltonian, together with the corresponding eigenvectors, are
responsible for the difference between chain and ring models which displays in
the boundary effects at the ends of the chain and translation invariance of the
periodic ring.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 11:25:57 GMT"
},
{
"version": "v2",
"created": "Sat, 24 Mar 2007 13:28:36 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Feldman",
"K. E.",
""
]
] |
quant-ph/0703054 | Subhashish Banerjee | Subhashish Banerjee and R. Ghosh | Dynamics of decoherence without dissipation in a squeezed thermal bath | Accepted for publication in J. Phys. A: Math. Theor.; 23 pages, 8
figures | null | null | RRI-TP-10 | quant-ph cond-mat.stat-mech | null | We study a generic open quantum system where the coupling between the system
and its environment is of an energy-preserving quantum nondemolition (QND)
type. We obtain the general master equation for the evolution of such a system
under the influence of a squeezed thermal bath of harmonic oscillators. From
the master equation it can be seen explicitly that the process involves
decoherence or dephasing without any dissipation of energy. We work out the
decoherence-causing term in the high and zero temperature limits and check that
they match with known results for the case of a thermal bath. The decay of the
coherence is quantified as well by the dynamics of the linear entropy of the
system under various environmental conditions. We make a comparison of the
quantum statistical properties between QND and dissipative types of evolution
using a system of two-level atom and a harmonic oscillator.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 13:54:33 GMT"
},
{
"version": "v2",
"created": "Mon, 25 Jun 2007 13:39:31 GMT"
},
{
"version": "v3",
"created": "Tue, 2 Oct 2007 14:51:11 GMT"
}
] | 2007-10-02T00:00:00 | [
[
"Banerjee",
"Subhashish",
""
],
[
"Ghosh",
"R.",
""
]
] |
quant-ph/0703055 | Subhashish Banerjee | Subhashish Banerjee, Joyee Ghosh and R. Ghosh | Phase diffusion pattern in quantum nondemolition systems | 18 pages, REVTeX, 8 figures | Phys. Rev. A 75, 062106 (2007) | 10.1103/PhysRevA.75.062106 | null | quant-ph cond-mat.stat-mech | null | We quantitatively analyze the dynamics of the quantum phase distribution
associated with the reduced density matrix of a system, as the system evolves
under the influence of its environment with an energy-preserving quantum
nondemolition (QND) type of coupling. We take the system to be either an
oscillator (harmonic or anharmonic) or a two-level atom (or equivalently, a
spin-1/2 system), and model the environment as a bath of harmonic oscillators,
initially in a general squeezed thermal state. The impact of the different
environmental parameters is explicitly brought out as the system starts out in
various initial states. The results are applicable to a variety of physical
systems now studied experimentally with QND measurements.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 14:00:03 GMT"
},
{
"version": "v2",
"created": "Fri, 29 Jun 2007 13:05:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Banerjee",
"Subhashish",
""
],
[
"Ghosh",
"Joyee",
""
],
[
"Ghosh",
"R.",
""
]
] |
quant-ph/0703056 | Daniel Lehmann | Daniel Lehmann | Quantic Superpositions and the Geometry of Complex Hilbert Spaces | 29 pages. This 2nd version differs from the first in that
superposition of states x and y is now defined as a one-parameter operation:
r x + (1-r) y whereas version 1 defined it as a two-parameters operation: r x
+ (1-r) e^{i \phi} y | International Journal of Theoretical Physics, 47(5) 2008 pp.
1333-1353 | 10.1007/s10773-007-9576-y | Leibniz Center for Research in Computer Science, TR-2007-114, Hebrew
University, Jerusalem | quant-ph | null | The concept of a superposition is a revolutionary novelty introduced by
Quantum Mechanics. If a system may be in any one of two pure states x and y, we
must consider that it may also be in any one of many superpositions of x and y.
An in-depth analysis of superpositions is proposed, in which states are
represented by one-dimensional subspaces, not by unit vectors as in Dirac's
notation. Superpositions must be considered when one cannot distinguish between
possible paths, i.e., histories, leading to the current state of the system. In
such a case the resulting state is some compound of the states that result from
each of the possible paths. States can be compounded, i.e., superposed in such
a way only if they are not orthogonal. Since different classical states are
orthogonal, the claim implies no non-trivial superpositions can be observed in
classical systems. The parameter that defines such compounds is a proportion
defining the mix of the different states entering the compound. Two quantities,
p and theta, both geometrical in nature, relate one-dimensional subspaces in
complex Hilbert spaces: the first one is a measure of proximity relating two
rays, the second one is an angle relating three rays. The properties of the
operation of superposition are very different from those that govern linear
combination of vectors.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 13:52:38 GMT"
},
{
"version": "v2",
"created": "Wed, 22 Aug 2007 13:05:40 GMT"
}
] | 2008-04-07T00:00:00 | [
[
"Lehmann",
"Daniel",
""
]
] |
quant-ph/0703057 | Raul Oscar Vallejos | Romulo F. Abreu, Raul O. Vallejos | Statistical bounds on the dynamical production of entanglement | preprint format, 14 pages, 2 figures | null | 10.1103/PhysRevA.75.062335 | null | quant-ph | null | We present a random-matrix analysis of the entangling power of a unitary
operator as a function of the number of times it is iterated. We consider
unitaries belonging to the circular ensembles of random matrices (CUE or COE)
applied to random (real or complex) non-entangled states. We verify numerically
that the average entangling power is a monotonic decreasing function of time.
The same behavior is observed for the "operator entanglement" --an alternative
measure of the entangling strength of a unitary. On the analytical side we
calculate the CUE operator entanglement and asymptotic values for the
entangling power. We also provide a theoretical explanation of the time
dependence in the CUE cases.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 14:40:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Abreu",
"Romulo F.",
""
],
[
"Vallejos",
"Raul O.",
""
]
] |
quant-ph/0703058 | Vladislav Khalilov | I.V. Mamsurov and F.Kh. Chibirova | Weakly bound electrons in external magnetic field | 4 pages | null | null | null | quant-ph | null | The effect of the uniform magnetic field on the electron in the spherically
symmetric square-well potential is studied. A transcendental equation that
determines the electron energy spectrum is derived. The approximate value of
the lowest (bound) energy state is found. The approximate wave function and
probability current density of this state are constructed.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 15:12:22 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mamsurov",
"I. V.",
""
],
[
"Chibirova",
"F. Kh.",
""
]
] |
quant-ph/0703059 | Leandro Aolita | L. Aolita and S. P. Walborn | Quantum communication without alignment using multiple-qubit
single-photon states | null | Phys. Rev. Lett. 98, 100501 (2007) | 10.1103/PhysRevLett.98.100501 | null | quant-ph | null | We propose a scheme for encoding logical qubits in a subspace protected
against collective rotations around the propagation axis using the polarization
and transverse spatial degrees of freedom of single photons. This encoding
allows for quantum key distribution without the need of a shared reference
frame. We present methods to generate entangled states of two logical qubits
using present day down-conversion sources and linear optics, and show that the
application of these entangled logical states to quantum information schemes
allows for alignment-free tests of Bell's inequalities, quantum dense coding
and quantum teleportation.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 16:00:33 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Mar 2007 21:07:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Aolita",
"L.",
""
],
[
"Walborn",
"S. P.",
""
]
] |
quant-ph/0703060 | Andreas Doering | A. Doering, C.J. Isham | A Topos Foundation for Theories of Physics: I. Formal Languages for
Physics | 36 pages, no figures | J.Math.Phys.49:053515,2008 | 10.1063/1.2883740 | null | quant-ph gr-qc math-ph math.MP | null | This paper is the first in a series whose goal is to develop a fundamentally
new way of constructing theories of physics. The motivation comes from a desire
to address certain deep issues that arise when contemplating quantum theories
of space and time. Our basic contention is that constructing a theory of
physics is equivalent to finding a representation in a topos of a certain
formal language that is attached to the system. Classical physics arises when
the topos is the category of sets. Other types of theory employ a different
topos. In this paper we discuss two different types of language that can be
attached to a system, S. The first is a propositional language, PL(S); the
second is a higher-order, typed language L(S). Both languages provide deductive
systems with an intuitionistic logic. The reason for introducing PL(S) is that,
as shown in paper II of the series, it is the easiest way of understanding, and
expanding on, the earlier work on topos theory and quantum physics. However,
the main thrust of our programme utilises the more powerful language L(S) and
its representation in an appropriate topos.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 16:00:51 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Doering",
"A.",
""
],
[
"Isham",
"C. J.",
""
]
] |
quant-ph/0703061 | Maurice de Gosson | Maurice de Gosson, Franz Luef | Remarks on the Fact that the Uncertainty Principle Does Not Determine
the Quantum State | To appaer in Phys. Lett. A | null | null | null | quant-ph | null | We discuss the relation between density matrices and the uncertainty
principle; this allows us to justify and explain a recent statement by Man'ko
et al. We thereafter use Hardy's uncertainty principle to prove a new result
for Wigner distributions dominated by a Gaussian and we relate this result to
the coarse-graining of phase-space by "quantum blobs".
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 17:30:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"de Gosson",
"Maurice",
""
],
[
"Luef",
"Franz",
""
]
] |
quant-ph/0703062 | Andreas Doering | A. Doering, C.J. Isham | A Topos Foundation for Theories of Physics: II. Daseinisation and the
Liberation of Quantum Theory | 34 pages, no figures | J.Math.Phys.49:053516,2008 | 10.1063/1.2883742 | null | quant-ph gr-qc math-ph math.MP | null | This paper is the second in a series whose goal is to develop a fundamentally
new way of constructing theories of physics. The motivation comes from a desire
to address certain deep issues that arise when contemplating quantum theories
of space and time. Our basic contention is that constructing a theory of
physics is equivalent to finding a representation in a topos of a certain
formal language that is attached to the system. Classical physics arises when
the topos is the category of sets. Other types of theory employ a different
topos. In this paper, we study in depth the topos representation of the
propositional language, PL(S), for the case of quantum theory. In doing so, we
make a direct link with, and clarify, the earlier work on applying topos theory
to quantum physics. The key step is a process we term `daseinisation' by which
a projection operator is mapped to a sub-object of the spectral presheaf--the
topos quantum analogue of a classical state space. In the second part of the
paper we change gear with the introduction of the more sophisticated local
language L(S). From this point forward, throughout the rest of the series of
papers, our attention will be devoted almost entirely to this language. In the
present paper, we use L(S) to study `truth objects' in the topos. These are
objects in the topos that play the role of states: a necessary development as
the spectral presheaf has no global elements, and hence there are no
microstates in the sense of classical physics. Truth objects therefore play a
crucial role in our formalism.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 16:29:59 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Doering",
"A.",
""
],
[
"Isham",
"C. J.",
""
]
] |
quant-ph/0703063 | Maurice de Gosson | Maurice de Gosson, Franz Luef | Quantum States and Hardy's Formulation of the Uncertainty Principle : a
Symplectic Approach | To appear in Lett. Math. Phys | null | 10.1007/s11005-007-0150-6 | null | quant-ph | null | We express the condition for a phase space Gaussian to be the Wigner
distribution of a mixed quantum state in terms of the symplectic capacity of
the associated Wigner ellipsoid. Our results are motivated by Hardy's
formulation of the uncertainty principle for a function and its Fourier
transform. As a consequence we are able to state a more general form of Hardy's
theorem.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 17:37:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"de Gosson",
"Maurice",
""
],
[
"Luef",
"Franz",
""
]
] |
quant-ph/0703064 | Andreas Doering | A. Doering, C.J. Isham | A Topos Foundation for Theories of Physics: III. The Representation of
Physical Quantities With Arrows | 38 pages, no figures | J.Math.Phys.49:053517,2008 | 10.1063/1.2883777 | null | quant-ph gr-qc math-ph math.MP | null | This paper is the third in a series whose goal is to develop a fundamentally
new way of viewing theories of physics. Our basic contention is that
constructing a theory of physics is equivalent to finding a representation in a
topos of a certain formal language that is attached to the system. In paper II,
we studied the topos representations of the propositional language PL(S) for
the case of quantum theory, and in the present paper we do the same thing for
the, more extensive, local language L(S). One of the main achievements is to
find a topos representation for self-adjoint operators. This involves showing
that, for any physical quantity A, there is an arrow
$\breve{\delta}^o(A):\Sig\map\SR$, where $\SR$ is the quantity-value object for
this theory. The construction of $\breve{\delta}^o(A)$ is an extension of the
daseinisation of projection operators that was discussed in paper II. The
object $\SR$ is a monoid-object only in the topos, $\tau_\phi$, of the theory,
and to enhance the applicability of the formalism, we apply to $\SR$ a topos
analogue of the Grothendieck extension of a monoid to a group. The resulting
object, $\kSR$, is an abelian group-object in $\tau_\phi$. We also discuss
another candidate, $\PR{\mathR}$, for the quantity-value object. In this
presheaf, both inner and outer daseinisation are used in a symmetric way.
Finally, there is a brief discussion of the role of unitary operators in the
quantum topos scheme.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 16:46:58 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Doering",
"A.",
""
],
[
"Isham",
"C. J.",
""
]
] |
quant-ph/0703065 | Sebastian Slama | Sebastian Slama, Gordon Krenz, Simone Bux, Claus Zimmermann, and
Philippe W. Courteille | Cavity-enhanced superradiant Rayleigh scattering with ultra-cold and
Bose-Einstein condensed atoms | 10 pages, 10 figures | Physical Review A 75, 063620 (2007) | 10.1103/PhysRevA.75.063620 | null | quant-ph | null | We report on the observation of collective atomic recoil lasing and
superradiant Rayleigh scattering with ultracold and Bose-Einstein condensed
atoms in an optical ring cavity. Both phenomena are based on instabilities
evoked by the collective interaction of light with cold atomic gases. This
publication clarifies the link between the two effects. The observation of
superradiant behavior with thermal clouds as hot as several tens of
$\mu\textrm{K}$ proves that the phenomena are driven by the cooperative
dynamics of the atoms, which is strongly enhanced by the presence of the ring
cavity.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 17:05:49 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Jul 2007 16:08:19 GMT"
}
] | 2007-07-19T00:00:00 | [
[
"Slama",
"Sebastian",
""
],
[
"Krenz",
"Gordon",
""
],
[
"Bux",
"Simone",
""
],
[
"Zimmermann",
"Claus",
""
],
[
"Courteille",
"Philippe W.",
""
]
] |
quant-ph/0703066 | Andreas Doering | A. Doering, C.J. Isham | A Topos Foundation for Theories of Physics: IV. Categories of Systems | 38 pages, no figures | J.Math.Phys.49:053518,2008 | 10.1063/1.2883826 | null | quant-ph gr-qc math-ph math.MP | null | This paper is the fourth in a series whose goal is to develop a fundamentally
new way of building theories of physics. The motivation comes from a desire to
address certain deep issues that arise in the quantum theory of gravity. Our
basic contention is that constructing a theory of physics is equivalent to
finding a representation in a topos of a certain formal language that is
attached to the system. Classical physics arises when the topos is the category
of sets. Other types of theory employ a different topos. The previous papers in
this series are concerned with implementing this programme for a single system.
In the present paper, we turn to considering a collection of systems: in
particular, we are interested in the relation between the topos representation
for a composite system, and the representations for its constituents. We also
study this problem for the disjoint sum of two systems. Our approach to these
matters is to construct a category of systems and to find a topos
representation of the entire category.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 17:06:08 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Doering",
"A.",
""
],
[
"Isham",
"C. J.",
""
]
] |
quant-ph/0703067 | Bryan Ellis | Bryan Ellis, Ilya Fushman, Dirk Englund, Bingyang Zhang, Yoshihisa
Yamamoto, and Jelena Vuckovic | Dynamics of Quantum Dot Photonic Crystal Lasers | null | null | null | null | quant-ph | null | Quantum dot photonic crystal membrane lasers were fabricated and the large
signal modulation characteristics were studied. We find that the modulation
characteristics of quantum dot lasers can be significantly improved using
cavities with large spontaneous emission coupling factor. Our experiments show,
and simulations confirm, that the modulation rate is limited by the rate of
carrier capture into the dots to around 30GHz in our present system.
| [
{
"version": "v1",
"created": "Wed, 7 Mar 2007 21:11:55 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ellis",
"Bryan",
""
],
[
"Fushman",
"Ilya",
""
],
[
"Englund",
"Dirk",
""
],
[
"Zhang",
"Bingyang",
""
],
[
"Yamamoto",
"Yoshihisa",
""
],
[
"Vuckovic",
"Jelena",
""
]
] |
quant-ph/0703068 | Guo-Feng Zhang Dr | Guo-feng Zhang, Zi-yu Chen | The entanglement character between atoms in the non-degenerate two
photons Tavis-Cummings model | 1tex and 2 eps figures. accepted by Optics Communications | Optics Communications 275 (2007) 274-277 | 10.1016/j.optcom.2007.03.022 | null | quant-ph | null | The entanglement character including the so-called sudden death effect
between atoms in the non-degenerate two photons Tavis-Cummings model is studied
by means of concurrence. The results show that the so-called sudden death
effect occurs only for some kind of initial states. In other words, the
phenomenon is sensitive to the initial conditions. One can expect the
resurrection of the original entanglement to occur in a periodic way following
each sudden death event. The length of the time interval for the zero
entanglement is dependent on not only the degree of entanglement of the initial
state but also the initial state. And the influence of dipole-dipole
interaction and different atomic initial states on entanglement between atoms
are discussed. The sudden death effect can be weakened by the introducing of
dipole-dipole interaction.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 01:59:31 GMT"
}
] | 2011-02-19T00:00:00 | [
[
"Zhang",
"Guo-feng",
""
],
[
"Chen",
"Zi-yu",
""
]
] |
quant-ph/0703069 | Renato Renner | Renato Renner | Symmetry implies independence | LaTeX, contains 4 figures | Nature Physics 3, 645 - 649 (2007) | 10.1038/nphys684 | null | quant-ph | null | Given a quantum system consisting of many parts, we show that symmetry of the
system's state, i.e., invariance under swappings of the subsystems, implies
that almost all of its parts are virtually identical and independent of each
other. This result generalises de Finetti's classical representation theorem
for infinitely exchangeable sequences of random variables as well as its
quantum-mechanical analogue. It has applications in various areas of physics as
well as information theory and cryptography. For example, in experimental
physics, one typically collects data by running a certain experiment many
times, assuming that the individual runs are mutually independent. Our result
can be used to justify this assumption.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 10:56:44 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Renner",
"Renato",
""
]
] |
quant-ph/0703070 | Hartmut Wachter | Hartmut Wachter | Non-relativistic Schroedinger theory on q-deformed quantum spaces I,
Mathematical framework and equations of motion | 48 pages, no figures, Latex | null | null | null | quant-ph | null | The aim of these three papers (I, II, and III) is to develop a q-deformed
version of non-relativistic Schroedinger theory. Paper I introduces the
fundamental mathematical and physical concepts. The braided line and the
three-dimensional q-deformed Euclidean space play the role of position space.
For both cases the algebraic framework is extended by a time element. A short
review of the elements of q-deformed analysis on the spaces under consideration
is given. The time evolution operator is introduced in a consistent way and its
basic properties are discussed. These reasonings are continued by proposing
q-deformed analogs of the Schroedinger and the Heisenberg picture.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 14:23:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wachter",
"Hartmut",
""
]
] |
quant-ph/0703071 | Hrvoje Nikolic | H. Nikolic | Quantum nonlocality without hidden variables: An algorithmic approach | 4 pages, corrected typos | null | null | null | quant-ph hep-th math-ph math.MP | null | Is quantum mechanics (QM) local or nonlocal? Different
formulations/interpretations (FI) of QM, with or without hidden variables,
suggest different answers. Different FI's can be viewed as different
algorithms, which leads us to propose an algorithmic definition of locality
according to which a theory is local if and only if there exists at least one
FI in which all irreducible elements of that FI are local. The fact that no
such FI of QM is known strongly supports quantum nonlocality.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 14:30:30 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Mar 2007 14:21:51 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Nikolic",
"H.",
""
]
] |
quant-ph/0703072 | Hartmut Wachter | Hartmut Wachter | Non-relativistic Schroedinger theory on q-deformed quantum spaces II,
The free non-relativistic particle and its interactions | 48 pages, no figures, Latex | null | null | null | quant-ph | null | This is the second part of a paper about a q-deformed analog of
non-relativistic Schroedinger theory. It applies the general ideas of part I
and tries to give a description of one-particle states on q-deformed quantum
spaces like the braided line or the q-deformed Euclidean space in three
dimensions. Hamiltonian operators for the free q-deformed particle in one as
well as three dimensions are introduced. Plane waves as solutions to the
corresponding Schroedinger equations are considered. Their completeness and
orthonormality relations are written down. Expectation values of position and
momentum observables are taken with respect to one-particle states and their
time-dependence is discussed. A potential is added to the free-particle
Hamiltonians and q-analogs of the Ehrenfest theorem are derived from the
Heisenberg equations of motion. The conservation of probability is proved.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 14:37:12 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wachter",
"Hartmut",
""
]
] |
quant-ph/0703073 | Hartmut Wachter | Hartmut Wachter | Non-relativistic Schroedinger theory on q-deformed quantum spaces III,
Scattering theory | 42 pages, 2 figures, Latex | null | null | null | quant-ph | null | This is the third part of a paper about non-relativistic Schroedinger theory
on q-deformed quantum spaces like the braided line or the three-dimensional
q-deformed Euclidean space. Propagators for the free q-deformed particle are
derived and their basic properties are discussed. A time-dependent formulation
of scattering is proposed. In this respect, q-analogs of the Lippmann-Schwinger
equation are given. Expressions for their iterative solutions are written down.
It is shown how to calculate S-matrices and transition probabilities.
Furthermore, attention is focused on the question what becomes of unitarity of
S-matrices in a q-deformed setting. The examinations are concluded by a
discussion of the interaction picture and its relation to scattering processes.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 14:50:41 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Wachter",
"Hartmut",
""
]
] |
quant-ph/0703074 | Brett Barwick | Brett Barwick, Chris Corder, James Strohaber, Nate Chandler-Smith,
Cornelis Uiterwaal and Herman Batelaan | Laser-induced ultrafast electron emission from a field emission tip | 10 pages, 5 figures | null | 10.1088/1367-2630/9/5/142 | null | quant-ph | null | We show that a field emission tip electron source that is triggered with a
femtosecond laser pulse can generate electron pulses shorter than the laser
pulse duration (~100 fs). The emission process is sensitive to a power law of
the laser intensity, which supports an emission mechanism based on multiphoton
absorption followed by over-the-barrier emission. Observed continuous
transitions between power laws of different orders are indicative of field
emission processes. We show that the source can also be operated so that
thermionic emission processes become significant. Understanding these different
emission processes is relevant for the production of sub-cycle electron pulses.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 16:22:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Barwick",
"Brett",
""
],
[
"Corder",
"Chris",
""
],
[
"Strohaber",
"James",
""
],
[
"Chandler-Smith",
"Nate",
""
],
[
"Uiterwaal",
"Cornelis",
""
],
[
"Batelaan",
"Herman",
""
]
] |
quant-ph/0703075 | Faisal El-Orany Dr. | Faisal A. A. El-Orany, Wahiddin M R B, Obada A-S F | Single-atom entropy squeezing for two two-level atoms interacting with a
single-mode radiation field | 15 pages, 4 figures, comments are most welcome | null | 10.1016/j.optcom.2008.01.051 | null | quant-ph | null | In this paper we consider a system of two two-level atoms interacting with a
single-mode quantized electromagnetic field in a lossless resonant cavity via
$l$-photon-transition mechanism. The field and the atoms are initially prepared
in the coherent state and the excited atomic states, respectively. For this
system we investigate the entropy squeezing, the atomic variances, the von
Neumann entropy and the atomic inversions for the single-atom case. We show
that the more the number of the parties in the system the less the amounts of
the nonclassical effects exhibited in the entropy squeezing.
The entropy squeezing can give information on the corresponding von Neumann
entropy. Also the nonclassical effects obtained form the asymmetric atoms are
greater than those obtained form the symmetric atoms. Finally, the entropy
squeezing gives better information than the atomic variances only for the
asymmetric atoms.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 19:30:05 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Nov 2007 10:07:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"El-Orany",
"Faisal A. A.",
""
],
[
"B",
"Wahiddin M R",
""
],
[
"F",
"Obada A-S",
""
]
] |
quant-ph/0703076 | P. Marecki | P. Marecki | Balanced homodyne detectors in QFT | Revised version with minor mistakes removed | Phys. Rev. A 77, 012101 (2008) | 10.1103/PhysRevA.77.012101 | null | quant-ph | null | Within the dipole approximation we describe the interaction of a photodiode
with the quantum electric field. The diode is modelled by an electron in a
bound state which upon interaction, treated perturbatively in the paper, can
get excited to one of the scattering states. We furthermore analyze a balanced
homodyne detector (BHD) with a local oscillator (LO) consisting of two
photodiodes illuminated by a monochromatic coherent state. We show, that to the
leading order the BHD's output measures the expectation value of the quantum
electric field, in the state without the LO, restricted to the frequency of the
LO. The square of the output measures the two-point function of the quantum
field. This shows that the BHDs provide tools for measurements of sub-vacuum
(negative) expectation values of the squares quantum fields and thus for test
of Quantum Energy Inequality - like bounds, or other QFT effects under the
influence of external conditions.
| [
{
"version": "v1",
"created": "Thu, 8 Mar 2007 20:14:56 GMT"
},
{
"version": "v2",
"created": "Sat, 22 Mar 2008 09:32:38 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Marecki",
"P.",
""
]
] |
quant-ph/0703077 | Mahmoud Abdel-Aty | Mahmoud Abdel-Aty and H. Moya-Cessa | Sudden death and long-lived entanglement of two three-level trapped ions | 10 pages, 3 figures | Physics Letters A, Volume 369, Issues 5-6, 1 October 2007, Pages
372-376 | 10.1016/j.physleta.2007.05.003 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The dynamical properties of quantum entanglement in two three-level trapped
ions interacting with a laser field are studied in terms of the negative
eigenvalues of the partial transposition of the density operator. In contrast
to the usual belief that destroying the entanglement can be observed due to the
environment, it is found that the Stark shift can also produce sudden death of
entanglement and long-lived entanglement between the qubits that are prepared
initially in separable states or mixed states.
| [
{
"version": "v1",
"created": "Fri, 9 Mar 2007 08:30:36 GMT"
},
{
"version": "v2",
"created": "Tue, 6 Jan 2009 11:20:35 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Abdel-Aty",
"Mahmoud",
""
],
[
"Moya-Cessa",
"H.",
""
]
] |
quant-ph/0703078 | Omar Mustafa | Omar Mustafa | Energy-levels crossing and radial Dirac equation: Supersymmetry and
quasi-parity spectral signatures | 15 pages, no figures | Int. J. Theor. Phys. 47, 1300 (2008) | 10.1007/s10773-007-9564-2 | null | quant-ph | null | The (3+1)-dimensional Dirac equation with position dependent mass in 4-vector
electromagnetic fields is considered. Using two over-simplified examples (the
Dirac-Coulomb and Dirac-oscillator fields), we report energy-levels crossing as
a spectral property or as an effect of the hidden supersymmetric quantum
mechanical language and/or quasi-parity signatures. Under different settings of
the related interactions' way-of-coupling into Dirac equation, it is observed
that the two ultimate/effective descendents, Dirac-Coulomb and
Dirac-oscillator, exhibit different conditions on the energy-levels crossings.
| [
{
"version": "v1",
"created": "Fri, 9 Mar 2007 12:01:11 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Apr 2007 09:08:22 GMT"
},
{
"version": "v3",
"created": "Mon, 20 Aug 2007 07:47:06 GMT"
}
] | 2008-04-04T00:00:00 | [
[
"Mustafa",
"Omar",
""
]
] |
quant-ph/0703079 | Massimiliano Federico Sacchi | Massimiliano F. Sacchi | Phase-covariant cloning of coherent states | 6 pages, 2 figures; updated references and minor corrections; in
press on Physical Review A | Phys. Rev. A 75, 042328 (2007) | 10.1103/PhysRevA.75.042328 | null | quant-ph | null | We consider the problem of phase-covariant cloning for coherent states. We
show that an experimental scheme based on ideal phase measurement and
feedforward outperforms the semiclassical procedure of ideal phase measurement
and preparation in terms of fidelity. A realistic scheme where the ideal phase
measurement is replaced with double-homodyne detection is shown to be unable to
overcome the semiclassical cloning strategy. On the other hand, such a
realistic scheme is better than semiclassical cloning based on double-homodyne
phase measurement and preparation.
| [
{
"version": "v1",
"created": "Fri, 9 Mar 2007 17:41:28 GMT"
},
{
"version": "v2",
"created": "Tue, 27 Mar 2007 15:20:35 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Sacchi",
"Massimiliano F.",
""
]
] |
quant-ph/0703080 | Rubens Ramos Viana | Fabio Alencar Mendonca and Rubens Viana Ramos | Quantum bit string commitment protocol using polarization of mesoscopic
coherent states | 10 pages and 1 figure | null | null | null | quant-ph | null | In this work, we propose a quantum bit string commitment protocol using
polarization of mesoscopic coherent states. The protocol is described and its
security against brute force and quantum cloning machine attack is analyzed.
| [
{
"version": "v1",
"created": "Fri, 9 Mar 2007 20:04:18 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Mendonca",
"Fabio Alencar",
""
],
[
"Ramos",
"Rubens Viana",
""
]
] |
quant-ph/0703081 | Peter Brooke G | Peter G. Brooke | Decoherence-free quantum-information processing using dipole-coupled
qubits | 7 pages, 5 figures | Phys. Rev. A 75, 022320 (2007) | 10.1103/PhysRevA.75.022320 | null | quant-ph | null | We propose a quantum-information processor that consists of decoherence-free
logical qubits encoded into arrays of dipole-coupled qubits. High-fidelity
single-qubit operations are performed deterministically within a
decoherence-free subsystem without leakage via global addressing of bichromatic
laser fields. Two-qubit operations are realized locally with four physical
qubits, and between separated logical qubits using linear optics. We show how
to prepare cluster states using this method. We include all
non-nearest-neighbor effects in our calculations, and we assume the qubits are
not located in the Dicke limit. Although our proposal is general to any system
of dipole-coupled qubits, throughout the paper we use nitrogen-vacancy (NV)
centers in diamond as an experimental context for our theoretical results.
| [
{
"version": "v1",
"created": "Fri, 9 Mar 2007 22:24:08 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Brooke",
"Peter G.",
""
]
] |
quant-ph/0703082 | Milos Drezgic | Milosh Drezgich, Shankar Sastry | On the Quantum Circuit Complexity Equivalence | QIP 2007 | null | null | null | quant-ph | null | Nielsen \cite{Nielsen05} recently asked the following question: "What is the
minimal size quantum circuit required to exactly implement a specified $%
\mathit{n}$-qubit unitary operation $U$, without the use of ancilla qubits?"
Nielsen was able to prove that a lower bound on the minimal size circuit is
provided by the length of the geodesic between the identity $I$ and $U$, where
the length is defined by a suitable Finsler metric on $SU(2^{n})$. We prove
that the minimum circuit size that simulates $U$ is in linear relation with the
geodesic length and simulation parameters, for the given Finsler structure $F$.
As a corollary we prove the highest lower bound of $O(\frac{%
n^{4}}{p}d_{F_{p}}^{2}(I,U)L_{F_{p}}(I,\tilde{U})) $and the lowest upper bound
of $\Omega (n^{4}d_{F_{p}}^{3}(I,U))$, for the standard simulation technique.
Therefore, our results show that by standard simulation one can not expect a
better then $n^{2}$ times improvement in the upper bound over the result from
Nielsen, Dowling, Gu and Doherty \cite{Nielsen06}. Moreover, our equivalence
result can be applied to the arbitrary path on the manifold including the one
that is generated adiabatically.
| [
{
"version": "v1",
"created": "Fri, 9 Mar 2007 21:23:41 GMT"
}
] | 2010-01-19T00:00:00 | [
[
"Drezgich",
"Milosh",
""
],
[
"Sastry",
"Shankar",
""
]
] |
quant-ph/0703083 | Ting Yu | Ting Yu and J. H. Eberly | Negative Entanglement Measure, and What It Implies | 4 pages, 5 figures, submitted to Special Issue in Journal of Modern
Optics in honor of Peter Knight | J. Mod. Opt. 54, 2289-2296 (2007) | 10.1080/09500340701432581 | null | quant-ph | null | In this paper, we extract from concurrence its variable part, denoted
$\Lambda$, and use $\Lambda$ as a time-dependent measure of "distance", either
postive or negative, from the separability boundary. We use it to investigate
entanglement dynamics of two isolated but initially entangled qubits, each
coupled to its own environment.
| [
{
"version": "v1",
"created": "Sat, 10 Mar 2007 12:40:31 GMT"
}
] | 2007-10-02T00:00:00 | [
[
"Yu",
"Ting",
""
],
[
"Eberly",
"J. H.",
""
]
] |
quant-ph/0703084 | C. H. Raymond Ooi Dr. | C. H. Raymond Ooi | Phase Controlled Continuously Entangled Two-Photon Laser with Double
$\Lambda$ Scheme | 6 pages (two-column), 4 figures. submitted to a journal on 14
February 2007 | null | null | null | quant-ph | null | We show that an absolute coherent phase of a laser can be used to manipulate
the entanglement of photon pairs of two-photon laser. Our focus is on the
generation of a continuous source of entangled photon pairs in the double
$\Lambda $ (or Raman) scheme. We study the dependence of steady state
entanglement on the phase and laser parameters. We obtain a relationship
between entanglement and two-photon correlation. We derive conditions that give
steady state entanglement for the Raman-EIT scheme and use it to identify
region of steady state macroscopic entanglement. No entanglement is found for
the double resonant Raman scheme for any laser parameters.
| [
{
"version": "v1",
"created": "Sat, 10 Mar 2007 13:27:45 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Ooi",
"C. H. Raymond",
""
]
] |
quant-ph/0703085 | Marcelo Aparecido Marchiolli Dr. | Marcelo A. Marchiolli, Maurizio Ruzzi, Diogenes Galetti | Discrete squeezed states for finite-dimensional spaces | 16 pages; 3 figures | Physical Review A 76 (2007) 032102 | 10.1103/PhysRevA.76.032102 | IFT-P.002/2007 | quant-ph | null | We show how discrete squeezed states in an $N^{2}$-dimensional phase space
can be properly constructed out of the finite-dimensional context. Such
discrete extensions are then applied to the framework of quantum tomography and
quantum information theory with the aim of establishing an initial study on the
interference effects between discrete variables in a finite phase-space.
Moreover, the interpretation of the squeezing effects is seen to be direct in
the present approach, and has some potential applications in different branches
of physics.
| [
{
"version": "v1",
"created": "Sat, 10 Mar 2007 15:57:58 GMT"
},
{
"version": "v2",
"created": "Fri, 6 Jul 2007 11:12:06 GMT"
},
{
"version": "v3",
"created": "Fri, 7 Sep 2007 10:41:57 GMT"
}
] | 2011-11-09T00:00:00 | [
[
"Marchiolli",
"Marcelo A.",
""
],
[
"Ruzzi",
"Maurizio",
""
],
[
"Galetti",
"Diogenes",
""
]
] |
quant-ph/0703086 | Matthias Schork | Toufik Mansour, Matthias Schork, Simone Severini | Wick's theorem for q-deformed boson operators | 9 pages | J. Phys. A: Math. Theor. 40 (2007) 8393-8401 | 10.1088/1751-8113/40/29/014 | null | quant-ph | null | In this paper combinatorial aspects of normal ordering arbitrary words in the
creation and annihilation operators of the q-deformed boson are discussed. In
particular, it is shown how by introducing appropriate q-weights for the
associated ``Feynman diagrams'' the normally ordered form of a general
expression in the creation and annihilation operators can be written as a sum
over all q-weighted Feynman diagrams, representing Wick's theorem in the
present context.
| [
{
"version": "v1",
"created": "Sun, 11 Mar 2007 15:49:44 GMT"
}
] | 2007-07-07T00:00:00 | [
[
"Mansour",
"Toufik",
""
],
[
"Schork",
"Matthias",
""
],
[
"Severini",
"Simone",
""
]
] |
quant-ph/0703087 | Daowen Qiu | Lvzhou Li, Daowen Qiu | Determining the equivalence for 1-way quantum finite automata | Comments are welcome | null | null | null | quant-ph | null | In this paper, we focus on determining the equivalence for {\it 1-way quantum
finite automata with control language} (CL-1QFAs) defined by Bertoni et al and
{\it measure-many 1-way quantum finite automata} (MM-1QFAs) introduced by
Kondacs and Watrous. More specifically, we obtain that: \begin{enumerate}
\item[(i)] Two CL-1QFAs ${\cal A}_1$ and ${\cal A}_2$ with control languages
(regular languages) ${\cal L}_1$ and ${\cal L}_2$, respectively, are equivalent
if and only if they are $(c_1n_1^2+c_2n_2^2-1)$-equivalent. Furthermore, if
${\cal L}_1$ and ${\cal L}_2$ are given in the form of DFAs, with $m_1$ and
$m_2$ states, respectively, then there exists a polynomial-time algorithm
running in time $O ((m_1n_1^2+m_2n_2^2)^4)$ that takes as input ${\cal A}_1$
and ${\cal A}_2$ and determines whether they are equivalent. \item[(ii)] Two
MM-1QFAs ${\cal A}_1$ and ${\cal A}_2$ with $n_1$ and $n_2$ states,
respectively, are equivalent if and only if they are
$(3n_1^2+3n_2^2-1)$-equivalent. Furthermore, there is a polynomial-time
algorithm running in time $O ((3n_1^2+3n_2^2)^4)$ that takes as input ${\cal
A}_1$ and ${\cal A}_2$ and determines whether ${\cal A}_1$ and ${\cal A}_2$ are
equivalent.
| [
{
"version": "v1",
"created": "Sun, 11 Mar 2007 16:35:39 GMT"
},
{
"version": "v2",
"created": "Sat, 21 Apr 2007 00:56:10 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Li",
"Lvzhou",
""
],
[
"Qiu",
"Daowen",
""
]
] |
quant-ph/0703088 | Ting Yu | Chung-Hsien Chou, Ting Yu and B. L. Hu | Exact Master Equation and Quantum Decoherence of Two Coupled Harmonic
Oscillators in a General Environment | 35 pages, revtex, no figures, 2nd version, references added, to
appear in PRE | Phys.Rev.E77:011112,2008 | 10.1103/PhysRevE.77.011112 | null | quant-ph cond-mat.stat-mech gr-qc | null | In this paper we derive an exact master equation for two coupled quantum
harmonic oscillators interacting via bilinear coupling with a common
environment at arbitrary temperature made up of many harmonic oscillators with
a general spectral density function. We first show a simple derivation based on
the observation that the two-harmonic oscillator model can be effectively
mapped into that of a single harmonic oscillator in a general environment plus
a free harmonic oscillator. Since the exact one harmonic oscillator master
equation is available [Hu, Paz and Zhang, Phys. Rev. D \textbf{45}, 2843
(1992)], the exact master equation with all its coefficients for this two
harmonic oscillator model can be easily deduced from the known results of the
single harmonic oscillator case. In the second part we give an influence
functional treatment of this model and provide explicit expressions for the
evolutionary operator of the reduced density matrix which are useful for the
study of decoherence and disentanglement issues. We show three applications of
this master equation: on the decoherence and disentanglement of two harmonic
oscillators due to their interaction with a common environment under Markovian
approximation, and a derivation of the uncertainty principle at finite
temperature for a composite object, modeled by two interacting harmonic
oscillators. The exact master equation for two, and its generalization to $N$,
harmonic oscillators interacting with a general environment are expected to be
useful for the analysis of quantum coherence, entanglement, fluctuations and
dissipation of mesoscopic objects towards the construction of a theoretical
framework for macroscopic quantum phenomena.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 05:13:09 GMT"
},
{
"version": "v2",
"created": "Sun, 9 Dec 2007 14:55:53 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Chou",
"Chung-Hsien",
""
],
[
"Yu",
"Ting",
""
],
[
"Hu",
"B. L.",
""
]
] |
quant-ph/0703089 | Deepak Sridharan | Deepak Sridharan and Edo Waks | Generating entanglement between quantum dots with different resonant
frequencies based on Dipole Induced Transparency | null | null | 10.1103/PhysRevA.78.052321 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We describe a method for generating entanglement between two spatially
separated dipoles coupled to optical micro-cavities.
The protocol works even when the dipoles have different resonant frequencies
and radiative lifetimes.
This method is particularly important for solid-state emitters, such as
quantum dots, which suffer from large inhomogeneous broadening. We show that
high fidelities can be obtained over a large dipole detuning range without
significant loss of efficiency. We analyze the impact of higher order photon
number states and cavity resonance mismatch on the performance of the protocol.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 18:48:23 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Oct 2008 22:58:15 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sridharan",
"Deepak",
""
],
[
"Waks",
"Edo",
""
]
] |
quant-ph/0703090 | Zheng-Yuan Xue | Zheng-Yuan Xue, Z. D. Wang | Simple unconventional geometric scenario of one-way quantum computation
with superconducting qubits inside a cavity | Accepted version with minor amendments. To appear in Phys. Rev. A | Phys. Rev. A 75, 064303 (2007). | 10.1103/PhysRevA.75.064303 | null | quant-ph | null | We propose a simple unconventional geometric scenario to achieve a kind of
nontrivial multi-qubit operations with superconducting charge qubits placed in
a microwave cavity. The proposed quantum operations are insensitive not only to
the thermal state of cavity mode but also to certain random operation errors,
and thus may lead to high-fidelity quantum information processing. Executing
the designated quantum operations, a class of highly entangled cluster states
may be generated efficiently in the present scalable solid-state system,
enabling one to achieve one-way quantum computation.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 08:20:31 GMT"
},
{
"version": "v2",
"created": "Wed, 14 Mar 2007 07:58:09 GMT"
},
{
"version": "v3",
"created": "Mon, 23 Apr 2007 04:30:35 GMT"
}
] | 2007-06-25T00:00:00 | [
[
"Xue",
"Zheng-Yuan",
""
],
[
"Wang",
"Z. D.",
""
]
] |
quant-ph/0703091 | Hannah Venzl | Hannah Venzl and Matthias Freyberger | Quantum estimation of a damping constant | 7 pages, 5 figures | Phys. Rev. A 75, 042322 (2007) | 10.1103/PhysRevA.75.042322 | null | quant-ph | null | We discuss an interferometric approach to the estimation of quantum
mechanical damping. We study specific classes of entangled and separable probe
states consisting of superpositions of coherent states. Based on the assumption
of limited quantum resources we show that entanglement improves the estimation
of an unknown damping constant.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 13:50:26 GMT"
},
{
"version": "v2",
"created": "Thu, 19 Apr 2007 17:50:52 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Venzl",
"Hannah",
""
],
[
"Freyberger",
"Matthias",
""
]
] |
quant-ph/0703092 | Vit Jakubsky | Vit Jakubsky | Thermodynamics of Pseudo-Hermitian Systems in Equilibrium | 9 pages, 2 figures, to appear in Mod.Phys.Lett. A; historical part of
sec. 2.1 reformulated, references corrected; typos corrected | Mod. Phys. Lett. A22, 1075 (2007) | 10.1142/S0217732307023419 | null | quant-ph | null | In study of pseudo(quasi)-hermitian operators, the key role is played by the
positive-definite metric operator. It enables physical interpretation of the
considered systems. In the article, we study the pseudo-hermitian systems with
constant number of particles in equilibrium. We show that the explicit
knowledge of the metric operator is not essential for study of thermodynamic
properties of the system. We introduce a simple example where the physically
relevant quantities are derived without explicit calculation of either metric
operator or spectrum of the Hamiltonian.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 14:18:12 GMT"
},
{
"version": "v2",
"created": "Mon, 19 Mar 2007 13:39:49 GMT"
},
{
"version": "v3",
"created": "Tue, 20 Mar 2007 07:49:57 GMT"
}
] | 2011-11-17T00:00:00 | [
[
"Jakubsky",
"Vit",
""
]
] |
quant-ph/0703093 | Matteo G. A. Paris | Matteo G A Paris, Giulio Landolfi, Giulio Soliani | Generalized measurement of the non-normal two-boson operator $Z_\gamma =
a_1 + \gamma a_2^\dag$ | 8 pages, 2 figures, slightly revised version | J. Phys. A: Math. Theor. 40 (2007) F531-F537. | null | null | quant-ph | null | We address the generalized measurement of the two-boson operator $Z_\gamma=
a_1 + \gamma a_2^\dag$ which, for $|\gamma|^2 \neq 1$, is not normal and cannot
be detected by a joint measurement of quadratures on the two bosons. We
explicitly construct the minimal Naimark extension, which involves a single
additional bosonic system, and present its decomposition in terms of two-boson
linear SU(2) interactions. The statistics of the measurement and the added
noise are analyzed in details. Results are exploited to revisit the
Caves-Shapiro concept of generalized phase observable based on heterodyne
detection.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 17:48:34 GMT"
},
{
"version": "v2",
"created": "Wed, 9 May 2007 17:24:15 GMT"
}
] | 2007-06-12T00:00:00 | [
[
"Paris",
"Matteo G A",
""
],
[
"Landolfi",
"Giulio",
""
],
[
"Soliani",
"Giulio",
""
]
] |
quant-ph/0703094 | Carsten Henkel | C. Henkel (Universit\"at Potsdam, Germany) | Laser theory in manifest Lindblad form | 13 pages, 8 figures, to be published in J Phys B (minor revision) | J. Phys. B: At. Mol. Opt. Phys. 40 (2007) 2359-71 | 10.1088/0953-4075/40/12/012 | null | quant-ph | null | We discuss the laser theory for a single-mode laser with nonlinear gain. We
focus in particular on a micromaser which is pumped with a dilute beam of
excited atoms crossing the laser cavity. In the weak-coupling regime, an
expansion in the coupling strength is developed that preserves the Lindblad
form of the master equation, securing the positivity of the density matrix.
This expansion breaks rapidly down above threshold. This can be improved with
an alternative approach, not restricted to weak coupling: the Lindblad
operators are expanded in orthogonal polynomials adapted to the probability
distribution for the atom-laser interaction time. Results for the photon
statistics and the laser linewidth illustrate the theory.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 21:06:12 GMT"
},
{
"version": "v2",
"created": "Sun, 6 May 2007 21:37:47 GMT"
}
] | 2007-06-06T00:00:00 | [
[
"Henkel",
"C.",
"",
"Universität Potsdam, Germany"
]
] |
quant-ph/0703095 | Marco Piani | Andrzej Grudka, Michal Horodecki, Pawel Horodecki, Ryszard Horodecki,
Marco Piani | Entanglement-swapping boxes and their communication properties | Accepted for publication in Phys. Rev. A as a Rapid Communication | Phys. Rev. A 77, 060307(R) (2008) | 10.1103/PhysRevA.77.060307 | null | quant-ph | null | We pose the fundamental question of communication properties of primitives
irrespectively of their implementation. To illustrate the idea we introduce the
concept of entanglement-swapping boxes, i.e. we consider any quantum operations
which perform entanglement swapping, not necessarily via simple quantum
teleportation. We ask a question about the properties of such boxes., i.e. what
local operations and how much classical communication are needed to perform
them. We also ask if any box which performs entanglement swapping can be used
to establish classical communication. We show that each box needs at least two
bits of classical communication to perform it. It is also shown that each box
can be used for classical communication and, most importantly, that there exist
boxes which allow to communicate at most one bit. Surprisingly we find basic
irreversibility in the process of entanglement swapping with respect to its
communication properties.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 08:33:02 GMT"
},
{
"version": "v2",
"created": "Fri, 23 May 2008 19:43:59 GMT"
}
] | 2008-06-19T00:00:00 | [
[
"Grudka",
"Andrzej",
""
],
[
"Horodecki",
"Michal",
""
],
[
"Horodecki",
"Pawel",
""
],
[
"Horodecki",
"Ryszard",
""
],
[
"Piani",
"Marco",
""
]
] |
quant-ph/0703096 | Steve Flammia | Nicolas C. Menicucci, Steven T. Flammia, Hussain Zaidi, Olivier
Pfister | Ultracompact Generation of Continuous-Variable Cluster States | 4 pages, 1 figure; v2 improved discussion of the implications of our
result; added discussion of finite squeezing effects | Phys. Rev. A 76, 010302(R) (2007) | 10.1103/PhysRevA.76.010302 | null | quant-ph | null | We propose an experimental scheme that has the potential for large-scale
realization of continuous-variable (CV) cluster states for universal quantum
computation. We do this by mapping CV cluster-state graphs onto two-mode
squeezing graphs, which can be engineered into a single optical parametric
oscillator (OPO). The desired CV cluster state is produced directly from a
joint squeezing operation on the vacuum using a multi-frequency pump beam. This
method has potential for ultracompact experimental implementation. As an
illustration, we detail an experimental proposal for creating a four-mode
square CV cluster state with a single OPO.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 16:58:49 GMT"
},
{
"version": "v2",
"created": "Wed, 30 May 2007 01:23:31 GMT"
}
] | 2007-12-23T00:00:00 | [
[
"Menicucci",
"Nicolas C.",
""
],
[
"Flammia",
"Steven T.",
""
],
[
"Zaidi",
"Hussain",
""
],
[
"Pfister",
"Olivier",
""
]
] |
quant-ph/0703097 | Remigiusz Augusiak | Piotr Badzi\k{a}g, Pawe{\l} Horodecki, Ryszard Horodecki, Remigiusz
Augusiak | Separability in terms of a single entanglement witness | 4.4 pages, 1 figure, published version | Physical Review A 88, 010301(R) (2013) | 10.1103/PhysRevA.88.010301 | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The separability problem is formulated in terms of a characterization of a
single entanglement witness. More specifically, we show that any (in general
multipartite) state \varrho is separable if and only if a specially constructed
entanglement witness W_{\varrho} is weakly optimal, i.e., its expectation value
vanishes on at least one product vector. Interestingly, the witness can always
be chosen to be decomposable. Our result changes the conceptual aspect of the
separability problem and rises some questions about properties of positive
maps.
| [
{
"version": "v1",
"created": "Mon, 12 Mar 2007 23:17:47 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Jun 2013 15:41:30 GMT"
},
{
"version": "v3",
"created": "Sun, 7 Jul 2013 16:01:06 GMT"
}
] | 2016-08-17T00:00:00 | [
[
"Badziąg",
"Piotr",
""
],
[
"Horodecki",
"Paweł",
""
],
[
"Horodecki",
"Ryszard",
""
],
[
"Augusiak",
"Remigiusz",
""
]
] |
quant-ph/0703098 | Yan-Kui Bai | Yan-Kui Bai, Dong Yang, Z. D. Wang | Multipartite quantum correlation and entanglement in four-qubit pure
states | 7 pages, 3 figues | Phys. Rev. A 76, 022336 (2007) | 10.1103/PhysRevA.76.022336 | null | quant-ph | null | Based on the quantitative complementarity relations, we analyze thoroughly
the properties of multipartite quantum correlations and entanglement in
four-qubit pure states. We find that, unlike the three-qubit case, the single
residual correlation, the genuine three- and four-qubit correlations are not
suited to quantify entanglement. More interestingly, from our qualitative and
numerical analysis, it is conjectured that the sum of all the residual
correlations may constitute a good measure for the total multipartite
entanglement in the system.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 02:19:54 GMT"
},
{
"version": "v2",
"created": "Sat, 1 Sep 2007 12:57:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bai",
"Yan-Kui",
""
],
[
"Yang",
"Dong",
""
],
[
"Wang",
"Z. D.",
""
]
] |
quant-ph/0703099 | Satoshi Ishizaka | Satoshi Ishizaka | Dilemma that cannot be resolved by biased quantum coin flipping | 5 pages and 1 figure. Accepted version | Phys. Rev. Lett. 100, 070501 (2008) | 10.1103/PhysRevLett.100.070501 | null | quant-ph | null | We show that a biased quantum coin flip (QCF) cannot provide the performance
of a black-boxed biased coin flip, if it satisfies some fidelity conditions.
Although such a QCF satisfies the security conditions of a biased coin flip, it
does not realize the ideal functionality, and therefore, does not fulfill the
demands for universally composable security. Moreover, through a comparison
within a small restricted bias range, we show that an arbitrary QCF is
distinguishable from a black-boxed coin flip unless it is unbiased on both
sides of parties against insensitive cheating. We also point out the difficulty
in developing cheat-sensitive quantum bit commitment in terms of the
uncomposability of a QCF.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 15:08:42 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 02:16:57 GMT"
},
{
"version": "v3",
"created": "Mon, 26 Nov 2007 13:38:17 GMT"
},
{
"version": "v4",
"created": "Tue, 27 Nov 2007 09:00:40 GMT"
},
{
"version": "v5",
"created": "Fri, 11 Jan 2008 05:24:29 GMT"
}
] | 2008-02-20T00:00:00 | [
[
"Ishizaka",
"Satoshi",
""
]
] |
quant-ph/0703100 | Ethem Akturk | O. Ozcan, E. Akturk, R. Sever | Time Dependent Entropy of Constant Force Motion | 9 pages, 3 figures | null | null | null | quant-ph | null | Time dependent entropy of constant force motion is investigated. Their joint
entropy so called Leipnik's entropy is obtained. The main purpose of this work
is to calculate Leipnik's entropy by using time dependent wave function which
is obtained by the Feynman path integral method. It is found that, in this
case, the Leipnik's entropy increase with time and this result has same
behavior free particle case.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 10:21:59 GMT"
},
{
"version": "v2",
"created": "Mon, 19 Mar 2007 12:32:50 GMT"
},
{
"version": "v3",
"created": "Sun, 23 Sep 2007 10:52:01 GMT"
}
] | 2007-09-23T00:00:00 | [
[
"Ozcan",
"O.",
""
],
[
"Akturk",
"E.",
""
],
[
"Sever",
"R.",
""
]
] |
quant-ph/0703101 | Orhan Bayrak | O. Bayrak and I. Boztosun | Analytical Solutions to the Hulthen and the Morse Potentials by using
the Asymptotic Iteration Method | 13 pages and 2 tables | Journal of Molecular Structure: THEOCHEM 802 (2007) 17 | 10.1063/1.2733182 | null | quant-ph | null | We present the exact analytical solution of the radial Schr\"{o}dinger
equation for the deformed Hulth\'{e}n and the Morse potentials within the
framework of the Asymptotic Iteration Method. The bound state energy
eigenvalues and corresponding wave functions are obtained explicitly. Our
results are in excellent agreement with the findings of the other methods.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 11:34:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bayrak",
"O.",
""
],
[
"Boztosun",
"I.",
""
]
] |
quant-ph/0703102 | Orhan Bayrak | A. Soylu, O. Bayrak and I. Boztosun | The Energy Eigenvalues of the Two Dimensional Hydrogen Atom in a
Magnetic Field | 13 pages and 5 tables | Int. J. Mod. Phys. E 15 (2006) 1263 | 10.1142/S021830130600482X | null | quant-ph | null | In this paper, the energy eigenvalues of the two dimensional hydrogen atom
are presented for the arbitrary Larmor frequencies by using the asymptotic
iteration method. We first show the energy eigenvalues for the no magnetic
field case analytically, and then we obtain the energy eigenvalues for the
strong and weak magnetic field cases within an iterative approach for $n=2-10$
and $m=0-1$ states for several different arbitrary Larmor frequencies. The
effect of the magnetic field on the energy eigenvalues is determined precisely.
The results are in excellent agreement with the findings of the other methods
and our method works for the cases where the others fail.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 11:41:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Soylu",
"A.",
""
],
[
"Bayrak",
"O.",
""
],
[
"Boztosun",
"I.",
""
]
] |
quant-ph/0703103 | Dan Kenigsberg | Berry Groisman, Dan Kenigsberg and Tal Mor | "Quantumness" versus "Classicality" of Quantum States | 4 and a bit pages, RevTeX | null | null | null | quant-ph | null | Entanglement is one of the pillars of quantum mechanics and quantum
information processing, and as a result the quantumness of nonentangled states
has typically been overlooked and unrecognized. We give a robust definition for
the classicality versus quantumness of a single multipartite quantum state, a
set of states, and a protocol using quantum states. We show a variety of
nonentangled (separable) states that exhibit interesting quantum properties,
and we explore the ``zoo'' of separable states; several interesting subclasses
are defined based on their diagonalizing bases, and their non-classical
behavior is investigated.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 13:37:54 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Groisman",
"Berry",
""
],
[
"Kenigsberg",
"Dan",
""
],
[
"Mor",
"Tal",
""
]
] |
quant-ph/0703104 | Robert Littlejohn | Vincenzo Aquilanti, Hal M. Haggard, Robert G. Littlejohn, Liang Yu | Semiclassical analysis of Wigner $3j$-symbol | 7 figure files | J. Phys. A: Math. Theor. 40 5637 (2007) | 10.1088/1751-8113/40/21/013 | null | quant-ph | null | We analyze the asymptotics of the Wigner $3j$-symbol as a matrix element
connecting eigenfunctions of a pair of integrable systems, obtained by lifting
the problem of the addition of angular momenta into the space of Schwinger's
oscillators. A novel element is the appearance of compact Lagrangian manifolds
that are not tori, due to the fact that the observables defining the quantum
states are noncommuting. These manifolds can be quantized by generalized
Bohr-Sommerfeld rules and yield all the correct quantum numbers. The geometry
of the classical angular momentum vectors emerges in a clear manner. Efficient
methods for computing amplitude determinants in terms of Poisson brackets are
developed and illustrated.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 15:31:19 GMT"
}
] | 2014-03-12T00:00:00 | [
[
"Aquilanti",
"Vincenzo",
""
],
[
"Haggard",
"Hal M.",
""
],
[
"Littlejohn",
"Robert G.",
""
],
[
"Yu",
"Liang",
""
]
] |
quant-ph/0703105 | Giuliano Benenti | Giuliano Benenti, Giuliano Strini | A bird's eye view of quantum computers | 6 pages, 1 figure | Quantum Biosystems 1, 21 (2007) | null | null | quant-ph | null | Quantum computers are discussed in the general framework of computation, the
laws of physics and the foundations of quantum mechanics.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 15:47:07 GMT"
}
] | 2007-06-13T00:00:00 | [
[
"Benenti",
"Giuliano",
""
],
[
"Strini",
"Giuliano",
""
]
] |
quant-ph/0703106 | Mohamad Ali Jafarizadeh | M. A. Jafarizadeh, R. Sufiani | Bell-states diagonal entanglement witnesses for relativistic and
non-relativistic multispinor systems in arbitrary dimensions | 62 pages | null | 10.1103/PhysRevA.77.012105 | null | quant-ph | null | Two kinds of Bell-states diagonal (BSD) entanglement witnesses (EW) are
constructed by using the algebra of Dirac $\gamma$ matrices in the space-time
of arbitrary dimension $d$, where the first kind can detect some BSD
relativistic and non-relativistic $m$-partite multispinor bound entangled
states in Hilbert space of dimension $2^{m\lfloor d/2\rfloor}$, including the
bipartite Bell-type and iso-concurrence type states in the four-dimensional
space-time ($d=4$). By using the connection between Hilbert-Schmidt measure and
the optimal EWs associated with states, it is shown that as far as the spin
quantum correlations is concerned, the amount of entanglement is not a
relativistic scalar and has no invariant meaning. The introduced EWs are
manipulated via the linear programming (LP) which can be solved exactly by
using simplex method. The decomposability or non-decomposability of these EWs
is investigated, where the region of non-decomposable EWs of the first kind is
partially determined and it is shown that, all of the EWs of the second kind
are decomposable. These EWs have the preference that in the bipartite systems,
they can determine the region of separable states, i.e., bipartite
non-detectable density matrices of the same type as the EWs of the first kind
are necessarily separable. Also, multispinor EWs with non-polygon feasible
regions are provided, where the problem is solved by approximate LP, and in
contrary to the exactly manipulatable EWs, both the first and second kind of
the optimal approximate EWs can detect some bound entangled states.
Keywords: Relativistic entanglement, Entanglement Witness, Multispinor,
Linear Programming, Feasible Region. PACs Index: 03.65.Ud
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 15:51:25 GMT"
},
{
"version": "v2",
"created": "Sun, 16 Sep 2007 13:46:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Jafarizadeh",
"M. A.",
""
],
[
"Sufiani",
"R.",
""
]
] |
quant-ph/0703107 | Dan Kenigsberg | Michel Boyer, Dan Kenigsberg and Tal Mor | Quantum Key Distribution with Classical Bob | 4 and a bit pages, 1 figure, RevTeX | null | 10.1103/PhysRevLett.99.140501 | null | quant-ph cs.CR | null | Secure key distribution among two remote parties is impossible when both are
classical, unless some unproven (and arguably unrealistic)
computation-complexity assumptions are made, such as the difficulty of
factorizing large numbers. On the other hand, a secure key distribution is
possible when both parties are quantum.
What is possible when only one party (Alice) is quantum, yet the other (Bob)
has only classical capabilities? We present a protocol with this constraint,
and prove its robustness against attacks: we prove that any attempt of an
adversary to obtain information (and even a tiny amount of information)
necessarily induces some errors that the legitimate users could notice.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 16:02:59 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Boyer",
"Michel",
""
],
[
"Kenigsberg",
"Dan",
""
],
[
"Mor",
"Tal",
""
]
] |
quant-ph/0703108 | Carlos Saavedra Dr | G. Lima, F. A. Torres-Ruiz, L. Neves, A. Delgado, C. Saavedra and S.
P\'adua | State reconstruction for composite systems of two spatial qubits | 3 Figures | null | 10.1088/1742-6596/84/1/012012 | null | quant-ph | null | Pure entangled states of two spatial qudits have been produced by using the
momentum transverse correlation of the parametric down-converted photons [Phys.
Rev. Lett. \textbf{94} 100501]. Here we show a generalization of this process
to enable the creation of mixed states of spatial qudits and by using the
technique proposed we generate mixed states of spatial qubits. We also report
how the process of quantum tomography is experimentally implemented to
characterize these states. This tomographic reconstruction is based on the free
evolution of spatial qubits, coincidence detection and a filtering process. The
reconstruction method can be generalized for the case of two spatial qudits.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 16:07:18 GMT"
},
{
"version": "v2",
"created": "Wed, 11 Jul 2007 21:53:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lima",
"G.",
""
],
[
"Torres-Ruiz",
"F. A.",
""
],
[
"Neves",
"L.",
""
],
[
"Delgado",
"A.",
""
],
[
"Saavedra",
"C.",
""
],
[
"Pádua",
"S.",
""
]
] |
quant-ph/0703109 | Giovanna Morigi Dr | Priscilla Ca\~nizares, Tobias G\"orler, Juan Pablo Paz, Giovanna
Morigi, and Wolfgang Schleich | Signatures of non-locality in the first-order coherence of the scattered
light | 5 pages, one figure, submitted to Laser Physics, special issue in
memory of Herbert Walther | Laser Physics 17, 903-907 (2007). | 10.1134/S1054660X0707002X | null | quant-ph cond-mat.other | null | The spatial coherence of an atomic wavepacket can be detected in the
scattered photons, even when the center-of-mass motion is in the quantum
coherent superposition of two distant, non-overlapping wave packets. Spatial
coherence manifests itself in the power spectrum of the emitted photons, whose
spectral components can exhibit interference fringes as a function of the
emission angle. The contrast and the phase of this interference pattern provide
information about the quantum state of the center of mass of the scattering
atom.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 18:03:14 GMT"
}
] | 2007-07-17T00:00:00 | [
[
"Cañizares",
"Priscilla",
""
],
[
"Görler",
"Tobias",
""
],
[
"Paz",
"Juan Pablo",
""
],
[
"Morigi",
"Giovanna",
""
],
[
"Schleich",
"Wolfgang",
""
]
] |
quant-ph/0703110 | Giulio Chiribella | G. Chiribella, G. M. D'Ariano, and D. M. Schlingemann | Realization of continuous-outcome measurements on finite dimensional
quantum systems | 6 pages, no figures | null | null | null | quant-ph | null | This note contains the complete mathematical proof of the main Theorem of the
paper "How continuous measurements in finite dimension are actually discrete"
(quant-ph/0702068), thus showing that in finite dimension any measurement with
continuous set of outcomes can be simply realized by randomizing some classical
parameter and conditionally performing a measurement with finite outcomes.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 18:07:14 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Chiribella",
"G.",
""
],
[
"D'Ariano",
"G. M.",
""
],
[
"Schlingemann",
"D. M.",
""
]
] |
quant-ph/0703111 | Paul Lett | C. F. McCormick, A. M. Marino, V. Boyer, P. D. Lett | Strong low-frequency quantum correlations from a four-wave mixing
amplifier | 4 pages, 4 figures. Major rewrite of the previous version. New
experimental results and further analysis | null | 10.1103/PhysRevA.78.043816 | null | quant-ph | null | We show that a simple scheme based on nondegenerate four-wave mixing in a hot
atomic vapor behaves like a near-perfect phase-insensitive optical amplifier,
which can generate bright twin beams with a measured quantum noise reduction in
the intensity difference of more than 8 dB, close to the best optical
parametric amplifiers and oscillators. The absence of a cavity makes the system
immune to external perturbations, and the strong quantum noise reduction is
observed over a large frequency range.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 18:56:13 GMT"
},
{
"version": "v2",
"created": "Wed, 26 Mar 2008 18:47:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"McCormick",
"C. F.",
""
],
[
"Marino",
"A. M.",
""
],
[
"Boyer",
"V.",
""
],
[
"Lett",
"P. D.",
""
]
] |
quant-ph/0703112 | Martin Roetteler | Markus Grassl, Andreas Klappenecker, Martin Roetteler | Graphs, Quadratic Forms, and Quantum Codes | 5 pages, 2 figures, paper presented at the 2002 IEEE International
Symposium on Information Theory | Proceedings 2002 IEEE International Symposium on Information
Theory (ISIT 2002), Lausanne, Switzerland, June/July 2002, p. 45 | 10.1109/ISIT.2002.1023317 | null | quant-ph cs.IT math.IT | null | We show that any stabilizer code over a finite field is equivalent to a
graphical quantum code. Furthermore we prove that a graphical quantum code over
a finite field is a stabilizer code. The technique used in the proof
establishes a new connection between quantum codes and quadratic forms. We
provide some simple examples to illustrate our results.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 21:19:16 GMT"
}
] | 2009-05-24T00:00:00 | [
[
"Grassl",
"Markus",
""
],
[
"Klappenecker",
"Andreas",
""
],
[
"Roetteler",
"Martin",
""
]
] |
quant-ph/0703113 | Martin Roetteler | Salah A. Aly, Markus Grassl, Andreas Klappenecker, Martin Roetteler,
Pradeep Kiran Sarvepalli | Quantum Convolutional BCH Codes | 4 pages, minor changes, accepted for publication at the 10th Canadian
Workshop on Information Theory (CWIT'07) | Proceedings 2007 Canadian Workshop on Information Theory (CWIT
2007), Edmonton, Canada, June 2007, pp. 180-183 | 10.1109/CWIT.2007.375730 | null | quant-ph cs.IT math.IT | null | Quantum convolutional codes can be used to protect a sequence of qubits of
arbitrary length against decoherence. We introduce two new families of quantum
convolutional codes. Our construction is based on an algebraic method which
allows to construct classical convolutional codes from block codes, in
particular BCH codes. These codes have the property that they contain their
Euclidean, respectively Hermitian, dual codes. Hence, they can be used to
define quantum convolutional codes by the stabilizer code construction. We
compute BCH-like bounds on the free distances which can be controlled as in the
case of block codes, and establish that the codes have non-catastrophic
encoders.
| [
{
"version": "v1",
"created": "Tue, 13 Mar 2007 21:25:34 GMT"
},
{
"version": "v2",
"created": "Mon, 9 Apr 2007 14:55:52 GMT"
}
] | 2009-05-24T00:00:00 | [
[
"Aly",
"Salah A.",
""
],
[
"Grassl",
"Markus",
""
],
[
"Klappenecker",
"Andreas",
""
],
[
"Roetteler",
"Martin",
""
],
[
"Sarvepalli",
"Pradeep Kiran",
""
]
] |
quant-ph/0703114 | Guo-Qiang Zhu | Guo-Qiang Zhu | Geometric Phase for degenerate states of spin-1 and spin-1/2 pair | 5 pages, no figures | null | 10.2478/s11534-007-0026-5 | null | quant-ph | null | The geometric phase of a bi-particle model is discussed. For different
initial states, especially when the initial state is pure or mixed, the
geometric phase will show different properties. The relationship between the
geometric phase and the entanglement or mixedness of the initial state is
considered.
| [
{
"version": "v1",
"created": "Wed, 14 Mar 2007 01:14:00 GMT"
},
{
"version": "v2",
"created": "Thu, 5 Apr 2007 05:23:00 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zhu",
"Guo-Qiang",
""
]
] |
quant-ph/0703115 | Liang He | Liang He, Yu-xi Liu, S. Yi, C. P. Sun, and Franco Nori | Control of photon propagation via electromagnetically induced
transparency in lossless media | 10 pages, 5 figures | Phys. Rev. A 75, 063818 (2007) | 10.1103/PhysRevA.75.063818 | null | quant-ph cond-mat.stat-mech | null | We study the influence of a lossless material medium on the coherent storage
and quantum state transfer of a quantized probe light in an ensemble of
$\Lambda $-type atoms. The medium is modeled as uniformly distributed two-level
atoms with same energy level spacing, coupling to a probe light. This coupled
system can be simplified to a collection of two-mode polaritons which couple to
one transition of the $\Lambda$-type atoms. We show that, when the other
transition of $\Lambda$-type atoms is controlled by a classical light, the
electromagnetically induced transparency can also occur for the polaritons. In
this case the coherent storage and quantum transfer for photon states are
achievable through the novel dark states with respect to the polaritons. By
calculating the corresponding dispersion relation, we find the ensemble of the
three-level atoms with $\Lambda$-type transitions may serve as quantum memory
for it slows or even stops the light propagation through the mechanism of
electromagnetically induced transparency. the corresponding dispersion
relation, we find the ensemble of the three-level atoms with $\Lambda$-type
transitions may serve as quantum memory for it slows or even stops the light
propagation through the mechanism of electromagnetically induced transparency.
| [
{
"version": "v1",
"created": "Wed, 14 Mar 2007 01:49:53 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Feb 2008 05:27:45 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"He",
"Liang",
""
],
[
"Liu",
"Yu-xi",
""
],
[
"Yi",
"S.",
""
],
[
"Sun",
"C. P.",
""
],
[
"Nori",
"Franco",
""
]
] |
quant-ph/0703116 | X.L. Zhang | X.L. Zhang, K.L. Gao, M. Feng | Efficient and High-Fidelity Generation of Atomic Cluster State with
Cavity-QED and Linear Optics | 7 pages, 3 figures, to appear in Phys. Rev. A | null | null | null | quant-ph | null | We propose a scheme to generate cluster states of atomic qubits by using
cavity quantum electrodynamics (QED) and linear optics, in which each atom is
confined in a resonant optical cavity with two orthogonally polarized modes.
Our scheme is robust to imperfect factors such as dissipation, photon loss, and
detector inefficiency. Discussions are made for experimental feasibility of our
scheme.
| [
{
"version": "v1",
"created": "Wed, 14 Mar 2007 02:18:21 GMT"
}
] | 2007-05-23T00:00:00 | [
[
"Zhang",
"X. L.",
""
],
[
"Gao",
"K. L.",
""
],
[
"Feng",
"M.",
""
]
] |
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