http://pra.aps.org/ Recently published articles in Phys. Rev. A in the Table of Content section "Quantum information" en-us Copyright (c) 2009 The American Physical Society 2009-11-05T23:48:39-05:00 assocpub@aps.org rss@aps.org hourly 4 2009-11-05T23:48:39-05:00 rss@aps.org http://link.aps.org/doi/10.1103/PhysRevA.80.052305 Author(s): Boris F. Samsonov<br/>The necessary and sufficient conditions for minimization of the generalized rate error for discriminating among N pure qubit states are reformulated in terms of Bloch vectors representing the states. For the direct optimization problem, an algorithmic solution to these conditions is indicated. A sol...<br/>[Phys. Rev. A 80, 052305] Published Wed Nov 04, 2009 Boris F. Samsonov 2009-11-04T00:00:00-05:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.052305 Phys. Rev. A 80, 052305 text/html article Physical Review A 80 5 2009-11-04T00:00:00-05:00 052305 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.052304 Author(s): Animesh Datta<br/>We calculate the quantum discord between two free modes of a scalar field, which start in a maximally entangled state and then undergo a relative constant acceleration. In a regime where there is no distillable entanglement due to the Unruh effect, we show that there is a finite amount of quantum di...<br/>[Phys. Rev. A 80, 052304] Published Wed Nov 04, 2009 Animesh Datta 2009-11-04T00:00:00-05:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.052304 Phys. Rev. A 80, 052304 text/html article Physical Review A 80 5 2009-11-04T00:00:00-05:00 052304 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.052303 Author(s): Adam Miranowicz, Marco Piani, Paweł Horodecki, and Ryszard Horodecki<br/>Inseparability criteria for continuous and discrete bipartite quantum states based on moments of annihilation and creation operators are studied by developing the idea of Shchukin-Vogel criterion [Phys. Rev. Lett. 95, 230502 (2005)]. If a state is separable, then the corresponding matrix of moments ...<br/>[Phys. Rev. A 80, 052303] Published Tue Nov 03, 2009 Adam Miranowicz, Marco Piani, Paweł Horodecki, and Ryszard Horodecki 2009-11-03T00:00:00-05:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.052303 Phys. Rev. A 80, 052303 text/html article Physical Review A 80 5 2009-11-03T00:00:00-05:00 052303 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.052302 Author(s): D. B. Hume, C. W. Chou, T. Rosenband, and D. J. Wineland<br/>We have investigated theoretically and experimentally a method for preparing Dicke states in trapped atomic ions. We consider a linear chain of N ion qubits that is prepared in a particular Fock state of motion |m⟩ . The m phonons are removed by applying a laser pulse globally to the N qubits and ...<br/>[Phys. Rev. A 80, 052302] Published Mon Nov 02, 2009 D. B. Hume, C. W. Chou, T. Rosenband, and D. J. Wineland 2009-11-02T00:00:00-05:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.052302 Phys. Rev. A 80, 052302 text/html article Physical Review A 80 5 2009-11-02T00:00:00-05:00 052302 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.052301 Author(s): F. M. Andrade and M. G. E. da Luz<br/>Coin and scattering are the two major formulations for discrete quantum walks models, each believed to have its own advantages in different applications. Although they are related in some cases, it was an open question their equivalence in arbitrary topologies. Here we present a general construction...<br/>[Phys. Rev. A 80, 052301] Published Mon Nov 02, 2009 F. M. Andrade and M. G. E. da Luz 2009-11-02T00:00:00-05:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.052301 Phys. Rev. A 80, 052301 text/html article Physical Review A 80 5 2009-11-02T00:00:00-05:00 052301 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042333 Author(s): Thomas Barthel, Carlos Pineda, and Jens Eisert<br/>A fermionic operator circuit is a product of fermionic operators of usually different and partially overlapping support. Further elements of fermionic operator circuits (FOCs) are partial traces and partial projections. The presented framework allows for the introduction of fermionic versions of kno...<br/>[Phys. Rev. A 80, 042333] Published Fri Oct 30, 2009 Thomas Barthel, Carlos Pineda, and Jens Eisert 2009-10-30T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042333 Phys. Rev. A 80, 042333 text/html article Physical Review A 80 4 2009-10-30T00:00:00-04:00 042333 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042332 Author(s): A. Romanelli<br/>We generalize the discrete quantum walk on the line using a time-dependent unitary coin operator. We find an analytical relation between the long-time behaviors of the standard deviation and the coin operator. Selecting the coin time sequence allows to obtain a variety of predetermined asymptotic wa...<br/>[Phys. Rev. A 80, 042332] Published Thu Oct 29, 2009 A. Romanelli 2009-10-29T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042332 Phys. Rev. A 80, 042332 text/html article Physical Review A 80 4 2009-10-29T00:00:00-04:00 042332 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042331 Author(s): Giuliano G. La Guardia<br/>Three code constructions generating new families of good nonbinary quantum codes are presented in this paper. The first two ones are derived from Hermitian self-orthogonal non-narrow-sense Bose-Chaudhuri-Hocquenghem (BCH) codes. The third one is derived from q -ary ( q≠2 is a prime power) Steaneâ€...<br/>[Phys. Rev. A 80, 042331] Published Wed Oct 28, 2009 Giuliano G. La Guardia 2009-10-28T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042331 Phys. Rev. A 80, 042331 text/html article Physical Review A 80 4 2009-10-28T00:00:00-04:00 042331 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042330 Author(s): Christian K. Burrell<br/>A generalized depolarizing channel acts on an N -dimensional quantum system to compress the “Bloch ball” in N^{2} −1 directions; it has a corresponding compression vector. We investigate the geometry of these compression vectors and prove a conjecture of Dixit and Sudarshan [Phys. Rev. A 78, 0...<br/>[Phys. Rev. A 80, 042330] Published Tue Oct 27, 2009 Christian K. Burrell 2009-10-27T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042330 Phys. Rev. A 80, 042330 text/html article Physical Review A 80 4 2009-10-27T00:00:00-04:00 042330 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042329 Author(s): Hideomi Nihira and C. R. Stroud, Jr.<br/>In this paper we explore the possibility of a steady-state entanglement of two two-level atoms inside a pumped cavity by taking into account cavity leakage and the spontaneous emission of photons by the atoms. We describe the system in the dressed state picture in which the coherence is built into t...<br/>[Phys. Rev. A 80, 042329] Published Tue Oct 27, 2009 Hideomi Nihira and C. R. Stroud, Jr. 2009-10-27T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042329 Phys. Rev. A 80, 042329 text/html article Physical Review A 80 4 2009-10-27T00:00:00-04:00 042329 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042328 Author(s): Cosmo Lupo, Laleh Memarzadeh, and Stefano Mancini<br/>The notion of forgetfulness, used in discrete quantum memory channels, is slightly weakened in order to be applied to the case of continuous channels. This is done in the context of quantum memory channels with Markovian noise. As a case study, we apply the notion of weak forgetfulness to a bosonic ...<br/>[Phys. Rev. A 80, 042328] Published Tue Oct 27, 2009 Cosmo Lupo, Laleh Memarzadeh, and Stefano Mancini 2009-10-27T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042328 Phys. Rev. A 80, 042328 text/html article Physical Review A 80 4 2009-10-27T00:00:00-04:00 042328 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042327 Author(s): M. Hor-Meyll, A. Auyuanet, C. V. S. Borges, A. Aragão, J. A. O. Huguenin, A. Z. Khoury, and L. Davidovich<br/>We propose an all-optical setup, which couples different degrees of freedom of a single photon, to investigate entanglement generation by a common environment. The two qubits are represented by the photon polarization and Hermite-Gauss transverse modes, while the environment corresponds to the photo...<br/>[Phys. Rev. A 80, 042327] Published Mon Oct 26, 2009 M. Hor-Meyll, A. Auyuanet, C. V. S. Borges, A. Aragão, J. A. O. Huguenin, A. Z. Khoury, and L. Davidovich 2009-10-26T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042327 Phys. Rev. A 80, 042327 text/html article Physical Review A 80 4 2009-10-26T00:00:00-04:00 042327 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042326 Author(s): M. J. Testolin, J. H. Cole, and L. C. L. Hollenberg<br/>We describe how the effect of charge noise on a pair of spins coupled via the exchange interaction can be calculated by modeling charge fluctuations as a random telegraph noise process using probability density functions. We develop analytic expressions for the time-dependent superoperator of a pair...<br/>[Phys. Rev. A 80, 042326] Published Fri Oct 23, 2009 M. J. Testolin, J. H. Cole, and L. C. L. Hollenberg 2009-10-23T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042326 Phys. Rev. A 80, 042326 text/html article Physical Review A 80 4 2009-10-23T00:00:00-04:00 042326 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042325 Author(s): D. Sugny, L. Bomble, T. Ribeyre, O. Dulieu, and M. Desouter-Lecomte<br/>Implementation of quantum controlled-NOT (CNOT) gates in realistic molecular systems is studied using stimulated Raman adiabatic passage (STIRAP) techniques optimized in the time domain by genetic algorithms or coupled with optimal control theory. In the first case, with an adiabatic solution (a ser...<br/>[Phys. Rev. A 80, 042325] Published Fri Oct 23, 2009 D. Sugny, L. Bomble, T. Ribeyre, O. Dulieu, and M. Desouter-Lecomte 2009-10-23T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042325 Phys. Rev. A 80, 042325 text/html article Physical Review A 80 4 2009-10-23T00:00:00-04:00 042325 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042324 Author(s): Li-Yi Hsu and Keng-Shuo Wu<br/>In this paper, we investigate multipartite unlockable stabilized bound entanglement. First, the mathematical structure of these stabilized bound entangled states is studied. Second, since stabilizer states are the local equivalent to the graph states, we study such stabilized mixed states in the gra...<br/>[Phys. Rev. A 80, 042324] Published Fri Oct 23, 2009 Li-Yi Hsu and Keng-Shuo Wu 2009-10-23T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042324 Phys. Rev. A 80, 042324 text/html article Physical Review A 80 4 2009-10-23T00:00:00-04:00 042324 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042323 Author(s): Masahiro Hotta<br/>We analyze a protocol of quantum energy teleportation that transports energy from the left edge of a linear ion crystal to the right edge by local operations and classical communication at a speed considerably greater than the speed of a phonon in the crystal. A probe qubit is strongly coupled with ...<br/>[Phys. Rev. A 80, 042323] Published Thu Oct 22, 2009 Masahiro Hotta 2009-10-22T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042323 Phys. Rev. A 80, 042323 text/html article Physical Review A 80 4 2009-10-22T00:00:00-04:00 042323 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042322 Author(s): Leonardo Neves, Gustavo Lima, Aldo Delgado, and Carlos Saavedra<br/>We show that the quantum disentanglement eraser implemented on a two-photon system from parametric downconversion is a general method to create hybrid photonic entanglement, namely the entanglement between different degrees of freedom of the photon pair. To demonstrate this, we generate and characte...<br/>[Phys. Rev. A 80, 042322] Published Thu Oct 22, 2009 Leonardo Neves, Gustavo Lima, Aldo Delgado, and Carlos Saavedra 2009-10-22T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042322 Phys. Rev. A 80, 042322 text/html article Physical Review A 80 4 2009-10-22T00:00:00-04:00 042322 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042321 Author(s): Jian Yang, Xiao-Hui Bao, Han Zhang, Shuai Chen, Cheng-Zhi Peng, Zeng-Bing Chen, and Jian-Wei Pan<br/>In this paper, we report a realization of synchronization-free quantum teleportation and narrowband three-photon entanglement through interfering narrowband photon sources. Since both the single-photon and the entangled photon pair utilized are completely autonomous, it removes the requirement of hi...<br/>[Phys. Rev. A 80, 042321] Published Thu Oct 22, 2009 Jian Yang, Xiao-Hui Bao, Han Zhang, Shuai Chen, Cheng-Zhi Peng, Zeng-Bing Chen, and Jian-Wei Pan 2009-10-22T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042321 Phys. Rev. A 80, 042321 text/html article Physical Review A 80 4 2009-10-22T00:00:00-04:00 042321 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042320 Author(s): Heng Shen, Xiaolong Su, Xiaojun Jia, and Changde Xie<br/>We propose two types of quantum dense coding communication networks with optical continuous variables, in which a quadripartite entangled state of the optical field with totally three-party correlations of quadrature amplitudes is utilized. In the networks, the exchange of information between any tw...<br/>[Phys. Rev. A 80, 042320] Published Thu Oct 22, 2009 Heng Shen, Xiaolong Su, Xiaojun Jia, and Changde Xie 2009-10-22T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042320 Phys. Rev. A 80, 042320 text/html article Physical Review A 80 4 2009-10-22T00:00:00-04:00 042320 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042319 Author(s): Feng Mei, Mang Feng, Ya-Fei Yu, and Zhi-Ming Zhang<br/>We present a scheme for scalable quantum information processing with atomic ensembles and flying photons. Using the Rydberg blockade, we encode the qubits in the collective atomic states, which could be manipulated fast and easily due to the enhanced interaction in comparison to the single-atom case...<br/>[Phys. Rev. A 80, 042319] Published Tue Oct 20, 2009 Feng Mei, Mang Feng, Ya-Fei Yu, and Zhi-Ming Zhang 2009-10-20T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042319 Phys. Rev. A 80, 042319 text/html article Physical Review A 80 4 2009-10-20T00:00:00-04:00 042319 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042318 Author(s): Eduardo Martín-Martínez and Juan León<br/>We introduce an arbitrary number of accessible modes when analyzing bipartite entanglement degradation due to Unruh effect between two partners Alice and Rob. Under the single mode approximation (SMA) a fermion field only had a few accessible levels due to Pauli exclusion principle conversely to bos...<br/>[Phys. Rev. A 80, 042318] Published Tue Oct 20, 2009 Eduardo Martín-Martínez and Juan León 2009-10-20T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042318 Phys. Rev. A 80, 042318 text/html article Physical Review A 80 4 2009-10-20T00:00:00-04:00 042318 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042317 Author(s): Leonid P. Pryadko and Gregory Quiroz<br/>We consider the effect of broadband decoherence on the performance of refocusing sequences, having in mind applications of dynamical decoupling in concatenation with quantum error correcting codes as the first stage of coherence protection. Specifically, we construct cumulant expansions of effective...<br/>[Phys. Rev. A 80, 042317] Published Tue Oct 20, 2009 Leonid P. Pryadko and Gregory Quiroz 2009-10-20T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042317 Phys. Rev. A 80, 042317 text/html article Physical Review A 80 4 2009-10-20T00:00:00-04:00 042317 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042316 Author(s): Nguyen Ba An and Jaewan Kim<br/>We consider a type of (M+N) -mode entangled coherent states and propose a simple deterministic scheme to generate these states that can fly freely in space. We then exploit such free-flying states to teleport certain kinds of superpositions of multimode coherent states. We also address the issue of ...<br/>[Phys. Rev. A 80, 042316] Published Tue Oct 20, 2009 Nguyen Ba An and Jaewan Kim 2009-10-20T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042316 Phys. Rev. A 80, 042316 text/html article Physical Review A 80 4 2009-10-20T00:00:00-04:00 042316 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.040303 Author(s): Hayato Goto and Kouichi Ichimura<br/>A scheme for fault-tolerant quantum computation (FTQC) with probabilistic two-qubit gates is proposed. The error thresholds for FTQC are estimated by numerical simulations, where the conditional error probability (the error probability under the condition of “success”) is taken into account in a...<br/><img src="http://prola.aps.org/graphics/rapid30x30.gif" width="30" height="30" alt="Rapid Communication"/><br/>[Phys. Rev. A 80, 040303] Published Tue Oct 20, 2009 Hayato Goto and Kouichi Ichimura 2009-10-20T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.040303 Phys. Rev. A 80, 040303 text/html article Physical Review A 80 4 2009-10-20T00:00:00-04:00 040303 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.044303 Author(s): J. Dajka, M. Mierzejewski, and J. Łuczka<br/>We consider a system consisting of a large number of interacting qubits and study the geometric phase of one of them. The many body interaction is analyzed within a mean-field approach when the reduced dynamics of a single qubit is described by a nonlinear Hartree equation. Generally, the geometric ...<br/>[Phys. Rev. A 80, 044303] Published Mon Oct 19, 2009 J. Dajka, M. Mierzejewski, and J. Łuczka 2009-10-19T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.044303 Phys. Rev. A 80, 044303 text/html article Physical Review A 80 4 2009-10-19T00:00:00-04:00 044303 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042315 Author(s): Lian-Ao Wu, Yu-xi Liu, and Franco Nori<br/>We consider an exact state transmission, where a density matrix in one information processor A at time t=0 is exactly equal to that in another processor B at a later time. We demonstrate that there always exists a complete set of orthogonal states, which can be employed to perform the exact state tr...<br/>[Phys. Rev. A 80, 042315] Published Mon Oct 19, 2009 Lian-Ao Wu, Yu-xi Liu, and Franco Nori 2009-10-19T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042315 Phys. Rev. A 80, 042315 text/html article Physical Review A 80 4 2009-10-19T00:00:00-04:00 042315 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042314 Author(s): Dariusz Chruściński, Andrzej Kossakowski, and Gniewomir Sarbicki<br/>It is shown that entanglement witnesses constructed via the family of spectral conditions are decomposable, i.e., cannot be used to detect bound entanglement. It supports several observations that bound entanglement reveals highly nonspectral features.<br/>[Phys. Rev. A 80, 042314] Published Mon Oct 19, 2009 Dariusz Chruściński, Andrzej Kossakowski, and Gniewomir Sarbicki 2009-10-19T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042314 Phys. Rev. A 80, 042314 text/html article Physical Review A 80 4 2009-10-19T00:00:00-04:00 042314 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042313 Author(s): C. Ricardo Viteri, Yu Tomita, and Kenneth R. Brown<br/>We calculate the critical temperature of the Ising model on a set of graphs representing a concatenated three-bit error-correction code. The graphs are derived from the stabilizer formalism used in quantum error correction. The stabilizer for a subspace is defined as the group of Pauli operators who...<br/>[Phys. Rev. A 80, 042313] Published Mon Oct 19, 2009 C. Ricardo Viteri, Yu Tomita, and Kenneth R. Brown 2009-10-19T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042313 Phys. Rev. A 80, 042313 text/html article Physical Review A 80 4 2009-10-19T00:00:00-04:00 042313 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.042312 Author(s): Jaromír Fiurášek and Michal Mičuda<br/>We investigate optimal discrimination between two projective quantum measurements on a single qubit. We consider a scenario where the measurement that should be identified can be performed twice and we show that adaptive discrimination strategy, entangled probe states, and feed forward all help to i...<br/>[Phys. Rev. A 80, 042312] Published Fri Oct 16, 2009 Jaromír Fiurášek and Michal Mičuda 2009-10-16T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.042312 Phys. Rev. A 80, 042312 text/html article Physical Review A 80 4 2009-10-16T00:00:00-04:00 042312 Quantum information Quantum information http://link.aps.org/doi/10.1103/PhysRevA.80.044302 Author(s): Jacob Dunningham, Veiko Palge, and Vlatko Vedral<br/>Recent work has argued that the concepts of entanglement and nonlocality must be taken seriously even in systems consisting of only a single particle. These treatments, however, are nonrelativistic, and, if single-particle entanglement is fundamental, it should also persist in a relativistic descrip...<br/>[Phys. Rev. A 80, 044302] Published Thu Oct 15, 2009 Jacob Dunningham, Veiko Palge, and Vlatko Vedral 2009-10-15T00:00:00-04:00 Personal use only, all commercial or other reuse prohibited 10.1103/PhysRevA.80.044302 Phys. Rev. A 80, 044302 text/html article Physical Review A 80 4 2009-10-15T00:00:00-04:00 044302 Quantum information Quantum information