Entanglement and communication-reducing properties of noisy N-qubit states

Author(s): W. Laskowski, T. Paterek, Č. Brukner, M. Zukowski

Journal: Phys. Rev. A

Volume: 81

Page(s): 042101

Year: 2010

DOI Number: http://dx.doi.org/10.1103/PhysRevA.81.042101

Link: Link to publication

Abstract:

We consider properties of states of many qubits, which arise after sending certain entangled states via various noisy channels (white noise, colored noise, local depolarization, dephasing, and amplitude damping). Entanglement of these states and their ability to violate certain classes of Bell inequalities are studied. States which violate them allow a higher than classical efficiency in solving related distributed computational tasks with constrained communication. This is a direct property of such states—not requiring their further modification via stochastic local operations and classical communication such as entanglement purification or distillation procedures. We identify families of multiparticle states which are entangled but nevertheless allow the local realistic description of specific Bell experiments. For some of them, the “gap” between the critical values for entanglement and violation of Bell inequality remains finite even in the limit of infinitely many qubits.

Note: http://arxiv.org/abs/0906.0860

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