Tuesday, April 10, 2012

1204.1900 (M. Ramzan)

Decoherence dynamics of geometric measure of quantum discord and
measurement-induced nonlocality for noninertial observers at finite
temperature
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M. Ramzan
Quantum discord quantifies the total non-classical correlations in a mixed state. It is the difference between total correlation, measured by quantum mutual information, and the classical correlation. Another step forward towards the quantification of quantum discord was by Dakic, Vedral, and Brukner [Phys. Rev. Lett. 105,190502 (2010)] who introduced the geometric measure of quantum discord (GMQD) and derived an explicit formula for a two-qubit state. Recently, Luo and Fu [Phys. Rev. Lett. 106, 120401 (2011)] introduced measurement-induced nonlocality (MIN) as a measure of nonlocality for a bipartite quantum system. The dynamics of GMQD is recently considered by Song et al. [arXiv: quant/ph.1203.3356] and Zhang et al. [Eur. Phys. J. D 66, 34 (2012)] for inertial observers. However, the topic requires due attention in noninertial frames, particularly, from the perspective of MIN. Here I consider X-structured bipartite quantum system in noninertial frames and analyze the decoherence dynamics of GMQD and MIN at finite temperature. The dynamics under the influence of amplitude damping, depolarizing and phase flip channels is discussed. It is worth-noting that initial state entanglement plays an important role in bipartite states. It is possible to distinguish the Bell, Werner and general type initial quantum states using GMQD. It is seen that depolarizing channel heavily influences the GMQD and MIN as compared to the amplitude damping channel. The behaviour of phase flip channel is symmetrical around 50% decoherence. No sudden death of GMQD and MIN occurs at finite temperature even in the presence of decoherence. It is also shown that the Bell diagonal states are more robust than Werner like states at finite temperature. Furthermore, the effects of environment and the acceleration of the accelerated partner are comparable at finite temperature.
View original: http://arxiv.org/abs/1204.1900

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