Quantum-discord amplification induced by a quantum phase transition via a cavity-Bose-Einstein-condensate system

摘要

We propose a theoretical scheme to realize a sensitive amplification of quantum discord (QD) between two atomic qubits via a cavity-Bose-Einstein- condensate (BEC) system which was used to realize the Dicke quantum phase transition (QPT) for the first time [K. Baumann, C. Guerlin, F. Brennecke, and T. Esslinger, Nature (London)0028-083610.1038ature09009 464, 1301 (2010)]. It is shown that influence of the cavity-BEC system upon the two qubits is equivalent to a phase decoherence environment. It is found that QPT in the cavity-BEC system is the physical mechanism of the sensitive QD amplification.