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International Journal of Quantum Information

ENHANCING STATIONARY ENTANGLEMENT OF TWO QUBITS OR QUTRITS BY COLLECTIVELY INTERACTING WITH A COMMON THERMAL RESERVOIR

Shangbin Li, Jing‐Bo Xu

Published Dec 1, 2008• 1 citation
Publisher

Abstract

The stationary entanglement and Bell violation of two qubits collectively interacting with a common thermal reservoir is investigated, and the analytical relations among average thermal photon number of the reservoir, entanglement and Bell violation of two qubits are given in detail. The initial fraction of Bell singlet state determines whether the common thermal reservoir can enhance the entanglement of two qubits or not in this case. Moreover, the stationary maximally entangled mixed state can emerge in the collective decay of two qubits in a thermal reservoir at zero-temperature only if the fraction of Bell singlet state in the initial state is not smaller than 2/3. Furthermore, it is shown that the collective decay can induce the entanglement of two qutrits initially in the maximally mixed state, and induce distillable entanglement from bound entangled states.

DOI
10.1142/s0219749908004407

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A relaxation process of a two-qubit system is studied by means of the quantum master equation.The two qubits interact with each other via the Ising-type coupling, and one of the two qubits is placed under the influence of a thermal reservoir and the other is isolated from an environmental system.It is shown that the interaction between the two qubits significantly affects the relaxation process.The synthetic effect of the interaction between the qubit-qubit interaction and qubit-reservoir interaction induces the entanglement suddenbirth and the violation of the Bell inequality, even if there is no entanglement in an initial state of the two qubits.
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