Non-Markovian entanglement dynamics between two coupled qubits in the same environment

• Published in: Journal of physics. A, Mathematical and theoretical Mathematical and theoretical, 2009-04, Vol.42 (15), p.155303-155303 (13)
• Main Authors: Cui, Wei, Xi, Zairong, Pan, Yu
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Physics
• ISSN: 1751-8121; 1751-8113; 1751-8121
• DOI: 10.1088/1751-8113/42/15/155303

We analyze the dynamics of the entanglement in two independent non-Markovian channels. In particular, we focus on the entanglement dynamics as a function of the initial states and the channel parameters, such as the temperature and the ratio r between omega0, the characteristic frequency of the quantum system of interest, and omegac, the cut-off frequency of the Ohmic reservoir. We give a stationary analysis of the concurrence and find that the dynamic of non-Markovian entanglement concurrence at temperature kBT = 0 is different from the kBT > 0 case. We find that 'entanglement sudden death' (ESD) depends on the initial state when kBT = 0, otherwise the concurrence always disappears at a finite time when kBT > 0, which means that the ESD must happen. The main result of this paper is that the non-Markovian entanglement dynamic is fundamentally different from the Markovian one. In the Markovian channel, entanglement decays exponentially and vanishes only asymptotically, but in the non-Markovian channel the concurrence oscillates, especially in the high temperature case. Then an open-loop controller adjusted by the temperature is proposed to control the entanglement and prolong the ESD time.