Department of Physics, University of Illinois, 1110 W. Green Street, Urbana, Illinois 61801, USA.
J Chem Phys. 2013 Mar 21;138(11):114109. doi: 10.1063/1.4795159.
We use numerically exact iterative path integral methods to investigate the decoherence and entanglement dynamics of a tunneling pair of two coupled qubits (spins) system interacting with a dissipative bath. We find that decoherence is generally accompanied by the destruction of entanglement, although the specifics of this destruction depend sensitively on the parameters of the Hamiltonian (qubit-qubit coupling and/or energy bias), the strength of dissipation, the temperature, and the choice of initial condition. We also observe that dissipation can in some cases generate a substantial amount of entanglement. Finally, if an entangled eigenstate exists which does not couple to the environment, the long-time entanglement can significantly exceed the value corresponding to the Boltzmann equilibrium state.
我们使用数值精确的迭代路径积分方法来研究与耗散浴相互作用的两个耦合量子比特（自旋）系统的隧穿对的退相干和纠缠动力学。我们发现，退相干通常伴随着纠缠的破坏，尽管这种破坏的具体情况强烈依赖于哈密顿量的参数（量子比特-量子比特耦合和/或能量偏置）、耗散的强度、温度和初始条件的选择。我们还观察到，在某些情况下，耗散可以产生大量的纠缠。最后，如果存在一个不与环境耦合的纠缠本征态，那么长时间的纠缠可以显著超过对应于玻尔兹曼平衡态的纠缠值。
