Entanglement evolution via quantum resonances
Entanglement evolution via quantum resonances
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通过量子共振的纠缠演化
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
M. Merkli
中科院分区：
文献类型：
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作者：
M. Merkli
我们考虑两个量子比特与局部和集体热库的相互作用。每个自旋-库相互作用由能量交换和能量守恒通道组成。我们证明了一个共振表示的减少动力学的自旋，有效的所有时间t 0，误差（小相互作用）估计严格，均匀的时间。与非相互作用的能量差相关的子空间独立地演化，将约化密度矩阵划分为联合演化矩阵元素的动态解耦簇。在每个子空间内的动力学是马尔可夫与发电机完全由共振数据的完整的哈密顿。基于共振表象，我们研究了纠缠（并发）的演化。我们证明了，当热化发生时，任何初始态的纠缠都会在有限时间内消失，并且不会恢复。对于一类具体的初始纠缠自旋态，我们发现明确的边界纠缠生存和死亡时间。
We consider two qubits interacting with local and collective thermal reservoirs. Each spin-reservoir interaction consists of an energy exchange and an energy conserving channel. We prove a resonance representation of the reduced dynamics of the spins, valid for all times t ⩾ 0, with errors (small interaction) estimated rigorously, uniformly in time. Subspaces associated to non-interacting energy differences evolve independently, partitioning the reduced density matrix into dynamically decoupled clusters of jointly evolving matrix elements. Within each subspace the dynamics is Markovian with a generator determined entirely by the resonance data of the full Hamiltonian. Based on the resonance representation we examine the evolution of entanglement (concurrence). We show that, whenever thermalization takes place, entanglement of any initial state dies out in a finite time and will not return. For a concrete class of initially entangled spin states we find explicit bounds on entanglement survival and death ti...