Decoherence in the quantum Ising model with transverse dissipative interaction in the strong-coupling regime
Decoherence in the quantum Ising model with transverse dissipative interaction in the strong-coupling regime
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DOI：
10.1103/physreva.98.052109
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发表时间：
2018-11-07
影响因子：
2.9
通讯作者：
Rastelli, G.
中科院分区：
文献类型：
--
作者：
Weisbrich, H.;Saussol, C.;Rastelli, G.
本文研究了有限大小的量子伊辛晶格在横向耗散相互作用下的退相干动力学，即假设与水浴的耦合垂直于自旋相互作用的方向，平行于外磁场。在小横场极限下，通过强耦合展开得到了本征态和谱，并由此导出了马尔可夫极限下的Lindblad方程。在温度低于能隙和弱耗散的情况下，退相干动力学可以被限制为只考虑两个简并基态和第一激发子空间。后者是由成对的拓扑激发（畴壁或扭结），这是量子离域沿着链由于小磁场。我们发现，这些激发态中的一些形成一个弛豫自由子空间，即，他们不衰减到基态。
We study the decoherence dynamics of a quantum Ising lattice of finite size with a transverse dissipative interaction, namely, the coupling with the bath is assumed perpendicular to the direction of the spins interaction and parallel to the external magnetic field. In the limit of small transverse field, the eigenstates and spectrum are obtained by a strong-coupling expansion, from which we derive the Lindblad equation in the Markovian limit. At temperature lower than the energy gap and for weak dissipation, the decoherence dynamics can be restricted to take only the two degenerate ground states and the first excited subspace into account. The latter is formed by pairs of topological excitations (domain walls or kinks), which are quantum delocalized along the chain due to the small magnetic field. We find that some of these excited states form a relaxation-free subspace, namely, they do not decay to the ground states.