Decay of Loschmidt echo enhanced by quantum criticality
Decay of Loschmidt echo enhanced by quantum criticality
复制标题
量子临界性增强了洛施密特回波的衰变
DOI：
10.1103/physrevlett.96.140604
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发表时间：
2006-04-14
影响因子：
8.6
通讯作者：
Sun, CP
中科院分区：
文献类型：
--
作者：
Quan, HT;Song, Z;Sun, CP
我们研究了量子系统从纯状态到混合状态的过渡，该量子是由周围系统耦合的量子临界性引起的。为了定量地表征该过渡，我们仔细检查了E loschmidt Echo（le）的行为，该e echo（le）在横向场中建模为ISING模型，该模型的表现是量子测量中的测量设备。发现E的量子临界行为强烈影响其增强LE衰减的能力：接近横向场的临界值，这需要发生量子相变的发生，量子相变的发生，降低密度矩阵的外部元素描述了S消失的密度矩阵急剧。
We study the transition of a quantum system S from a pure state to a mixed one, which is induced by the quantum criticality of the surrounding system E coupled to it. To characterize this transition quantitatively, we carefully examine the behavior of the Loschmidt echo (LE) of E modeled as an Ising model in a transverse field, which behaves as a measuring apparatus in quantum measurement. It is found that the quantum critical behavior of E strongly affects its capability of enhancing the decay of LE: near the critical value of the transverse field entailing the happening of quantum phase transition, the off-diagonal elements of the reduced density matrix describing S vanish sharply.