Dynamics of a quantum phase transition in the random Ising model: Logarithmic dependence of the defect density on the transition rate
Dynamics of a quantum phase transition in the random Ising model: Logarithmic dependence of the defect density on the transition rate
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DOI：
10.1103/physrevb.74.064416
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发表时间：
2006-08-01
影响因子：
3.7
通讯作者：
Dziarmaga, Jacek
中科院分区：
文献类型：
--
作者：
Dziarmaga, Jacek
从顺磁到铁磁的量子相变是由随时间变化的外磁场驱动的。对于任何速率的转变，演化都是非绝热的，有限密度的缺陷在铁磁态被激发。激发态密度只与跃迁速率成对数关系。这与Kibble-Zurek机制对纯系统预测的任何通常的幂定律标度都有本质的不同。无论转变有多慢，缺陷密度大体上保持不变。
A quantum phase transition from paramagnetic to ferromagnetic phase is driven by a time-dependent external magnetic field. For any rate of the transition the evolution is nonadiabatic and finite density of defects is excited in the ferromagnetic state. The density of excitations has only logarithmic dependence on the transition rate. This is qualitatively different than any usual power law scaling predicted for pure systems by the Kibble-Zurek mechanism. No matter how slow the transition is the defect density remains more or less the same.