Disorder-induced rounding of certain quantum phase transitions.
Disorder-induced rounding of certain quantum phase transitions.
复制标题
无序引起的某些量子相变的舍入。
DOI：
10.1103/physrevlett.90.107202
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发表时间：
2002
影响因子：
8.6
通讯作者：
T. Vojta
中科院分区：
文献类型：
--
作者：
T. Vojta
研究了猝灭无序对过阻尼动力学系统量子相变的影响。对于伊辛序参量对称性无序破坏尖锐的相变通过舍入，因为一个静态序参量可以发展在罕见的空间区域。这导致耦合常数的序参数的指数依赖。在有限温度下，稀有区的静态有序被破坏。这恢复了相变，并导致临界温度和耦合强度之间的双指数关系。我们讨论了基于Lifshitz-tail参数的行为，并通过模型系统的模拟来说明结果。
We study the influence of quenched disorder on quantum phase transitions in systems with overdamped dynamics. For Ising order-parameter symmetry disorder destroys the sharp phase transition by rounding because a static order parameter can develop on rare spatial regions. This leads to an exponential dependence of the order parameter on the coupling constant. At finite temperatures the static order on the rare regions is destroyed. This restores the phase transition and leads to a double-exponential relation between critical temperature and coupling strength. We discuss the behavior based on Lifshitz-tail arguments and illustrate the results by simulations of a model system.