Thermal Ising transitions in the vicinity of two-dimensional quantum critical points
Thermal Ising transitions in the vicinity of two-dimensional quantum critical points
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DOI：
10.1103/physrevb.93.155157
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发表时间：
2016-02
影响因子：
3.7
通讯作者：
S. Hesselmann;S. Wessel
中科院分区：
文献类型：
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作者：
S. Hesselmann;S. Wessel
量子临界点附近有序相转变温度的标度以及量子临界区内的序参数涨落提供了关于量子临界点的普遍性质的有价值的信息。在这里，我们用量子蒙特卡罗模拟详细地研究了在量子临界点附近呈现有限温度伊辛跃迁的二维量子系统的这些关系，该量子临界点属于以下两种情况中的普适类：(I)正方形晶格上横向磁场中量子伊辛模型的三维伊辛模型，或者(Ii)蜂窝晶格上具有最近邻排斥的半填充无自旋费米子系统的手征伊辛跃迁。虽然第一种情况允许大规模模拟根据量子临界点的临界指数的已知值来高精度地评估标度预测，但对于后一种情况，我们提取了与序参数涨落有关的临界指数$\nu$和$\eta$的值，我们结合最近从基态量子蒙特卡罗计算和分析方法中得到的其他估计进行了讨论。
The scaling of the transition temperature into an ordered phase close to a quantum critical point as well as the order parameter fluctuations inside the quantum critical region provide valuable information about universal properties of the underlying quantum critical point. Here, we employ quantum Monte Carlo simulations to examine these relations in detail for two-dimensional quantum systems that exhibit a finite-temperature Ising-transition line in the vicinity of a quantum critical point that belongs to the universality class of either (i) the three-dimensional Ising model for the case of the quantum Ising model in a transverse magnetic field on the square lattice or (ii) the ${\it chiral}$ Ising transition for the case of a half-filled system of spinless fermions on the honeycomb lattice with nearest-neighbor repulsion. While the first case allows large-scale simulations to assess the scaling predictions to a high precision in terms of the known values for the critical exponents at the quantum critical point, for the later case we extract values of the critical exponents $\nu$ and $\eta$, related to the order parameter fluctuations, which we discuss in relation to other recent estimates from ground state quantum Monte Carlo calculations as well as analytical approaches.