Quantum Critical Behavior of the Superfluid-Mott Glass Transition
Quantum Critical Behavior of the Superfluid-Mott Glass Transition
复制标题
超流体-莫特玻璃转变的量子临界行为
DOI：
10.1103/physrevb.94.134501
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发表时间：
2016
影响因子：
3.7
通讯作者：
Yury Kiselev
中科院分区：
文献类型：
--
作者：
T. Vojta;J. Crewse;M. Puschmann;D. Arovas;Yury Kiselev
我们研究了具有粒子-空穴对称性的稀释型二维量子转子模型中零温度超流到绝缘体的相变。我们将哈密顿量映射到一个经典的具有柱状无序的$(2+1)$维XY模型上，并用大规模的蒙特卡罗模拟对其进行了分析。对于低于晶格渗流阈值的稀释物，系统经历了一般的超流-莫特玻璃化转变。与无序系统中的其他量子相变不同，它的临界行为是普适的(与稀释无关的)指数为$z=1.52(3)$，$\nu=1.16(5)$，$\beta/\nu=0.48(2)$，$\Gamma/\nu=2.52(4)$，和$\eta=-0.52(4)$。这些值与较早的蒙特卡罗结果相一致，并有所改进。莱特牧师。92,015703(2004年)]同时(部分)排除文献中的其他发现。作为普适性的进一步检验，我们还考虑了经典哈密顿量的软自旋版本。此外，我们还研究了跨越晶格渗流阈值的渗流量子相变，其临界行为由晶格渗流指数决定，这与最近的理论预测一致。我们将我们的结果与无序系统相变的一般分类联系起来，并简要讨论了实验。
We investigate the zero-temperature superfluid to insulator transitions in a diluted two-dimensional quantum rotor model with particle-hole symmetry. We map the Hamiltonian onto a classical $(2+1)$-dimensional XY model with columnar disorder which we analyze by means of large-scale Monte Carlo simulations. For dilutions below the lattice percolation threshold, the system undergoes a generic superfluid-Mott glass transition. In contrast to other quantum phase transitions in disordered systems, its critical behavior is of conventional power-law type with universal (dilution-independent) critical exponents $z=1.52(3)$, $\nu=1.16(5)$, $\beta/\nu= 0.48(2)$, $\gamma/\nu=2.52(4)$, and $\eta=-0.52(4)$. These values agree with and improve upon earlier Monte-Carlo results [Phys. Rev. Lett. 92, 015703 (2004)] while (partially) excluding other findings in the literature. As a further test of universality, we also consider a soft-spin version of the classical Hamiltonian. In addition, we study the percolation quantum phase transition across the lattice percolation threshold; its critical behavior is governed by the lattice percolation exponents in agreement with recent theoretical predictions. We relate our results to a general classification of phase transitions in disordered systems, and we briefly discuss experiments.