Zhang Xue-Feng, He Yin-Chen, Eggert Sebastian, Moessner Roderich, Pollmann Frank
Department of Physics, Chongqing University, Chongqing 401331, People's Republic of China.
Max-Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany.
Phys Rev Lett. 2018 Mar 16;120(11):115702. doi: 10.1103/PhysRevLett.120.115702.
We use large scale quantum Monte Carlo simulations to study an extended Hubbard model of hard core bosons on the kagome lattice. In the limit of strong nearest-neighbor interactions at 1/3 filling, the interplay between frustration and quantum fluctuations leads to a valence bond solid ground state. The system undergoes a quantum phase transition to a superfluid phase as the interaction strength is decreased. It is still under debate whether the transition is weakly first order or represents an unconventional continuous phase transition. We present a theory in terms of an easy plane noncompact CP^{1} gauge theory describing the phase transition at 1/3 filling. Utilizing large scale quantum Monte Carlo simulations with parallel tempering in the canonical ensemble up to 15552 spins, we provide evidence that the phase transition is continuous at exactly 1/3 filling. A careful finite size scaling analysis reveals an unconventional scaling behavior hinting at deconfined quantum criticality.
我们使用大规模量子蒙特卡罗模拟来研究 kagome 晶格上硬核玻色子的扩展哈伯德模型。在 1/3 填充时强最近邻相互作用的极限下，挫折与量子涨落之间的相互作用导致价键固体基态。随着相互作用强度降低，系统经历量子相变到超流相。该转变是弱一级相变还是代表非常规连续相变仍存在争议。我们提出了一种基于易平面非紧致 CP^{1} 规范理论的理论，用于描述 1/3 填充时的相变。利用在正则系综中采用并行回火的大规模量子蒙特卡罗模拟，模拟自旋数高达 15552，我们提供了证据表明在精确的 1/3 填充时相变是连续的。仔细的有限尺寸标度分析揭示了暗示解禁量子临界性的非常规标度行为。
