Variational Monte Carlo study of symmetric mass generation in a bilayer honeycomb lattice model
Variational Monte Carlo study of symmetric mass generation in a bilayer honeycomb lattice model
复制标题
DOI：
10.1103/physrevb.108.125130
复制
发表时间：
2022-12
影响因子：
3.7
通讯作者：
W. Hou;Yi-Zhuang You
中科院分区：
文献类型：
--
作者：
W. Hou;Yi-Zhuang You
我们研究了半填充时自旋 1/2 费米子的双层蜂窝晶格模型，以及跨两层的费米子自旋的局部海森堡耦合。使用变分蒙特卡罗（VMC）模拟，我们证明了随着海森堡耦合强度的增加，系统经历了从狄拉克半金属相到对称带隙相的直接转变，称为对称质量生成（SMG）。该跃迁不涉及自发对称破缺或拓扑序，并被提议作为费米子解禁量子临界点（fDQCP）的一个例子。我们的模拟表明，费米子部分子双线性质量在转变点处打开，而由于变分波函数中的相关因子引入的量子涨落，所有对称性仍然保留。从仿真数据中，我们提取了SMG临界点处的临界指数$\nu=0.96\pm0.03$和费米子标度维数$\Delta_c=1.31\pm0.04$，这与(2+1)D中fDQCP的场理论预测一致。这些发现支持费米子在 SMG 临界点分裂的假设。
We investigate a bilayer honeycomb lattice model of spin-1/2 fermions at half-filling with local Heisenberg coupling of fermion spins across the two layers. Using variational Monte Carlo (VMC) simulation, we demonstrate that the system undergoes a direct transition from a Dirac semimetal phase to a symmetric gapped phase, known as symmetric mass generation (SMG), as the Heisenberg coupling strength is increased. The transition does not involve spontaneous symmetry breaking or topological order and has been proposed as an example of the fermionic deconfined quantum critical point (fDQCP). Our simulation shows that a fermionic parton bilinear mass opens at the transition point while all symmetries are still preserved thanks to the quantum fluctuations introduced by the correlation factor in the variational wave function. From the simulation data, we extract the critical exponent $\nu=0.96\pm0.03$ and the fermion scaling dimension $\Delta_c=1.31\pm0.04$ at the SMG critical point, which are consistent with the field theoretical prediction of fDQCP in (2+1)D. These findings support the hypothesis that the fermion fractionalizes at the SMG critical point.