论文标题
带有斑块相互作用的狄拉克费米斯。 I. su（2）带有毛线和脱合量子关键的相图
Dirac fermions with plaquette interactions. I. SU(2) phase diagram with Gross-Neveu and deconfined quantum criticalities
论文作者
论文摘要
我们研究了一个扩展的哈伯德模型的基态相图，其在正方形的晶格上半填充$π$ -Flux跳，并具有无偏见的大型辅助尺寸量子蒙特卡洛模拟。作为相互作用强度的函数，出现了一个中间相，该相实现了两个相互作用驱动的量子临界点，在DIRAC半准和弱价键固体（VBS）阶的绝缘阶段之间，第二个临界点，第二个分隔VBS顺序和抗fiferromagnetic绝缘阶段。这些有趣的量子临界点分别以毛刺和脱合的量子关键点和临界指数$η_\ text {vbs} = 0.6（1）$和$η_\ text {Af text {af} = 0.58（3）$满足cft Boottrap Beottrap绑定。我们还研究了旋转激发的动力学特性，并在第一个过渡附近发现自旋隙打开，并在第二个过渡上关闭。讨论了我们的发现在实现费米昂系统中脱合量子临界的相关性，以及与晶格模型具有进一步扩展相互作用（例如量子Moiré系统中的晶格模型）的意义。
We investigate the ground state phase diagram of an extended Hubbard model with $π$-flux hopping term at half-filling on a square lattice, with unbiased large-scale auxiliary-field quantum Monte Carlo simulations. As a function of interaction strength, there emerges an intermediate phase which realizes two interaction-driven quantum critical points, with the first between the Dirac semimetal and an insulating phase of weak valence bond solid (VBS) order, and the second separating the VBS order and an antiferromagnetic insulating phase. These intriguing quantum critical points are respectively bestowed with Gross-Neveu and deconfined quantum criticalities, and the critical exponents $η_\text{VBS}=0.6(1)$ and $η_\text{AF}=0.58(3)$ at deconfined quantum critical point satisfy the CFT Bootstrap bound. We also investigate the dynamical properties of the spin excitation and find the spin gap open near the first transition and close at the second. The relevance of our findings in realizing deconfined quantum criticality in fermion systems and the implication to lattice models with further extended interactions such as those in quantum Moiré systems, are discussed.
