The phase transition between the valence-bond-solid (VBS) and nematic phases, the so-called deconfined criticality, was investigated for the quantum S=1-spin model on the spatially anisotropic triangular lattice with the biquadratic interaction by means of the numerical diagonalization method. We calculated both VBS- and nematic-order parameters, aiming to clarify the nature of this transition from complementary viewpoints. Simulating the clusters with N \le 20 spins, we estimate the correlation-length critical exponent as ν=0.95(14). We also calculated Fisher's exponent (anomalous dimension) for each order parameter.
Gauge-constrained Spinon Complexes Near Deconfined Quantum Criticality
University of Tokyo（东京大学）；Institute of Solid-State Physics, University of Tokyo（东京大学固体物理研究所）；Trans-scale Quantum Science Institute, The University of Tokyo（东京大学跨尺度量子科学研究所）；University of Chongqing（重庆大学）；Department of Physics, University of Chongqing（重庆大学物理学院）
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 …
We continue recent efforts to discover examples of deconfined quantum criticality in one-dimensional models. In this work we investigate the transition between a $\mathbb{Z}_3$ ferromagnet and a phase with valence bond solid (VBS) order in a spin chain with $\mathbb{Z}_3\times\mathbb{Z}_3$ global symmetry. We study a model with alternating projective representations on the sites of the two sublattices, allowing the Hamiltonian to connect to an exactly solvable point having VBS order with the character of SU(3)-invariant singlets. Such a model does not admit a Lieb-Schultz-Mattis theorem typica…
Deconfined Boundary Phase Transition of a Quantum Critical Heisenberg Model
School of Microelectronics & Data Science, Anhui University of Technology（安徽工业大学微电子与数据科学学院）；Kavli Institute for Theoretical Sciences and School of Quantum, University of Chinese Academy of Sciences（中国科学院大学量子学院和理论科学 Kavli 研究所）
From Quantum Dimers to the $π$-flux Toric Code via Deconfined Multicriticality
International Centre for Theoretical Sciences, Tata Institute of Fundamental Research（国际理论科学中心，塔塔基础研究所）；Department of Engineering and Physics, Karlstad University（卡尔斯特德大学工程与物理系）；Nordita, KTH Royal Institute of Technology and Stockholm University（诺迪塔，皇家理工学院和斯德哥尔摩大学）
Inspired by our recent works[1, 2] of SU(2) and SU(4) Dirac fermions subjected to plaquette interactions on square lattice, here we extend the large-scale quantum Monte Carlo investigations to the phase digram of correlated Dirac fermions with SU(6) and SU(8) symmetries subjected to the plaquette interaction on the same lattice. From SU(2) to SU(8), the rich phase diagram exhibits a plethora of emerging quantum phases such as the Dirac semimetal, the antiferromagnetic Mott insulator, valence bond solid (VBS) and the Dirac spin liquid and phase transitions including the Gross-Neveu chiral trans…
