2023/06/20 by Xiao Wang, Linhao Li, Wang, Xiao +3 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum many-body systems #Strongly Correlated Electrons (cond-mat.str-el) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.2306.11446
openalex publication_date 2023/06/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this letter, we propose and study a ladder triangular cluster model which possesses a ℤ2 symmetry and an anti-unitary ℤ^\mathbbT2 symmetry generated by the spin-flip and complex conjugation, respectively. The phase diagram of the model hosts a critical line between a spontaneous symmetry breaking phase and a symmetry protected topological phase. Along the critical line, one endpoint exhibits symmetry-enriched Ashkin-Teller universality (SEATU), while other critical points fall into the symmetry-enriched Ising universality (SEIU). Both universality classes accommodate symmetry protected degenerate edge modes under open boundary conditions. This degeneracy can be lifted with a gap opening when proper perturbation is applied to the boundary. With system size (L) increasing, at the point of SEATU, the gap closes following L-1. In contrast, for the critical points of SEIU apart from a point with the known gap closing as L-14, other points surprisingly show exponentially gap closing. The coexistence of different gap closing behaviors for critical points of the same symmetry-enriched universality goes beyond the the usual understanding of symmetry-enriched universality class, implying a fine and rich structure of phase transition and universality class.