Exotic Thermal Transitions with Spontaneous Symmetry Breaking

TL;DR

This paper demonstrates that topological orders can lead to exotic thermal phase transitions with spontaneous symmetry breaking, revealing new universality classes distinct from conventional ones, and discusses implications for strongly correlated materials.

Contribution

It introduces a novel class of thermal phase transitions influenced by topological order, expanding understanding beyond traditional symmetry-based classifications.

Findings

Exotic Ising and XY transitions share the same universality class.

Exotic universality class is more stable under phonons and disorder.

Topological orders are essential for classifying thermal transition universality classes.

Abstract

We show that exotic spontaneous symmetry breaking appears in thermal topological phases by perturbing the exact solutions of quantum rotor models coupled to the three-dimensional toric code. The exotic Ising and XY transitions are shown to be in the same universality class in drastic contrast to the conventional Wilson-Fisher classes without topological orders. Our results indicate that topological orders must be included to pin down universality classes of thermal transitions in addition to order parameter symmetry and spatial dimension. We evaluate all the critical exponents and find that the exotic universality class is more stable under the couplings to acoustic phonons and disorder. Applying our results to experiments, we provide a plausible scenario in puzzlings of strongly correlated systems, including the absence of specific heat anomaly in doped RbFe$_2$As$_2$.