July 31, 2023 to August 4, 2023
America/Chicago timezone

Symmetry Breaking and Clock Model Interpolation in 2D Classical O(2) Spin Systems

Aug 4, 2023, 9:00 AM
Comitium (WH2SE)




Leon Hostetler (Michigan State University)


Motivated by attempts to quantum simulate lattice models with continuous Abelian symmetries using discrete approximations, we study an extended-O(2) model that differs from the ordinary O(2) model by the addition of an explicit symmetry breaking term. Its coupling allows to smoothly interpolate between the O(2) model (zero coupling) and a $q$-state clock model (infinite coupling). In the latter case, a $q$-state clock model can also be defined for non-integer values of $q$. Thus, such a limit can also be considered as an analytic continuation of an ordinary $q$-state clock model to non-integer $q$. In previous work, we established the phase diagram of the model in the infinite coupling limit. We showed that for non-integer $q$, there is a second-order phase transition at low temperature and a crossover at high temperature. In this work, we establish the phase diagram at finite values of the coupling using Monte Carlo and tensor methods. We show that for non-integer $q$, the second-order phase transition at low temperature and crossover at high temperature persist to finite coupling. For integer $q=2,3,4$, there is a second-order phase transition at infinite coupling (i.e. the clock models). At intermediate coupling, there are second-order phase transitions, but the critical exponents vary with the coupling. At small coupling, the second-order phase transitions may turn into BKT transitions.

Topical area Quantum Computing and Quantum Information

Primary authors

Leon Hostetler (Michigan State University) Ryo Sakai (Syracuse University) Jin Zhang (U. of Iowa) Alexei Bazavov (Michigan State University) Yannick Meurice (U. of Iowa)

Presentation materials