Phases and phase transitions of a disordered quantum clock model*

We investigate the effects of quenched randomness on the phase diagram and the phase transitions of the quantum clock model. To this end, we map the model onto a (1+1)-dimensional classical spin Hamiltonian with correlated disorder which we study by means of large-scale Monte-Carlo simulations. For weak randomness, the model features an emerging quasi-long-range ordered XY phase that separates the symmetry-broken long-range ordered phase from the disordered phase. With increasing randomness, the XY phase shrinks and vanishes in a tricritical point. Along all phase boundaries, we characterize the critical behaviors and relate them to the Harris Criterion, strong-disorder renormalization group predictions [1], as well as the properties of disorderd rotor Hamiltonians [2].

[1] T. Senthil and S. N. Majumdar, Phys. Rev. Lett. 76, 3001 (1996).

[2] F. Hrahsheh and T. Vojta, Phys. Rev. Lett. 109,265303 (2012).