Journal of Physics A Mathematical and General
Transfer matrix study of the chiral clock model in the Hamiltonian limit
H. U. Everts, Heinrich Röder
Abstract
The logarithm of the transfer matrix of the two-dimensional, three state chiral clock model is shown to be equivalent to a one-dimensional non-Hermitian quantum Hamiltonian. In the region of small chirality the critical behaviour of the quantum model is investigated by a series expansion and by finite-size scaling. A single phase boundary between a modulated paramagnetic and a ferromagnetic phase is located with good accuracy. Both methods yield comparable results for the critical exponent beta of the wavevector of the modulated high temperature phase. The critical exponents nu x , nu tau for the correlation lengths obtained from finite-size scaling point towards the existence of a Lifshitz point at finite chirality. The results of the series expansion for the exponent nu x , however, are inconsistent with finite-size scaling. For larger chirality the authors' finite-size results clearly reveal the occurrence of an incommensurate phase with algebraically decaying correlations between the ferromagnetic and the modulated paramagnetic phase. They analyse the critical behaviour of this incommensurate phase at its melting line and determine the exponent eta that controls the algebraic decay of correlations.