CHIRAL EXPONENTS OF THE SQUARE-LATTICE FRUSTRATED XY MODEL - A MONTE-CARLO TRANSFER-MATRIX CALCULATION

Thermal and chiral critical exponents of the fully frustrated XY model on a square lattice are obtained from a finite-size scaling analysis of the free energy of chiral domain walls. Data were obtained by exten sive Monte Carlo transfer-matrix computations for infinite strips of w idths up to 14 lattice spacings. Two transfer matrices were implemente d, one for each of the two principal lattice directions. The results o f both are consistent, but the critical exponents differ significantly from the pure Ising values. This is in agreement with other recent Mo nte Carlo simulations. Our results also support the identification of the critical behavior of this model with that along the line of transi tions of simultaneous ordering or becoming critical of Ising and plana r rotor degrees of freedom in the XY-Ising model studied recently.