A new method to calculate a 2d ising universality transition point : application near the ashkin-teller multicritical point

Abstract

We propose a new method to numerically calculate transition points that belongs to 2D Ising universality class for quantum spin models. Generally, near the multicritical point, in conventional methods, a finite size correction becomes very large. To suppress the effect of the multicritical point, we use a z-axis twisted boundary condition and a y-axis twisted boundary condition. We apply our method to an S = 1/2 bond-alternating XXZ model. The multicritical point of this model has a BKT transition, where the correlation length diverges singularly. However, with our method, the convergence of calculation is highly improved, thus we can calculate the transition point even near the multicritical point.

References in corpus (5)

• Twist Boundary Conditions of Quantum Spin Chains near the Gaussian Fixed Points
• $SU(2)/Z_2$ symmetry of the BKT transition and twisted boundary conditio n
• Phase diagram of the S=1/2 quantum spin chain with bond alternation
• Phase Diagrams of S=3/2, 2 XXZ Spin Chains with Bond-Alternation
• Entanglement convertibility by sweeping through the quantum phases of the alternating bonds $XXZ$ chain