Monte Carlo simulations of resonating-valence-bond U(1) dynamics.

Abstract

In the auxiliary-field formulation of Baskaran and Anderson, and of Nakamura and Matsui for the {ital t}-{ital J} model including cases with weak interlayer hoppings, Monte Carlo simulations are performed with respect to U(1) phase dynamics of nearest-neighbor singlet annihilation operators. Parameters fixed throughout simulations are the intralayer hopping, {ital t}=0.3 eV, and nearest-neighbor antiferromagnetic coupling, {ital J}=0.1 eV. Thermal-cycle simulations are performed for various values of parameters, interlayer hopping, 0{le}{ital t}{prime}{le}0.06 eV, and hole density, 0.005{le}{delta}{le}0.07, and phase transitions are observed. The transitions exhibit phase coherence up to global U(1) rotation in the low-temperature phase, but the phase configurations show that they are of the flux phase, violating time-reversal and parity symmetry invariance. For small {delta}, a nonperiodic flux phase is observed. The transitions are basically those violating the discrete symmetries due to the frustration of the forces involved.