Phase glass and zero-temperature phase transition in a randomly frustrated two-dimensionalquantum rotor model

Abstract

The ground state of the quantum rotor model in two dimensions with random phase frustrationis investigated. Extensive Monte Carlo simulations are performed on the corresponding(2+1)-dimensional classical model under the entropic sampling scheme. For weak quantumfluctuation, the system is found to be in a phase glass phase characterized by a finitecompressibility and a finite value for the Edwards–Anderson order parameter, signifyinglong-range phase rigidity in both spatial and imaginary time directions. The scalingproperties of the model near the transition to the gapped, Mott insulator state withvanishing compressibility are analyzed. At the quantum critical point, the dynamicexponent is greater than one. Correlation length exponents in the spatial and imaginary timedirections are given by and , respectively; both assume values greater than 0.6723 of the pure case. We speculate thatthe phase glass phase is superconducting rather than metallic in the zero-currentlimit.