Superfluid density and compressibility at the superfluid-Mott glass transition

TL;DR

This study uses large-scale Monte Carlo simulations to analyze the critical behavior of superfluid density and compressibility at the quantum phase transition between superfluid and Mott glass phases in disordered bosonic systems.

Contribution

It provides the first detailed numerical investigation of critical exponents for superfluid density and compressibility at this transition, confirming generalized Josephson relations.

Findings

Both superfluid density and compressibility exhibit power-law critical behavior.

Critical exponents are consistent with generalized Josephson relations.

Results enhance understanding of quantum phase transitions in disordered bosonic systems.

Abstract

Systems of disordered interacting bosons with particle-hole symmetry can undergo a quantum phase transition between the superfluid phase and the Mott glass phase which is a gapless incompressible insulator. We employ large-scale Monte Carlo simulations of a two-dimensional site-diluted quantum rotor model to investigate the properties of the superfluid density and the compressibility at this transition. We find that both quantities feature power-law critical behavior with exponents governed by generalized Josephson relations.