Universal critical temperature for Kosterlitz-Thouless transitions in bilayer quantum magnets

TL;DR

This paper demonstrates through quantum Monte Carlo simulations that the critical temperature for Kosterlitz-Thouless transitions in bilayer quantum magnets is a universal quantity proportional to the magnetic field, independent of microscopic details.

Contribution

The study provides the first numerical evidence supporting the universality of the proportionality constant ppa in the KT transition temperature for bilayer quantum magnets.

Findings

Supports universality of ppa through simulations

Determines numerical value of ppa

Proposes experimental tests for quantum-mechanical universality

Abstract

Recent experiments show that double layer quantum Hall systems may have a ground state with canted antiferromagnetic order. In the experimentally accessible vicinity of a quantum critical point, the order vanishes at a temperature T_{KT} = \kappa H, where H is the magnetic field and \kappa is a universal number determined by the interactions and Berry phases of the thermal excitations. We present quantum Monte Carlo simulations on a model spin system which support the universality of \kappa and determine its numerical value. This allows experimental tests of an intrinsically quantum-mechanical universal quantity, which is not also a property of a higher dimensional classical critical point.