Static properties of the dissipative random quantum Ising ferromagnetic chain

TL;DR

This paper investigates how dissipation influences the static properties and phase transitions of one-dimensional quantum Ising chains with disorder, revealing an extended ordered phase and a generalized localization transition.

Contribution

It introduces a Monte Carlo simulation approach to study dissipative quantum Ising chains and generalizes the Caldeira-Leggett localization transition to finite clusters.

Findings

Dissipation extends the ordered phase in the quantum Ising chain.

A generalized Caldeira-Leggett localization transition is identified for finite clusters.

Dissipation affects the quantum phase transition and Griffiths phase in the infinite chain.

Abstract

We study the zero temperature static properties of dissipative ensembles of quantum Ising spins arranged on periodic one dimensional finite clusters and on an infinite chain. The spins interact ferro-magnetically with nearest-neighbour pure and random couplings. They are subject to a transverse field and coupled to an Ohmic bath of quantum harmonic oscillators. We analyze the coupled system using Monte Carlo simulations of the classical two-dimensional counterpart model. The coupling to the bath enhances the extent of the ordered phase, as found in mean-field spin-glasses. In the case of finite clusters we show that a generalization of the Caldeira-Leggett localization transition exists. In the case of the infinite random chain we study the effect of dissipation on the transition and the Griffiths phase.