Percolation transition and dissipation in quantum Ising magnets

TL;DR

This paper investigates how dissipation influences the quantum phase transition in diluted transverse-field Ising magnets near percolation, revealing a novel transition characterized by large frozen clusters and unique magnetic phenomena.

Contribution

It introduces a new percolation quantum phase transition in dissipative quantum Ising magnets, highlighting the role of large frozen clusters and their effects on magnetic properties.

Findings

Discontinuous magnetization-field curve observed.

Exotic hysteresis phenomena identified.

Singular behavior in susceptibility and specific heat.

Abstract

We study the effects of dissipation on a randomly diluted transverse-field Ising magnet close to the percolation threshold. For weak transverse fields, a novel percolation quantum phase transition separates a superparamagnetic cluster phase from an inhomogeneously ordered ferromagnetic phase. The properties of this transition are dominated by large frozen and slowly fluctuating percolation clusters. This leads to a discontinuous magnetization-field curve and exotic hysteresis phenomena as well as highly singular behavior of magnetic susceptibility and specific heat. We compare our results to the smeared transition in generic dissipative random quantum Ising magnets. We also discuss the relation to metallic quantum magnets and other experimental realizations.