Quantum phase diagrams of Dicke-Ising models by a wormhole algorithm

TL;DR

This paper introduces a quantum Monte Carlo wormhole algorithm to study the phase diagrams of Dicke-Ising models, revealing superradiant phase transitions and novel light-matter correlated phases on different lattice geometries.

Contribution

The paper presents a new wormhole algorithm for simulating Dicke-Ising models, enabling detailed analysis of phase diagrams and critical phenomena in light-matter interacting quantum systems.

Findings

Superradiant phase transitions follow Dicke model universality class.

Second-order transition between normal and superradiant phases for ferromagnetic case.

Light-matter analogue of a lattice supersolid with combined order parameters.

Abstract

We gain quantitative insights on effects of light-matter interactions on correlated quantum matter by quantum Monte Carlo simulations. We introduce a wormhole algorithm for the paradigmatic Dicke-Ising model which combines the light-matter interaction of the Dicke model with Ising interactions. The quantum phase diagram for ferro- and antiferromagnetic interactions on the chain and the square lattice is determined. The occurring superradiant phase transitions are in the same universality class as the Dicke model leading to a well-known peculiar finite-size scaling that we elucidate in terms of scaling above the upper critical dimension. For the ferromagnetic case, the transition between the normal and the superradiant phase is of second order with Dicke criticality (first order) for large (small) longitudinal fields separated by a multicritical point. For antiferromagnetic interactions, we establish the light-matter analogue of a lattice supersolid with off-diagonal superradiant and diagonal magnetic order and determine the nature of all transition lines.