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TT: Fachverband Tiefe Temperaturen

TT 24: Quantum-Critical Phenomena

TT 24.6: Talk

Tuesday, March 19, 2024, 10:45–11:00, H 2053

Quantum Monte Carlo simulation of the Dicke-Ising model on hypercubic lattices — Anja Langheld, •Max Hörmann, and Kai Phillip Schmidt — Department Physik, Staudtstraße 7, Friedrich-Alexander Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany

We study the Ising model in a light-induced quantized transverse field [1, 2] using quantum Monte Carlo to investigate the influence of light-matter interactions on correlated quantum matter. To avoid a direct sampling of the photons, we develop a quantum Monte Carlo algorithm based on the recently introduced wormhole algorithm for spin-boson systems [3], in which the bosonic degrees of freedom are integrated out analytically.

We provide quantitative phase diagrams and critical properties for ferromagnetic as well as antiferromagnetic interactions on hypercubic lattices. For antiferromagnetic interactions, we confirm the existence of a non-trivial intermediate phase, displaying magnetic order and finite photon density at the same time, predicted by a semi-classical mean-field study [1]. However, this intermediate phase turns out to be much smaller and certain phase transitions turn out to be of first order rather than of second order. In the case of ferromagnetic interactions, a change in the order of the quantum phase transition for finite Ising coupling and longitudinal field is observered.

[1] J. Rohn et al., Phys. Rev. Research 2 (2020) 023131

[2] Y. Zhang et al., Sci Rep 4 (2014) 4083

[3] M. Weber et al., Phys. Rev. Lett. 119 (2017) 097401

Keywords: Light-matter interaction; Quantum Monte Carlo; Dicke-Ising model; Mean field; Stochastic Series Expansion