Tricritical point in the quantum Hamiltonian mean-field model
Abstract
Engineering long-range interactions in experimental platforms has been achieved with great success in a large variety of quantum systems in recent years. Inspired by this progress, we propose a generalization of the classical Hamiltonian mean-field model to fermionic particles. We study the phase diagram and thermodynamic properties of the model in the canonical ensemble for ferromagnetic interactions as a function of temperature and hopping. At zero temperature, small charge fluctuations drive the many-body system through a first order quantum phase transition from an ordered to a disordered phase at zero temperature. At higher temperatures, the fluctuation-induced phase transition remains first order initially and switches to second order only at a tricritical point. Our results offer an intriguing example of tricriticality in a quantum system with long-range couplings, which bears direct experimental relevance. The analysis is performed by exact diagonalization and mean-field theory.
Cite
@article{arxiv.2202.08855,
title = {Tricritical point in the quantum Hamiltonian mean-field model},
author = {Harald Schmid and Johannes Dieplinger and Andrea Solfanelli and Sauro Succi and Stefano Ruffo},
journal= {arXiv preprint arXiv:2202.08855},
year = {2022}
}