Second-order phase transitions and divergent linear response in dynamical mean-field theory
Strongly Correlated Electrons
2024-06-17 v2
Abstract
Second-order phase transitions appear as a divergence in one of the linear response functions. For a system of correlated electrons, the relevant divergent response can and does involve many-particle observables, most famously the double occupancy. Generally, evaluating the linear response function of many-particle observables requires a many-particle generalization of the Bethe-Salpeter equation. However, here I show that the divergence of linear response functions in dynamical mean-field theory is governed by a two-particle Bethe-Salpeter equation, even for many-particle observables. The reason for this is that the divergence at the second-order phase transition is produced by the self-consistent feedback of the dynamical mean-field.
Cite
@article{arxiv.2401.04042,
title = {Second-order phase transitions and divergent linear response in dynamical mean-field theory},
author = {Erik G. C. P. van Loon},
journal= {arXiv preprint arXiv:2401.04042},
year = {2024}
}