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arXiv · 2307.00849

Protection of Correlation-Induced Phase Instabilities by Exceptional Susceptibilities

Matthias Reitner·Lorenzo Crippa·Dominik Robert Fus·Jan Carl Budich·Alessandro Toschi·Giorgio Sangiovanni
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Abstract

At thermal equilibrium, we find that generalized susceptibilities encoding the static physical response properties of Hermitian many-electron systems possess inherent non-Hermitian (NH) matrix symmetries. This leads to the generic occurrence of exceptional points (EPs), i.e., NH spectral degeneracies, in the generalized susceptibilities of prototypical Fermi-Hubbard models, as a function of a single parameter such as chemical potential. We demonstrate that these EPs are necessary to promote correlation-induced thermodynamic instabilities, such as phase-separation occurring in the proximity of a Mott transition, to a topologically stable phenomenon.

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Matthias Reitner, Lorenzo Crippa, Dominik Robert Fus, Jan Carl Budich, Alessandro Toschi, Giorgio Sangiovanni. 2023-07-03. Protection of Correlation-Induced Phase Instabilities by Exceptional Susceptibilities. https://doi.org/10.1103/physrevresearch.6.l022031

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