Item

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.