Excited-state quantum phase transitions studied from a non-Hermitian perspective
Excited-state quantum phase transitions studied from a non-Hermitian perspective
A main distinguishing feature of non-Hermitian quantum mechanics is the presence of exceptional points (EPs). They correspond to the coalescence of two energy levels and their respective eigenvectors. Here, we use the Lipkin-Meshkov-Glick (LMG) model as a test bed to explore the strong connection between EPs and the onset of …