title: Coulomb analogy for non-Hermitian degeneracies near quantum phase transitions.
abstract: Degeneracies near the real axis in a complex-extended parameter space of a Hermitian Hamiltonian are studied. We present a method to measure distributions of such degeneracies on the Riemann sheet of a selected level and apply it in classification of quantum phase transitions. The degeneracies are shown to behave similarly as complex zeros of a partition function.
authors.affiliation: Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickách 2, 180 00 Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Cejnar
authors.forename: Stefan
authors.initials: S
authors.lastname: Heinze
authors.forename: Michal
authors.initials: M
authors.lastname: Macek