Classification of superconducting orders in nonhermitian systems

TL;DR

This paper explores how nonhermitian effects alter superconducting states, introducing a new classification scheme and analyzing experimental signatures like density of states and spin susceptibility.

Contribution

It develops a classification scheme for nonhermitian superconductors using bi-orthogonal basis and discusses experimental signatures.

Findings

New classes of nonhermitian superconducting states identified

Modified Green's function formalism with bi-orthogonal basis

Distinct density of states and spin susceptibility signatures

Abstract

We have investigated the effects of nonhermiticity on superconducting states. We have shown the definition of the time-ordered product in the Green's function requires the introduction of a bi-orthogonal basis in nonhermitian systems. This modification allows a classification scheme of nonhermitian superconductors with new classes of states not present in hermitian systems. Furthermore, we have discussed the density of state profiles and signatures in spin susceptibility measurements for different nonhermitian superconducting orders using the simplest case of BCS superconductors.