We study a topological superconductor capable of exchanging particles with an environment. This additional interaction breaks particle-number symmetry and can be modelled by means of an integrable Hamiltonian, building on the class of Richardson-Gaudin pairing models. The isolated system supports zero-energy modes at a topological phase transition, which disappear when allowing for particle exchange with an environment. However, it is shown from the exact solution that these still play an important role in system-environment particle exchange, which can be observed through resonances in low-energy and -momentum level occupations. These fluctuations signal topologically protected Read-Green points and cannot be observed within traditional mean-field theory.
@article{arxiv.1601.03990,
title = {Read-Green resonances in a topological superconductor coupled to a bath},
author = {Pieter W. Claeys and Stijn De Baerdemacker and Dimitri Van Neck},
journal= {arXiv preprint arXiv:1601.03990},
year = {2016}
}