Topological phases induced by charge fluctuations in Majorana wires

Shustin, M.S., Aksenov, S.V., Burmistrov, I.S.// Physical Review B//

The influence of many-body interactions on topological phases is one of the problems that still remains urgent in modern condensed-matter theory. In this study we address this issue within perturbative theory framework by considering topological phase transitions related to charge correlations in the extended Kitaev chain model that belongs to the BDI symmetry class. Obtained corrections to a zero-frequency quasiparticle Green's function allow to separate the mean-field and fluctuation contributions to a total winding number. As a result, the phase transitions caused solely by the latter are unveiled. We thoroughly analyze the mechanism of such transitions in terms of fluctuation-induced nodal points and spectrum renormalization. Additionally, features of other quasiparticle properties such as effective mass and damping are discussed in the context of topological phase transitions.