Resonant generation of $p$-wave Cooper pair in non-Hermitian Kitaev chain at exceptional point

Abstract

We investigate a non-Hermitian extension of Kitaev chain by considering imaginary $p$-wave pairing amplitudes. The exact solution shows that the phase diagram consists two phases with real and complex \ Bogoliubov-de-gens spectra, associated with $\mathcal{P}\mathcal{T}$-symmetry breaking, which is separated by a hyperbolic exceptional line. The exceptional points (EPs) correspond to a specific Cooper pair state $(1+c_k^{†}{c}_{-k}^{†})|0⟩$\ with movable $k$ when the parameters vary along the exceptional line. The non-Hermiticity around EP supports resonant generation of such a pair state from the vacuum state of fermions via the critical dynamic process. In addition, we propose a scheme to generate a superconducting state through a dynamic method.

8 pages,4 figures