Abstract

We address the question of stability and existence of a pure odd frequency superconducting state. While in the literature there are some general considerations concerning its stability, it remains unclear if such a system can exist and, if so, what conditions it should fulfill in order to be stable. To provide some explicit examples, we discuss several models and analyze them with respect to stability and odd frequency behaviour. Additionally, we discuss the article [1], which proposes a ground state wave function for an odd frequency state. We believe there is a mistake in the normalization of the wave function, wich we present in detail.

[1] Hari P Dahal et al. “Wave function for odd-frequency superconductors”. In: New Journal of Physics 11.6 (June 2009), p. 065005. doi: 10.1088/1367-2630/11/6/065005.