Topologically enabled superconductivity

Abstract

Majorana zero modes are a much sought-after consequence of one-dimensional topological superconductivity. Here, we show that, in turn, zero modes accompanying dynamical instanton events strongly enhance -- in some cases even enable -- superconductivity. We find that the dynamics of a one-dimensional topological triplet superconductor is governed by a $\theta$ term in the action. For isotropic triplets, this term enables algebraic charge-$2e$ superconductivity, which is destroyed by fluctuations in nontopological superconductors. For anisotropic triplets, zero modes suppress quantum phase slips and stabilize superconductivity over a large region of the phase diagram. We present predictions of correlation functions and thermodynamics for states of topologically enhanced superconductivity.

15 pages, 3 figures; Accepted and revised version: the structure has been revised, the discussion of the anisotropic case has mostly been relegated to the appendix. A discussion of the influence of dynamical gauge fields, as well as some numerical results on dynamic zero modes have been added. The exponent of the isotropic single-fermion correlator has been corrected

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