Observation of Induced Chern-Simons Term in P- and T- violating Superconductors

TL;DR

This paper demonstrates that P- and T-violating superconductors induce a topologically invariant Chern-Simons term in the electromagnetic action, leading to a novel Hall effect observable without external magnetic fields.

Contribution

It introduces the induction of a Chern-Simons term in superconductors violating P and T symmetries, linking topological invariants to superconducting electromagnetic properties.

Findings

Induction of a nearly topological Chern-Simons term with a coefficient close to the fine structure constant.

Prediction of an unusual Hall effect observable via SQUID without external magnetic fields.

The Ginzburg-Landau action is extended to include P- and T-odd electromagnetic terms.

Abstract

We show in this letter that P- and T-odd terms of the electromagnetic potentials (P; parity, T; time reversal) are induced and lead an unusual phenomenon in P- and T-violating superconductors discovered recently. The Ginzburg-Landau action includes this term in the gauge invariant manner. The coefficient of the term is nearly topological invariant with a small correction and equals to the fine structure constant approximately. Unusual ``Hall effect'' {\it without external} magnetic field could be observed by SQUID.