Dipolar bogolons: from superfluids to Pfaffians

TL;DR

This paper investigates the structure of bogolons in various paired superfluids, revealing their dipolar current and charge patterns, and resolving previous contradictions by self-consistent treatment of the pair field.

Contribution

It introduces a self-consistent approach to understanding bogolons, showing their dipolar patterns in neutral, superconducting, and quantum Hall superfluid systems.

Findings

Neutral superfluids exhibit dipolar current patterns with zero net current.

Superconductors confine these patterns within a penetration depth due to Maxwell electrodynamics.

Paired quantum Hall states display dipolar charge and current distributions influenced by Chern-Simons theory.

Abstract

We study the structure of Bogoliubov quasiparticles, 'bogolons,' the fermionic excitations of paired superfluids that arise from fermion (BCS) pairing, including neutral superfluids, superconductors, and paired quantum Hall states. The naive construction of a stationary quasiparticle in which the deformation of the pair field is neglected leads to a contradiction: it carries a net electrical current even though it does not move. However, treating the pair field self-consistently resolves this problem: In a neutral superfluid, a dipolar current pattern is associated with the quasiparticle for which the total current vanishes. When Maxwell electrodynamics is included, as appropriate to a superconductor, this pattern is confined over a penetration depth. For paired quantum Hall states of composite fermions, the Maxwell term is replaced by a Chern-Simons term, which leads to a dipolar charge distribution and consequently to a dipolar current pattern.