Robust superfluid phases of 3He in aerogel

TL;DR

This paper investigates the possible superfluid phases of helium-3 in aerogel, identifying 'robust' order parameters that can sustain long-range order despite the disorder introduced by the aerogel.

Contribution

It introduces a phenomenological model describing superfluid phases of 3He in aerogel and identifies robust order parameters suitable for the A-like phase.

Findings

Identification of 'robust' order parameters that withstand random fields

Proposal of Equal Spin Pairing states as candidates for observed phases

Analysis of superfluid phases near the transition temperature

Abstract

Within a phenomenological approach possible forms of the order parameter of the superfluid phases of 3He in a vicinity of the transition temperature are discussed. Effect of aerogel is described by a random tensor field interacting with the orbital part of the order parameter. With respect to their interaction with the random tensor field a group of "robust" order parameters which can maintain long-range order in a presence of the random field is specified. Robust order parameters, corresponding to Equal Spin Pairing (ESP) states are found and proposed as candidates for the observed A-like superfluid phase of liquid 3He in aerogel.