Deformed aerogels in the superfluid 3He

TL;DR

This paper develops a phenomenological theory describing how elastic deformations of aerogels induce anisotropy in superfluid 3He, affecting its order parameter orientation, with estimates based on microscopic models.

Contribution

It introduces a new phenomenological framework linking aerogel deformations to superfluid 3He order parameter orientation, including coefficient estimation from microscopic models.

Findings

Deformations induce global anisotropy in superfluid 3He.

The theory applies to isotropic and nematically ordered aerogels.

Coefficients are estimated using microscopic modeling.

Abstract

Deformed aerogels induce a global anisotropy in the superfluid 3He and orient the orbital part of its order parameter. Here a phenomenological theory of the orientational effect of elastic deformations of aerogels on the superfluid phases of 3He in the spirit of conventional theory of elasticity is formulated. Phenomenological coefficients, entering basic relations, depend on properties of given aerogel in the non-deformed state. Examples of originally isotropic silica aerogel and axially symmetric "nematically ordered" aerogel are considered. Values of phenomenological coefficients are estimated with the aid of a simple microscopic model. An example of a nonuniform deformation of "nematically ordered" aerogel is discussed.