The Superfluid Glass Phase of 3He-A

TL;DR

This paper provides experimental evidence for a superfluid glass phase in 3He-A within aerogel, showing that disorder destroys long-range order, which confirms theoretical predictions about disorder-induced glassy states in superfluids.

Contribution

The study experimentally demonstrates the existence of a superfluid glass phase in 3He-A caused by disorder, validating longstanding theoretical predictions.

Findings

NMR measurements show destruction of long-range orientational order in 3He-A in aerogel.

Superfluid 3He-A generated by warming from 3He-B maintains long-range order.

Evidence supports the theoretical prediction of a superfluid glass phase due to disorder.

Abstract

It is established theoretically that an ordered state with continuous symmetry is inherently unstable to arbitrarily small amounts of disorder [1, 2]. This principle is of central importance in a wide variety of condensed systems including superconducting vortices [3, 4], Ising spin models [5] and their dynamics [6], and liquid crystals in porous media [7, 8], where some degree of disorder is ubiquitous, although its experimental observation has been elusive. Based on these ideas it was predicted [9] that 3He in high porosity aerogel would become a superfluid glass. We report here our nuclear magnetic resonance measurements on 3He in aerogel demonstrating destruction of long range orientational order of the intrinsic superfluid orbital angular momentum, confirming the existence of a superfluid glass. In contrast, 3He-A generated by warming from superfluid 3He-B has perfect long-range orientational order providing a mechanism for switching off this effect.