Parametric instability of homogeneous precession of spin in the superfluid 3He-B

TL;DR

This paper investigates the stability of homogeneous spin precession in superfluid 3He-B, revealing that at low temperatures it becomes unstable due to parametric excitation of spin waves, explaining the observed catastrophic relaxation.

Contribution

It demonstrates the occurrence of Suhl instability in superfluid 3He-B and estimates the transition temperature to the unstable state.

Findings

Homogeneous precession becomes unstable at low temperatures.

Growth increments for all spin wave modes are calculated at zero temperature.

Transition temperature to instability is estimated.

Abstract

Stability of homogeneous precession of spin due to parametric excitation of spin waves is considered as the explanation of the "catastrophic relaxation", that is observed in the superfluid 3He-B. It is shown, that at sufficiently low temperatures homogeneous precession of spin becomes unstable (Suhl instability). At zero temperature increments of growth for all spin wave modes are found. Estimation of the temperature of transition to the unstable state is made.