Nonlinear excitation of second sound in quantum solutions He3-He4 due to light wave absorption

TL;DR

This paper investigates how light wave absorption can nonlinear excite second sound in superfluid He3-He4, deriving wave equations and estimating the amplification distance for observable second-sound waves.

Contribution

It introduces a nonlinear wave model for light-induced second sound in superfluid helium mixtures and provides quantitative estimates of wave amplification distances.

Findings

Derived nonlinear wave equations for second sound and light interaction

Estimated the nonlinear interaction length for observable second sound

Provided numerical estimates for wave amplification in superfluid helium

Abstract

Nonlinear excitation of second sound in superfluid solutions He3-He4 by light waves due to their absorption is discussed. Nonlinear wave equations that model the interaction of second-sound waves with light waves are derived, the expression for the nonlinear interaction length is obtained and an order-of-magnitude numerical estimate of the distance at which a second-sound wave could be amplified from a fluctuation level up to observable values is performed.