Electromagnetic and phonon modes for superfluid He-4 with a disk resonator

TL;DR

This paper investigates electromagnetic and phonon modes in superfluid helium-4 with a dielectric disk resonator, revealing the structure and properties of c-photons and c-phonons in this system.

Contribution

It introduces a detailed analysis of electromagnetic and phonon mode distributions and calculates the wave function of c-phonons in a superfluid helium-4 system with a disk resonator.

Findings

Distribution of electromagnetic fields inside and outside the resonator identified

Wave function of c-phonons calculated showing specific symmetry properties

c-phonons have definite energy and angular momentum but not definite in-plane momentum

Abstract

We find the distribution of the electromagnetic field inside and outside a dielectric disk resonator placed in He-II. It is shown that this field consists of a collection of "circular" (c-) photons. The wave function \Psi_c of a c-phonon for the He-II + disk system is calculated in the zero-order approximation in interaction. Due to the symmetry of the problem, the structure of \Psi_c is such that a c-phonon possesses, similarly to a c-photon of the resonator, a definite energy and an angular momentum with respect to the disk axis, but it does not possess a definite momentum in the disk plane.