Microstructure of He II in the presence of boundaries

TL;DR

This paper investigates the microstructure of superfluid helium-2 near boundaries, revealing two possible orderings with different dispersion laws and showing how boundaries influence the system's microstructure and energy.

Contribution

It introduces a novel ordering in Bose systems under boundary conditions, differing from traditional models by modifying the dispersion law parameter.

Findings

Identifies two possible orderings with different dispersion laws.

Shows boundaries influence microstructure and ground-state energy.

Finds the new ordering has lower energy at weak interactions.

Abstract

We have studied the microstructure of a system of interacting Bose particles under zero boundary conditions and have found two possible orderings. One ordering is traditional and is characterized by the Bogolyubov dispersion law E^2 = (h^2 k^2/2m)^{2} + qn\nu(k)[h^2 k^2/m] (with q=1) at a weak interaction. The second one is new and is characterized by the same dispersion law, but with q=2^{-f}, where $f$ is the number of noncyclic coordinates. At a weak interaction, the ground-state energy is less for the new solution. The boundaries affect the bulk microstructure due to the difference of the topologies of closed and open systems.