The free energy of dilute Bose gases at low temperatures interacting via strong potentials

TL;DR

This paper establishes a lower bound on the free energy of dilute Bose gases at low temperatures with strong interactions, confirming the Lee-Huang-Yang conjecture and providing a simplified proof for hard-core potentials.

Contribution

It provides a new, simplified proof of the free energy lower bound for strongly interacting dilute Bose gases, including hard-core potentials, confirming the Lee-Huang-Yang conjecture.

Findings

Lower bound on free energy matches Lee-Huang-Yang conjecture

Simplified proof technique for strong interactions

Includes case of hard-core potentials

Abstract

We consider a dilute Bose gas in the thermodynamic limit and prove a lower bound on the free energy for low temperatures which is in agreement with the conjecture of Lee-Huang-Yang on the excitation spectrum of the system. Combining techniques of \cite{FS2} and \cite{HHNST}, we give a simpler and shorter proof resolving the case of strong interactions, including the hard-core potential.