New theory of superfluidity. Method of equilibrium density matrix

TL;DR

This paper introduces a new theoretical approach using the density matrix formalism to analyze superfluidity in a quantum Bose gas, revealing a phase transition similar to superfluid helium at temperatures above Bose condensation.

Contribution

The paper develops a variational density matrix method to study equilibrium states and thermodynamic properties of a zero-spin boson gas, identifying a novel phase transition.

Findings

Identifies a phase transition akin to superfluid helium at higher temperatures.

Calculates thermodynamic properties such as chemical potential and internal energy.

Provides a new theoretical framework for superfluidity in Bose gases.

Abstract

The variational theory of equilibrium boson system state to have been previously developed by the author under the density matrix formalism is applicable for researching equilibrium states and thermodynamic properties of the quantum Bose gas which consists of zero-spin particles. Particle pulse distribution function is obtained and duly employed for calculation of chemical potential, internal energy and gas capacity temperature dependences. It is found that specific phase transition, which is similar to transition of liquid helium to its superfluid state, occurs at the temperature exceeding that of the Bose condensation.