Infrared behavior of dipolar Bose systems at low temperatures

TL;DR

This paper investigates the low-temperature infrared behavior of three-dimensional dipolar Bose systems, focusing on their excitation spectrum, superfluid properties, and hydrodynamics, revealing key parameters that govern their physics.

Contribution

It provides a rigorous analysis of the infrared behavior, deriving equations for two-fluid hydrodynamics and calculating excitation spectra, damping, and superfluid properties specific to dipolar Bose systems.

Findings

Spectrum and damping of low-lying excitations calculated.

Infrared behavior governed by compressibility and dipole interaction strength.

Velocities of first and second sound derived.

Abstract

We rigorously discuss the infrared behavior of the uniform three dimensional dipolar Bose systems. In particular, it is shown that low-temperature physics of the system is controlled by two parameters, namely isothermal compressibility and intensity of the dipole-dipole interaction. By using hydrodynamic approach we calculate the spectrum and damping of low-lying excitations and analyze infrared behavior of the one-particle Green's function. The low-temperature corrections to the anisotropic superfluid density as well as condensate depletion are found. Additionally we derive equations of the two-fluid hydrodynamics for dipolar Bose systems and calculate velocities of first and second sound.