Thermal Conductivity of an Ultracold Paramagnetic Bose Gas

TL;DR

This paper derives the anisotropic thermal conductivity tensor for an ultracold Bose gas of dipolar lanthanide atoms, revealing how microscopic interactions influence macroscopic heat transport and enabling control of thermal phenomena.

Contribution

It provides an analytical derivation of the thermal conductivity tensor considering dipolar interactions in a non-degenerate Bose gas, highlighting anisotropic effects.

Findings

Thermal conductivity tensor exhibits anisotropy due to dipolar interactions.

Heat diffusion is preferentially orthogonal to dipole orientation.

Tuning atomic interactions can control macroscopic thermal behavior.

Abstract

We analytically derive the transport tensor of thermal conductivity in an ultracold, but not yet quantum degenerate, gas of Bosonic lanthanide atoms using the Chapman-Enskog procedure. The tensor coefficients inherit an anisotropy from the anisotropic collision cross section for these dipolar species, manifest in their dependence on the dipole moment, dipole orientation, and $s$-wave scattering length. These functional dependencies open up a pathway for control of macroscopic gas phenomena via tuning of the microscopic atomic interactions. As an illustrative example, we analyze the time evolution of a temperature hot-spot which shows preferential heat diffusion orthogonal to the dipole orientation, a direct consequence of anisotropic thermal conduction.