Spin relaxation in a one-dimensional large-spin degenerate Fermi gas

TL;DR

This paper investigates spin relaxation dynamics in a one-dimensional large-spin Fermi gas, revealing how incoherent collisions dominate at low densities and differ from higher-dimensional cases, using a quantum Boltzmann approach.

Contribution

It provides a detailed analysis of spin relaxation in 1D Fermi gases, highlighting the unique density dependence of incoherent collisions compared to 3D systems.

Findings

Incoherent collision rates increase slower with density in 1D than in 3D.

In 1D, incoherent collisions dominate at lower densities.

Far-from-equilibrium spin dynamics reflect enhanced correlations at low densities.

Abstract

In this work, we study the dynamics of an atomic harmonically trapped large-spin Fermi gas in one dimension (1D). We investigate the interplay of different collision processes. Coherent spin oscillations, driven by spin-changing forward scattering are captured by a mean-field description and scale linearly with density regardless of the dimension of the system. Conversely, "incoherent" collision processes which e.g. lead to the damping of spin oscillations, behave differently. In the usual three-dimensional (3D) case, the rate of incoherent processes increases faster with density than mean-field effects, but in 1D it increases slower. This means, that in the 1D case, incoherent collisions become more important at lower densities. We study these effects by deriving and integrating a quantum Boltzmann equation. We demonstrate that the well known fact that in one dimension, interaction-induced correlations become more dominant at low densities can be observed in far-from-equilibrium spin dynamics.