Linearly stable and causal relativistic first-order spin hydrodynamics

TL;DR

This paper derives first-order relativistic spin hydrodynamics equations from kinetic theory, demonstrating their causality and stability under specific conditions, thus advancing the theoretical framework for dissipative spin fluids.

Contribution

It provides a derivation of causal and stable first-order spin hydrodynamics equations from kinetic theory with specific matching conditions.

Findings

Equations are causal and stable in any Lorentz frame.

Stability depends on certain conditions on transport coefficients.

The derivation is valid near homogeneous global equilibrium.

Abstract

We derive equations of motion for dissipative spin hydrodynamics from kinetic theory up to first order in a gradient expansion. Choosing a specific form of the matching conditions, relating the change in the spin potential to the spin diffusion and spin energy, we then show that the equations of motion, linearized around homogeneous global equilibrium, are causal and stable in any Lorentz frame, if certain sufficient conditions on the transport coefficients are fulfilled.