Boost invariant spin hydrodynamics within the first order in derivative expansion

TL;DR

This paper develops and numerically solves boost-invariant first-order spin hydrodynamics equations, including the spin equation of state, revealing stable and unstable solutions within a 10 fm/c evolution timeframe.

Contribution

It introduces a consistent first-order spin hydrodynamics framework with an integrated spin equation of state and analyzes the stability of solutions.

Findings

Stable solutions identified under certain conditions

Unstable solutions also observed depending on parameters

Results complement recent studies on spin system stability

Abstract

Boost-invariant equations of spin hydrodynamics confined to the first-order terms in gradients are numerically solved. The spin equation of state, relating the spin density tensor to the spin chemical potential, is consistently included in the first order. Depending on its form and the structure of the spin transport coefficients, we find solutions which are both stable and unstable within the considered evolution times of 10 fm/c. These findings are complementary to the recent identification of stable and unstable modes for perturbed uniform spin systems described by similar hydrodynamic frameworks.