Thermodynamics of ideal spin fluids and pseudo-gauge ambiguity
High Energy Physics - Theory
2026-03-17 v2 High Energy Physics - Phenomenology
Nuclear Theory
Abstract
Conserved currents of relativistic spin fluids derived from microscopic models are known to violate local thermodynamic relations. We present a systematic analysis of pseudo-gauge improvements in ideal spin hydrodynamics and identify a family of pseudo-gauges where standard thermodynamic relations are satisfied. We quantify pseudo-gauge ambiguities in the spin equation of state and derive universal thermodynamic relations that apply to conserved currents in any pseudo-gauge. As an application, we extract the thermodynamic variables and equations of state for free Dirac fermions and scalar fields.
Keywords
Cite
@article{arxiv.2601.14421,
title = {Thermodynamics of ideal spin fluids and pseudo-gauge ambiguity},
author = {Jay Armas and Akash Jain},
journal= {arXiv preprint arXiv:2601.14421},
year = {2026}
}
Comments
Supplementary Mathematica Notebook available at http://github.com/ajainphysics/Mathematica-Notebooks/. v2: Added a new appendix and fixed typos