Frame Dependence in Generalized Chiral Kinetic Theory

TL;DR

This work addresses the frame dependence of distribution functions in generalized chiral kinetic theory (GCKT) for massive fermions under vorticity and electromagnetic fields. By deriving explicit frame transformation rules based on a timelike vector $n^mu$ and analyzing global equilibrium with varying EM fields, the authors show that the Wigner functions are uniquely determined up to first order in $\hbar$. The approach combines the Wigner-function formalism with a systematic semiclassical expansion, yielding explicit forms for the zeroth- and first-order distributions and clarifying the role of side-jump terms and mass corrections. The results resolve prior ambiguities in equilibrium solutions and provide a consistent framework for quantum transport in relativistic systems such as heavy-ion collisions, with potential applications to massive fermion transport in gauge backgrounds.

Abstract

We investigate the frame dependence of distribution functions within the framework of generalized chiral kinetic theory. Based on the derived transformation rules governing the choice of frame, we analytically obtain the global equilibrium solution in the presence of vorticity and electromagnetic fields. Our results show that, under the assumption of a varying electromagnetic field, these equilibrium solutions can be uniquely determined.