Quantum kinetic theory for dynamical spin polarization from QED-type interaction

Understand

We investigate the dynamical spin polarization of a massless electron probing an electron plasma in locally thermal equilibrium via the Moller scattering from the quantum kinetic theory.

• We derive an axial kinetic equation delineating the dynamical spin evolution in the presence of the collision term with quantum corrections up to $\mathcal{O}(\hbar)$ and the leading-logarithmic order in coupling by using the hard-thermal-loop (HTL) approximation, from which we extract the spin-polarization rate induced by the spacetime gradients of the medium.
• When the electron probe approaches local equilibrium, we further simplify the collision term into a relaxation-time expression.
• Our kinetic equation may be implemented in the future numerical simulations for dynamical spin polarization.