Short-scale quantum kinetic theory including spin–orbit interactions

We present a quantum kinetic theory for spin-1/2 particles, including the spin–orbit interaction, retaining particle dispersive effects to all orders in ħ , based on a gauge-invariant Wigner transformation. Compared to previous works, the spin–orbit interaction leads to a new term in the kinetic equation, containing both the electric and magnetic fields. Like other models with spin–orbit interactions, our model features “hidden momentum”. As an example application, we calculate the dispersion relation for linear electrostatic waves in a magnetized plasma, and electromagnetic waves in a unmagnetized plasma. In the former case, we compare the Landau damping due to spin–orbit interactions to that due to the free current. We also discuss our model in relation to previously published works. Graphic abstract