Searching axion-like particles (ALP) through their coupling to fermions in the experiments like CASPEr and QUAX naturally motivates constructing a more fundamental formalism to describe the physics beyond these experiments. In this paper, we will find a quantum Boltzmann equation (QBE) for fermions sourced by the forward scattering of fermions. We will show that this kind of source terms can produce precessing magnetization of fermions that are going to be measured in experimental test. We also investigate the neutrino’s magnetic moment using QBE to find more about neutrino’s features.
