Contribution from the interaction Hamiltonian to the expectation value   of particle number with the non-equilibrium quantum field theory
  We develop the method analyzing particle number non-conserving phenomena with non-equilibrium quantum field theory. In this study, we consider a CP violating model with interaction Hamiltonian that breaks particle number conservation. To derive the quantum Boltzmann equation for the particle number, we solve Schwinger-Dyson equation, which are obtained from two particle irreducible closed-time-path (2PI CTP) effective action. In this calculation, we show the contribution from interaction Hamiltonian to the time evolution of expectation value of particle number. 
Ryuuichi Hotta (Hiroshima U.), Takuya Morozumi (Hiroshima U.),   Hiroyuki Takata (Tomsk State Pedagogical U.)
hep-th hep-ph