ﻻ يوجد ملخص باللغة العربية
We derive an expression of the kinetic entropy current in the nonequilibrium $O(N)$ scalar theory from the Schwinger-Dyson (Kadanoff-Baym) equation with the 1st order gradient expansion. We show that our kinetic entropy satisfies the H-theorem for the leading order of the gradient expansion with the next-to-leading order self-energy of the $1/N$ expansion in the symmetric phase, and that entropy production occurs as the Greens function evolves with an nonzero collision term. Entropy production stops at local thermal equilibrium where the collision term contribution vanishes and the maximal entropy state is realized. Next we also compare our entropy density with that in thermal equilibrium which is given from thermodynamic potential or equivalently 2 particle irreducible effective action. We find that our entropy density corresponds to that in thermal equilibrium with the next-to-leading order skeletons of the $1/N$ expansion if skeletons with energy denominators in momentum integral can be regularized appropriately. We have a possibility that memory correction terms remain in entropy current if not regularized.
We derive Boltzmann equations for massive spin-1/2 fermions with local and nonlocal collision terms from the Kadanoff--Baym equation in the Schwinger--Keldysh formalism, properly accounting for the spin degrees of freedom. The Boltzmann equations are
This review provides a written version of the lectures presented at the Schladming Winter School 2008, Austria, on Nonequilibrium Aspects of Quantum Field Theory. In particular, it shows the way from quantum-field theory - in two-particle irreducible
Linear response functions are calculated for symmetric nuclear matter of normal density by time-evolving two-time Greens functions with conserving self-energy insertions, thereby satisfying the energy-sum rule. Nucleons are regarded as moving in a me
Linear density response functions are calculated for symmetric nuclear matter of normal density by time-evolving two-time Greens functions in real time. Of particular interest is the effect of correlations. The system is therefore initially time-evol
Three related analyses of $phi^4$ theory with $O(N)$ symmetry are presented. In the first, we review the $O(N)$ model over the $p$-adic numbers and the discrete renormalization group transformations which can be understood as spin blocking in an ultr