2022-01-20T21:27:28Zhttps://tsukuba.repo.nii.ac.jp/oaioai:tsukuba.repo.nii.ac.jp:000278842021-03-02T07:17:45ZNonequilibrium two-particle irreducible evolution of the O(N) model with longitudinal expansion八田, 佳孝Hatta, YoshitakaNishiyama, Akihiro© 2012 American Physical SocietyMotivated by the problem of thermalization in heavy ion collisions, we present numerical simulations of the nonequilibrium evolution of the O(N) model in 1+2 dimensions with longitudinal expansion and in the presence of a background field. We work in the next-to-leading-order approximation of the 1/N expansion and consider both the strong and weak coupling cases. Special emphasis is put on the difference between the two-particle irreducible formalism and the classical statistical approach. In the two-particle irreducible case at strong coupling, we find some evidence of the Bose-Einstein (exponential) distribution in the expanding system.American Physical Society2012-10engjournal articlehttp://hdl.handle.net/2241/117836https://tsukuba.repo.nii.ac.jp/records/2788410.1103/PhysRevD.86.0760021550-7998AA00773624Physical review D867076002https://tsukuba.repo.nii.ac.jp/record/27884/files/PRD_86-7.pdfapplication/pdf398.8 kB2013-12-25