2010 Fiscal Year Final Research Report

Quasi-equilibrium evolution in self-gravitating and long-range interacting systems

Research Project

Project/Area Number	21740188
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Particle/Nuclear/Cosmic ray/Astro physics
Research Institution	Japan Atomic Energy Agency
Principal Investigator	TATEKAWA Takayuki Japan Atomic Energy Agency, システム計算科学センター, 博士研究員 (60350477)
Project Period (FY)	2009 – 2010
Keywords	統計物理 / 重力 / 長距離力 / N体シミュレーション / 非平衡 / GPGPU
Research Abstract	In long-range interacting systems such as self-gravitating system, it is known that relaxation time is quite long. Then during relaxation process in the long-range interacting systems, quasi-equilibrium state which is independent of initial conditions often appears. We discuss the models which can describe the quasi-equilibrium state with both analytic methods from statistical mechanics and N-body particles simulation. Then we showed that the density distribution of King model is represented by using Langevin equation in self-gravitating system. We showed that, in negative specific heat region, the quasi-equilibrium state in 2-dimensional HMF model can be fitted by maximum state of non-extensive entropy. On the other hand, in positive specific heat region, we cannot fit the quasi-equilibrium state with maximum state of non-extensive entropy.