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

• 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
• Project Status: Completed (Fiscal Year 2010)
• Budget Amount: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2010: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2009: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
• 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 / 統計力学 / 多体問題 / 緩和過程

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.

Research Products

• [Journal Article] Stochastic dynamics toward the steady state of self-gravitating systems (2011)
  • Author(s): Tohru Tashiro, Takayuki Tatekawa
  • Journal Title: Numerical Simulations/Book2 (Intech)
  • Peer Reviewed
• [Journal Article] Stochastic dynamics toward the steady state of self-gravitating systems (2011)
  • Author(s): Tohru Tashiro, Takayuki Tatekawa
  • Journal Title: Numerical Simulations (InTech-Open Access Publisher) Volume: 2(印刷中)
  • Peer Reviewed
• [Journal Article] Brownian dynamics around the core of self-gravitating systems (2010)
  • Author(s): Tohru Tashiro, Takayuki Tatekawa
  • Journal Title: Journal of the Physical Society of Japan Vol.79, No.6
  • NAID: 40017143653
  • Peer Reviewed
• [Journal Article] Brownian dynamics around the core of self-gravitating systems (2010)
  • Author(s): Tohru Tashiro, Takayuki Tatekawa
  • Journal Title: J.Phys.Soc.Jpn. Volume: 79
  • NAID: 40017143653
  • Peer Reviewed
• [Presentation] Transient states in two-dimensional long-range interacting system (2010)
  • Author(s): 立川崇之
  • Organizer: The XXIV International Conference on Statistical Physics of the International Union for Pure and Applied Physics (STATPHYS 24)
  • Place of Presentation: オーストラリア・ケアンズ
  • Year and Date: 2010-07-23
• [Presentation] Transient states in two-dimensional long-range interacting system (2010)
  • Author(s): Takayuki Tatekawa, Masa-aki Sakagami, Atsushi Taruya, Takashi Okamura, Stefano Ruffo
  • Organizer: The XXIV International Conference on Statistical Physics of the International Union for Pure and Applied Physics (STATPHYS 24)
  • Place of Presentation: Cairns, Australia
• [Presentation] Transient states in two-dimensional N-body systems (2010)
  • Author(s): Takayuki Tatekawa, Masa-aki Sakagami, Atsushi Taruya, Takashi Okamura, Stefano Ruffo
  • Organizer: The 13th Slovenia-Japan seminar on nonlinear science and Waseda AICS symposium on nonlinear and nonequilibrium phenomena in complex systems
  • Place of Presentation: 早稲田大学
• [Remarks] ホームページ等
  • URL: http://www2.yukawa.kyoto-u.ac.jp/~tatekawa/
• [Remarks]
  • URL: http://www2.yukawa.kyoto-u.ac.jp/~tatekawa/