学术报告（1月13日）

主持人：姚道新教授

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摘要：In the summer of 1953, at Los Alamos Scientific Laboratory, Enrico Fermi, John Pasta, and Stanislaw Ulam initiated a series of studies on the MANIAC-1 digital computer. These studies were aimed at exploring how simple, multi-degree of freedom nonlinear mechanical systems obeying reversible deterministic dynamics evolve in time, presumably to an equilibrium state describable by statistical mechanics. FPU’s goal was to gain insight into the fundamental question of “the arrow of time.” Their expectation was that the approach to equilibrium would occur by mixing behavior among the many linear modes. Their intention was then to study more complex nonlinear systems, with the eventual hope of modeling turbulence computationally.

      The results of this first study of the so-called “Fermi-Pasta-Ulam (FPU) problem,” which were published in 1955 and characterized by Fermi as a “little discovery, ” showed instead of the expected mixing of linear modes a striking series of (near) recurrences of the initial state and no evidence of equipartition. This work heralded the beginning of both computational physics and (modern) nonlinear science. In particular, the work marked the first systematic study of a nonlinear system by digital computers (“experimental mathematics”). I will review the consequences of this remark numerical experiment and show how it remains of active interest still today, more than sixty years later.

报告人简介：

    David Campbell教授现为美国波士顿大学物理系、电子与计算机工程、材料科学与工程的专职教授，国际刊物《Chaos》的创刊编辑，美国物理学会会士，美国物理学会Julius Edgar Lilienfeld 奖，杨振宁访问学者（香港中文大学），Stanislaw M. Ulam 学者。Campbell教授于哈佛大学获得本科学位，剑桥大学获得博士学位（理论物理与应用数学）。曾任美国洛斯阿拉莫斯实验室的非线性中心主任（1985-1992），美国伊利诺伊大学香槟分校UIUC的物理系主任（1992-2000），美国波士顿大学的工学院院长（2000-2005），美国波士顿大学的教务长（2004-2011）。研究方向包括非线性科学、凝聚态理论、高能粒子物理，迄今已发表科学论文200余篇，编辑出版科学专著10部。