剑桥大学 E.K.H Salje 教授讲座通知
Salje教授，英国剑桥大学（University of Cambridge）教授。1975年博士毕业于德国汉诺威大学，是英国皇家科学院院士，英国皇家艺术院院士，德国科学院院士以及西班牙皇家科学院和艺术院院士。曾任英国剑桥大学克莱尔学院(Clare Hall)院长、克莱尔学院学术委员会主任，地球物理系（Department of Earth Science）系主任，剑桥大学-麻省理工学院联合研究院项目主席，德国洪堡协会英国分会主席等职务。目前还担任法国勒芒大学、西班牙毕尔巴勒大学、法国巴黎第六大学等国际知名大学的访问教授，以及美国洛斯阿拉莫斯国家实验室乌拉姆学者（Ulam scholar）。
Salje教授是国际知名的材料科学家、地球物理学家，他是德国洪堡顾问委员会委员，德国马普所顾问委员会委员，欧洲铁电会议发起人，德国汉堡大学董事会成员，英国议会下院科学与技术办公室成员，英国皇家科学院核废料处理顾问委员会委员，英国帕格沃式协会成员（British Pugwash Group），。Salje教授担任多个国际知名杂志编委，在各种国际会议上多次作特邀报告，迄今为止共发表原创性论文300余篇，H因子54。
Symmetry and its Breaking----fundamental idea in art and science
Ekhard K.H. Salje Cambridge University
To describe physical processes by their ‘inherent’ symmetry has been highly successful, from elementary particles to collective phenomena in solid state physics, protein folding, and complex systems. The concept of symmetry existed before physics revolutionized human thoughts at a time near 1750, as Ortega y Gasset postulates, and one may wonder whether symmetry arguments belong to that part of physics which he described as ‘circus tricks’ which are part of, but do not constitute, physics. A physical argument becomes ‘plausible’ if it relates to another train of thoughts which often originates from pre-scientific time, if such times existed at all. I will argue that symmetry is not a universal human concept but that it has cultural connotations. Some cultures did not established certain symmetry elements in their art work, such as the diad in pre-columbian art, or seem to have avoided them in visual and musical representations, such as in Japan and, partly, in China. Some symmetries were predominant in Europe, such as the spiral symmetry in the Minoan, but not the Nuragic culture and disappeared after 750BC in the archaic period to resurface much later in Iran and India. Symmetry is better understood if we see it together with the idea of ‘breaking the symmetry’, a wide spread idea in 20th and 21th century physics.
Modern ideas of convexity, convex hulls, and structural phase transitions live very much inside this intellectual framework. Most of the relevant symmetries are related to Shubnikov-Heesch colored space groups and their representations. I will discuss the relevance of phase transition as a symmetry breaking process which is much more tightly constraint than using the rather loose definitions of symmetry as previously applied. Nevertheless, the chirality of order parameters chimes very much with ideas of spiral symmetries and other symmetry breaking processes (e.g. on a small scale where symmetry is much harder to define) may still be discovered which involve more complex symmetries to be broken.编辑： 星火