报告题目：Topological Order and Defects, and PhaseTransitions in Two Dimensions
报 告 人：John Michael Kosterlitz，2016年诺贝尔物理学奖获得者
Born in Aberdeen, Scotland, in 1943,Kosterlitz earned his Ph.D. from Oxford University in 1969. After anappointment as a postdoctoral researcher at Torino University in Italy, hebecame a research fellow at Birmingham University in 1970 before coming toBrown in 1982. He is a fellow of the American Physical Society and received theMaxwell Medal from the U.K. Institute of Physics in 1980. In 2000 he wasawarded the Lars Onsager Prize by the American Physical Society. In 2016, hewas awarded the Nobel Prize in Physics with David Thouless and DuncanHaldane. He was inducted into the American Academy of Arts and Sciencesas a fellow in 2007, and was elected a member of the US National Academy ofSciences in 2017.
Man's understanding of matter, the distinct phases of it,started from water, or vapor, water, ice. The vapor-water transition, thephenomenon of condensation, was first understood by van der Waals (Nobel Prizein Physics 1910). But the melting transition of solid has eluded us,still in 3D. We made the breakthrough in understanding 2D melting andphase transitions that got us the Nobel Prize. In 1D, there is no solidto melt which was understood by Lev Landau (Nobel Prize in Physics 1962) longtime ago. Landau's ideas of characterizing matter based on brokensymmetries and long-range order gave us the tools to understand many things innature, magnets, in particular. But Laudau's idea was too strict, itturns out long-range order was not the most essential property of being asolid, it's the shear rigidity that makes solid a solid. In two-dimensions,Thouless and I proved that you can have a solid-liquid transition based on theunbinding of topological defects. It turns out this idea has broadapplications to the understanding of many materials, superfluid helium films,magnets, liquid crystals, and quantum spin chains (Haldane, co-Nobel laureate).