内容摘要：Quantum field theory has developed models with intricate and subtle geometric structure, like the supersymmetric nonlinear sigma model or the superstring model. We have turned these models into geometric variational models. The resulting Euler-Lagrange equations are coupled nonlinear systems of elliptic equations that present novel challenges for geometric analysis. For solve them, the underlying symmetries，in particular conformal invariance, play a key role. 报告人简介：Professor Jurgen Jost was born on June 9, 1956 in Münster. Study of mathematics, physics, economics and philosophy at Bonn Univ. (1975- 1980), PhD in Mathematics (1980), Professor Ruhr Univ. Bochum (1984-1996),Director and Scientific Member at the Max Planck Institute for Mathematics in the Sciences (since 1996), Honorary Professor at Leipzig Univ. (1998), External Member Santa Fe Institute for the Sciences of Complexity, New Mexico, USA. Member of the German National Academy of Sciences Leopoldina, Academy of Sciences and Literature at Mainz, Saxonian Academy of Sciences.Gottfried-Wilhelm-Leibniz Award of the DFG (1993), ERC Advanced Grant (2010).