时间：2025年12月3日（周三）15:00-16:30
ZOOM ID: 960 2547 0854
PASSCOD: 2025
主持人：Hongguang Liu, ITS
主讲人：Klaus Fredenhagen, Hamburg University
主讲人简介：I studied physics in Hamburg, my Ph.D. advisors were Gert Roepstorff and Rudolf Haag. I had postdoc positions in Hamburg and Freiburg, then a Heisenberg fellowship at Freiburg, Marseille and Hamburg, interrupted by a guest professorship in Göttingen. In 1987 I became associate professor at Freie Universität Berlin and in 1990 full professor in Hamburg as a successor of Rudolf Haag. In 1997 I spent a semester in Leipzig as a Leibniz professor.
My main research topic is algebraic quantum field theory. In 1981 I found (together with Detlev Buchholz) a generalization of the theory of superselection sectors which nowadays plays a certain role in error correction for quantum information. It followed an analytical and numerical investigation of lattice gauge theories (together with Mihail Marcu) which led in particular to a new order parameter, known as the Fredenhagen-Marcu parameter (1985). A collaboration with Rudolf Haag ended in a new derivation of Hawking radiation (1990). A generalization of the theory of superselection sectors (with Karl-Henning Rehren and Bert Schroer, 1991) to low dimensional quantum field theory (including conformal field theory) resulted in braid group statistics of particle like excitations. In 1995 Sergio Doplicher, John Roberts and I postulated uncertainty relations of spacetime coordinates due to gravitational effects and constructed a related model of a noncommutative spacetime. Later I concentrated on quantum field theory on curved spacetime, on the basis of observations of Marek Radzikowsky on the wavefront set of 2-point functions (together with Romeo Brunetti 2000). In cooperation with Romeo Brunetti, Michael Dütsch and Kasia Rejzner we developed a perturbative version of algebraic quantum field theory (2010). More recently, Detlev Buchholz and I developed a nonperturbative construction of models of algebraic quantum field theory (2019), which then was further elaborated together with Romeo Brunetti, Michael Dütsch and Kasia Rejzner.
讲座主题：Causality and Quantum Physics: 100 years of Quantum Field Theory
讲座摘要：Quantum field theory is the attempt to unify the principles of quantum physics with the principles of special relativity. In particular the finite velocity of propagation of information is a challenge for a consistent theory.
It is as well the origin of divergences, which up to now prohibit the rigorous construction of a realistic quantum field theory, as also a crucial structure with allows far reaching conclusions.
