Klaus Fredenhagen | |
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Born | |
Nationality | German |
Alma mater | University of Hamburg |
Scientific career | |
Fields | Physics |
Institutions | University of Hamburg |
Thesis | Die Quantenelektrodynamik mit einem Freiheitsgrad fuer das Photonfeld (1976) |
Doctoral advisor |
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Klaus Fredenhagen (born 1 December 1947) is a German theoretical physicist who works on the mathematical foundations of quantum field theory. [1]
Klaus Fredenhagen was born on 1 December 1947 in Celle, a German city in Lower Saxony. He graduated in 1976 [2] from the University of Hamburg under the supervision of Gert Roepstorff and Rudolf Haag. [3] In 1985 he became a privatdozent and in 1990 a full professor at the second theory institute of the Hamburg University. [4] Since 2013 he has been a professor emeritus and has continued to be active in research. [5]
His research interests are algebraic quantum field theory and quantum field theory in curved spacetime. In 1981 he proved the existence of antiparticles in massive quantum field theories without using the CPT-invariance. [6] In 1990 he and Rudolf Haag made important contributions to the understanding of the Hawking radiation of black holes on a rigorous mathematical footing. [7] In 1994, together with Sergio Doplicher and John E. Roberts, he investigated the mathematical foundations of quantum gravity in terms of the quantum structure of spacetime at the Planck scale. [8] In 1996, together with Romeo Brunetti, he started working on the generalization of the Epstein-Glaser renormalization procedure of interacting quantum field theories in curved spacetime using techniques from the microlocal analysis. [9] He is currently working, together with Detlev Buchholz, on a new C*-algebraic approach to interacting quantum field theories. [10]
In 1987 Klaus Fredenhagen was awarded the physics prize of the Göttingen Academy of Sciences [11] and in 1997 he was Leibniz Professor [12] at the University of Leipzig. [13] In December 2017 the workshop Quantum Physics meets Mathematics was held in honor of his 70th birthday at the University of Hamburg. [14]
Edward Witten is an American mathematical and theoretical physicist. He is a Professor Emeritus in the School of Natural Sciences at the Institute for Advanced Study in Princeton. Witten is a researcher in string theory, quantum gravity, supersymmetric quantum field theories, and other areas of mathematical physics. Witten's work has also significantly impacted pure mathematics. In 1990, he became the first physicist to be awarded a Fields Medal by the International Mathematical Union, for his mathematical insights in physics, such as his 1981 proof of the positive energy theorem in general relativity, and his interpretation of the Jones invariants of knots as Feynman integrals. He is considered the practical founder of M-theory.
In theoretical physics, twistor theory was proposed by Roger Penrose in 1967 as a possible path to quantum gravity and has evolved into a widely studied branch of theoretical and mathematical physics. Penrose's idea was that twistor space should be the basic arena for physics from which space-time itself should emerge. It has led to powerful mathematical tools that have applications to differential and integral geometry, nonlinear differential equations and representation theory, and in physics to general relativity, quantum field theory, and the theory of scattering amplitudes. Twistor theory arose in the context of the rapidly expanding mathematical developments in Einstein's theory of general relativity in the late 1950s and in the 1960s and carries a number of influences from that period. In particular, Roger Penrose has credited Ivor Robinson as an important early influence in the development of twistor theory, through his construction of so-called Robinson congruences.
Algebraic quantum field theory (AQFT) is an application to local quantum physics of C*-algebra theory. Also referred to as the Haag–Kastler axiomatic framework for quantum field theory, because it was introduced by Rudolf Haag and Daniel Kastler (1964). The axioms are stated in terms of an algebra given for every open set in Minkowski space, and mappings between those.
The chronology protection conjecture is a hypothesis first proposed by Stephen Hawking that laws of physics beyond those of standard general relativity prevent time travel on all but microscopic scales - even when the latter theory states that it should be possible. The permissibility of time travel is represented mathematically by the existence of closed timelike curves in some solutions to the field equations of general relativity. The chronology protection conjecture should be distinguished from chronological censorship under which every closed timelike curve passes through an event horizon, which might prevent an observer from detecting the causal violation.
In particle physics, a plekton is a theoretical kind of particle that obeys a different style of statistics with respect to the interchange of identical particles. That is, it would be neither a boson nor a fermion, but subject to a braid statistics. Such particles have been discussed as a generalization of the braid characteristics of the anyon to dimension > 2.
In mathematical physics, noncommutative quantum field theory is an application of noncommutative mathematics to the spacetime of quantum field theory that is an outgrowth of noncommutative geometry and index theory in which the coordinate functions are noncommutative. One commonly studied version of such theories has the "canonical" commutation relation:
In theoretical physics, quantum field theory in curved spacetime (QFTCS) is an extension of quantum field theory from Minkowski spacetime to a general curved spacetime. This theory treats spacetime as a fixed, classical background, while giving a quantum-mechanical description of the matter and energy propagating through that spacetime. A general prediction of this theory is that particles can be created by time-dependent gravitational fields (multigraviton pair production), or by time-independent gravitational fields that contain horizons. The most famous example of the latter is the phenomenon of Hawking radiation emitted by black holes.
Rudolf Haag was a German theoretical physicist, who mainly dealt with fundamental questions of quantum field theory. He was one of the founders of the modern formulation of quantum field theory and he identified the formal structure in terms of the principle of locality and local observables. He also made important advances in the foundations of quantum statistical mechanics.
Karl-Henning Rehren is a German physicist who focuses on algebraic quantum field theory.
Detlev Buchholz is a German theoretical physicist. He investigates quantum field theory, especially in the axiomatic framework of algebraic quantum field theory.
In mathematical physics, the concept of quantum spacetime is a generalization of the usual concept of spacetime in which some variables that ordinarily commute are assumed not to commute and form a different Lie algebra. The choice of that algebra still varies from theory to theory. As a result of this change some variables that are usually continuous may become discrete. Often only such discrete variables are called "quantized"; usage varies.
Hans-Jürgen Borchers was a mathematical physicist at the Georg-August-Universität Göttingen who worked on operator algebras and quantum field theory. He introduced Borchers algebras and the Borchers commutation relations and Borchers classes in quantum field theory. He was awarded the Max Planck Medal in 1994. Among his students is Jakob Yngvason.
Basil J. Hiley, is a British quantum physicist and professor emeritus of the University of London.
Twistor string theory is an equivalence between N = 4 supersymmetric Yang–Mills theory and the perturbative topological B model string theory in twistor space.
Sergio Doplicher is an Italian mathematical physicist, who mainly dealt with the mathematical foundations of quantum field theory and quantum gravity.
Adrian Kent is a British theoretical physicist, Professor of Quantum Physics at the University of Cambridge, member of the Centre for Quantum Information and Foundations, and Distinguished Visiting Research Chair at the Perimeter Institute for Theoretical Physics. His research areas are the foundations of quantum theory, quantum information science and quantum cryptography. He is known as the inventor of relativistic quantum cryptography. In 1999 he published the first unconditionally secure protocols for bit commitment and coin tossing, which were also the first relativistic cryptographic protocols. He is a co-inventor of quantum tagging, or quantum position authentication, providing the first schemes for position-based quantum cryptography. In 2005 he published with Lucien Hardy and Jonathan Barrett the first security proof of quantum key distribution based on the no-signalling principle.
Roberto Longo is an Italian mathematician, specializing in operator algebras and quantum field theory.
In mathematical physics, two-dimensional Yang–Mills theory is the special case of Yang–Mills theory in which the dimension of spacetime is taken to be two. This special case allows for a rigorously defined Yang–Mills measure, meaning that the (Euclidean) path integral can be interpreted as a measure on the set of connections modulo gauge transformations. This situation contrasts with the four-dimensional case, where a rigorous construction of the theory as a measure is currently unknown.
Giovanni Felder is a Swiss mathematical physicist and mathematician, working at ETH Zurich. He specializes in algebraic and geometric properties of integrable models of statistical mechanics and quantum field theory.
Anatol Odzijewicz was Polish mathematician and physicist. The main areas of his research were the theory of Banach groupoids and algebroids related to the structure of W*-algebras, quantization of physical systems by means of the coherent state map, as well as quantum and classical integrable systems.