Niklas Beisert (born 1977 in Hamburg) is a German theoretical physicist, known for his research on quantum field theory and string theory.
Niklas Beisert is the son of the architect and art historian Anna Katharina Beisert-Zülch (of the University of Hildesheim) and the architect Thomas Beisert (of the company APB Planungsgesellschaft mbH Architekten). Anna Katharina Beisert-Zülch's father was the neuroscientist Klaus-Joachim Zülch (1910–1988). [1] Niklas Beisert studied physics, as a scholarship holder of the Studienstiftung des Deutschen Volkes (German Academic Scholarship Foundation), at the Technical University of Munich from 1996 to 2001, when he received his Diplom . For the academic year 1999–2000 he attended an M.Sc. course at Imperial College London. After receiving his Diplom he was a researcher the Max Planck Institute for Gravitational Physics in Golm-Potsdam. In 2004 he received his doctorate from the Humboldt University of Berlin. His doctoral dissertation The Dilation Operator of N=4 Super-Yang-Mills Theory and Integrability was supervised by Matthias Staudacher. [2] As a post-doctoral fellow, Beisert was at Princeton University (as a Dicke Fellow), where he became an assistant professor in 2005. From 2006 to 2011 he was group leader of the theory group Dualität und Integrable Strukturen (Duality and Integrable Structures) at the Max Planck Institute for Gravitational Physics in Golm-Potsdam. Since 2011 is a full professor at ETH Zurich. He is married and the father of three children. [3]
Beisert does research on integrable structures (i.e., structures that allow exact solvability) and symmetries in (four-dimensional) gauge field theory and string theory related to the AdS/CFT correspondence. The AdS/CFT correspondence expresses an equivalence in the description of gauge theories (as used in the standard model of elementary particle physics) and string theories, but has not yet been proven or disproven. By applying techniques that have been used for exactly integrable systems in solid-state physics (such as one-dimensional spin chains [4] [5] and the Bethe ansatz [6] [7] [8] ), Beisert, Staudacher, and colleagues made progress in gauge/string duality for the case of supersymmetric gauge field theories with maximal symmetry (planar N=4 supersymmetric Yang-Mills theory, with symmetry group 𝖕𝖘𝖚(2,2|4)). This research effort was pioneered by the University of Uppsala's Joseph Minahan and Konstantin Zarembo, who previously found evidence of integrable structures. [9] The resulting research developments in the solution of supersymmetric gauge field theories for large N was described by David Gross, at the Strings-07 conference in Madrid, as the most interesting development in string theory in the preceding year. [10]
He received in 2005 the Otto Hahn Medal of the Max Planck Society [3] and in 2007 the Gribov Medal of the European Physical Society. [11] In 2006 he was awarded a two-year Sloan Research Fellowship. In 2013 he received the New Horizons in Physics Prize. [3]
In theoretical physics, the anti-de Sitter/conformal field theory correspondence is a conjectured relationship between two kinds of physical theories. On one side are anti-de Sitter spaces (AdS) that are used in theories of quantum gravity, formulated in terms of string theory or M-theory. On the other side of the correspondence are conformal field theories (CFT) that are quantum field theories, including theories similar to the Yang–Mills theories that describe elementary particles.
Nathan "Nati" Seiberg is an Israeli American theoretical physicist who works on quantum field theory and string theory. He is currently a professor at the Institute for Advanced Study in Princeton, New Jersey, United States.
In quantum field theory, Seiberg duality, conjectured by Nathan Seiberg in 1994, is an S-duality relating two different supersymmetric QCDs. The two theories are not identical, but they agree at low energies. More precisely under a renormalization group flow they flow to the same IR fixed point, and so are in the same universality class. It is an extension to nonabelian gauge theories with N=1 supersymmetry of Montonen–Olive duality in N=4 theories and electromagnetic duality in abelian theories.
Montonen–Olive duality or electric–magnetic duality is the oldest known example of strong–weak duality or S-duality according to current terminology. It generalizes the electro-magnetic symmetry of Maxwell's equations by stating that magnetic monopoles, which are usually viewed as emergent quasiparticles that are "composite", can in fact be viewed as "elementary" quantized particles with electrons playing the reverse role of "composite" topological solitons; the viewpoints are equivalent and the situation dependent on the duality. It was later proven to hold true when dealing with a N = 4 supersymmetric Yang–Mills theory. It is named after Finnish physicist Claus Montonen and British physicist David Olive after they proposed the idea in their academic paper Magnetic monopoles as gauge particles? where they state:
There should be two "dual equivalent" field formulations of the same theory in which electric (Noether) and magnetic (topological) quantum numbers exchange roles.
In theoretical physics, the anti-de Sitter/quantum chromodynamics correspondence is a goal to describe quantum chromodynamics (QCD) in terms of a dual gravitational theory, following the principles of the AdS/CFT correspondence in a setup where the quantum field theory is not a conformal field theory.
Igor R. Klebanov is an American theoretical physicist. Since 1989, he has been a faculty member at Princeton University, where he is currently a Eugene Higgins Professor of Physics and the director of the Princeton Center for Theoretical Science. In 2016, he was elected to the National Academy of Sciences. Since 2022, he is the director of the Simons Collaboration on Confinement and QCD Strings.
The quantum Heisenberg model, developed by Werner Heisenberg, is a statistical mechanical model used in the study of critical points and phase transitions of magnetic systems, in which the spins of the magnetic systems are treated quantum mechanically. It is related to the prototypical Ising model, where at each site of a lattice, a spin represents a microscopic magnetic dipole to which the magnetic moment is either up or down. Except the coupling between magnetic dipole moments, there is also a multipolar version of Heisenberg model called the multipolar exchange interaction.
In theoretical physics, a logarithmic conformal field theory is a conformal field theory in which the correlators of the basic fields are allowed to be logarithmic at short distance, instead of being powers of the fields' distance. Equivalently, the dilation operator is not diagonalizable.
Matthias Staudacher is a German theoretical physicist who has done significant work in the area of quantum field theory and string theory.
In strong interaction physics, light front holography or light front holographic QCD is an approximate version of the theory of quantum chromodynamics (QCD) which results from mapping the gauge theory of QCD to a higher-dimensional anti-de Sitter space (AdS) inspired by the AdS/CFT correspondence proposed for string theory. This procedure makes it possible to find analytic solutions in situations where strong coupling occurs, improving predictions of the masses of hadrons and their internal structure revealed by high-energy accelerator experiments. The most widely used approach to finding approximate solutions to the QCD equations, lattice QCD, has had many successful applications; It is a numerical approach formulated in Euclidean space rather than physical Minkowski space-time.
Warren Siegel is a theoretical physicist specializing in supersymmetric quantum field theory and string theory. He was a professor at the C. N. Yang Institute for Theoretical Physics at Stony Brook University. He retired in Fall of 2022.
N = 4 supersymmetric Yang–Mills (SYM) theory is a relativistic conformally invariant Lagrangian gauge theory describing the interactions of fermions via gauge field exchanges. In D=4 spacetime dimensions, N=4 is the maximal number of supersymmetries or supersymmetry charges.
In theoretical physics, 3D mirror symmetry is a version of mirror symmetry in 3-dimensional gauge theories with N=4 supersymmetry, or 8 supercharges. It was first proposed by Kenneth Intriligator and Nathan Seiberg, in their 1996 paper "Mirror symmetry in three-dimensional gauge theories", as a relation between pairs of 3-dimensional gauge theories, such that the Coulomb branch of the moduli space of one is the Higgs branch of the moduli space of the other. It was demonstrated using D-brane cartoons by Amihay Hanany and Edward Witten 4 months later, where they found that it is a consequence of S-duality in type IIB string theory.
Jan Christoph Plefka is a German theoretical physicist working in the field of quantum field theory and string theory.
In theoretical physics, an M5-brane is a fundamental brane of M-theory. As such, it can be described explicitly as a black brane solution to eleven-dimensional supergravity, the low-energy limit of M-theory. In particular, it carries a magnetic charge under the 3-form gauge field of the 11-dimensional supergravity multiplet. The M5-brane is the electric-magnetic dual of the M2-brane.
Supersymmetric localization is a method to exactly compute correlation functions of supersymmetric operators in certain supersymmetric quantum field theories such as the partition function, supersymmetric Wilson loops, etc. The method can be seen as an extension of the Berline–Vergne– Atiyah– Bott formula for equivariant integration to path integrals of certain supersymmetric quantum field theories. Although the method cannot be applied to general local operators, it does provide the full nonperturbative answer for the restricted class of supersymmetric operators. It is a powerful tool which is currently extensively used in the study of supersymmetric quantum field theory. The method, built on the previous works by E.Witten, in its modern form involves subjecting the theory to a nontrivial supergravity background, such that the fermionic symmetry preserved by the latter can be used to perform the localization computation, as in.
Higher-spin theory or higher-spin gravity is a common name for field theories that contain massless fields of spin greater than two. Usually, the spectrum of such theories contains the graviton as a massless spin-two field, which explains the second name. Massless fields are gauge fields and the theories should be (almost) completely fixed by these higher-spin symmetries. Higher-spin theories are supposed to be consistent quantum theories and, for this reason, to give examples of quantum gravity. Most of the interest in the topic is due to the AdS/CFT correspondence where there is a number of conjectures relating higher-spin theories to weakly coupled conformal field theories. It is important to note that only certain parts of these theories are known at present and not many examples have been worked out in detail except some specific toy models.
Olaf Lechtenfeld is a German mathematical physicist, academic and researcher. He is a full professor at the Institute of Theoretical Physics at Leibniz University, where he founded the Riemann Center for Geometry and Physics.
In statistical physics, the Inozemtsev model is a spin chain model, defined on a one-dimensional, periodic lattice. Unlike the prototypical Heisenberg spin chain, which only includes interactions between neighboring sites of the lattice, the Inozemtsev model has long-range interactions, that is, interactions between any pair of sites, regardless of the distance between them.
Germán Sierra is a Spanish theoretical physicist, author, and academic. He is Professor of Research at the Institute of Theoretical Physics Autonomous University of Madrid-Spanish National Research Council.