General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations.
Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics. It deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the vicinity of black holes or similar compact astrophysical objects, such as neutron stars, as well as in the early stages of the universe moments after the Big Bang.
Edward Witten is an American theoretical physicist known for his contributions to string theory, topological quantum field theory, and various areas of mathematics. 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.
John Carlos Baez is an American mathematical physicist and a professor of mathematics at the University of California, Riverside (UCR) in Riverside, California. He has worked on spin foams in loop quantum gravity, applications of higher categories to physics, and applied category theory. Additionally, Baez is known on the World Wide Web as the author of the crackpot index.
Julian Seymour Schwinger was a Nobel Prize-winning American theoretical physicist. He is best known for his work on quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order. Schwinger was a physics professor at several universities.
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.
Joseph Gerard Polchinski Jr. was an American theoretical physicist and string theorist.
John Henry Schwarz is an American theoretical physicist. Along with Yoichiro Nambu, Holger Bech Nielsen, Joël Scherk, Gabriele Veneziano, Michael Green, and Leonard Susskind, he is regarded as one of the founders of string theory.
Michael Boris Green is a British physicist and a pioneer of string theory. He is a Professor of Theoretical Physics in the School of Physics and Astronomy at Queen Mary University of London, emeritus professor in the Department of Applied Mathematics and Theoretical Physics and a Fellow of Clare Hall, Cambridge. He was Lucasian Professor of Mathematics from 2009 to 2015.
Eva Silverstein is an American theoretical physicist, cosmologist, and string theorist. She is a professor of physics at Stanford University and director of the Modern Inflationary Cosmology collaboration within the Simons Foundation Origins of the Universe initiative.
Bryce Seligman DeWitt was an American theoretical physicist noted for his work in gravitation and quantum field theory.
In particle physics, the history of quantum field theory starts with its creation by Paul Dirac, when he attempted to quantize the electromagnetic field in the late 1920s. Major advances in the theory were made in the 1940s and 1950s, leading to the introduction of renormalized quantum electrodynamics (QED). The field theory behind QED was so accurate and successful in predictions that efforts were made to apply the same basic concepts for the other forces of nature. Beginning in 1954, the parallel was found by way of gauge theory, leading by the late 1970s, to quantum field models of strong nuclear force and weak nuclear force, united in the modern Standard Model of particle physics.
Anthony Zee is a Chinese-American physicist, writer, and a professor at the Kavli Institute for Theoretical Physics and the physics department of the University of California, Santa Barbara.
Emil John Martinec is an American string theorist, a physics professor at the Enrico Fermi Institute at the University of Chicago, and director of the Kadanoff Center for Theoretical Physics. He was part of a group at Princeton University that developed heterotic string theory in 1985.
Thanu Padmanabhan was an Indian theoretical physicist and cosmologist whose research spanned a wide variety of topics in gravitation, structure formation in the universe and quantum gravity. He published nearly 300 papers and reviews in international journals and ten books in these areas. He made several contributions related to the analysis and modelling of dark energy in the universe and the interpretation of gravity as an emergent phenomenon. He was a Distinguished Professor at the Inter-University Centre for Astronomy and Astrophysics (IUCAA) at Pune, India.
Steven Scott Gubser was a professor of physics at Princeton University. His research focused on theoretical particle physics, especially string theory, and the AdS/CFT correspondence. He was a widely cited scholar in these and other related areas.
Craig Callender is a professor of philosophy at the University of California, San Diego. His main areas of research are philosophy of science, philosophy of physics and metaphysics.
Phenomenological quantum gravity is the research field that deals with the phenomenology of quantum gravity. The relevance of this research area derives from the fact that none of the candidate theories for quantum gravity has yielded experimentally testable predictions. Phenomenological models are designed to bridge this gap by allowing physicists to test for general properties that the hypothetical correct theory of quantum gravity has. Furthermore, due to this current lack of experiments, it is not known for sure that gravity is indeed quantum, and so evidence is required to determine whether this is the case. Phenomenological models are also necessary to assess the promise of future quantum gravity experiments.
Bryan Ronald Webber, FRS, FInstP is a British physicist and academic. He was a Fellow of Emmanuel College, Cambridge from 1973 to 2010, and Professor of Theoretical Physics at the University of Cambridge from 1999 to 2010. He has been awarded the Dirac Medal by the Institute of Physics, the Sakurai Prize by the American Physical Society and the High Energy and Particle Physics Prize by the European Physical Society.
In physics, a non-relativistic spacetime is any mathematical model that fuses n–dimensional space and m–dimensional time into a single continuum other than the (3+1) model used in relativity theory.
