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.
In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries the gravitational force. Thus, string theory is a theory of quantum gravity.
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.
Mathematical physics refers to the development of mathematical methods for application to problems in physics. The Journal of Mathematical Physics defines the field as "the application of mathematics to problems in physics and the development of mathematical methods suitable for such applications and for the formulation of physical theories". An alternative definition would also include those mathematics that are inspired by physics.
Laurent Freidel is a French theoretical physicist and mathematical physicist known mainly for his contributions to quantum gravity, including loop quantum gravity, spin foam models, doubly special relativity, group field theory, relative locality and most recently metastring theory. He is currently a faculty member at Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada.
David Orlin Hestenes is a theoretical physicist and science educator. He is best known as chief architect of geometric algebra as a unified language for mathematics and physics, and as founder of Modelling Instruction, a research-based program to reform K–12 Science, Technology, Engineering, and Mathematics (STEM) education.
In general relativity, Regge calculus is a formalism for producing simplicial approximations of spacetimes that are solutions to the Einstein field equation. The calculus was introduced by the Italian theoretician Tullio Regge in 1961.
The Wheeler–DeWitt equation for theoretical physics and applied mathematics, is a field equation attributed to John Archibald Wheeler and Bryce DeWitt. The equation attempts to mathematically combine the ideas of quantum mechanics and general relativity, a step towards a theory of quantum gravity.
Dame Mary Lucy Cartwright was a British mathematician. She was one of the pioneers of what would later become known as chaos theory. Along with J. E. Littlewood, Cartwright saw many solutions to a problem which would later be seen as an example of the butterfly effect.
Tullio Eugenio Regge was an Italian theoretical physicist.
Causal dynamical triangulation theorized by Renate Loll, Jan Ambjørn and Jerzy Jurkiewicz, is an approach to quantum gravity that, like loop quantum gravity, is background independent.
Dorothy Maud Wrinch was a mathematician and biochemical theorist best known for her attempt to deduce protein structure using mathematical principles. She was a champion of the controversial 'cyclol' hypothesis for the structure of proteins.
Helen Fay Dowker is a British physicist who is a current professor of theoretical physics at Imperial College London.
Bertha Swirles, Lady Jeffreys was an English physicist, academic and scientific author who carried out research on quantum theory in its early days. She was associated with Girton College, University of Cambridge, as student and Fellow, for over 70 years.
Phyllis Nicolson was a British mathematician and physicist best known for her work on the Crank–Nicolson method together with John Crank.
Shahn Majid is an English pure mathematician and theoretical physicist, trained at Cambridge University and Harvard University and, since 2001, a Professor of Mathematics at the School of Mathematical Sciences, Queen Mary, University of London.
Bob Coecke is a Belgian theoretical physicist and logician who was professor of Quantum foundations, Logics and Structures at Oxford University until 2020, when he became Chief Scientist of Cambridge Quantum Computing, and after the merger with Honeywell Quantum Systems, Chief Scientist of Quantinuum. In January 2023 he also became Distinguished Visiting Research Chair at the Perimeter Institute for Theoretical Physics. He pioneered categorical quantum mechanics, Quantum Picturalism, ZX-calculus, DisCoCat model for natural language, and quantum natural language processing (QNLP). He is a founder of the Quantum Physics and Logic community and conference series, and of the applied category theory community, conference series, and diamond-open-access journal Compositionality.
Ruth Ann Watson Gregory is a British mathematician and physicist, currently Head of Department of Physics and Professor of Theoretical Physics at King's College London. Her fields of specialisation are general relativity and cosmology.
Andrew J. Hanson is an American theoretical physicist and computer scientist. Hanson is best known in theoretical physics as the co-discoverer of the Eguchi-Hanson Metric, the first Gravitational instanton. This Einstein metric is asymptotically locally Euclidean and self-dual, closely parallel to the Yang-Mills instanton. He is also known as the co-author of Constrained Hamiltonian Systems and of Gravitation, Gauge Theories, and Differential Geometry, which attempted to bridge the gap between theoretical physicists and mathematicians at a time when concepts relevant to the two disciplines were rapidly unifying. His subsequent work in computer science focused on computer graphics and visualization of exotic mathematical objects, including widely used images of the Calabi-Yau quintic cross-sections used to represent the hidden dimensions of 10-dimensional string theory. He is the author of Visualizing Quaternions.
