|
Gregory–Laflamme Instability
The Gregory–Laflamme instability (after Ruth Gregory and Raymond Laflamme) is a result in theoretical physics which states that certain black strings and branes are unstable in dimensions higher than four. In their seminal papers in 1993 and 1994, Gregory and Laflamme showed that certain branes and Higher-dimensional Einstein gravity black string solutions in theories of gravity in higher dimensions D \ge 5 are found to exhibit an instability to small perturbations. The end point of this instability has been studied to higher dimensions and a critical dimension In the renormalization group analysis of phase transitions in physics, a critical dimension is the dimensionality of space at which the character of the phase transition changes. Below the lower critical dimension there is no phase transition. ... has been found to exist below which the end state of instability is a black hole phase, i.e., for 5 \le D \le 13. Above the critical dimension the instability drives to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruth Gregory
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.News Centre King's College London, University of London. Retrieved 03 February 2021. Her fields of specialisation are and .Ruth Gregory TEDxCLE. Retrieved 2016-02-28. Education Gregory earned her PhD fr ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raymond Laflamme
Raymond Laflamme (born 1960), Officer of the Order of Canada, OC, Royal Society of Canada, FRSC is a Canadian theoretical physicist and founder and until mid 2017, was the director of the Institute for Quantum Computing at the University of Waterloo. He is also a professor in the Department of Physics and Astronomy at the University of Waterloo and an associate faculty member at Perimeter Institute for Theoretical Physics. Laflamme is currently a Canada Research Chair in Quantum Information. In December 2017, he was named as one of the appointees to the Order of Canada. As Stephen Hawking's PhD student, he first became famous for convincing Hawking that time does not reverse in a contracting universe, along with Don Page (physicist), Don Page. Hawking told the story of how this happened in his famous book A Brief History of Time in the chapter The Arrow of Time. Later on Laflamme made a name for himself in quantum computing and Quantum information, quantum information theory, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theoretical Physics
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena. The advancement of science generally depends on the interplay between experimental studies and theory. In some cases, theoretical physics adheres to standards of mathematical rigour while giving little weight to experiments and observations.There is some debate as to whether or not theoretical physics uses mathematics to build intuition and illustrativeness to extract physical insight (especially when normal experience fails), rather than as a tool in formalizing theories. This links to the question of it using mathematics in a less formally rigorous, and more intuitive or heuristic way than, say, mathematical physics. For example, while developing special relativity, Albert Einstein was concerned wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black String
In general relativity, a black brane is a solution of the equations that generalizes a black hole solution but it is also extended—and translationally symmetric—in ''p'' additional spatial dimensions. That type of solution would be called a black ''p''-brane. In string theory, the term black brane describes a group of D1-branes that are surrounded by a horizon. With the notion of a horizon in mind as well as identifying points as zero-branes, a generalization of a black hole is a black p-brane. However, many physicists tend to define a black brane separate from a black hole, making the distinction that the singularity of a black brane is not a point like a black hole, but instead a higher dimensional object. A BPS black brane is similar to a BPS black hole. They both have electric charges. Some BPS black branes have magnetic charges. The metric for a black ''p''-brane in a ''n''-dimensional spacetime is: : ^ = \left( \eta_ + \frac u_a u_b \right) d \sigma^a d \sigma^b + \l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brane
In string theory and related theories such as supergravity theories, a brane is a physical object that generalizes the notion of a point particle to higher dimensions. Branes are dynamical objects which can propagate through spacetime according to the rules of quantum mechanics. They have mass and can have other attributes such as charge. Mathematically, branes can be represented within categories, and are studied in pure mathematics for insight into homological mirror symmetry and noncommutative geometry. ''p''-branes A point particle can be viewed as a brane of dimension zero, while a string can be viewed as a brane of dimension one. In addition to point particles and strings, it is possible to consider higher-dimensional branes. A ''p''-dimensional brane is generally called "''p''-brane". The term "''p''-brane" was coined by M. J. Duff ''et al.'' in 1988; "brane" comes from the word "membrane" which refers to a two-dimensional brane. A ''p''-brane sweeps out a (''p''+1) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Higher-dimensional Einstein Gravity
Higher-dimensional Einstein gravity is any of various physical theories that attempt to generalise to higher dimensions various results of the well established theory of standard (four-dimensional) Einstein gravity, that is, general relativity. This attempt at generalisation has been strongly influenced in recent decades by string theory. At present, this work can probably be most fairly described as extended theoretical speculation. Currently, it has no ''direct'' observational and experimental support, in contrast to four-dimensional general relativity. However, this theoretical work has led to the possibility of proving the existence of extra dimensions. This is best demonstrated by the proof of Harvey Reall and Roberto Emparan that there is a 'black ring' solution in 5 dimensions. If such a 'black ring' could be produced in a particle accelerator such as the Large Hadron Collider, this would provide the evidence that higher dimensions exist. Exact solutions The higher-dime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity
In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong interaction, 1036 times weaker than the electromagnetic force and 1029 times weaker than the weak interaction. As a result, it has no significant influence at the level of subatomic particles. However, gravity is the most significant interaction between objects at the macroscopic scale, and it determines the motion of planets, stars, galaxies, and even light. On Earth, gravity gives weight to physical objects, and the Moon's gravity is responsible for sublunar tides in the oceans (the corresponding antipodal tide is caused by the inertia of the Earth and Moon orbiting one another). Gravity also has many important biological functions, helping to guide the growth of plants through the process of gravitropism and influencing the circ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Higher Dimensions
In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coordinate is needed to specify a point on itfor example, the point at 5 on a number line. A surface, such as the boundary of a cylinder or sphere, has a dimension of two (2D) because two coordinates are needed to specify a point on itfor example, both a latitude and longitude are required to locate a point on the surface of a sphere. A two-dimensional Euclidean space is a two-dimensional space on the plane. The inside of a cube, a cylinder or a sphere is three-dimensional (3D) because three coordinates are needed to locate a point within these spaces. In classical mechanics, space and time are different categories and refer to absolute space and time. That conception of the world is a four-dimensional space but not the one that was found necessary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Dimension
In the renormalization group analysis of phase transitions in physics, a critical dimension is the dimensionality of space at which the character of the phase transition changes. Below the lower critical dimension there is no phase transition. Above the upper critical dimension the critical exponents of the theory become the same as that in mean field theory. An elegant criterion to obtain the critical dimension within mean field theory is due to V. Ginzburg. Since the renormalization group sets up a relation between a phase transition and a quantum field theory, this has implications for the latter and for our larger understanding of renormalization in general. Above the upper critical dimension, the quantum field theory which belongs to the model of the phase transition is a free field theory. Below the lower critical dimension, there is no field theory corresponding to the model. In the context of string theory the meaning is more restricted: the ''critical dimension'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
