M-theory is a theory in physics that unifies all consistent versions of superstring theory. The existence of such a theory was first conjectured by Edward Witten at the string theory conference at the University of Southern California in the summer of 1995. Witten's announcement initiated a flurry of research activity known as the second superstring revolution. Background Quantum gravity and strings One of the deepest problems in modern physics is the problem of quantum gravity. Number of dimensions In everyday life, there are three familiar dimensions of space (up/down, left/right, and forward/backward), and there is one dimension of time (later/earlier). Despite the obvious relevance of four-dimensional spacetime for describing the physical world, there are several reasons why physicists often consider theories in other dimensions. Dualities Main articles: S-duality and T-duality A diagram of string theory dualities. and winding number in the dual description. .
Superstring theory'Superstring theory' is a shorthand for supersymmetric string theory because unlike bosonic string theory, it is the version of string theory that accounts for both fermions and bosons and incorporates supersymmetry to model gravity. Since the second superstring revolution, the five superstring theories are regarded as different limits of a single theory tentatively called M-theory. Background The deepest problem in theoretical physics is harmonizing the theory of general relativity, which describes gravitation and applies to large-scale structures (stars, galaxies, super clusters), with quantum mechanics, which describes the other three fundamental forces acting on the atomic scale. The development of a quantum field theory of a force invariably results in infinite possibilities. History Lack of experimental evidence Superstring theory is based on supersymmetry. Extra dimensions Superstring theory is not the first theory to propose extra spatial dimensions.
Edward WittenEdward Witten (born August 26, 1951) is an American theoretical physicist and professor of mathematical physics at the Institute for Advanced Study in Princeton, New Jersey. Witten is a researcher in string theory, quantum gravity, supersymmetric quantum field theories, and other areas of mathematical physics. In addition to his contributions to physics, Witten's work has significantly impacted pure mathematics. In 1990, he became the first physicist to be awarded a Fields Medal by the International Mathematical Union, awarded for his 1981 proof of the positive energy theorem in general relativity. Early life and education Witten was born in Baltimore, Maryland, to a Jewish family. He is the son of Lorraine (Wollach) Witten and Louis Witten, a theoretical physicist specializing in gravitation and general relativity. Research Fields medal work In a written address to the ICM, Michael Atiyah said of Witten, M-theory Other work Awards and honors
FieldFrom Wikipedia, the free encyclopedia Jump to navigationJump to search Field may refer to: Expanses of open ground People Places Science Mathematics Physics Engineering and computing Sociology and politics Businesses Field Enterprises, a defunct private holding company Field Communications, a division of Field EnterprisesField Records, a record label Technical uses Other See alsoMatrix (mathematics)Two-dimensional array of numbers with specific operations The m rows are horizontal and the n columns are vertical. Each element of a matrix is often denoted by a variable with two subscripts. For example, a2,1 represents the element at the second row and first column of a matrix A. The numbers, symbols or expressions in the matrix are called its entries or its elements. The horizontal and vertical lines of entries in a matrix are called rows and columns, respectively. The size of a matrix is defined by the number of rows and columns that it contains. Matrices are commonly written in box brackets or parentheses: The entry in the i-th row and j-th column of a matrix A is sometimes referred to as the i,j, (i,j), or (i,j)th entry of the matrix, and most commonly denoted as ai,j, or aij. Sometimes, the entries of a matrix can be defined by a formula such as ai,j = f(i, j). In this case, the matrix itself is sometimes defined by that formula, within square brackets or double parentheses. and A.
string theory | Explanation & DefinitionString theory, in particle physics, a theory that attempts to merge quantum mechanics with Albert Einstein’s general theory of relativity. The name string theory comes from the modeling of subatomic particles as tiny one-dimensional “stringlike” entities rather than the more conventional approach in which they are modeled as zero-dimensional point particles. The theory envisions that a string undergoing a particular mode of vibration corresponds to a particle with definite properties such as mass and charge. Read More on This Topic cosmology: Superunification and the Planck era Why should a net baryon fraction initially of zero be more appealing aesthetically than 10−9? Relativity and quantum mechanics In 1905 Einstein unified space and time (see space-time) with his special theory of relativity, showing that motion through space affects the passage of time. Predictions and theoretical difficulties Facts Matter. The announcement was universally ignored. Dimensions and vibrations
String theoryTheoretical framework in physics String theory is a broad and varied subject that attempts to address a number of deep questions of fundamental physics. String theory has been applied to a variety of problems in black hole physics, early universe cosmology, nuclear physics, and condensed matter physics, and it has stimulated a number of major developments in pure mathematics. Because string theory potentially provides a unified description of gravity and particle physics, it is a candidate for a theory of everything, a self-contained mathematical model that describes all fundamental forces and forms of matter. Despite much work on these problems, it is not known to what extent string theory describes the real world or how much freedom the theory allows in the choice of its details. String theory was first studied in the late 1960s as a theory of the strong nuclear force, before being abandoned in favor of quantum chromodynamics. Fundamentals Strings Extra dimensions Dualities Branes M-theory
Theory of relativityThe theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity. Special relativity applies to elementary particles and their interactions, describing all their physical phenomena except gravity. General relativity explains the law of gravitation and its relation to other forces of nature. It applies to the cosmological and astrophysical realm, including astronomy. The theory transformed theoretical physics and astronomy during the 20th century, superseding a 200-year-old theory of mechanics created primarily by Isaac Newton. It introduced concepts including spacetime as a unified entity of space and time, relativity of simultaneity, kinematic and gravitational time dilation, and length contraction. In the field of physics, relativity improved the science of elementary particles and their fundamental interactions, along with ushering in the nuclear age. Development and acceptance Special relativity
General relativityTheory by Albert Einstein, covering gravitation in curved spacetime Slow motion computer simulation of the black hole binary system GW150914 as seen by a nearby observer, during 0.33 s of its final inspiral, merge, and ringdown. The star field behind the black holes is being heavily distorted and appears to rotate and move, due to extreme gravitational lensing, as spacetime itself is distorted and dragged around by the rotating black holes. General relativity (GR, also known as the general theory of relativity or GTR) is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics. General relativity generalizes special relativity and supersedes Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. Einstein's theory has important astrophysical implications. History From classical mechanics to general relativity and . B.