- "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."
A theoretical framework that seeks to unify all the forces of the universe.
Special relativity: The theory of special relativity is the foundation on which string theory is built. It explains how the laws of physics remain the same in all inertial reference frames, and introduces the concept of spacetime as a single entity.
Quantum mechanics: Quantum mechanics is the study of how particles behave in the sub-atomic realm. It introduces concepts such as wave-particle duality, the uncertainty principle, and quantum entanglement.
General relativity: General relativity is a theory of gravitation that accounts for the curvature of spacetime caused by massive objects. It is important to understand how this theory is reconciled with quantum mechanics in string theory.
Topology: Topology is the study of the properties of space that are preserved under continuous transformations. In string theory, the topology of spacetime plays a crucial role in determining the properties of string configurations.
Algebraic geometry: Algebraic geometry is the study of geometric objects defined by polynomial equations. In string theory, algebraic geometry is used to describe the moduli space of string configurations.
Supersymmetry: Supersymmetry is a concept in physics that introduces a symmetry between particles with integer spin and particles with half-integer spin. It is essential in string theory because it allows for the cancellation of unwanted divergences.
Branes: Branes are extended objects that exist in higher dimensional spacetime. In string theory, they play a crucial role in the theory's formulation and can give rise to different types of particles.
Dualities: Dualities are a crucial concept in string theory that link apparently different physical theories into a unified whole. They allow for the exploration of strong-coupling regimes which are difficult to study using perturbation theory.
Calabi-Yau manifolds: Calabi-Yau manifolds are complex six-dimensional spaces that play a central role in string theory. They are used to compactify the extra dimensions required by string theory to match the observed four-dimensional world.
String interactions: String interactions are essential in understanding the behavior of strings in spacetime. They are described using string scattering amplitudes, which are calculated using various tools such as conformal field theory and perturbative calculations.
Type I string theory: A closed string theory that contains both open and closed strings. The open strings carry gauge theory interactions and the closed strings have gravity.
Type IIA string theory: A closed string theory with supersymmetry that contains only closed strings.
Type IIB string theory: A closed string theory with supersymmetry that contains only closed strings.
Heterotic string theory: A theory with a mix of open and closed strings that has both gauge theory and gravity interactions.
M-Theory: This is a type of string theory that involves eleven dimensions in space and time (versus the usual ten in other theories).
F-Theory: A gauge theory that lives on complex eight-dimensional space and is formulated in terms of seven-branes.
Little string theory: A lower-dimensional version of string theory that is used to study the behavior of strings at very high energies.
Matrix theory: A matrix model that is used to describe the dynamics of strings in a way that is consistent with quantum mechanics.
- "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."
- "String theory has contributed a number of advances to mathematical physics, which have been applied to a variety of problems in black hole physics, early universe cosmology, nuclear physics, and condensed matter physics."
- "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."
- "One of the challenges of string theory is that the full theory does not have a satisfactory definition in all circumstances."
- "It later developed into superstring theory, which posits a connection called supersymmetry between bosons and the class of particles called fermions."
- "Five consistent versions of superstring theory were developed before it was conjectured in the mid-1990s that they were all different limiting cases of a single theory in 11 dimensions known as M-theory."
- "In late 1997, theorists discovered an important relationship called the anti-de Sitter/conformal field theory correspondence (AdS/CFT correspondence), which relates string theory to another type of physical theory called a quantum field theory."
- "One of the challenges of string theory is that the full theory does not have a satisfactory definition in all circumstances."
- "Another issue is that the theory is thought to describe an enormous landscape of possible universes, which has complicated efforts to develop theories of particle physics based on string theory."
- "These issues have led some in the community to criticize these approaches to physics."
- "These issues have led some in the community to... question the value of continued research on string theory unification."
- "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."
- "It later developed into superstring theory, which posits a connection called supersymmetry between bosons and the class of particles called fermions."
- "Five consistent versions of superstring theory were developed before it was conjectured in the mid-1990s that they were all different limiting cases of a single theory in 11 dimensions known as M-theory."
- "String theory has contributed a number of advances to mathematical physics, which have been applied to a variety of problems in black hole physics, early universe cosmology, nuclear physics, and condensed matter physics."
- "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."