In

physicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

,

**Matrix string theory** is a set of equations that describe

superstring theorySuperstring theory is an attempt to explain all of the particles and fundamental forces of nature in one theory by modelling them as vibrations of tiny supersymmetric strings...

in a non-perturbative framework. Type IIA string theory can be shown to be equivalent to a maximally supersymmetric two-dimensional

gauge theoryIn physics, gauge invariance is the property of a field theory in which different configurations of the underlying fundamental but unobservable fields result in identical observable quantities. A theory with such a property is called a gauge theory...

, the gauge group of which is U(N) for a large value of

*N*. This Matrix string theory was first proposed by

Luboš MotlLuboš Motl is a Czech theoretical physicist who keeps a blog commenting on physics, global warming and politics. His scientific research concentrated on string theory, of which he has been a passionate defender. He proposed Matrix string theory in 1997.Motl was born in Plzeň, Czech Republic...

in 1997 and later independently in a more complete paper by

Robbert DijkgraafRobertus Henricus "Robbert" Dijkgraaf is a Dutch mathematical physicist and string theorist.Robertus Henricus Dijkgraaf was born on 24 January 1960 in Ridderkerk, Netherlands. He currently lives in Amsterdam, Netherlands...

,

Erik VerlindeErik Peter Verlinde is a Dutch theoretical physicist and string theorist. He is the identical twin brother of physicist Herman Verlinde. The Verlinde formula, which is important in conformal field theory and topological field theory, is named after him. His research deals with string theory,...

, and

Herman VerlindeHerman Louis Verlinde is a Dutch theoretical physicist and string theorist. He is a professor at Princeton University. He is also the identical twin brother of Erik Verlinde.-External links:**...

. Another matrix string theory equivalent to Type IIB string theory was constructed in 1996 by Ishibashi, Kawai, Kitazawa and Tsuchiya. This version is known as the IKKT matrix model.

## M(atrix) Theory

**M(atrix) theory** (also known as

**BFSS-Matrix theory**) is a fundamental formulation of

M-theoryIn theoretical physics, M-theory is an extension of string theory in which 11 dimensions are identified. Because the dimensionality exceeds that of superstring theories in 10 dimensions, proponents believe that the 11-dimensional theory unites all five string theories...

as a

Random matrixIn probability theory and mathematical physics, a random matrix is a matrix-valued random variable. Many important properties of physical systems can be represented mathematically as matrix problems...

model. Matrix string theory is related to M(atrix) theory in the same sense that superstring theory is related to M-theory.

M(atrix) theory is written in terms of interacting D0-branes (zero-dimensional Dirichlet branes) in infinite momentum frame. It was proposed by

BanksTom Banks is a theoretical physicist at University of California, Santa Cruz and a professor at Rutgers University. His work centers around string theory and its applications to high energy particle physics and cosmology. He received his Ph.D...

,

FischlerWilly Fischler born in 1949 in Antwerpen, Belgium is a theoretical physicist and string theorist. He is currently the Jane and Roland Blumberg Centennial Professor of Physics at the University of Texas at Austin, where he is affiliated with the Weinberg theory group.Fischler is, among other things,...

, Shenker, and Susskind in 1996. See also the discussion in

M-theoryIn theoretical physics, M-theory is an extension of string theory in which 11 dimensions are identified. Because the dimensionality exceeds that of superstring theories in 10 dimensions, proponents believe that the 11-dimensional theory unites all five string theories...

.

## External links