Overview
In the 20th century, two theoretical frameworks emerged for formulating the laws of physics. The first is 展开

One approach to formulating string theory and studying its properties is provided by the anti-de Sitter/conformal field theory (AdS/CFT) correspondence. This is a theoretical result which … 展开

In addition to influencing research in theoretical physics, string theory has stimulated a number of major developments in pure mathematics. Like many developing ideas in theoretical physics, string theory does not at present have a 展开

Prior to 1995, theorists believed that there were five consistent versions of superstring theory (type I, type IIA, type IIB, and two versions of heterotic string theory). This understanding changed in 1995 when Edward Witten suggested that the five theories were … 展开

In general relativity, a black hole is defined as a region of spacetime in which the gravitational field is so strong that no particle or radiation can escape. In the currently accepted models of stellar evolution, black holes are thought to arise when massive stars … 展开

In addition to being an idea of considerable theoretical interest, string theory provides a framework for constructing models of real-world physics that combine general … 展开

Early results
Some of the structures reintroduced by string theory arose for the first time much earlier as part of the program of classical unification started by 展开