Quantum string theory

String theory is a new theory of fundamental interactions which is still under development. The basic idea is to replace point-like elementary particles with fundamental strings, which are line-like objects of very small length. The mathematical apparatus of string theory is very involved and is based on ideas from conformal field theory, infinite-dimensional algebras and Einstein's General Relativity. Although a complete picture of string theory is not yet available, there are indications that string theory may describe unification of gravity with other fundamental interactions.