Wikipedia:Today's featured article/December 8, 2013

The anti-de Sitter/conformal field theory correspondence is a conjecture in theoretical physics that relates two kinds of physical theories. On one side of the correspondence are conformal field theories, including theories similar to the Yang–Mills theories that describe elementary particles. On the other are anti-de Sitter spaces (cross section depicted), which are used in theories of quantum gravity, formulated in terms of string theory or M-theory. Proposed by Juan Maldacena in late 1997, the AdS/CFT correspondence represents a major advance in our understanding of string theory and quantum gravity. This is because it provides a non-perturbative formulation of string theory and because it is the most successful realization of the holographic principle, an idea in quantum gravity originally proposed by Gerard 't Hooft. In addition, it provides a powerful toolkit for studying strongly coupled quantum field theories and has been used to study many aspects of nuclear and condensed matter physics by translating problems in those subjects into more mathematically tractable problems in string theory. (Full article...)