The Universe as a symphony of vibrating 'strings'
Einstein's mathematical formulation of his general theory of relativity predicted an expanding Universe and the existence of black holes, both of which have since been observed. Ever-increasing sophistication of experimental techniques has also brought an explosion of discoveries related to interactions on very small scales. However, classical mathematical descriptions often fall short in describing interactions of elementary particles and some behaviours are unexpected when quantum effects are taken into account. One mathematical theory that gained exceptional prominence in an effort to unite classical and quantum descriptions is string theory. Researchers working on the EU-funded 'String theory and noncommutative geometry' (STRING) project were also attracted by its beautiful mathematical formalism. According to string theory, at the heart of every elementary particle is a tiny string-like filament. The differences between one particle and another arise from how their internal strings vibrate. The mathematics revealed that one of these notes had properties matching those of the graviton, a hypothetical particle that should carry the force of gravity from one location to another. In other words, gravity and quantum mechanics are playing by the same rules. During the STRING project, researchers explored further implications for physical models related to gravity and quantum field theories. Specifically, STRING focused on how different kinds of algebraic groups can be defined as symmetries of physical models. The exceptional Lie groups were studied in the context of supergravity and gauge field theories. Knowledge of their geometrical properties was then applied to classify different types of black hole orbits. The exceptional Lie groups had first been constructed using different algebras to build a so-called 'magic square' that contained simpler Lie groups. Within the STRING project, researchers developed a software programme dedicated to computing the generators of Lie groups entering the magic square. Written in Mathematica, this is freely available here(opens in new window). Project work resulted in the assimilation of important contributions related to mathematical descriptions of physical models of the Universe. The cross-fertilisation between mathematics and physics has been particularly rich with one area shedding light on another. Geometrical features of string theory have been revealed, as well as the theory's value by the influence it has on quantum information theory.
Keywords
Universe, black holes, string theory, noncommutative geometry, quantum information
