Neil Turok

Neil Geoffrey Turok (born 1958) is a South African-born theoretical physicist. He has made seminal contributions to the study of phase transitions in the early universe and their observational consequences. In 1994 he was appointed Professor of Physics at Princeton University. In 1997 he assumed the Chair of Mathematical Physics (1967) in the Department of Applied Mathematics and Theoretical Physics at Cambridge.

With his collaborators, Turok developed the theory of cosmic strings, textures and other global topological defects, and worked out how the theories could be tested against observational data. In 1997, he performed decisive calculations disproving the cosmic string and texture theories of galaxy formation. He also made pioneering contributions to the theory of electroweak baryogenesis whereby the matter-antimatter asymmetry of the universe could have originated at the electroweak phase transition. This theory will be tested by forthcoming experiments investigating the Higgs sector of the standard model.

In the mid 1990's, with his collaborators he calculated the polarisation pattern of the cosmic microwave sky, pointing out that the polarisation and temperature patterns would be correlated. The prediction was subsequently confirmed in fine detail by the WMAP satellite and other experiments. He also developed a key test for the presence of a cosmological constant, also subsequently confirmed.

In 1994, Turok and collaborators showed how a realistic open universe could be formed during inflation. Such open inflationary bubbles are the basis of the picture of eternal inflation developed by others. Along with Stephen Hawking, he developed the Hawking-Turok Instanton theory which describes how such open universes could have originated.

In 2001, he and his collaborators proposed the ekpyrotic model of the early universe, according to which the big bang is explained as the consequence of a collision between two "brane-worlds", separated by a tiny extra dimension. With Paul Steinhardt, he developed the cyclic model of the universe, an extension of the ekpyrotic model which allows for repeated big bangs occurring in a potentially endless sequence. The predictions of this model are in agreement with current cosmological data. In 2006, Steinhardt and Turok showed how this model could naturally incorporate a mechanism for relaxing the cosmological constant to very small values, consistent with current observations.

In 2003, Professor Turok founded the African Institute for Mathematical Sciences.

External links

• Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge.

Further reading

• The Hawking-Turok Instanton theory: Turok's Inflationary Theory Work, Physics 303, University of Victoria, British Columbia.
• Hawking, Stephen. "Inflation: An Open and Shut Case (April '98)", lecture on joint work with Neil Turok.