Rob G Leigh

Professor

Ph.D., Physics, University of Texas at Austin, 1991

Professor Rob Leigh received his bachelor's degree in theoretical physics from the University of Guelph in 1986, and his PhD in theoretical particle physics, from the University of Texas, Austin in 1991. He held postdoctoral research appointments at the University of California, Santa Cruz and Rutgers University. He joined the Department of Physics at Illinois in 1996. He has done outstanding work in string theory, supersymmetric field theory, and other topics in particle physics and early Universe cosmology. Professor Leigh's work lies at the heart of current efforts to build a fundamental theory of matter, including quantum gravity effects.

As a graduate student, Professor Leigh participated, along with J. Dai and J.G. Polchinski, in the discovery of D-branes in string theory. These non-perturbative states are unique to string theory and are analogous to magnetic monopoles in field theory. The study of D-branes is fundamental to modern string theory and, in particular, to string duality, where the strong coupling limit of one string is related to the weak coupling limit of another. As part of this early work, Professor Leigh published an important paper reporting his computation of the effective action for D-branes. His current research on D-branes involves their relevance to the problem of black hole entropy and the compactification of string theories.

Other Activities

Superstring Theory
Superstring theory is our only candidate for a consistent unification of quantum field theory and gravity. It provides a framework in which an understanding of the components of the standard model of particle physics may be sought. Research here includes studies of the nonperturbative aspects of string theory, including the special role played by D-branes, which are multidimensional solitonic states.

Nonperturbative Aspects of Supersymmetric Quantum Field Theories
The study of supersymmetric field theories is of great interest, since it is possible to obtain exact nonperturbative information, which may be of use in understanding the strong coupling regime of realistic field theories. There is an important property, known as duality, which connects the physical observables of one field theory to another. The full consequences of duality in non-Abelian gauge theories is only now being worked out, and there are important connections to string theory and gravity.

Additional Information

My research group has been involved in a large array of projects over the past year. Our primary focus is on using string theory methods to study strongly coupled field theory systems, such as QCD. We also have studied aspects of gravitational systems in the context of the AdS/CFT correspondence. We have done extensive work on entanglement entropy, focussing on detailed calculations in interacting field theories, an recent example of which is our work on Chern-Simons theory. Finally, an active long-term project concerns the low energy physics of materials that have a superconducting phase at relatively high temperatures.

Honors and awards:

• Arnold O. Beckman Award, UIUC, December 2004
• Outstanding Junior Investigator, DOE, 1997-2000

Selected Publications:

• S. Kawai, E. Keski-Vakkuri, R. G. Leigh, and S. Nowling. Brane decay and an initial spacelike singularity. Phys. Rev. Lett. 96, 031301 (2006).
• R. Biswas, E. Keski-Vakkuri, R.G. Leigh, S. Nowling, and E. Sharpe. The taming of closed time-like curves. JHEP-Journal of High Energy Physics, 0401, 064 (2004).
• V. Jejjala, R.G. Leigh, and D. Minic. The cosmological constant and the deconstruction of gravity. Phys. Lett. B 556, 71-79 (2003).
• R.G. Leigh and A.C. Petkou. Holography of the N=1 higher-spin theory on AdS(4). JHEP-Journal of High Energy Physics 2003, 0306, 011 (2003).
• V. Jejjala, R.G. Leigh, and D. Minic. Deconstruction and holography. J. Cosmology and Astroparticle Phys. 0306, 002 (2003).
• V. Jejjala, R.G. Leigh, and D. Minic. Deconstructing the cosmological constant. General Relativity & Gravitation 35, 2089-2095 (2003).
• R.G. Leigh, K. Okuyama, and M. Rozali. pp waves and holography. Phys. Rev. D 66, 046004 (2002).