String Theory Seminar
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Mon, 17/01/2011 12:00 |
David Berman (Queen Mary University of London) |
String Theory Seminar  |
L3 |
| Abstract: We reformulate M-theory in terms of a generalised metric that combines the usual metric and the three form potential. The U-duality group is then a manifest symmetry. | |||
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Mon, 24/01/2011 12:00 |
Mathew Bullimore (Oxford) |
String Theory Seminar |
L3 |
| Recently, there has been exciting progress in scattering amplitudes in supersymmetric gauge theories, one aspect of which is the remarkable duality between amplitudes and Wilson loops. I will explain how the complete planar S-matrix of N=4 super Yang-Mills theory is encoded in the complex analogue of a Wilson loop in holomorphic Chern-Simons theory on twistor space. The dynamics of the theory are encoded in loop equations, which describe deformations of the Wilson Loop and provide new insight into the nature of the amplitude-Wilson loop duality. The loop equations themselves yield powerful recursive methods for scattering amplitudes which are revealed as holomorphic skein relations by interpreting the Wilson loop as the complex analogue of a knot invariant. The talk will be based on the preprint arXiv:1101.1329. | |||
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Mon, 31/01/2011 12:00 |
Toby Wiseman (Imperial College) |
String Theory Seminar |
L3 |
| Abstract: I will begin by reviewing the use of Ricci flow and the associated Ricci soliton equation to provide constructive numerical algorithms to find static vacuum black holes. I will then describe recent progress to generalize these methods to stationary black holes. I will present new results found using these methods, firstly on stationary black holes in spherical boxes, and secondly, black holes localized on a Randall-Sundrum brane. The latter case hopefully resolves the validity of a phenomenologically striking and important conjecture, and also has relevance to AdS-CFT. | |||
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Mon, 07/02/2011 12:00 |
Fay Dowker (Imperial College) |
String Theory Seminar |
L3 |
| Abstract: In the continuum the answer to the title question is "no". But if spacetime is atomic then the answer is yes. And it so happens that there is rather compelling circumstantial evidence that spacetime is actually discrete at the Planck scale. So now the question becomes, why if spacetime is discrete should it take the form of a discrete causal structure or *order*? The answer is that if you don't put causal order in fundamentally you don't get it out – at least that's what known models of "emergent spacetime" indicate. If we want to make life easy for ourselves in quantum gravity, then, we should plump for discrete causal order (a "causal set") as the inner basis for spacetime. That, however raises the spectre of wild nonlocality. I will describe recent progress that shows that this wildness can be tamed. In particular we now have an approximately local action for causal sets and I'll explain what that means. | |||
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Mon, 14/02/2011 12:00 |
Volker Braun (Dublin Institute of Advanced Studies) |
String Theory Seminar |
L3 |
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Mon, 21/02/2011 12:00 |
James Sparks (Oxford) |
String Theory Seminar |
L3 |
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Mon, 28/02/2011 12:00 |
String Theory Seminar |
L3 | |
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Mon, 07/03/2011 12:00 |
Nick Dorey (Cambridge) |
String Theory Seminar |
L3 |
