Forthcoming events in this series
Wed, 06 Jun 2007
12:00
12:00
L3
Constructing Gauge Theory Amplitudes
Ruth Britto
(Amsterdam)
Abstract
Gauge theory amplitudes lie at the meeting ground of perturbative QCD and
twistor string theory. The past three years have seen dramatic
developments in the analytic computation of amplitudes and their
interpretation in twistor space geometry. I will discuss applications to
collider experiments and describe direct, systematic procedures for deriving
one-loop amplitudes from tree amplitudes, using new insights regarding
unitarity.
Mon, 04 Jun 2007
12:00
12:00
L3
Evaluating gauge-theoretic amplitudes with twistor diagrams
Andrew Hodges
(Oxford)
Abstract
Amplitudes in gauge theory at tree-level can be expressed economically
in terms of twistor diagrams (hep-th/0503060, hep-th/0512336). This
formalism has recently been used to write down the 8-field scattering
amplitudes in a simple form, going beyond the results previously obtained
(hep-th/0603101). This talk will give an elementary account of how this is
done.
Wed, 30 May 2007
12:00
12:00
L3
Mon, 28 May 2007
12:00
12:00
L3
Mon, 14 May 2007
12:00
12:00
L3
Self-dual supergravity and twistor theory
Martin Wolf
(Imperial College, London)
Abstract
By generalizing and extending some of the earlier results derived by
Manin and by Merkulov, a twistor description is given of four-dimensional
N-extended (gauged) self-dual supergravity with and without cosmological
constant. In particular, superconformal structures are introduced and used
as a starting point to define complex quaternionic, quaternionic Kaehler and
hyper-Kaehler supermanifolds. A supersymmetry generalization of the Penrose
and Ward constructions are presented.
Mon, 07 May 2007
12:00
12:00
L3
Mon, 30 Apr 2007
12:00
12:00
L3
D-brane superpotentials and RG flows on the quintic
Ilka Brunner
(ETH Zurich)
Abstract
The behaviour of D2-branes on the quintic under complex structure
deformations is analysed by combining Landau-Ginzburg techniques with methods
from conformal field theory. It is shown that the boundary renormalisation group
flow induced by the bulk deformations is realised as a gradient flow of the
effective space time superpotential which is calculated explicitly to all orders
in the boundary coupling constant.
Thu, 15 Feb 2007
12:00
12:00
L3
Wed, 31 Jan 2007
12:00
12:00
L2
Fri, 08 Dec 2006
14:00
14:00
L3
Mon, 27 Nov 2006
12:00
12:00
L3
Twisted Tori and (new) String Vacua
Ruben Minasian
(Ecole Polytechnique and Imperial)
Abstract
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Mon, 20 Nov 2006
12:00
12:00
L3
Mon, 13 Nov 2006
12:00
12:00
L3
Heterotic Twistor Strings
David Skinner
(Oxford)
Abstract
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Mon, 06 Nov 2006
12:00
12:00
L3
Quantizing BPS Black Holes in 4 Dimensions
Boris Pioline
(Universite Paris VI et VII and ENS)
Abstract
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Mon, 23 Oct 2006
12:00
12:00
L3
Einstein Geometry and Conformal Field Theory
James Sparks
(Oxford)
Abstract
I shall describe two recent results
in Sasaki-Einstein geometry, which is the odd-dimensional cousin of Kahler-Einstein geometry, and how they are related to four-dimensional
superconformal field theory (SCFT) via the AdS/CFT correspondence. The first is a proof that the
volumes of such Einstein manifolds are always algebraic numbers, which reflects
a similar statement about central charges in SCFTs
due to Intriligator and Wecht.
The second descibes two simple holomorphic obstructions to the existence of such Einstein
metrics. In such obstructed cases the non-existence of the dual superconformal fixed point may be proven by a simle application of the unitarity
bound and the “a-theorem”, respectively, and these may be related
directly to the geometrical obstructions via AdS/CFT
arguments. On the mathematical side, these are new simple obstructions to the
existence of Kahler-Einstein metrics on Fano orbifolds.
/notices/events/abstracts/string-theory/mt06/sparks.shtml
Mon, 12 Jun 2006
12:00
12:00
L3
Instantons, hypermultiplets and Quaternion-K\"ahler geometry
Stefan Vandoren
(Utrecht)
Abstract
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Tue, 06 Jun 2006
14:00
14:00
L3