Mon, 07 Jun 2010

12:00 - 13:00
L3

The torsional conifold: fivebranes and the Klebanov-Strassler theory

Dario Martelli
(Kings College London)
Abstract
We study a gravity solution corresponding to fivebranes wrapped on the S^2 of the resolved conifold. By changing a parameter the solution continuously interpolates between the deformed conifold with flux and the resolved conifold with branes. Therefore, it displays a geometric transition, purely in the supergravity context. The solution is a simple example of torsional geometry and may be thought of as a non-Kahler analog of the conifold. By U-duality transformations we can add D3 brane charge and recover the solution in the form originally derived by Butti et al. This describes the baryonic branch of the Klebanov-Strassler theory. Far along the baryonic branch the field theory gives rise to a fuzzy two-sphere. This corresponds to the D5 branes wrapping the two-sphere of the resolved conifold in the gravity solution.
Mon, 24 May 2010

12:00 - 13:00
L3

String Theory and Many-Body Physics

Djordje Minic
(VirginiaTech)
Abstract
Recent theoretical advances in string theory relate in an unexpected way the physics of gravity in certain D dimensional space-times with the dynamics of quantum field theories living on the associated (D-1) dimensional space-time boundary. This unsuspected relationship offers a remarkable new tool for dealing with some outstanding problems in condensed matter physics. In the first part of the talk I aim to explain both the intuitive and technical underpinnings of these new developments. In the second half of the talk I will present some recent results on aging in systems far from equilibrium and also some new avenues for research in condensed matter physics which involve the interplay of gauge fields, membranes and many-body systems. In particular this last work opens up an exciting possibility for fundamentally new states of condensed matter.
Mon, 17 May 2010

12:00 - 13:00
L3

Aspects of heterotic Calabi-Yau compactifications

James Gray
(Oxford)
Abstract
I will discuss various aspects of Calabi-Yau compactifications appropriate for use in models of string phenomenology. Topics covered will include transitions between and deformations of bundles as well as consequences of stability walls for phenomenology.
Mon, 10 May 2010

12:00 - 13:00
L3

Crystal Melting and Wall Crossing for Donaldson-Thomas Invariants

Masahito Yamazaki
(Tokyo)
Abstract
I will describe the wall crossing phenomena for (generalized) Donaldson-Thomas invariants (also known as BPS invariants) from a physicist's perspective; the topics include crystal melting and its thermodynamic limit, M-theory derivation of wall crossing, and open wall crossing.
Mon, 26 Apr 2010

12:00 - 13:00
L3

On Fields over Fields

Yang-Hui He
(Oxford)
Abstract
We investigate certain arithmetic properties of field theories. In particular, we study the vacuum structure of supersymmetric gauge theories as algebraic varieties over number fields of finite characteristic. Parallel to the Plethystic Programme of counting the spectrum of operators from the complex geometry, we investigate the Hasse-Weil zeta functions and the associated Dirichlet expansions. We find curious dualities wherein the geometrical properties and asymptotic behaviour of one gauge theory is governed by the number theoretic nature of another.
Wed, 28 Apr 2010
11:30
L3

tba

Ivan Reilly
(Auckland)
Tue, 15 Jun 2010

12:00 - 13:00
L3

Analytic torsion for twisted de Rham complexes

Varghese Mathai (Adelaide)
Abstract

I will define and discuss the properties of the analytic torsion of

twisted cohomology and briefly of Z_2-graded elliptic complexes

in general, as an element in the graded determinant line of the

cohomology of the complex, generalizing most of the variants of Ray-

Singer analytic torsion in the literature. IThe definition uses pseudo-

differential operators and residue traces. Time permitting, I will

also give a couple of applications of this generalized torsion to

mathematical physics. This is joint work with Siye Wu.

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