Triangle Seminars
Monday, 29 Jan 2007
Type II actions from 11-dimensional Chern-Simons theories
Dmitriy Belov
(Imperial College)
Abstract:
This paper continues the discussion of hep-th/0605038, applying the
holographic formulation of self-dual theory to the Ramond-Ramond
fields of type II supergravity. We formulate the RR partition
function, in the presence of nontrivial H-fields, in terms of the
wavefunction of an 11-dimensional Chern-Simons theory. Using the
methods of hep-th/0605038 we show how to formulate an action principle
for the RR fields of both type IIA and type IIB supergravity, in the
presence of RR current. We find a new topological restriction on
consistent backgrounds of type IIA supergravity, namely the fourth Wu
class must have a lift to the H-twisted cohomology.
This paper continues the discussion of hep-th/0605038, applying the
holographic formulation of self-dual theory to the Ramond-Ramond
fields of type II supergravity. We formulate the RR partition
function, in the presence of nontrivial H-fields, in terms of the
wavefunction of an 11-dimensional Chern-Simons theory. Using the
methods of hep-th/0605038 we show how to formulate an action principle
for the RR fields of both type IIA and type IIB supergravity, in the
presence of RR current. We find a new topological restriction on
consistent backgrounds of type IIA supergravity, namely the fourth Wu
class must have a lift to the H-twisted cohomology.
Posted by: IC
Tuesday, 30 Jan 2007
Teleparallelism: difficult word but simple way of reinterpreting the Dirac Equation
Dmitri Vassiliev
(UCL)
Abstract:
The main result of the talk is a new representation for the Weyl Lagrangian (massless Dirac Lagrangian). As the dynamical variable we use the coframe, i.e. field of orthonormal bases. We write down a simple Lagrangian and show that variation of the resulting action with respect to the coframe produces the Weyl equation. The advantage of our approach is that it does not require the use of spinors, Pauli matrices or covariant differentiation. The only geometric concepts we use are those of a metric, differential form, wedge product and exterior derivative.
The construction presented in the talk is similar to that used in the so-called Cosserat theory of elasticity (multipolar elasticity).
Reference: D.Vassiliev, Phys. Rev. D75, 025006 (2007).
The main result of the talk is a new representation for the Weyl Lagrangian (massless Dirac Lagrangian). As the dynamical variable we use the coframe, i.e. field of orthonormal bases. We write down a simple Lagrangian and show that variation of the resulting action with respect to the coframe produces the Weyl equation. The advantage of our approach is that it does not require the use of spinors, Pauli matrices or covariant differentiation. The only geometric concepts we use are those of a metric, differential form, wedge product and exterior derivative.
The construction presented in the talk is similar to that used in the so-called Cosserat theory of elasticity (multipolar elasticity).
Reference: D.Vassiliev, Phys. Rev. D75, 025006 (2007).
Posted by: brunel
Wednesday, 31 Jan 2007
Anti-de Sitter black holes
📍 London
Harvey Reall
(University of Nottingham)
Topology Change in Thermal N=4 SYM and the AdS Black Hole at Weak Coupling
Prem Kumar
(Swansea)
Thursday, 1 Feb 2007
N=2 Braine Surgery
Christian Romelsberger
(Trinity Dublin)
Abstract:
I present the generating functions which count the BPS operators in the chiral ring of a N=2 quiver gauge theory that lives on N D3 branes probing an ALE singularity. The difficulty in this computation arises from the fact that this quiver gauge theory has a moduli space of vacua that splits into many branches – the Higgs, the Coulomb and mixed branches. As a result there can be operators which explore those different branches and the counting gets complicated by having to deal with such operators while avoiding over or under counting. The solution to this problem turns out to be very elegant and is presented in this note. Some surprises with surgery of generating functions arises.
I present the generating functions which count the BPS operators in the chiral ring of a N=2 quiver gauge theory that lives on N D3 branes probing an ALE singularity. The difficulty in this computation arises from the fact that this quiver gauge theory has a moduli space of vacua that splits into many branches – the Higgs, the Coulomb and mixed branches. As a result there can be operators which explore those different branches and the counting gets complicated by having to deal with such operators while avoiding over or under counting. The solution to this problem turns out to be very elegant and is presented in this note. Some surprises with surgery of generating functions arises.
Posted by: IC
Friday, 2 Feb 2007
Balanced metrics in string theory
Mike Douglas
(Rutgers)