Triangle Seminars
Monday, 5 Dec 2005
Cosmological Aspects of Loop Quantum Gravity
Johannes Brunnemann
(AEI Potsdam)
Abstract:
One main reason to quantize gravity is the hope that the singularities of classical General Relativity will be absent within the framework of a quantum theory of gravity. One candidate for such a theory is the well developed framework of Loop Quantum Gravity. During the last years remarkable results concerning the big bang singularity have been achieved within symmetry reduced cosmological models of Loop Quantum Cosmology. In this talk we will address the question whether these results are characteristic also for the full, unreduced theory. As a first step towards answering that question we will present an explicit analysis of the geometric operator corresponding to the classical inverse scale factor occurring in cosmological models which has been performed within the full theory. The results will be discussed.
One main reason to quantize gravity is the hope that the singularities of classical General Relativity will be absent within the framework of a quantum theory of gravity. One candidate for such a theory is the well developed framework of Loop Quantum Gravity. During the last years remarkable results concerning the big bang singularity have been achieved within symmetry reduced cosmological models of Loop Quantum Cosmology. In this talk we will address the question whether these results are characteristic also for the full, unreduced theory. As a first step towards answering that question we will present an explicit analysis of the geometric operator corresponding to the classical inverse scale factor occurring in cosmological models which has been performed within the full theory. The results will be discussed.
Posted by: KCL
Higher Spin Gauge Theories and Unfolded Dynamics
Misha Vasiliev
(Lebedev Institute)
Abstract:
I review the structure of higher spin gauge theories in various dimensions, with some emphasize on the infinite-dimensional higher spin symmetries and unfolded dynamics approach. If I have time, I would also discuss how this approach works in the standard field theories like Yang-Mills and Einstein gravity.
I review the structure of higher spin gauge theories in various dimensions, with some emphasize on the infinite-dimensional higher spin symmetries and unfolded dynamics approach. If I have time, I would also discuss how this approach works in the standard field theories like Yang-Mills and Einstein gravity.
Posted by: IC
Tuesday, 6 Dec 2005
Random matrix theory and symmetric spaces
Ulrika Magnea
(Turin)
Abstract:
We define some elementary concepts concerning the description
of random matrix ensembles in terms of symmetric spaces.
We also discuss examples of how the mapping to symmetric spaces
can be used in some physical contexts in which a random matrix
description is applied.
We define some elementary concepts concerning the description
of random matrix ensembles in terms of symmetric spaces.
We also discuss examples of how the mapping to symmetric spaces
can be used in some physical contexts in which a random matrix
description is applied.
Posted by: KCL
Wednesday, 7 Dec 2005
Exploring the M-theory effective action
📍 London
Michael Green
(DAMTP)
Abstract:
This talk will survey recently deduced features of the ten-dimensional
effective action for four gravitons in type II string theories. Duality
with M-theory together with supersymmetry leads to a number of
nontrivial higher derivative four-graviton interactions whose
non-perturbative structure is completely determined by a collection of
Poisson equations on moduli space and is consistent
with data provided by string perturbation theory.
This talk will survey recently deduced features of the ten-dimensional
effective action for four gravitons in type II string theories. Duality
with M-theory together with supersymmetry leads to a number of
nontrivial higher derivative four-graviton interactions whose
non-perturbative structure is completely determined by a collection of
Poisson equations on moduli space and is consistent
with data provided by string perturbation theory.
Posted by: KCL
Supersymmetric Non-linear Sigma Models and Generalized Complex Geometry
📍 London
Ulf Lindstrom
(Uppsala)
Friday, 9 Dec 2005
Worldline approach to vector and antisymmetric tensor fields
📍 London
Fiorenzo Bastianelli
(Bologna)
Abstract:
We study the quantization on the torus of the N=2 spinning particle
coupled to spacetime gravity to obtain a worldline representation
of the effective action of an arbitrary antisymmetric tensor field.
This representation contains on top of the usual proper time a new
modular parameter implementing the reduction to a single tensor field.
Then we describe how to use it: (i) to calculate the first few
Seeley-DeWitt coefficients for antisymmetric tensor fields of arbitrary
rank in arbitrary dimensions, (ii) to derive exact duality relations,
and (iii) to compute some correlation functions.
We study the quantization on the torus of the N=2 spinning particle
coupled to spacetime gravity to obtain a worldline representation
of the effective action of an arbitrary antisymmetric tensor field.
This representation contains on top of the usual proper time a new
modular parameter implementing the reduction to a single tensor field.
Then we describe how to use it: (i) to calculate the first few
Seeley-DeWitt coefficients for antisymmetric tensor fields of arbitrary
rank in arbitrary dimensions, (ii) to derive exact duality relations,
and (iii) to compute some correlation functions.
Posted by: KCL