Triangle Seminars
Wednesday, 5 Nov 2014
F-theory on singular spaces
📍 London
Andres Collinucci
(ULB, Brussels)
Abstract:
F-theory paints a beautiful picture that relates gauge theories to purely geometric information, whereby the Dynkin diagrams of gauge groups come to life as 2-cycles of internal spaces. The caveat is that, such spaces are necessarily singular, and treating them sensibly requires resolving or deforming the singularities.
Recently, my collaborator R. Savelli and I have proposed a new strategy that allows one to deal with singular spaces directly. It is based on Eisenbud’s so-called matrix factorisations. This remarkably simple concept has very deep connections to the mathematics of singularities.
In this talk, I will review the basic notions needed to formulate the issues, assuming only standard knowledge of string theory. Then, after introducing our proposal, I will show examples of its applications, such as computations of chiral spectra for bound states of 7-branes.
F-theory paints a beautiful picture that relates gauge theories to purely geometric information, whereby the Dynkin diagrams of gauge groups come to life as 2-cycles of internal spaces. The caveat is that, such spaces are necessarily singular, and treating them sensibly requires resolving or deforming the singularities.
Recently, my collaborator R. Savelli and I have proposed a new strategy that allows one to deal with singular spaces directly. It is based on Eisenbud’s so-called matrix factorisations. This remarkably simple concept has very deep connections to the mathematics of singularities.
In this talk, I will review the basic notions needed to formulate the issues, assuming only standard knowledge of string theory. Then, after introducing our proposal, I will show examples of its applications, such as computations of chiral spectra for bound states of 7-branes.
Posted by: KCL
Gerbes on the Lattice
Ron Reid-Edwards
(Hull)
Abstract:
Abelian gerbes play a ubiquitous role in string and supergravity theories. It is conjectured that non-abelian gerbe theories exist, but a satisfactory explicit construction of such a theory has not yet been achieved. Inspired by the possibility that a non-abelian theory of gerbes may be possible on non-conventional spacetimes, I will consider a toy model on a lattice that allows one to make some progress in this problem. In this talk, I will show how abelian gerbe theories may be described naturally on the lattice. I will outline a non-abelian generalisation and show how, under dimensional reduction, such theories give rise to lattice Yang-Mills.
Abelian gerbes play a ubiquitous role in string and supergravity theories. It is conjectured that non-abelian gerbe theories exist, but a satisfactory explicit construction of such a theory has not yet been achieved. Inspired by the possibility that a non-abelian theory of gerbes may be possible on non-conventional spacetimes, I will consider a toy model on a lattice that allows one to make some progress in this problem. In this talk, I will show how abelian gerbe theories may be described naturally on the lattice. I will outline a non-abelian generalisation and show how, under dimensional reduction, such theories give rise to lattice Yang-Mills.
Posted by: IC
Enhanced ultraviolet cancellations in supergravity theories
Zvi Bern
(UCLA)
Thursday, 6 Nov 2014
A universal correction to higher spin entanglement entropy
Michael Ferlaino
(Swansea)
Abstract:
Within the context of the duality between higher spin gravitational theories and a semi-
classical limit of WN minimal models, we consider 2D CFTs with W1 symmetry at nite
temperature, deformed by the presence of a chemical potential for the spin{three current. As
a perturbative expansion in the chemical potential, we compute the Renyi and entanglement
entropies for a single interval. The leading correction is universal and matches the holographic
result, based on Wilson line functionals, obtained from the higher spin gravitational dual.
Within the context of the duality between higher spin gravitational theories and a semi-
classical limit of WN minimal models, we consider 2D CFTs with W1 symmetry at nite
temperature, deformed by the presence of a chemical potential for the spin{three current. As
a perturbative expansion in the chemical potential, we compute the Renyi and entanglement
entropies for a single interval. The leading correction is universal and matches the holographic
result, based on Wilson line functionals, obtained from the higher spin gravitational dual.
Posted by: QMW