Triangle Seminars
Wednesday, 27 Mar 2013
U(1) Symmetries in Global F-Theory Compactifications with GUTs
📍 London
Christoph Mayrhofer
(Heidelberg)
Abstract:
In this talk we will describe the construction of F-Theory GUT models for elliptically fibred Calabi-Yau fourfolds admitting a non-trivial Mordell-Weil group. We work out the matter spectrum and Yukawa couplings, including singlets, for these geometries and present the fluxes corresponding to the U(1) symmetries.'
In this talk we will describe the construction of F-Theory GUT models for elliptically fibred Calabi-Yau fourfolds admitting a non-trivial Mordell-Weil group. We work out the matter spectrum and Yukawa couplings, including singlets, for these geometries and present the fluxes corresponding to the U(1) symmetries.'
Posted by: KCL
Stationary holographic plasma quenches and numerical methods for non-Killing horizons
Pau Figueras
(DAMTP, Cambridge)
Abstract:
In this talk I will explain a new method to numerically construct stationary black holes with non-Killing horizons. As an example, we will use AdS/CFT to describe a time-independent CFT plasma flowing through a static spacetime which asymptotes to Minkowski in the flow's past and future, with a varying spatial geometry in-between. When the boundary geometry varies slowly, the holographic stress tensor is well-described by viscous hydrodynamics. For fast variations it is not, and the solutions are stationary analogs of dynamical quenches, with the plasma being suddenly driven out of equilibrium. We find evidence that these flows become unstable for sufficiently strong quenches and speculate that the instability may be turbulent. The gravitational dual of these flows are the first examples of
stationary black holes with non-Killing horizons.
In this talk I will explain a new method to numerically construct stationary black holes with non-Killing horizons. As an example, we will use AdS/CFT to describe a time-independent CFT plasma flowing through a static spacetime which asymptotes to Minkowski in the flow's past and future, with a varying spatial geometry in-between. When the boundary geometry varies slowly, the holographic stress tensor is well-described by viscous hydrodynamics. For fast variations it is not, and the solutions are stationary analogs of dynamical quenches, with the plasma being suddenly driven out of equilibrium. We find evidence that these flows become unstable for sufficiently strong quenches and speculate that the instability may be turbulent. The gravitational dual of these flows are the first examples of
stationary black holes with non-Killing horizons.
Posted by: IC
Thursday, 28 Mar 2013
Motivic Multiple Zeta Values and Superstring Amplitudes
Oliver Schlotterer
(Albert Einstein Institute)
Abstract:
I will discuss the mathematical structure of tree level amplitudes among massless superstring states. String corrections to these amplitudes take a compact and elegant form once the contributions from different classes of multiple zeta values (MZVs) are disentangled. The idea is to lift MZVs to their motivic versions endowed with a Hopf algebra structure: It induces an isomorphism which casts the amplitudes into a very symmetric form and represents the generalization of the symbol of a transcendental function. I will also comment on generalizations to loop amplitudes.
I will discuss the mathematical structure of tree level amplitudes among massless superstring states. String corrections to these amplitudes take a compact and elegant form once the contributions from different classes of multiple zeta values (MZVs) are disentangled. The idea is to lift MZVs to their motivic versions endowed with a Hopf algebra structure: It induces an isomorphism which casts the amplitudes into a very symmetric form and represents the generalization of the symbol of a transcendental function. I will also comment on generalizations to loop amplitudes.
Posted by: QMW