Calendar of Physics Talks Vienna

Holographic fluids, duality and integrability
Speaker:Marios Petropoulos (CPHT, Ecole Polytechnique, Palaiseau, France)
Abstract: I will show how one can reconstruct exact four-dimensional Einstein spaces from boundary data consisting of the three-dimensional boundary metric and the corresponding energy-momentum tensor. To this end, the data must be appropriately tuned and the way to proceed is inspired from gravitational self-duality. I will illustrate the method with the Robinson-Trautman family of Einstein spaces, and discuss how one can get insight on the transport properties of holographic fluids. Exotic situations such as the emergence of topologically massive gravity states will also be presented.
Date: Mon, 15.02.2016
Time: 14:00
Duration: 60 min
Location:ITP seminar room, 3rd floor (yellow tower), TU Wien, Wiedner Hauptstrasse 8-10, A 1040

Kounterterms in AdS Gravity
Speaker:Rodrigo Olea (Universidad Andres Bello, Santiago, Chile)
Abstract:We consider the addition of counterterms to AdS gravity which are a given polynomial of the extrinsic and intrinsic curvatures of the boundary. We show that they appear naturally from topological invariants and Chern-Simons densities. The connection to standard counterterms and Holographic Renormalization in asymptotically AdS spacetimes is worked out explicitly.
Date: Mon, 15.02.2016
Time: 15:00
Duration: 60 min
Location:ITP seminar room, 3rd floor (yellow tower), TU Wien, Wiedner Hauptstrasse 8-10, A 1040 Vienna

Pure Lovelock holographic superconductor
Speaker:Olivera Miskovic (Pontificia Universidad Catolica de Chile)
Abstract:We analyze phase transitions in a thermal quantum field theory holographically dual to Pure Gauss-Bonnet AdS black holes. An order parameter of the superconductor is described by a Stückelberg scalar field. In the probe limit, we find a phase transition of first and second order and discuss its physical implications.
Date: Mon, 15.02.2016
Time: 16:00
Duration: 60 min
Location:ITP seminar room, 3rd floor (yellow tower), TU Wien, Wiedner Hauptstrasse 8-10, A 1040 Vienna

Erwin Schrödinger Lecture: Ramanujan complexes and topological expanders
Speaker:Alex Lubotzky (Hebrew University of Jerusalem & ETH Zurich)
Abstract:Expander graphs in general, and Ramanujan graphs, in particular, have played a major role in computer science in the last 4 decades and more recently also in pure mathematics. In recent years a high dimensional theory of expanders is emerging. A notion of topological expanders was defined by Gromov who proved that the complete d-dimensional simplical complexes are such. He raised the basic question of existence of such bounded degree complexes of dimension d > 1. This question was answered recently (by T. Kaufman, D. Kazdhan and A. Lubotzky for d=2 and by T. Kaufman and S. Evra for general d) by showing that the d-skeleton of (d+1)-dimensional Ramanujan complexes provide such topological expanders. We will describe these developments and the general area of high dimensional expanders.
Date: Thu, 18.02.2016
Time: 17:00
Duration: 60 min
Location:Erwin Schrödinger International Institute, Boltzmanngasse 9, 1090 Wien, Boltzmann lecture hall

Weyl Anomalies and Quantum Cosmology
Speaker:Teresa Bautista (Paris, LPTHE & UPMC, Paris)
Abstract:I will talk about the cosmological consequences of Weyl anomalies arising from the renormalization of composite operators in a theory of gravity with a cosmological constant. Near two dimensions, the relevant anomaly can be computed explicitly using results from Liouville theory and leads to a non-local quantum effective action. The resulting quantum energy momentum tensor is non-local and leads to a decaying vacuum energy in a homogeneous and isotropic expanding universe. I will discuss a generalization of these results to four dimensions and possible implications for inflation and de Sitter spacetime.
Date: Fri, 19.02.2016
Time: 14:00
Duration: 60 min
Location:SEM 136, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna)
Contact:Daniel Grumiller