Calendar of Physics Talks Vienna

Matrix models and phase transitions in supersymmetric gauge theories in three dimensions
Speaker:Miguel Tierz ( Univ. de Lisboa)
Abstract:In part I of the talk, I will review in a pedagogical way the basic aspects of matrix models, with a view towards applications in a number of supersymmetric gauge theories in three dimensions. In part II, the more specialized part of the talk, we present a study of N=4 supersymmetric QED in three dimensions, on a three-sphere, with 2N massive hypermultiplets and a Fayet-Iliopoulos parameter. We identify the exact partition function of the theory with a conical (Mehler) function. This implies a number of analytical formulas, including a recurrence relation and a second-order differential equation. In the large N limit, the theory undergoes a second-order phase transition on a critical line in the parameter space. We will discuss the critical behavior and compute the two-point correlation function of a gauge invariant mass operator. (Joint work with Jorge G. Russo, arXiv:1610.08527
Date: Tue, 15.11.2016
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:S. Fredenhagen, H. Steinacker

Brout-Englert-Higgs physics: From foundations to phenomenology
Speaker:Axel Maas (Univ. Graz)
Abstract:im Rahmen des Teilchenphysikseminars
Date: Tue, 15.11.2016
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, H. Neufeld

Constraints on modified gravity potentials from orbit of star S2
Speaker:Dusko Borka (Vinca Institute of Nuclear Sciences, University of Belgrade)
Abstract:We investigate the possibility to explain the orbital precession of star S2 around the massive object at the Galactic Centre using Extended Theories of Gravity, i.e., gravitational potentials in total absence of dark matter. To this aim an analytic fourth-order theory of gravity non-minimally coupled with a massive scalar field is considered. We simulate the orbit of the star around the Galactic Centre in Yukawa-like and Sanders-like gravity potentials and compare it with telescope observations. Our approach seems to reliably constrain modified gravity models on an astronomical level.
Date: Wed, 16.11.2016
Time: 14:15
Location:TU Wien, Institute for Theoretical Physics, Seminar room DB gelb 10, Wiedner Hauptstraße 8 – 10, B (yellow tower), 10th floor
Contact:Christoph Lemell

Challenges in higher spins
Speaker:Stefan Fredenhagen (Univ. Wien)
Abstract:im Rahmen des Literaturseminars: Higher-spin gauge theories provide interesting, highly symmetric extensions of gravity. The only known interacting higher-spin gauge theories are the so-called Vasiliev theories. I will give an introduction to these theories and the unfolding formalism on which they are based. I will also discuss recent results which point out that the extraction of concrete equations of motion not only poses a technical, but also a conceptual challenge.
Date: Thu, 17.11.2016
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel

Geometric actions for three-dimensional gravity
Speaker:Hernan Gonzalez (TU Wien)
Abstract:The solution space of three-dimensional asymptotically anti-de Sitter Einstein gravity is known to coincide with the coadjoint representation of two copies of the Virasoro group. By using Chern-Simons formulation an implementing a Hamiltonian reduction one can associate separate geometric actions to each of the coadjoint orbits that partition the solution space.
Date: Thu, 17.11.2016
Time: 16:00
Duration: 60 min
Location:SEM 136, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna)
Contact:Daniel Grumiller

Second-Order Hydrodynamics and Universality in Non-Conformal Holographic Fluids
Speaker:Jonas Probst (Oxford University)
Abstract:As the precise gravity duals of theories realised in nature are unknown, we are particularly interested in universal properties of holographic models which may apply to all strongly coupled field theories. At the level of second-order hydrodynamics one particular combination of transport coefficients, H = 2ητπ − 4λ1 − λ2, has been shown to vanish universally in conformal holographic fluids. In this talk, I will discuss our recent results on second-order transport and on the fate of H in holographic models without conformal symmetry. I will present new Kubo formulae for five second-order coefficients including H in non-conformal fluids and show how they can be applied to holographic models. Focusing on holographic RG flows triggered by an arbitrary scalar operator of dimension 3, our work demonstrates that the transport coefficients always satisfy 2ητπ − 2 (κ − κ∗) − λ2 = 0.
Date: Fri, 18.11.2016
Time: 14:30
Location:Institute for Theoretical Physics, TU Wien, Seminar room, 10th floor, Wiedner Hauptstr. 8-10, 1040
Contact:Anton Rebhan