Calendar of Physics Talks Vienna

Higher-spin BMS symmetries in four dimensions and soft theorems
Speaker:Andrea Campoleoni (ETH Zürich)
Abstract:I will revisit Weinberg's constraints on the S-matrix of massless higher-spin particles from the viewpoint of the asymptotic symmetries at null infinity displayed by the corresponding fields. The analysis extends to arbitrary values of the spin the relation between asymptotic symmetries and soft theorems recently explored in gravity, and I will discuss the hints it provides on possible higher-spin extensions of the BMS symmetry.
Date: Mon, 16.10.2017
Time: 14:30
Duration: 60 min
Location:Fakultät für Physik, Christian-Doppler-Hörsaal, Strudlhofgasse 4, 1090 Wien
Contact:S. Fredenhagen

CoQuS Colloquium Seminar Talk by Pertti Hakonen
Speaker:Pertti Hakonen (CoQuS)
Abstract:"Fractional quantum Hall effect and Wigner crystallization in suspended graphene" For further information please visit www.coqus.at. The details of the talk will be announced the week before the Colloquium.
Date: Mon, 16.10.2017
Time: 16:30
Duration: 120 min
Location:Lise-Meitner Hörsaal, Strudelhofgasse 4, 1090 Vienna

Quantum Effects in Higher Spin Holography and Tensionless AdS Strings
Speaker:Shailesh Lal (Paris, LPTHE)
Abstract:It is expected that the AdS/CFT correspondence may be used to define a theory of tensionless strings in AdS space by setting the 't-Hooft coupling of the dual CFT to zero. Higher-spin/CFT dualities are heuristically a truncated version of this window of stringy AdS/CFT. We review one-loop tests of the Higher-spin/CFT dualities and describe extensions of such computations to various more `stringy' theories such as the bulk dual of free SU(N) Yang-Mills, and finally type IIB strings in AdS(5)xS(5). We also describe new techniques which make such computations possible. These computations are independent of supersymmetry, though we observe interesting simplifications which occur only for maximal supersymmetry. This is somewhat in contrast to the usual situation in higher-spin theories where superrsymmetry does not lead to any obvious simplifications. See 1603.05387, 1607.07651, 1701.01507.
Date: Tue, 17.10.2017
Time: 14:00
Duration: 60 min
Location:Schrodinger lecture hall (5th floor), University Vienna, Strudlhofgasse 4/Boltzmanngasse 5
Contact:Daniel Grumiller and Stefan Fredenhagen

Highly Charged Ion Interaction with Surfaces and 2D-Materials
Speaker:Dr. Richard A. Wilhelm (Institut für Angewandte Physik, TU Wien & Helmholtzzentrum Dresden-Rossendorf)
Abstract:The impact of highly charged ions onto a solid surface gives rise to processes like charge exchange, ion stopping, formation of electronic excitations at the surface, scattering and sputtering. Subsequently the large amount of deposited energy (up to some 10keV) can lead to the formation of individual nanostructures at the surface ranging from pits to craters and even to hillocks depending on the material's response to the ion impact [1]. To study the energy deposition and it's time dependence experimentally we recently used freestanding two-dimensional materials (e.g. graphene) as a target. By adjusting the ion's kinetic energy it's interaction time with the 2D-solid can be controlled. Spectroscopic measurement of the ion after transmission allows the observation of a rapid charge capture and deexcitation process [2]. At the same time the ion experiences a large charge state dependent s
Date: Tue, 17.10.2017
Time: 16:00
Location:TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B
Contact:Univ.Prof.Dr. Friedrich Aumayr

How to obtain physical results from lattice QCD simulations
Speaker:Christopher T. Sachrajda (University of Southampton)
Abstract:2. Vorlesung im Rahmen der Schrödinger-Gastprofessur 2017
Date: Tue, 17.10.2017
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, H. Neufeld, G. Ecker

The angulon quasiparticle: from molecules in superfluids to solid-state magnetism
Speaker:Mikhail Lemeshko (Institute of Science and Technology Austria)
Abstract:Recently we have predicted a new quasiparticle - the angulon - which is formed when a quantum impurity (such as an electron, atom, or molecule) exchanges its orbital angular momentum with a many-particle [1,2]. Soon thereafter we obtained strong evidence that angulons do exist, and are formed in experiments on molecules trapped inside superfluid helium nanodroplets [3,4]. In this presentation we will introduce the angulon concept, discuss novel physical phenomena [1,5] arising from the angular momentum exchange in quantum many-particle systems and describe the applications of angulons to modern experiments. [1] R. Schmidt, M. Lemeshko, PRL 114, 203001 (2015) [2] R. Schmidt, M. Lemeshko, PRX 6, 011012 (2016) [3] M. Lemeshko, PRL 118, 095301 (2017); Viewpoint: Physics 10, 20 (2017) [4] B. Shepperson et al., PRL 118, 203203 (2017) [5] E. Yakaboylu, M. Lemeshko, PRL 118, 085302 (2017)
Date: Wed, 18.10.2017
Time: 14:15
Location:Seminar room FH DB gelb 10, Institute for Theoretical Physics – Vienna University of Technology, Wiedner Hauptstraße 8 – 10, 10th floor, B (yellow tower)
Contact:Univ.Prof. Dr. Joachim Burgdörfer

Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector
Speaker:Dr. Graziano Venanzoni (INFN/Pisa)

Precision physics requires appropriate inclusion of higher order effects and the knowledge of very precise input parameters of the electroweak Standard Model. One of the basic input parameters is the effective QED coupling constant α(s) which depends on the energy scale because of charge screening by vacuum polarization. Hadronic non-perturbative effects limits the accuracy of α(s) from low energy to the Z mass scale. We present the measurement of the running of the QED coupling constant in the time-like region 0.6 < √s < 0.975 GeV with the KLOE detector at DAΦNE , using the ISR differential cross section dσ(e+e− → μ+μ− γ)/d√s. The result shows... [complete abstract: https://indico.smi.oeaw.ac.at/event/231] . 

Date: Wed, 18.10.2017
Time: 17:00
Duration: 60 min
Location:Stefan-Meyer-Institut, Boltzmanngasse 3, 1090 Wien, Seminarraum 3-2-08 (2. Stock)
Contact:Prof. Dr. Eberhard Widmann, Dr. Martin Simon

Exoplanets and general relativity
Speaker:Florian Steininger (Vienna)
Abstract:The first confirmation of the theory of general relativity was given by the perihelion precession of the planet mercury in our own solar system. In recent decades, we have expanded our scope to many new extra-solar planetary systems, making use of rapidly improving observational techniques. This has opened up the possibility of observing the effects of general relativity in distant systems, giving additional confidence in our understanding of the universe. I will present the findings of my bachelor thesis, concerning the impact of such a precession upon observable quantities in the system, as well as the methods used to extract them from the raw data.
Date: Thu, 19.10.2017
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel

Nonlinear Supersymmetry
Speaker:Chrysoula Markou (LPTHE, Paris)
Abstract:In theories with at least one spontaneously broken supersymmetry, the closure of the broken supersymmetry algebra can still be observed, while it is associated with a mismatch between the fermionic and bosonic degrees of freedom. Because of this, supersymmetry is said to be nonlinearly realized. Physical examples include effective models of the low-energy supersymmetry breaking, exact brane models in String Theory, as well as realizations of inflationary cosmology in supergravity. The recently revived constrained superfield formalism is a useful tool in studying nonlinear supersymmetry. We discuss the latest progress that has been made in regard to the partial breaking of N=2 supersymmetry. We explain a way of achieving the partial breaking, with one linearly and one nonlinearly realised supersymmetry, with the use of N=2 deformed vector and single-tensor superfields.
Date: Thu, 19.10.2017
Time: 16:00
Duration: 60 min
Location:10th floor seminar room in yellow tower of TU Wien Freihaus (Wiedner Hauptstrasse 8-10, A-1040 Vienna)
Contact:Timm Wrase