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Calendar of Physics Talks Vienna
| YUKAWAS OF LIGHT STRINGY STATES |
| Speaker: | Pascal Anastasopoulos (Univ. Wien) |
| Abstract: | We investigate light massive string states that appear at brane intersections.
They replicate the massless spectrum in a richer fashion and may be parametrically lighter than standard Regge excitations. We compute tri-linear Yukawa couplings of
such open-string states to massless ones and to one another. Due to ambiguities in
the normalisation of the vertex operators, that involve twist fields, we proceed via
factorization of appropriate scattering amplitudes. Some peculiar features are
observed that may lead to interesting signatures at colliders in the future.
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| Date: | Tue, 13.03.2018 |
| Time: | 13:45 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | S. Fredenhagen, D. Grumiller |
| In-situ Chemical Analysis of Solid-Liquid Interfaces by means of Rutherford Backscattering Spectrometry - An Approach to Direct Measurements of the Electric Double Layer Formation Dynamics |
| Speaker: | René Keller (Helmholtz-Zentrum Dresden-Rossendorf Dresden, Germany) |
| Abstract: | Rutherford Backscattering Spectrometry (RBS) represents a well-established and widely used analysis
technique for the non-destructive and quantitative determination of elemental compositions as well as depth
profiling at solid surfaces. However, since this technique utilizes a charged particle beam (typically 1-2MeV
H/He ions) measurements have to be performed in vacuum which just allows investigation of solid samples.
Liquids, gases or the interface of one of both with a solid surface are not accessible for measurements in this
setup. Therefore, we recently commissioned a new experimental setup that overcomes this hurdle. By
utilizing a thin (500nm) SiN-window we are able to perform online chemical analysis by means of RBS at the
solid-liquid (and solid-gaseous) interface. In this talk we will give an overview of this new experiment, point
out its strengths and limitations and give some |
| Date: | Tue, 13.03.2018 |
| Time: | 16:00 |
| Location: | Technische Universität Wien, Institut für Angewandte Physik, E134 yellow tower „B“, 5th floor, Sem.R. DB gelb 05 B (room number DB05L03), 1040 Wien, Wiedner Hauptstraße 8-10 |
| Contact: | Univ.Prof.Dr. Friedrich Aumayr |
| Small-x Resummation from Effective Field Theory |
| Speaker: | Aditya Pathak (Univ. Wien) |
| Abstract: | Over the last few decades a remarkable progress has been made in describing the QCD phenomenon perturbatively in the context of collider physics. However, there still remains one area that has been very challenging to tackle, both in terms of achieving the desired accuracy and improving our understanding of underlying physics: the forward scattering regime. In the limit where the incoming colliding particles barely graze each other and continue along their original directions one finds logarithmic enhancement of the cross section which is of a very different nature than that encountered
in typical collider situations. In this talk will focus on forward scattering in the case of Deep Inelastic Scattering (DIS), where this region is referred to as the "small-x" limit. I will go through our attempt to calculate the DIS cross section in this limit using the tools of Soft Collinear . . . |
| Date: | Tue, 13.03.2018 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, H. Neufeld |
| New Physics from Standard Model Measurements |
| Speaker: | Prof. Josh Ruderman (NYU) |
| Abstract: | We traditionally look for new physics at colliders by trying to separate signals from Standard Model (SM) backgrounds. This approach has led to striking constraints from the LHC, but no discovery of new physics beyond the SM. In this talk I will highlight the alternate approach of using precision measurements of SM processes to search for subtle effects of new physics that is otherwise hidden from traditional searches. I will highlight examples where precise measurements of top quark, lepton, and jet production can be used to look for new physics. |
| Date: | Wed, 14.03.2018 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | HEPHY Library |
| Contact: | Josef Pradler |
| The Weak Null Condition and Kaluza Klein Spacetimes |
| Speaker: | Zoe Wyatt (Edinburgh) |
| Abstract: | In string theory, our most developed theory of quantum gravity to date, one is interested in spacetimes of the form R{1+3}* K where K is some n-dimensional compact Ricci-flat manifold. In the first and simplest case considered by Kaluza and later Klein, K is the n-torus with the flat metric. An interesting question to ask is whether this solution to the Einstein equations, viewed as an initial value problem, is stable to small perturbations of the initial data. Motivated by this problem, I will outline the proof of stability in a restricted class of perturbations, and discuss the physical justification behind this restriction. Furthermore the resulting PDE system exhibits the weak-null condition, and I will discuss how it can be treated by generalising the proof of the non-linear stability of Minkowski spacetime given by Lindblad and Rodnianski.
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| Date: | Thu, 15.03.2018 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel, D. Fajman |
| Erwin Schrödinger Lecture: Weierstrass preparation theorem and singularities in arc spaces |
| Speaker: | Ngô Bảo Châu (University of Chicago) |
| Abstract: | Arc spaces have drawn considerable attention with the rise of the theory of motivic integration. In representation theory and harmonic analysis of/on groups defined over nonarchimedean local fields, arc spaces, and their singularities, also play a prominent role. The problem of understanding singularities of arc spaces becomes thus important both in motivic integration and geometric representation theory.
After earlier work of Grinberg and Kazhdan, Drinfeld gave a very convenient description of the formal completion of arc spaces with the help of a version of the Weierstrass preparation theorem with coefficients in Artin local rings. To go beyond the formal completion, we need a version of Weierstrass preparation theorem with arbitrary coefficients. I will describe the problems that arise in extending the Weiertrass preparation theorem to arbitrary coefficient rings and applications |
| Date: | Fri, 16.03.2018 |
| Time: | 15:15 |
| Duration: | 60 min |
| Location: | Boltzmann Lecture Hall, Erwin Schrödinger Institute for Mathematics and Physics, Boltzmanngasse 9, 1090 Wien |
| Contact: | secr@esi.ac.at |
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