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Calendar of Physics Talks Vienna
| Infrared Singularities and the Precision Frontier |
| Speaker: | Raoul Röntsch (CERN) |
| Abstract: | The results from the first decade of operation of the Large Hadron Collider (LHC) oblige the particle physics community to undertake a high precision program in order to fully exploit the large amount of data expected over the rest of the lifetime of the LHC. This program will uncover further details of the mechanism of electroweak symmetry breaking, and may point towards signs of physics Beyond the Standard Model.A key ingredient in precision theoretical calculations for the LHC is the treatment of infrared singularities in fixed-order calculations. Along with my collaborators, I have proposed and developed a new method of handling such singularities, the nested soft-collinear subtraction scheme. This approach fully exploits the universal singularity tructures of QCD amplitudes to formulate a straightforward procedure of ubtracting IR singularities, and results in a subtraction sche |
| Date: | Mon, 02.12.2019 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Kleiner Seminarraum, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, S. Plätzer, M. Procura |
| Fun Things To Do With Light |
| Speaker: | Daniel Dietze (CoQuS) |
| Abstract: | Light, as subject by itself and through its interaction with matter, has been the guiding motif throughout my career, from undergraduate studies at University to my current role in industry.
In this talk I will present a few examples of my encounters drawn from various scientific disciplines, spanning the electromagnetic spectrum from the UV over the visible all the way to the far infrared (or terahertz) region.
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| Date: | Mon, 02.12.2019 |
| Time: | 17:00 |
| Duration: | 90 min |
| Location: | Lise Meitner Hörsaal, Strudelhofgasse 4, 1. Stock, 1090 Wien |
| Contact: | CoQuS Administration |
| Two-dimensional BF theory as a CFT |
| Speaker: | Donald Ray Youmans (University of Geneva) |
| Abstract: | We present a construction of 2d TCFTs via gauge fixing topological gauge theories:Two-dimensional abelian BF theory is an example of a topological gauge theory.Imposing the Lorenz gauge-fixing condition introduces an auxiliary geometric datum in form of a metric.We will show that the theory becomes topological conformal,i.e.it depends only on the conformal structure of the introduced metric.Moreover, the stress-energy tensor is Q-exact (hence vanishes in Q-cohomology and therefore on physical states).The Q-primitive of the stress-energy tensor can be used to deform the model. In particular,the non-abelian theory can be seen as a deformation of the abelian one in the space of TCFTs.The former shares many features of a logarithmic CFT,such as the appearance of logarithmic singularities in OPEs.Notably,the presence of infinite Jordan cells of the Hamiltonian lead to vertex operators. |
| Date: | Tue, 03.12.2019 |
| Time: | 13:45 |
| Duration: | 60 min |
| Location: | TU Wien, Wiedner Hauptstraße 8, Red Area, 7th floor, Seminar Room DC07 A15 |
| Contact: | S. Fredenhagen, D. Grumiller |
| Site-specific electrochemical properties of (modified) single crystal electrodes |
| Speaker: | Albert K. Engstfeld (Ulm University, Institute of Surface Chemistry and Catalysis, Ulm/Germany) |
| Abstract: | Over the last decades, fundamental research on the electrochemical/-catalytic properties of low index single crystals has played an important role for the understanding and improvement of industrially relevant and more complex (electro-)catalyst materials. One of the fundamental questions deals with the elucidation of the activity of specific sites on a catalyst material, which should ultimately reveal the most active site. In this context, mono- or bimetallic single crystal electrodes provide suitable substrates, since the number of different sites on their surfaces is in general limited. Changing the number of these sites systematically allows, finally allows for a direct correlation between electrochemical/-catalytic properties and these sites. A rather versatile experimental appr |
| Date: | Tue, 03.12.2019 |
| 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. Ulrike Diebold |
| Speaker: | Malin Sjödahl (Lund University) |
| Abstract: | im Rahmen des Teilchenphysikseminars: In SU(3) color space we are used to thinking about a flow of color.
At the algebra level, the Lorentz group consists of two copies of su(2),
so one can ask oneself if there is a similar way of thinking about the
spacetime structure of scattering amplitudes.
In this presentation I answer this question with "Yes", and present the
"helicity flow method". I further argue that this method opens up for
shorter and more intuitive ways of calculating with Feynman diagrams.
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| Date: | Tue, 03.12.2019 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, S. Plätzer |
| CURRENT AND FUTURE TOPICS IN ACCELERATOR-BASED NEUTRINO PHYSICS |
| Speaker: | Joachim Kopp (Johannes Gutenberg-Unviersität Mainz & CERN) |
| Abstract: | Neutrino physics has evolved from a fringe topic in particle physics to one of its driving forces, with new flagship experiments being planned for instance in North America and Japan. In the first part of this colloquium, we first give an overview of the physics program at these experiments. In the second part, we comment on several persistent anomalies in neutrino oscillations over short distances, and on their cosmological implications. |
| Date: | Thu, 05.12.2019 |
| Time: | 09:30 |
| Duration: | 60 min |
| Location: | HEPHY Library |
| Contact: | Josef Pradler |
| The asymptotic shape of the landscape |
| Speaker: | Thomas Grimm (Utrecht University) |
| Abstract: | In this talk I will argue that in many string compactifications a rather universal algebraic structure, captured by asymptotic Hodge theory, emerges near the boundaries of field space. I describe how it can be used to introduce a classification of Calabi-Yau manifolds and viable flux scalar potentials. I then illustrate several physical applications. For example, I argue that one now can show the finiteness of self-dual flux vacua, check the asymptotic de Sitter conjecture for infinite distance limits, and uncovers universal constraints on axions. (Skype seminar) |
| Date: | Thu, 05.12.2019 |
| Time: | 10:30 |
| Duration: | 60 min |
| Location: | T.U. Wien, Freihaus, Conference room DA 09 E10, reachable through the 8th floor green stairs |
| Contact: | D. Andriot |
| Self-gravitating perfect-fluid tori around black holes: Bifurcations, ergoregions, and geometrical properties |
| Speaker: | Patryk Mach (Vienna) |
| Abstract: | Im Rahmen des Literaturseminars: I will discuss recent results in modeling stationary self-gravitating tori (disks) around black holes. Special emphasis will be put on general-relativistic Keplerian rotation in self-gravitating perfect-fluid tori and the interaction between the angular momentum of the torus and the spin of the black hole. Next, I will focus on general-relativistic effects characteristic for sufficiently massive tori: bifurcations in the parameter space of solutions, the existence of toroidal ergoregions connected with the tori, the appearance of local maxima of the circumferential radius, and the properties of circular, equatorial geodesics in the obtained spacetimes. |
| Date: | Thu, 05.12.2019 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Raum 218, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel, D. Fajman |
| Precision QCD for the LHC: a multifaceted approach |
| Speaker: | Jonathan Richard Gaunt (CERN) |
| Abstract: | A precise description of the QCD dynamics of proton-proton collisions at the LHC is needed to fully exploit the physics potential of this machine.The standard tool to make predictions at the LHC is the collinear factorisation formula,involving parton densities and perturbatively-computable partonic cross sections.One direction to improve precision is to compute the short-distance scattering cross sections at higher perturbative orders in QCD, and,for multiscale processes, to sum up large logarithms of the ratios of scales to successively higher precision. However,the level of precision achieved by the experiments necessitates that we also explore effects beyond the current factorisation paradigm.Of particular importance is to consider the effect of additional partonic interactions accompanying the 'primary' interaction:either a small number of additional hard interactions, or multiple .. |
| Date: | Thu, 05.12.2019 |
| Time: | 15:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Kleiner Seminarraum, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, S. Plätzer, M. Procura |
| Heavy quark momentum diffusion coefficient in 3D gluon plasma |
| Speaker: | Jarkko Peuron (ECT*, Trento, Italy) |
| Abstract: | We study the heavy-quark momentum diffusion coefficient in far from equilibrium gluon plasma in the self-similar regime using real-time lattice techniques. We use 3 methods for the extraction: an unequal time electric field 2-point correlator integrated over the time difference, hard loop (HTL) perturbation theory and a kinetic theory formula. The time-evolution of the momentum diffusion coefficient extracted using all three methods is consistent with an approximate t^(-1/2) power law. We also study the extracted diffusion coefficient as a function of the upper limit of the time integration. We find that combining HTL expressions with the infrared enhancement of the equal-time correlation function we have observed previously improves the agreement with the data for transient time behavior considerably. This is a gauge invariant confirmation of the observed infrared enhancement. |
| Date: | Thu, 05.12.2019 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | Seminar room FH gelb 10, Institute for Theoretical Physics – Vienna University of Technology, Wiedner Hauptstraße 8 – 10, 10th floor, B (yellow tower) |
| Contact: | K. Boguslavski, A. Rebhan |
| Heavy-flavour hadroproduction from collider to astroparticle physics |
| Speaker: | Maria Vittoria Garzelli ( DESY, Hamburg / INFN Mailand) |
| Abstract: | Charm and bottom quarks are abundantly produced at modern high-energy accelerators, giving rise to heavy-flavoured hadrons and jets which are detected
by the experiments. I will discuss the present status of the theory, what we can learn
by comparing theory predictions to open heavy-flavour production data, and open issues on which it would be worth focusing future research efforts, also in view of interesting applications in high-energy astroparticle physics.
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| Date: | Fri, 06.12.2019 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Hoang, S. Plätzer, M. Procura |
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