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Calendar of Physics Talks Vienna
| Chemical and Structural Properties of Highly Oxidized Metal Surfaces |
| Speaker: | Dan Killelea (Loyola University Chicago, Department of Chemistry & Biochemistry, Chicago, IL USA) |
| Abstract: | Understanding the interaction of oxygen with transition metal surfaces is important in many areas including corrosion and catalysis. Of interest to us is the formation and chemistry of subsurface oxygen (Osub); oxygen atoms dissolved in the near-surface region of catalytically active metals. To improve our understanding of this system, we use ultra-high vacuum (UHV) surface science techniques to characterize Ag and Rh surfaces after exposure to atomic oxygen (AO) to obtain O coverages in excess of 1 ML. Low-energy electron diffraction (LEED) and UHV Scanning Tunneling Microscopy (UHV-STM) characterize the various oxygenaceous structures produced, and we quantify the amount of oxygen with temperature programmed desorption (TPD). We have found that the surface temperature during deposition is an important factor for the formation of Osub and the consequent surface structures. Finally, we |
| Date: | Tue, 11.06.2019 |
| 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 |
| Upscaling Glasma simulations using machine learning |
| Speaker: | Andreas Ipp (TU Wien) |
| Abstract: | In this talk I want to present the ideas behind my FWF project proposal with the same title that recently got approved. I would first like to share my motivation on why I think machine learning will be increasingly interesting for physicists (for a more in-depth introduction see for example [1]).
I will then present my specific application - numerical simulations of the Glasma state, a precursor to the Quark-Gluon-Plasma state that can be created in relativistic heavy ion collisions. I will outline how machine learning tools might enable sufficiently accurate predictions of large-scale simulations that would exceed the capabilities of current supercomputers.
[1] A high-bias, low-variance introduction to Machine Learning for physicists, by Mehta et al., https://arxiv.org/abs/1803.08823 |
| Date: | Wed, 12.06.2019 |
| Time: | 10:30 |
| 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: | Anton Rebhan, Andreas Ipp, Kirill Boguslavski |
| A simple non-perturbative resummation scheme beyond mean-field |
| Speaker: | Philipp Stanzer (TU Wien) |
| Abstract: | Lunchseminar:While visiting Paul Romatschke at CU Boulder this spring, I started working on the resummation scheme, he introduced earlier this year (arXiv:1901.05483).
I will give an overview of this scheme, following the original paper. This very versatile scheme (finite temperature, various dimensions, bosons/fermions) can be implemented numerically (only 1-loop integrals) and allows to determine transport coefficients. Further it is designed to perform calculations at finite coupling.
In this talk I want to show how we apply this scheme to the Gross-Neveu model in 1+1 dimensions.
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| Date: | Wed, 12.06.2019 |
| Time: | 12:30 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strsse 17, common room, 1. Stock |
| Contact: | P.T. Chrusciel, D. Fajman |
| Dark Energy in String Theory |
| Speaker: | Susha Parameswaran (Liverpool University) |
| Abstract: | The main candidate for Dark Energy in string theory has been an anthropically selected tiny cosmological constant in a de Sitter vacuum, though explicit de Sitter vacua in string theory are difficult to construct. I will summarise the current status of de Sitter vacua in string theory, including recent Swampland Conjectures. I will then present a simple, well-motivated and robust alternative to a de Sitter vacuum - a string candidate for quintessence - that is consistent with current observations of dark energy and naturally satisfies conjectured swampland constraints, albeit with fine-tuned initial conditions. |
| Date: | Thu, 13.06.2019 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Institute for Theoretical Physics, TU Wien, Seminar room 10th floor (yellow area), Wiedner Haupstr. 8-10, 1040 |
| Contact: | Timm Wrase |
| The mystery of the Dark Matter Phenomenon |
| Speaker: | Paolo Salucci (SISSA, Trieste) |
| Abstract: | JOINT THEOR. PHYSICS SEMINAR:The distribution of the non-luminous matter in galaxies of different luminosity and Hubble type is much more than a proof of the existence of dark particles governing the structures of the Universe. The deeper we go into the knowledge of the dark component that embeds the stellar component of galaxies, the more we realize the profound interconnection present between the two of them.They are too complex to be arisen by two inert components that just share the same Gravitational field.The 30 years old paradigm which rests on a-priori knowledge of the nature of dark matter that has led to the scenario of collisionless dark matter in galaxy halos reveals itself to be insufficient to explain the observations. Here, we will review the complex but well-ordered scenario of the properties of the dark halos in relation with those of the baryonic components they host. |
| Date: | Thu, 13.06.2019 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Arbeitsgruppe Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock, 1090 Wien |
| Contact: | P.T. Chrusciel, D. Fajman |
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