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Calendar of Physics Talks Vienna
| Towards the computation of real-time observables in Yang-Mills theories on the lattice (Vienna Theory Lunch Seminar) |
| Speaker: | Paul Hotzy (TU Wien) |
| Abstract: | Lattice Quantum Chromodynamics (LQCD) is one of the most successful methods for making non-perturbative predictions in high-energy physics. Despite its achievements, traditional computational techniques encounter limitations â arising from the notorious sign problem â when dealing with dynamic observables in physical time or at non-vanishing chemical potential. Our recent work focuses on the complex Langevin (CL) method, which aims to circumvent these challenges by generalizing the Stochastic Quantization approach. We have significantly improved and successfully applied CL to real-time SU(N) gauge theories on a 1+3 dimensional lattice for the first time. In this talk, I present our recent advances in calculating unequal-time correlation functions directly from first principles. (... Full abstract on https://lunch-seminar.univie.ac.at ) |
| Date: | Tue, 16.04.2024 |
| Time: | 12:30 |
| Duration: | 75 min |
| Location: | TU Wien: Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room DB10E11 |
| Contact: | Florian Lindenbauer |
| The Case Against Smooth Null Infinity and the Persistence of Polyhomogeneity |
| Speaker: | Leonhard Kehrberger (U of Leipzig) |
| Abstract: | In this talk, I will describe recent and upcoming work on the asymptotic behaviour of gravitational radiation (linearised gravity around Schwarzschild) in a neighbourhood of spacelike infinity including past and future null infinity.
I will first set up a mathematical scattering framework in which one can understand the question of smoothness of null infinity on physical grounds.
I will then use this framework to present a basic sketch of the proof of the irregularity of null infinity in various physically motivated settings, together with a complete description of the semiglobal asymptotics of gravitational radiation one obtains instead.
In particular, I will discuss how a class of asymptotic conservation laws related to the Newman-Penrose charges can be used to infer the asymptotics for fixed angular modes, and describe how to use a persistence of polyhomogeneity result to sum up the i |
| Date: | Wed, 17.04.2024 |
| Time: | 14:15 |
| Duration: | 60 min |
| Location: | ESI Main Lecture Hall, Boltzmanngasse 9 |
| Contact: | P. Chrusciel |
| Poisson sigma models, Poisson diffeomorphisms, and holography |
| Speaker: | Dmitri Vassilevich (Universidade Federal do ABC, Brazil) |
| Abstract: | Dilaton gravities in 2D are particular cases of Poisson sigma models. I show how the target space (Poisson) diffeomorphism can be used to extend the JT/SYK correspondence to many other dilaton models including the ones which do not have AdS/dS/flat asymptotics.
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| Date: | Thu, 18.04.2024 |
| Time: | 17:00 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Seminar room on the 4th floor, yellow area |
| Contact: | Daniel Grumiller, Iva Lovrekovic |
| Ultrafast coherent electron dynamics in graphene - from petahertz-fast logic gates to Floquet dressing and valley currents |
| Speaker: | Peter Hommelhoff (University of Erlangen) |
| Abstract: | Monolayer graphene, the two-dimensional arrangement of carbon atoms, withstands high optical field strengths. Hence, electrons inside of graphene can be strongly driven, meaning that they can undergo ultrafast motion in momentum space. This intraband dynamics can lead
to interband transitions vie Landau-Zener transitions. Because of the finite probability of the transition, the Landau-Zener transition can act as a beam splitter. The oscillatory nature of the optical field in few cycle laser pulse results in subsequent Landau-Zener transitions, which lead to Landau-Zener-Stückelberg-Majorana interferometry, on (sub-) femtosecond time scales. Based on this, we can measure band structure parameters by reading out the electron's dynamical phase. Furthermore, we could also demonstrate a logic gate this way, an
essential ingredient of petahertz electronics. We will conclude by showing how |
| Date: | Fri, 19.04.2024 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Hörsaal ATI |
| Contact: | Philipp Haslinger |
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