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Calendar of Physics Talks Vienna
| Single-boson exchange decomposition for the extended Hubbard model with application to the optical conductivity (Vienna Theory Lunch Seminar) |
| Speaker: | Daniel Wieser (TU Wien) |
| Abstract: | In order to fully capture the effects of strong correlations on condensed matter, it is in principle necessary to solve the many-body Schrödinger equation. Because this is practically impossible for systems larger than a few electrons, numerous methods and approximations have been developed to date. After a short introduction to the Matsubara formalism, I will present two of them, namely the parquet- and the newly developed single-boson exchange decomposition. Subsequently, both approaches are applied to the extended Hubbard model in exact diagonalization to analyze the influence of vertex corrections on the optical conductivity. [[part of the "Vienna Theory Lunch Seminar, see https://lunch-seminar.univie.ac.at ]] |
| Date: | Tue, 05.11.2024 |
| Time: | 12:15 |
| Duration: | 75 min |
| Location: | TU Wien: Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room DB10E11 |
| Contact: | Florian Lindenbauer |
| Exploring Magnetic Quiver through Data Analysis and Machine Learning: Unveiling Patterns and Towards Predictive Models |
| Speaker: | Muyang Liu (University of Southern Denmark) |
| Abstract: | Magnetic quivers offer a powerful framework for investigating the Higgs branch of supersymmetric gauge theories across dimensions d=3,4,5, and 6, where fission and decay processes within quivers correspond to the Higgsing in the underlying theory. In this talk, I will introduce a brute-force scanning approach, enhanced by data analysis and machine learning, to systematically explore quiver architecture. This approach facilitates the use of machine learning models to uncover patterns and predict Hasse diagram pathways, automating the study of complex quiver structures. A moderate introduction to machine learning concepts will also be provided, making this talk accessible to newcomers and showcasing the potential of these tools for advancing research. |
| Date: | Tue, 05.11.2024 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock |
| Contact: | S. Fredenhagen, M. Sperling |
| Linear Power Corrections in Collider Processes |
| Speaker: | Paolo Nason (INFN) |
| Abstract: | In this talk I address recent advances regarding linear power corrections in collider processes, focusing on developments achieved within the large $\beta_0$ approximation framework. I present a general result that holds when massless partons are considered, offering a simplified approach to deriving both established and novel findings related to power corrections in collider processes. A key application of this result is the extension of linear power corrections calculations to hadronic shape variables in $e^+e^-$ annihilation, advancing from the two-jet to the three-jet regime. In this framework, I present recent fits to available LEP data and discuss the impact of the newly found corrections. Finally, I discuss recent results regarding massive partons, applied in particular to top production and decay processes. |
| Date: | Tue, 05.11.2024 |
| Time: | 16:15 |
| Duration: | 60 min |
| Location: | Erwin-Schroedinger-Hoersaal, Boltzmanngasse 5, 5. Stock |
| Contact: | A. Broggio |
| Wave-packet dynamics in locally periodic media |
| Speaker: | Alexander Watson (University of Minnesota) |
| Abstract: | By considering the dynamics of spectrally concentrated wave-packets propagating in media with a slowly-varying periodic structure, we rigorously derive a novel dynamical system for the evolution of observables associated to the wave, specifically its center of mass and momentum. The system corrects the standard result relating wave-packet velocity to the derivative of the dispersion band. The corrections include an anomalous velocity due to Berry curvature and an interesting "particle-field coupling'' effect where the evolution of the observables, which are discrete degrees of freedom, becomes coupled to the evolution of the wave-packet envelope, a continuous degree of freedom. Although our derivation focuses on the case of waves described by the linear Schrödinger equation, we expect that the derivation can be carried out for other linear PDE describing waves. |
| Date: | Wed, 06.11.2024 |
| Time: | 15:00 |
| Duration: | 60 min |
| Location: | Online via Zoom |
| Contact: | Piotr T. Chrusciel, David Fajman |
| Aspects of universality and symmetry in nonequilibrium quantum fields |
| Speaker: | Viktoria Noel (Heidelberg University) |
| Abstract: | Isolated systems far from thermal equilibrium can exhibit universal
dynamics near attractor solutions, known as nonthermal fixed points,
showing scaling behaviour in space and time. This resembles universal
behaviour in systems close to equilibrium and criticality but without
fine-tuning parameters. Such universality classes can be broad, with
many relativistic and nonrelativistic scalar fields forming one class,
and gauge and scalar fields another. However, a systematic
classification is still lacking. The role of phenomena like nonlinear
wave propagation and defect dynamics in these strongly correlated,
nonequilibrium systems remains unclear. In this talk, IâÂÂll discuss how
unequal-time correlation functions reveal relevant degrees of freedom in
nonequilibrium scenarios, and introduce an approach for extracting
symmetries in quantum many-body systems, aiming for a deeper
understanding o |
| Date: | Thu, 07.11.2024 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | TU Wien, Freihaus, Sem.R. DB gelb 05A |
| Contact: | Iva Lovrekovic, Ankit Aggarwal |
| Continuous Variables multimode quantum networks |
| Speaker: | Valentina Parigi (Sorbonne Université) |
| Abstract: | Theory and experiments of multipartite entangled Gaussian and non-Gaussian states arranged in spectral and time-multiplexing network structures [1,2] will be presented. We explore possible strategies to efficiently probe the networks and implement CV quantum information protocols in such a platform , including simulations on quantum complex environments [5], routing protocols [4] and reservoir computing [3]. |
| Date: | Fri, 08.11.2024 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | Helmut Rauch Lecture Hall |
| Contact: | Isabelle Safa |
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