CPT

Calendar of Physics Talks Vienna

Family of Weyl-algebras and the Carrollian limit (Vienna Theory Lunch Seminar)
Speaker:Robert Tiefenbacher (University of Vienna )
Abstract:Carrollian field theories arise from the idea of letting c go to 0. The interest in such bizarre field theories comes first of all from the fact that the result is not nonsensical and the connection to flat space holography and tachyons. We show a different approach to Carroll theories, where we scale a regular complex scalar field in such a way as to reproduce a Carroll theory in the limit. This allows us to construct a family of Weyl-algebras associated to the scaled complex fields and "limit" algebra. [ part of the Vienna Theory Lunch seminar, more information: https://lunch-seminar.univie.ac.at ]
Date: Tue, 21.01.2025
Time: 12:15
Duration: 75 min
Location:University of Vienna: Boltzmanngasse 5, 5th floor, Schrödinger Lecture Hall
Contact:Florian Lindenbauer

Foams and KZ-equations in Rozansky-Witten theories
Speaker:Babak Haghighat (Tsinghua University, BIMSA)
Abstract:In this talk, we present a geometric description of foams, which are prevalent in topological quantum field theories (TQFTs) based on quantum algebra, and reciprocally explore the geometry of Rozansky-Witten (RW) theory from an algebraic perspective. This approach illuminates various aspects of decorated TQFTs via geometry of the target space X of RW theory. Through the formulation of the Knizhnik-Zamolodchikov (KZ) equation within this geometric framework, we derive the corresponding braiding and associator morphisms. We discuss applications where the target space of RW theory emerges as the Coulomb branch of a compactified 6d SCFT or Little String Theory, with the latter being particularly intriguing as it results in a compact X.
Date: Tue, 21.01.2025
Time: 14:00
Duration: 60 min
Location:Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock
Contact:S. Fredenhagen, M. Sperling

Probing interacting dark sectors with cosmology
Speaker:Mathias Garny (TUM Munich)
Abstract:The absence of signals for WIMPs motivates an exploration of cosmological probes of the properties and identity of dark matter. Current and future CMB and large-scale structure surveys allow us to explore interacting dark sectors via precision measurements sensitive to structure formation on various length and time scales. In this talk we explore the possibility that the dark sector is only very weakly coupled to the Standard Model, but that its internal properties are governed by similar fundamental principles, specifically a (dark) non-Abelian gauge interaction. We show that this scenario can be tested in multiple ways via the impact of dark sector interactions on structure formation, and could also address open questions such as the Hubble tension. Finally, we sketch the production of this type of dark matter by freeze-in and point out some peculiar features of the internal dark secto
Date: Tue, 21.01.2025
Time: 16:15
Duration: 60 min
Location:Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock
Contact:A. Hoang, M. Procura

Remarkable symmetries of rotating black holes
Speaker:David Kubiznak (Charles University Prague)
Abstract:It is well known that the Kerr geometry admits a non-trivial Killing tensor andits `square root' known as the Killing-Yano tensor. These two objects stand behind the Carter's constant of geodesic motion as well as allow for separability of test field equations in this background. The situation is even more remarkable in higher dimensions, where a single object -- the principal Killing-Yano tensor -- generates a tower of explicit and hidden symmetries responsible for integrability of geodesics and separability of test fields around higher-dimensional rotating black holes. Interestingly, similar yet different structure is already present for the slowly rotating black holes described by the `magic square' version of the Lense-Thirring solutio , giving rise to a geometrically preferred spacetime that can be cast in the Painleve-Gullstrand form and admits a tower of exact rank-2 and higher r
Date: Wed, 22.01.2025
Time: 14:15
Duration: 60 min
Location:Seminar Room A, Währinger Str. 17, 1090 Wien, 2nd floor
Contact:P. Chrusciel, D. Fajman

Hydrodynamics, black holes and transport in strange metals: successes and new discoveries.
Speaker:Koenraad Schalm (Leiden University, Netherlands)
Abstract:Insights from the equivalence between the physics of certain strongly coupled systems and the mathematics of black holes have reignited an interest in using hydrodynamics to understand observed responses in laboratory experiments on strongly correlated electron materials. Many such systems are outside the regime of applicability of the Boltzmann equation, and one must resort to such novel approaches. A classic example is the strange metal phase in high Tc cuprate superconductors. There is now ample evidence that its physics can be explained by a strongly interacting quantum critical system of the type captured by black hole mathematics and its emergent hydrodynamics. Focussing on electrical conductivity, we show that the incorporation of lattice effects in such dual hydrodynamical/black hole approach can for the first time capture several puzzling observations in strange metals...
Date: Thu, 23.01.2025
Time: 17:00
Duration: 60 min
Location:TU Wien: Wiedner Hauptstr. 8-10, yellow area, 10th floor, seminar room DB10E11
Contact:Daniel Grumiller, Anton Rebhan, Ankit Aggarwal

Interfacing fast Photons with warm Rubidium Vapor
Speaker:Sonja Barkhofen (Universität Paderborn)
Abstract:In this talk, I will present our journey towards realizing long-range quantum communication using hybrid quantum network links. High-quality quantum light sources and robust quantum memories are essential building blocks for the development of functional quantum networks. We will explore different experimental platforms for these components and introduce our hybrid approach, which interfaces single photons emitted from semiconductor quantum dots with a warm rubidium vapor quantum memory - an important first step towards implementing quantum repeater protocols. In this context, we will carefully examine the interaction between light fields and atomic transitions to enhance our fundamental understanding of their joint dynamics.
Date: Fri, 24.01.2025
Time: 10:00
Duration: 45 min
Location:Helmut Rauch Lecture Hall
Contact:Eliza Agudelo