CPT

Calendar of Physics Talks Vienna

Probing Quantum Aspects of Gravitational Fields (Vienna Theory Lunch Seminar)
Speaker:Lin-Qing Chen (IQOQI & Uni Wien )
Abstract: Recent progress in table-top experiments offers the opportunity to show for the first time that gravity is not compatible with a classical description. However, in all current experimental proposals, such as the generation of gravitationally induced entanglement between two quantum sources of gravity, gravitational effects can be explained with the Newton potential. This is a limitation to the conclusions on the nature of gravity that can be drawn from these experiments. Here, I will introduce a theoretical framework that is suitable for this experimental regime, and we identify two effects that overcome the above-mentioned limitation. First, we show that the phase arising from the interaction between two generic quantum sources of gravity, cannot be reproduced with the Newton potential nor with any limit of (classical) general relativity. [ part of https://lunch-seminar.univie.ac.at ]
Date: Tue, 12.11.2024
Time: 12:15
Duration: 75 min
Location:University of Vienna, Boltzmanngasse 5, 5th floor, Schrödinger Lecture Hall
Contact:Florian Lindenbauer

Entanglement Resolution and boundary CFT
Speaker:Christian Northe (Czech Academy of Sciences)
Abstract:In this talk I will explain how computations in entanglement studies can be refined by the use of BCFT. The focus will lie on the entanglement spectrum, which is known to encode fundamental aspects of entanglement, such as topological signatures. Given a symmetry on an entangling subregion, the reduced density matrix decomposes into sectors corresponding to charge eigenvalues of the symmetry. I will discuss how the information or uncertainty in these sectors is quantified, first for U(1) symmetry and thereafter for the infinite-dimensional conformal symmetry in two spacetime dimensions. Finally, the information count of each sector will be compared leading to a simple yet striking lesson for gravity. If time permits, I will discuss how the celebrated Affleck-Ludwig boundary entropy decomposes into symmetry sectors.
Date: Tue, 12.11.2024
Time: 14:00
Duration: 60 min
Location:Erwin-Schroedinger-HS, Boltzmanngasse 5, 1090 Wien, 5.Stock
Contact:S. Fredenhagen, M. Sperling

Monte Carlo simulation of a planar accretion of the relativistic Vlasov gas onto a moving Schwarzschild black hole
Speaker:Adam Cieslik (Jagiellonian University)
Abstract:I will present the results of a Monte Carlo simulation of a planar accretion of the relativistic Vlasov gas onto a moving Schwarzschild black hole. The gas is assumed to be in thermal equilibrium at infinity, where it obeys the Maxwell-Jüttner distribution. This simulation methodology builds on the approach developed last year for a stationary Schwarzschild black hole. I will elucidate the modifications necessary for setting up the simulation for the complexities introduced by black hole motion. Furthermore, our Monte Carlo results consistently confirm the analytically derived exact expressions for particle current density in all examined cases.
Date: Wed, 13.11.2024
Time: 14:15
Duration: 60 min
Location:Seminarraum A, Waehringer Strasse 17, 2nd Floor
Contact:Piotr T. Chrusciel, David Fajman

Light transformation in Celestial and Carrollian CFT
Speaker:Sourish Banerjee (BITS-Pilani, Goa, India)
Abstract:In this talk I will briefly introduce Celestial CFT and Carrollian CFT and then go on to discuss the consequence of spacetime translations and Lorentz transformations on Celestial CFT OPEs. Working with the light transforms of the operators belonging to the modified Mellin basis, I will show that the leading order singularity in the OPE of such operators could be fixed purely using Poincare symmetries owing to the non-trivial action of the translations on these operators. I will discuss how this approach could potentially be useful for studying Celestial CFT without adverting to bulk physics. As another goal of this talk, I will discuss the significance of light transformation in Carrollian CFTs. In the special cases we considered, we show that light transformation equips us with a map between two branches of Carroll CFT in d = 3 dimension at the level of correlation functions.
Date: Thu, 14.11.2024
Time: 17:00
Duration: 60 min
Location:TU Wien Freihaus, Seminar room DB10E11 (10th floor, yellow area)
Contact:Daniel Grumiller, Ankit Aggarwal