Theoretical Physics @ UMONS – Collaboration meeting

Schedule

Titles and abstracts

Glenn Barnich | Memory of Robinson-Trautman waves

Abstract: The memory effect for Robinson-Trautman waves is explicitly worked out. In a first step, we construct the combined frame rotation and coordinate transformation in which Robinson-Trautman waves are manifestly locally asymptotically flat at future null infinity. This allows us to apply well-established results on how to derive the memory effect in this context. In a second step, we construct a suitably improved generalized mass aspect that provides a local Lyapunov function for the flow in the sense that it is manifestly positive. News-free solutions are studied in detail and shown to coincide with the vacuum sector of Euclidean Liouville theory. They correspond to a boosted and rescaled Schwarzschild black hole. As a by-product, we show that the displacement and non-linear memory effects in locally asymptotically flat spacetimes at future null infinity are invariant under supertranslations and covariant under $mathrm{BMS}_4$ Lorentz transformations and constant rescalings. A novel interpretation of modified flows that control the low harmonics in terms of keeping the system in its instantaneous rest frame is provided.

Pierre Bieliavsky | Twist, twist again

Abstract: I will review the notion of Drinfel’d twist as a deformation quantization machinery, and discuss the corresponding  notion of quantum groups.

Andrea Campoleoni | TBA
Abstract: TBA

Maxim Grigoriev | TBA

Abstract: TBA

Evgeny Skvortsov | Self-dual holography

Abstract: I will review the recent results on charting out the space of self-dual theories, which leads to new problems in deformation quantization and number theory. I will also discuss the place of these theories in AdS/CFT and celestial holography.