CPT

Calendar of Physics Talks Vienna

Hidden symmetries in cosmology and black holes
Speaker:Francesco Sartini (ENS Lyon)
Abstract:Cosmological models and black holes belong to classes of space-time metrics defined in terms of a finite number of degrees of freedom, for which the Einstein–Hilbert action reduces to a one-dimensional mechanical model. We investigate their classical symmetries and the algebra of the corresponding Noether charges. These dynamical symmetries have a geometric interpretation, not in terms of spacetime geometry, but in terms of motion on the field space. Moreover, they interplay with the fiducial scales, introduced to regulate the homogenous model, suggesting a relationship with the boundary symmetries of the full theory. Finally, the existence of these symmetries unravels new aspects of the physics of black holes and cosmology. It opens the way towards a rigorous group quantization of the reduced models, to the study of their holographic properties. It might have significant [...]
Date: Tue, 29.11.2022
Time: 14:00
Duration: 60 min
Location:ZOOM: Join Zoom Meeting https://tuwien.zoom.us/j/96128515992?pwd=V2k0TkNiYXFPM0p1NkE2OW4xODhyUT09 Meeting ID: 961 2851 5992 Password: s7BX7Pvp
Contact:D. Grumiller, S. Fredenhagen, E. Battista, R. Ruzziconi

Mining Perturbation Theory: Resurgence-Inspired Extrapolation and Analytic Continuation
Speaker: Prof. Gerald V. Dunne (University of Connecticut)
Abstract:What is the best way to extract information from a finite amount of perturbative information? This is a common problem in applications. We may only be able to compute a (small) finite number of coefficients of an expansion of a function about some special parameter point, and we wish to learn about the behaviour near another point (possibly very distant). I will discuss some recent work with Ovidiu Costin using resurgence ideas to address the mathematical question of optimal and near-optimal methods of analytic continuation, and I will illustrate with several applications in quantum field theory.
Date: Tue, 29.11.2022
Time: 16:15
Duration: 60 min
Location:via zoom https://tuwien.zoom.us/j/96505893692?pwd=TWNKUThEOW83anl1RDl5UDRaZVdNUT09
Contact:A. Hoang, M. Procura

The second law of black hole mechanics in effective field theory
Speaker:Harvey Reall (Cambridge)
Abstract:I shall discuss the second law of black hole mechanics in gravitational theories with higher derivative terms in the action. Wall has described a method for defining an entropy that satisfies the second law to linear order in perturbations around a stationary black hole. I shall explain how this can be extended to define an entropy that satisfies the second law to quadratic order in perturbations, provided that one treats the higher derivative terms in the sense of effective field theory. This talk is based on work with Stefan Hollands and Aron Kovacs.
Date: Thu, 01.12.2022
Time: 15:15
Duration: 60 min
Location:by zoom https://tuwien.zoom.us/j/96505893692?pwd=TWNKUThEOW83anl1RDl5UDRaZVdNUT09
Contact:P. Chrusciel, D. Fajman

Electroweak logarithms in inclusive cross sections
Speaker:Prof. Wouter Waalewijn (University of Amsterdam)
Abstract:I will present a framework to resum electroweak logarithms in inclusive processes, that enables resummation beyond leading logarithmic accuracy. I will discuss the factorization of the cross section in terms of PDFs and fragmentation functions and, surprisingly, soft functions. They appear because electroweak corrections to inclusive cross sections involve double logarithms, since the proton is not an electroweak singlet. I will also discuss the renormalization group equations in some detail, which can be used to carry out the resummation. Due to the chiral nature of the weak force, the evolution polarizes the distributions. I conclude by discussing extensions to measurements that are neither fully exclusive nor inclusive.
Date: Fri, 02.12.2022
Time: 16:15
Duration: 60 min
Location:Fakultaet fuer Physik, Erwin Schroedinger-HS, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, M. Procura