Relativistický seminář
Ústavu teoretické fyziky

Seminář se koná v úterý ve 13:10 v posluchárně ÚTF MFF UK
v 10. patře katedrové budovy v Tróji, V Holešovičkách 2, Praha 8

Příští semináře:

13. listopadu 2018
New closed solutions for thick fluid tori near black holes
Dr. Vojtěch Witzany
Astronomický ústav AV ČR
(seminář v angličtině)

When accretion onto a black hole occurs either at a fast or a slow rate, radiation stops cooling the accretion flow efficiently and the accretion disk becomes hot and geometrically thick. After a broader introduction to this topic, I will present new closed analytical solutions for geometrically thick fluid equilibria near black holes that can be used as initial conditions for simulations of such radiatively inefficient accretion flows. I will also show some simple magneto-hydrodynamic simulations in which we investigated possible consequences of varying the initial conditions for astrophysical predictions.

20. listopadu 2018
Gravitational microlensing by three-body systems
Dr. David Heyrovský
(seminář v angličtině)

Minulé semináře:

24. července 2018
The type D and the near-horizon geometry equations
Prof. Jerzy Lewandowski
Institute of Theoretical Physics, University of Warsaw
(seminář v angličtině)
25. září 2018
seminář přes skype
Black holes as probes of fundamental physics
Robert Benkel
University of Nottingham, UK
(seminář v angličtině)
27. září 2018
!!! Thursday from 13:10 !!!
Shadow of black holes at cosmological distances
Dr. Oleg Yu. Tsupko
Space Research Institute of Russian Academy of Sciences, Moscow
(seminář v angličtině)
2. října 2018
Remarks on ghost-free theories
Prof. Valeri P. Frolov
Department of Physics, University of Alberta, Edmonton
(seminář v angličtině)
5. října 2018
!!! FRIDAY from 13:10 !!!
Gravitational-wave astrophysics: a new era of discovery
Dr. Jessica McIver
California Institute of Technology
(seminář v angličtině)
5. října 2018
!!! FRIDAY, from 16:20 !!!
Hyperbolicity of relativistic fluids
Dr. David Hilditch
Centro Multidisciplinar de Astrofisica, IST, University of Lisbon
(seminář v angličtině)

I will discuss conditions for the well-posedness of the initial value problem for evolution type PDEs. Well-posedness is a necessary condition for any numerical approximation to converge in the limit of infinite resolution. The crucial condition is that of strong-hyperbolicity. I will then consider various fluid models and highlight in particular the difficulties faced in particular in the modeling of stars. Several popular formulations of MHD turn out to be ill-posed.

9. října 2018
Derrick’s theorem on curved spacetime and the stability of relativistic stars in modified gravity
Dr. Sante Carloni
Centro Multidisciplinar de Astrofisica, IST, University of Lisbon
(seminář v angličtině)

I will present a generalisation of Derick theorem to the case of curved spacetime. As a consequence of this generalisation, relativistic boson stars are proved to be always unstable. Derrick’s theorem has profound consequences also on modified gravity, and in particular on theories with an additional scalar degrees of freedom. I will comment extensively on these consequences.

16. října 2018
The next big thing: extreme-mass-ratio inspiral
(Impressions from 2018 Capra conference)
Dr. Tomáš Ledvinka
(seminář v angličtině)
23. října 2018
Uniformly accelerating, yet standing still
(On boost-rotation, topology of G-->0 limit of C-metric, higher dimensions, and linearized gravity)
Dr. David Kofroň
(seminář v angličtině)

The search for the C-metric in higher dimensions is still unsuccessful and ongoing project. I wanted, also unsuccessfully, to find a simple solution to general boost-rotation symmetric metric in higher dimensions (generalization of Bonnor-Swaminayaran solutions). Finally I ended up in the linearized gravity to gain some insight in this topics and to learn some lessons. Based on work in progress this would be more discussion open seminar than a lecture.

30. října 2018
Twistor equation on isolated horizons
Mgr. Dávid Matejov
(seminář v angličtině)

The seminar will be devoted to investigation of possible solutions of the celebrated twistor equation on a special spacetime domain representing a black hole - an isolated horizon. First, the basic definitions and results on isolated horizons will be summarized. Than we move to definition of the so called Penrose mass and explain how it is connected to the twistor equation. Finally, we will discuss our results and future plans.

6. listopadu 2018
Propagators of the wave equation on low-regularity spacetimes
Dr. Yafet Erasmo Sanchez Sanchez
Max Planck Institute for Mathematics, Bonn
(seminář v angličtině)

I will define classical and non-classical solutions of the wave equation. I will give some motivations about why low regularity scenarios are interesting. Finally, I will focus on the classical ones and discuss their relationship with quantum field theory in spacetimes with limited regularity.

Předchozí ročníky:

Jiří Bičák                                                                                                  Oldřich Semerák

© 1. listopadu 2018; Oldřich Semerák <>
© 13. listopadu 2018; vygenerováno pomocí aplikace seminar, verze 2.04 (2003-09-02); správce <>