jaro 2013

Probìhlé semináøe:

12. bøezna 2013
Active galactic nuclei at zero redshift
Prof. Steven N. Shore
Dipartimento di Fisica "Enrico Fermi", Universita di Pisa, Italia
(semináø v angliètinì)

Po semináøi bude s profesorem Shorem diskuse o jeho práci jednoho z vedoucích redaktorù èasopisu Astronomy and Astrophysics.

19. bøezna 2013
Øešení klasických sigma modelù a strun v zakøiveném pozadí
Katedra fyziky, FJFI ÈVUT
26. bøezna 2013
Black hole inequalities
Prof. Marcus Ansorg
Institute of Theoretical Physics, F. Schiller University Jena, Germany
(semináø v angliètinì)
2. dubna 2013
Higgs hair of a rotating black hole
dr. David Kubizòák
Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada
(semináø v angliètinì)

A cosmic string modeled by an abelian Higgs vortex is studied in the rotating black hole background of the Kerr geometry. It is shown that such a system displays much richer phenomenology than its static Schwarzschild/Reissner- Nordstrom cousins. In particular it is shown that the rotation generates a small electric flux near the horizon. For an extremal rotating black hole the two phases of the Higgs hair are possible: i) small black holes expel the Higgs field and (similar to Wald's solution) there is no flux through the horizon ii) large black holes are pierced by the Higgs hair. Backreaction of the Higgs vortex on the Kerr geometry will also be briefly studied, while it will be shown that it cannot be described as a mere conical deficit as might be expected.

9. dubna 2013
Semináø se nekoná
16. dubna 2013
Bondiho hmotnost jako limita Penroseovy hmotnosti
dr. Martin Scholtz
Katedra aplikované matematiky, Fakulta dopravní ÈVUT
23. dubna 2013
Self-energy anomaly of classical charges in higher dimensions
dr. Andrei Zelnikov
Theoretical Physics Institute, Department of Physics, University of Alberta, Edmonton
(semináø v angliètinì)
30. dubna 2013
Spinoptics in a curved spacetime
Prof. Valeri P. Frolov
Theoretical Physics Institute, Department of Physics, University of Alberta, Edmonton
(semináø v angliètinì)

In this talk we discuss how polarization of photons affects their motion in a gravitational field created by a rotating massive compact object. We briefly discuss gravito-electromagnetism analogy and demonstrate that spinoptical effects in many aspects are similar to the Stern-Gerlach effect. We use (3+1)-form of the Maxwell equations to derive a master equation for the propagation of monochromatic electromagnetic waves with a given helicity. We first analyze its solutions in the high frequency approximation using the 'standard' geometrical optics approach. After that we demonstrate how this 'standard' approach can be modified in order to include the effect of the helicity of photons on their motion. Such an improved approach reproduces the standard results of the geometrical optics at short distances. However, it modifies the asymptotic behavior of the circularly polarized beams in the late-time regime. We demonstrate that the corresponding equations for the circularly polarized beam can be effectively obtained by modification of the background geometry by including a small frequency dependent factor. We discuss motion of circularly polarized rays in the Kerr geometry. Applications of this formalism to the propagation of circular polarized photons in the Kerr spacetime are discussed.

7. kvìtna 2013
Linearized gravity and conserved charges / The black hole stability problem
Dipl.-Phys. Steffen Aksteiner, Prof. Lars Andersson
Center of Applied Space Technology and Microgravity (ZARM), Department of Production Engineering, University of Bremen / Division of Geometric Analysis and Gravitation, Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Potsdam
(semináø v angliètinì)
14. kvìtna 2013
Decoupling gravitational perturbations in higher dimensions
Dr. Mahdi Godazgar
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, UK
(semináø v angliètinì)

I will discuss the possibility of decoupling gravitational perturbations a la Teukolsky on higher dimensional black hole backgrounds.

21. kvìtna 2013
Atlas 2: package na diferenciální geometrii pro Mathematicu
Jakub Haláèek
ÚTF
28. kvìtna 2013
On the completeness of impulsive gravitational wave spacetimes
Clemens Sämann
DIANA, Faculty of Mathematics, University of Vienna
(semináø v angliètinì)

After briefly discussing the non-impulsive (smooth) case, we will show that every impulsive wave-type spacetime of the form $M=N\times R^2_1$, with line element $ds^2 = dh^2 + 2 du dv + f(x)\delta(u) du^2$ is geodesically complete. Here $(N,h)$ is an arbitrary connected, complete Riemannian manifold, $f$ is a smooth function and $\delta$ denotes the Dirac distribution on the hypersurface $u=0$. Moreover the geodesics behave as is physically expected.

10. èervence 2013
POZOR! Posunuto na støedu (od 13:10)!!!
Dark universe and marvels of gravity: exploring the idea of a geometric interpretation of the dark phenomenology
Dr. Sante Carloni
ESA Advanced Concepts Team, ESTEC, Noordwijk, The Netherlands
(semináø v angliètinì)

In this talk I will present the idea of a geometrical interpretation of dark phenomena on cosmological and astrophysical scales. In particular, I will review the status of our knowledge on the physics of extensions of General Relativity in relation with dark matter and dark energy and I will delineate the new challenges in this research field for the next years.

Další roèníky:

© 31. øíjna 2013; Oldøich Semerák <semerak@mbox.troja.mff.cuni.cz>
© 2. øíjna 2022; vygenerováno pomocí aplikace seminar, verze 2.04 (2003-09-02); správce <Pavel.Krtous@utf.mff.cuni.cz>