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Bremen-Oldenburg Relativity Seminar


                       Hovhannes Demirchyan
              Byurakan Astrophysical Observatory, Armenia

          "Astrophysical shock waves as impulsive signals"
            ABSTRACT BELOW

              Friday, 14. December 2018, 14:00 c.t.
          Lecture room W2 3-349, University of Oldenburg


                    AND


             Omar Jesus Franca Santiago
                National Autonomous University Mexico

      "Theories with Theta-couplings and some concrete applications"
            ABSTRACT BELOW

               Friday, 14. December 2018, 15:00 c.t.
          Lecture room W2 3-349, University of Oldenburg

 

ABSTRACTS:

"Astrophysical shock waves as impulsive signals":

Impulsive signals exist in lightlike hypersurfaces where Riemann curvature
tensor contains a Dirac delta function. Such hypersurfaces describe
astrophysical shock waves arising from supernovae, collision of neutron
stars and other cataclysmic events. These shock waves are a burst of matter
traveling with the speed of light and gravitational radiation which together
form the impulsive signal. We will discuss approaches for constructing
singular hypersurfaces in general space-time. As a particularly interesting
example we will discuss the construction of singular hypersurfaces in
Minkowski space.


"Theories with Theta-couplings and some concrete applications":

Through the last years the coupling of topological terms to certain field
theories has obtained a lot of interest in several branches of physics from
both experimental and theoretical point of view. In this talk we focus on
the Pontryagin term coupled by a scalar function theta to the Maxwell action,
known as theta-Electrodynamics, which models the effective behavior of
Topological Insulators (TIs). We also study how to add this theta-term to
Einstein-Hilbert action, resulting in theta-Gravity. Here we analyze two
applications. First, we apply theta-Electrodynamics to the radiation of a
point-like particle with constant velocity, whose radiation gives forward
and reverse Cerenkov radiation (RCR), which is very surprising
because RCR has been observed only in metamaterials. And finally,
in the context of theta-Gravity we will expose a black hole-like solution,
which provides a possibility to study the gravitational analog of TIs.

 

Konferenzen

2018

27. - 30. September 2018
22. German Conference of Women in Physics
Where: Oldenburg

10. - 21. September 2018
24th “Saalburg” Summer School
Where: Saalburg 

10. - 12. September 2018
RTG autumn workshop
Where: Bremen

1. - 7. July 2018
15th Marcel Grossmann Meeting
Where: Rome 

27. June 2018
RTG Colloquium
Where: Bremen

16. May 2018
RTG Colloquium
Where: Oldenburg

03. - 04. May 2018
13. Kosmologietag
Where: Bielefeld

18. April 2018
RTG Colloquium
Where: Bielefeld

19. - 23. March 2018
DPG Spring Meeting Würzburg
Where: Würzburg

15. March 2018
Bremen-Oldenburg Relativity Seminar
Where: Oldenburg

22. February 2018
Bremen-Oldenburg Relativity Seminar
Where: Oldenburg

22. February 2018 
Bremen-Oldenburg Relativity Seminar
Where: Bremen

21. February 2018
Fellow at Work
Where: Delmenhorst

19. - 20. February 2018
RTG Workshop
Where: Bremen

6. February 2018 
RTG Colloquium
Where: Bremen

5. February 2018
Guided tour through the observatory Oldenburg
Where: Oldenburg

25. January 2018
Workshop - Spiele mit der Macht
Where:Oldenburg

17. January 2018
Fellow lecture
Where: Delmenhorst

11. January 2018
Bremen-Oldenburg Relativity Seminar
Where: Bremen

10. January 2018
PhD Colloquium
Where: Bremen

9. January 2018
Seminartalk
Where: Bielefeld

2017

11 - 13 October 2017
RTG Autumn Workshop
Where: Oldenburg

28 September - 01 October 2017
21st German Conference of Women in Physics
Where: Ilmenau

18 -19 May 2017
12. Kosmologietag
Where: Center for Interdisciplinary Research, ZiF at Bielefeld University

13. - 17. March 2017
DPG Spring Meeting
Where: Universty of Bremen, ZARM

6 - 7 March 2017
GRK Workshop Hannover
Where: Hannover

We4p7mlbmas6mm8ter (stekmuophan.reimersmdet@uolp7g.deows) (Stand: 10.12.2018)