ELFT HÍRADÓ

[Balog Janos <balog.janos AT wigner.mta.hu>]

RMI Elméleti Osztály Szemináriuma
Tisztelettel meghívjuk



                                                  Jose Senovilla
                                      (Basque Country University 
UPV/EHU, Bilbao)



                              "What is the surface of a Black Hole?"


                címmel tartandó szemináriumára.


Kivonat:

Black Holes (BH) are fundamental objects in Physics predicted 
classically by General Relativity with intriguing consequences in 
Quantum Physics because they show a deep fundamental relation between 
Gravitation, Thermodynamics and Quantum Theory. The characteristic 
feature of a BH is its Event Horizon: the boundary of the region from 
where one can send signals to infinity. This Event Horizon is often 
identified as the surface of the BH but, surprisingly, this leads to 
several difficulties because the Event Horizon is teleological: it 
depends on future causes ---and actually on the whole future evolution 
of the spacetime.

In this talk I will discuss several ideas put forward to solve the 
problem of how to recognize, locally, the presence of a BH. Most of them 
rely on the concept of future "trapped surface", a fundamental concept 
introduced by Penrose in 1965. It is widely believed that closed trapped 
surfaces are the single most important ingredient in gravitational 
collapse and in the formation of BHs. Unfortunately, they seem to suffer 
from global problems similar to those of the Event Horizon: they are 
"clairvoyant", as they seem to be aware of things happening far away in 
space, non-locally. Thus, one has to resort to even newer ideas in order 
to define the instantaneous surface of dynamical BHs, such as a BH in 
formation. I will present two such ideas, one using the boundary of the 
region with future trapped surfaces, the other by introducing the novel 
concept of "cores" of a BH. The ups and downs of these novel ideas will 
be analyzed in detail.



Helye: Wigner FK RMI III.ép. Tanácsterem
Ideje: 2014. június 27. péntek du. 14:00 óra




Szívesen látunk minden érdeklődőt.
                                            Balog János