ELFT HÍRADÓ

[somogyi <somogyi.gabor AT wigner.hun-ren.hu>]

Wigner FK RMI Elméleti Osztály Szemináriuma
Tisztelettel meghívjuk


                  Paolo Meda
                  (University of Trento)


"The semiclassical Einstein equations and the stability of linearized 
solutions"


     címmel tartandó szemináriumára.


Kivonat:



The semiclassical formulation of gravity is discussed in the framework 
of algebraic quantum field theory in curved spacetimes. The main topic 
of the talk is the Semiclassical Einstein Equations, which describe the 
backreaction of a quantum scalar field on spacetime geometry. In the 
first part of the talk, it is shown that an initial-value problem for 
local solutions of the Semiclassical Einstein Equations can be 
formulated in cosmological spacetimes, after fixing four initial data on 
the scale factor of the Universe. In the second part of the talk, it is 
studied the problem of stability of linearized solutions, using a toy 
model which mimics the semiclassical equations in cosmological 
spacetimes. In this case, it is proved that, if the quantum field 
driving the backreaction is massive, then there are choices of 
renormalization constants for which linear perturbations with compact 
spatial support decay for large times, thus indicating stability of the 
underlying theory [arXiv:2007.14665, 2201.10288].



Helye: Wigner FK RMI III. ép. Tanácsterem
Ideje: 2023 október 27. péntek d.u. 14 óra

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                             Somogyi Gábor