Seminars

Winter term 2017/18


 

Singularity Avoidance in Bianchi Type I Models in Quantum Cosmology

Abstract: In this thesis the possibility of avoiding cosmological singularities in Bianchi type I models in the framework of quantum geometrodynamics is investigated. Therefore three different models are considered: one with a positive cosmological constant, one with matter that fulfills the barotropic equation of state p=ωρ, and one with a generalized Chaplygin gas. Those exhibit Big Bang, Big Rip and Big Brake singularities, respectively. In all cases the classical behaviour as well as the behaviour of the solution of the corresponding Wheeler-DeWitt equation is analyzed and compared to the isotropic flat FLRW case. It is found that the there are solutions fulfilling the DeWitt criterion for singularity avoidance, that in some cases the classical behaviour is modified by the anisotropy (i.e. introducing new or changing present singularities) and that the additional degrees of freedom can lead to dispersive behaviour of the wave packets.

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Geometry transition in covariant LQG: black to white

Abstract: Black holes may end their lifes by becoming white holes, as the result of a non-perturbative quantum-gravitational process. To the best of our knowledge, the transition is not forbidden by any physical principle and quantum theory should be in a position to describe relevant physics. In particular, estimates of characteristic timescales are within reach with currently available tools. We use the EPRL model to define a transition amplitude. The EPRL model represents the current state-of-the-art of the spinfoam quantization program, which provides a tentative definition for the regularized path-integral of gravity in the context of Loop Quantum Gravity. We will review the conceptual setup of this ongoing project, present results for the characteristic timescales and discuss implications for the information paradox.

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TBA

Abstract: TBA

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Integrable Cosmological Models with Liouville Scalar Fields

Abstract: TBA

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Integrable Cosmological Models with Liouville Scalar Fields

Abstract: TBA

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Some recent developments in relativistic quantum information theory

Abstract: Recently, there has been extensive literature devoted to investigations of quantum information theory within the framework of quantum field theory and quantum field theory in curved space-time. This emerging field of relativistic quantum information has been attracting increasing interest within the scientific community. In its essence, this subject aims at understanding the role that relativistic settings play in quantum information processes and quantum optics. In addition, relativistic quantum information theory also enables the investigation of quantum effects induced by gravity in order to uncover further information on space-time. Indeed, one of the most important implications of such studies is the realization of the observer-dependence property of quantum entanglement. In this talk a brief survey of recent developments in this research line will be given. In particular, some explorations into black-hole physics will be addressed.

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Date Time Speaker Topic Room
October 10 12:00 Organizational meeting
(Konferenzraum alte Theorie)
October 17 12:00 Friedrich Hehl A short note on the Wheeler-DeWitt metric Konferenzraum 1 (Neubau)
November 14 10:00 Dennis Piontek
(Master Colloquium)
Singularity Avoidance in Bianchi Type I Models in Quantum Cosmology HS 118, Room 1.019, AVZ I in Bonn
November 21 12:00 Marios Christodoulou (Marseille)
Geometry transition in covariant LQG: black to white Konferenzraum 1 (Neubau)
November 28 12:00 Xavier Calmet (Brighton)
TBA Konferenzraum 1 (Neubau)
December 5 12:00 Leonardo Chataignier
TBA Konferenzraum 1 (Neubau)
December 12 12:00 YiFan Wang
Integrable Cosmological Models with Liouville Scalar Fields Konferenzraum 1 (Neubau)
December 19 12:00 Gabriel Menezes (Rio de Janeiro)
Some recent developments in relativistic quantum information theory Konferenzraum 1 (Neubau)

 


Past seminars


Summer term 2017
Winter term 2016/17
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Winter term 2015/16
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