PIRSA:C17024 - Bounce Scenarios in CosmologyPODCAST Subscribe to podcast

Bounce Scenarios in Cosmology

Organizer(s): Neil Turok   Steffen Gielen  

Collection URL: http://pirsa.org/C17024

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PIRSA:17060094  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Welcome and Opening Remarks
Date: 26/06/2017 - 10:00 am

PIRSA:17060095  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Bounce in Loop Quantum Cosmology and its Implications
Speaker(s): Abhay Ashtekar
Abstract: There is a huge body of work in Loop Quantum Cosmology comprising of several thousand journal articles. I will provide an overview of conclusions, focusing on the difficult conceptual and mathematical issues that accompany the notion of a bounce and opening the way for phenomenological implications ... read more
Date: 26/06/2017 - 10:05 am

PIRSA:17060097  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Observable Consequences of a Bounce
Speaker(s): Ue-Li Pen
Abstract: I discuss potentially observable signatures of scalar and tensor decaying modes, which do not exist in inflation, and could be a probe of a bouncing universe.
Date: 26/06/2017 - 10:50 am

PIRSA:17060096  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Challenges for Bouncing Cosmologies
Abstract: I will review various approaches to bouncing cosmologies and will discuss challenges which the different approaches face.
Date: 26/06/2017 - 2:00 pm

PIRSA:17060098  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Emergent bouncing cosmology from quantum gravity condensates
Abstract: I will explain how cosmological dynamics emerge from the hydrodynamics of isotropic group field theory condensate states in the Gross-Pitaevskii approximation. The correct Friedmann equations are recovered in the classical limit for some choices of the parameters in the action for the group field th... read more
Date: 26/06/2017 - 2:45 pm

PIRSA:17060101  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Discussion Session 2
Date: 26/06/2017 - 4:00 pm

PIRSA:17060099  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Unitary Cosmological Bounces
Speaker(s): Claudia de Rham
Abstract: A non-singular cosmological bounce in the Einstein frame can only take place if the Null Energy Condition (NEC) is violated. I will explore the constraints imposed by demanding tree level unitarity on a cosmological background in single scalar field theories before focusing on the explicit constrain... read more
Date: 27/06/2017 - 10:00 am

PIRSA:17060100  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Quantum cosmological instabilities - with and without boundaries
Speaker(s): Jean-Luc Lehners
Abstract: The big bang singularity might be avoided by replacing it with a theory of initial conditions, or by considering a bounce from an earlier contracting phase. I will describe how both proposals can run into difficulties with instabilities when the spacetime must be treated semi-classically (i.e. when ... read more
Date: 27/06/2017 - 10:45 am

PIRSA:17060102  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Space(-time) structure in models of loop quantum gravity
Speaker(s): Martin Bojowald
Abstract: Loop quantum gravity has suggested modifications of the dynamics of cosmological models that could lead to a bounce at large curvature. However, the same modifications may alter the gauge structure of the theory, which is related to the structure of space-time. In a large class of examples the spac... read more
Date: 27/06/2017 - 2:00 pm

PIRSA:17060103  ( MP4 Medium Res , MP3 , PDF ) Which Format?
A Bouncing Universe approach to Fine Tuning
Speaker(s): Stephon Alexander
Date: 27/06/2017 - 2:45 pm

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