26 October 2021

Current trends in gravitation Seminar

Location: University Oldenburg - Online
When: 26.10.2021, 14:15 CEST

Speaker: Dennis Stock (University of Geneva, Switzerland)

Title: The Hawking energy of the observable universe

Abstract: Addressing cosmological questions exclusively based on observations requires a formulation on the past lightcone of a cosmic observer. In this talk, I will discuss the question of gravitational energy associated with the past lightcone by introducing Hawking’s quasi-local energy as a tentative measure of energy of the observable universe. The Hawking energy phenomenologically quantifies energy in terms of the amount of light bending. I will first discuss general properties such as well-definedness, positivity, and monotonicity of the Hawking energy on the past lightcone of a cosmic observer, before addressing the question of how it can be related to cosmic observables within linearly perturbed FLRW spacetimes.