12 May 2021

RTG Colloquium - Online (orig. University Oldenburg)

14:00- 16:30 CET


14:00 - 15:00 Dr. Kamal Hajian (HWK Delmenhorst): Black hole temperature in Horndeski gravity

Abstract: In Horndeski gravities, which are the most generic scalar-tensor theories without ghosts, the speed of graviton can be different w.r.t other massless particles/waves such as photons. We will show that this leads to a black hole temperature which is different from the standard Hawking temperature by an overall factor. The factor depends on black hole properties as well as the Lagrangian. Using this modified temperature, the first law of thermodynamics for black holes in Horndeski gravities is recovered.

15:00 - 15:30 Coffee break

15:30 - 16:30 Dr. Ivonne Zavala (Swansea University, Wales): Dark energy in string theory and supergravity

Abstract: I will review progress in understanding present day cosmological acceleration in string theory and supergravity.  I will first discuss recent progress and challenges on realising dynamical dark energy in these theories. Then, I will briefly discuss a recent new approach to de Sitter solutions in supergravity and its possible realisation in string theory.

More details can be found here.