The Gross-Pitaevskii equations of a static and spherically symmetric condensate of gravitons

by Dr Cristiano Germani (Institut de Ciències del Cosmos - Universitat de Barcelona)

Thursday 8 Feb 2018, 16:00 → 17:00 Europe/Rome

Aula Teorici (DIFA)

Considering the Dvali and Gomez assumption that the end state of a gravitational collapse is a Bose-Einstein condensate of gravitons, I will show how to construct the two Gross-Pitaevskii equations of a static and spherically symmetric configuration of the condensate. These two equations correspond to the constrained minimisation of the gravitational Hamiltonian with respect to the redshift and the Newtonian potential, per given number of gravitons. I will show that the effective geometry of the condensate is the one of a gravastar (a DeSitter star) with a sub-Planckian cosmological constant. Finally, applying these findings to the current observable Universe, I will show that the emergent cosmological constant of the condensate, inversely proportional to the square of the visible mass, matches unexpectedly well the observational value.