The collapse of Dark Energy

by Filippo Vernizzi (CEA-Saclay)

Friday 26 Mar 2010, 14:15 → 15:15 Europe/Zurich

Auditoire Stueckelberg (Univ. de Geneve)

I will present a study of the stability of single-field models of dark energy. I will show that no general pathology is associated to a negative equation of state, P < -rho; however, stability requires that for P < -rho dark energy behaves as a fluid with negligible speed of sound: clustering quintessence. Focussing on this particular scenario, I will study the clustering properties of dark energy in the nonlinear regime, using the spherical collapse model. Quintessence contributes to the mass of virialiazed objects at low redshift, which represents an observational signature for future galaxies and cluster surveys.