Is Clustering Dark Energy Non-linear? The AP Resummation Approach – Stefano Anselmi

Date: Tue. February 3rd, 2015, 11:30 am-12:30 pm
Location: Rockefeller 221

In order to gain insights on the mysterious component driving the acceleration of the Universe the future surveys will measure with unprecedent precision the density power spectrum in the non-linear range of scales and redshifts. On the theoretical hand those non-linearities require a comparable computational level. This is a tremendous effort that see deployed numerical (N-body), semi-analytical and analytical investigations. I this context I will present a powerful analytical resummation scheme first developed for LCDM and very recently extended to the Clustering Quintessence scenario, i.e. quintessence models with vanishing speed of sound. The approach I will expose allows predictions at few percent level beyond the Baryon Acoustic Oscillations range of scales, being in this way competitive with the mainly employed numerical tools. What makes it even more appealing is its possible extension to the Clustering Quintessence cosmologies where next to nothing is known on the numerical side. Doing this exercise we find: (i) an approximate and simple mapping between the smooth quintessence cosmologies and the vanishing speed of sound ones and (ii) an educated guess for the non-linear growth in models with generic speed of sound that, as a matter of fact, are even more difficult to handle.