Tuesdays 10:30 - 11:30 | Fridays 11:30 - 12:30
Showing votes from 2017-01-31 11:30 to 2017-02-03 12:30 | Next meeting is Friday May 22nd, 11:30 am.
Yes, but only for a parameter value that makes it almost coincide with the standard model. We reconsider the cosmological dynamics of a generalized Chaplygin gas (gCg) which is split into a cold dark matter (CDM) part and a dark energy (DE) component with constant equation of state. This model, which implies a specific interaction between CDM and DE, has a $\Lambda$CDM limit and provides the basis for studying deviations from the latter. Including matter and radiation, we use the (modified) CLASS code \cite{class} to construct the CMB and matter power spectra in order to search for a gCg-based concordance model that is in agreement with the SNIa data from the JLA sample and with recent Planck data. The results reveal that the gCg parameter $\alpha$ is restricted to $|\alpha|\lesssim 0.05$, i.e., to values very close to the $\Lambda$CDM limit $\alpha =0$. This excludes, in particular, models in which DE decays linearly with the Hubble rate.
Motivated by recent developments in black hole thermodynamics, we investigate van der Waals phase transitions of charged black holes in massive gravity. We find that massive gravity theories can exhibit strikingly different thermodynamic behaviour compared to that of Einstein gravity, and that the mass of the graviton can generate a range of new phase transitions for topological black holes that are otherwise forbidden.