Chaplygin-Kalb-Ramond Quartessence
arXiv:hep-th/0504082
Abstract
Unified dark matter/energy models (quartessence) based upon the Chaplygin gas D-brane fail owing to the suppression of structure formation by the adiabatic speed of sound. Including string theory effects, in particular the Kalb-Ramond field which becomes massive via the brane, we show how nonadiabatic perturbations allow successful structure formation.
9 pages, substantially expanded, arguments clarified, added references, results unchanged