Cosmological tachyon condensation

Understand

We consider the prospects for dark matter/energy unification in k-essence type theories.

• General mappings are established between the k-essence scalar field, the hydrodynamic and braneworld descriptions.
• We develop an extension of the general relativistic dust model that incorporates the effects of both pressure and the associated acoustic horizon.
• Applying this to a tachyon model, we show that this inhomogeneous "variable Chaplygin gas" does evolve into a mixed system containing cold dark matter like gravitational condensate in significant quantities.