DARK ENERGY/MATTER UNIFICATION

Let our Universe resemble a 4-dim bubble, floating in a flat (or AdS) 5-dim background, but insist on its evolution being governed by the standard Einstein-Hilbert action. The conserved bulk energy then parameterizes an intriguing deviation from general relativity with an essential built-in Einstein limit. Even an apparently ‘empty’ bubble Universe is effectively infested by a dark (= beyond Einstein) component. In particular, the geodetic evolution of a Λ-dominated toy Universe, absolutely free of genuine matter, gets translated into a specific FRW cosmology which is barely distinguishable from ΛCDM. A more realistic model presents a dark dominated era which bridges past (radiation/baryon dominated) and future (Λ-dominated) Einstein regimes. To prove the clumpiness property of our unified dark component, we have derived the geodesic brane analog of Schwarzschild solution. It is characterized by (i) Dark cosmological background, (ii) Newtonian limit, and quite serendipitously allows for (iii) Non-singular dusty core.