  We propose a cosmological model which exhibits the phenomenon of
self-acceleration: the Universe is attracted to the phase of accelerated
expansion at late times even in the absence of the cosmological constant. The
self-acceleration is inevitable in the sense that it cannot be neutralized by
any negative explicit cosmological constant. The model is formulated in the
framework of brane-world theories with a warped extra dimension. The key
ingredient of the model is the brane-bulk energy transfer which is carried by
bulk vector fields with a sigma-model-like boundary condition on the brane. We
explicitly find the 5-dimensional metric corresponding to the late-time de
Sitter expansion on the brane; this metric describes an AdS_5 black hole with
growing mass. The present value of the Hubble parameter implies the scale of
new physics of order 1 TeV, where the proposed model has to be replaced by
putative UV-completion. The mechanism leading to the self-acceleration has
AdS/CFT interpretation as occurring due to specific dynamics of conformal
matter interacting with external "electric" fields. The Universe expansion
history predicted by the model is distinguishable from the standard LambdaCDM
cosmology.
