  Holography is expected as one of the promising descriptions of quantum
general relativity. We present a model for a cosmological system involving two
holographic screens and find that their equilibrium exactly yields a standard
Friedmann-Robertson-Walker universe. We discuss its cosmological implications
by taking into account higher order quantum corrections and quantum nature of
horizon evaporation. We will show that this model could give rise to a
holographic inflation at high energy scales and realize a late-time
acceleration in a unified approach. We test our model from the SN Ia
observations and find it can give a nice fit to the data.

Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology;High Energy Physics - Theory