A Possible Solution to the Smallness Problem of Dark Energy
The smallness of the dark energy density has been recognized as the most crucial difficulty in understanding dark energy and also one of the most important questions in the new century. In a recent paper[1], we proposed a new dark energy model in which the smallness of the cosmological constant is naturally achieved by invoking the Casimir energy in a supersymmetry-breaking brane-world. In this paper we review the basic notions of this model. Various implications, perspectives, and subtleties of this model are briefly discussed.