Natural quintessence and large extra dimensions

We examine the late-time (nucleosynthesis and later) cosmological implications of brane-world scenarios having large (millimeter sized) extra dimensions. In particular, recent proposals for understanding why the extra dimensions are so large in these models indicate that moduli such as the radion appear (to four-dimensional observers) to be extremely light, with a mass of order 10-33 eV, allowing them to play the role of the light scalar of …