Stony Brook University
I will show how ultra-high-resolution measurements of the gravitational lensing of the Cosmic Microwave Background (CMB) can be used to measure the small-scale matter power spectrum. A robust measurement of structure on scales below 10 kiloparsecs today (M < 10^9 solar masses) with lensing of the CMB requires a telescope with roughly 20 arcsecond resolution or better, and would provide a firm anchor against which to match models of dark matter particle properties and the baryonic influence on the dark matter distribution. For example, a CMB survey at 90 GHz covering 4,000 square degrees of sky, with an instrumental sensitivity of 0.1 microKelvin-arcmin at 10 arcsecond resolution, could distinguish between cold dark matter and an alternative such as 1 keV warm dark matter or 10^−22 eV fuzzy dark matter with about 30-sigma significance, in the absence of baryonic effects; it may also allow one to distinguish between the impact of baryons and the particle nature of dark matter, since each potentially affects the shape of the lensing power spectrum differently. In addition, such a high-resolution, low-noise CMB Dark Matter Survey would also push the boundaries of our knowledge about the early Universe, dark energy, reionization, and galaxy evolution.