Institute for Advanced Study/Princeton University Early Universe/Cosmology Lunch Discussion

Topic 1: The primary statistic for extracting cosmological information from large-scale structure is the two-point correlation function. It is typically measured in hard-edged bins of separation between tracer pairs (in redshift space or sky angle, for example). In this talk, I will present a new estimator for the correlation function, the Continuous-Function Estimator, which generalizes the standard binned method to any basis function representation. This estimator can produce a continuous correlation function estimate with a small number of components; this is more scientifically appropriate and is critical for precise covariance matrix estimation. I will demonstrate the estimator with a basis designed to directly measure the baryon acoustic scale. I will discuss other potential applications of the Continuous-Function Estimator, such as investigating the dependence of clustering on galaxy properties and searching for anisotropies in large-scale structure. This talk is related to the work presented in <https://arxiv.org/abs/2011.01836&gt;.

Topic 2: Modern cosmology has been remarkably successful in describing the Universe from a second after the Big Bang until today. However, its physics before that time is still much less certain. It profoundly involves particle theory beyond the Standard Model to explain long-standing puzzles: the origin of the observed matter asymmetry, nature of dark matter, and cosmic inflation. In this talk, I will explain that fractions of a second after the Big Bang, relic feeble axion-SU(2) gauge fields can possibly relate and explain these seemingly unrelated phenomena in early and late cosmology. Moreover, these relics would provide a new window into the early Universe in the form of primordial chiral gravitational waves. This mechanism can possibly lead to a new paradigm for particle cosmology, and its smoking gun signature is testable by future CMB missions.