title: Clustering fossils from the early universe.
abstract: Many inflationary theories introduce new scalar, vector, or tensor degrees of freedom that may then affect the generation of primordial density perturbations. Here we show how to search a galaxy (or 21-cm) survey for the imprint of primordial scalar, vector, and tensor fields. These new fields induce local departures to an otherwise statistically isotropic two-point correlation function, or equivalently, nontrivial four-point correlation functions (or trispectra, in Fourier space), that can be decomposed into scalar, vector, and tensor components. We write down the optimal estimators for these various components and show how the sensitivity to these modes depends on the galaxy-survey parameters. New probes of parity-violating early-Universe physics are also presented.
authors.affiliation: Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21210, USA.
authors.forename: Donghui
authors.initials: D
authors.lastname: Jeong
authors.forename: Marc
authors.initials: M
authors.lastname: Kamionkowski
mesh_terms: D019419:Evolution, Planetary; D055608:Galaxies; D008962:Models, Theoretical