Clustering Fossils from the Early Universe
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.
Additional Information© 2012 American Physical Society. Received 1 March 2012; published 19 June 2012. This work was supported by DOE Grant No. DE-FG03-92-ER40701 and NASA Grant No. NNX12AE86G.
Published - Jeong2012p18881Phys_Rev_Lett.pdf