Year: 2004
Type: article
Abstract: Primordial vector modes describe vortical fluid perturbations in the early Universe. A regular solution exists with constant nonzero radiation vorticities on superhorizon scales. Baryons are tightly coupled to the photons, and the baryon velocity only decays by an order unity factor by recombination, leading to an observable CMB anisotropy signature via the Doppler effect. There is also a large B-mode CMB polarization signal, with significant power on scales larger than $l\ensuremath{\sim}2000.$ This B-mode signature is distinct from that expected from tensor modes or gravitational lensing, and makes a primordial vector to scalar mode power ratio $\ensuremath{\sim}{10}^{\ensuremath{-}6}$ detectable. Future observations aimed at detecting large scale B modes from gravitational waves will also be sensitive to regular vector modes at around this level.
Author: Antony Lewis
Institution: Canadian Institute for Theoretical Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2129794644