2004/09/30 by Arthur Kosowsky, Tina Kahniashvili, George Lavrelashvili +1 · 150 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Computational physics #Cosmic microwave background #Cosmology and Gravitation Theories #Faraday cage #Faraday effect #Faraday rotator #Geophysics and Gravity Measurements #Magnetic field #Optics #Physics #Polarization (electrochemistry) #Quantum electrodynamics #Quantum mechanics #Radio Astronomy Observations and Technology #Spectral density #astro-ph
paper · pdf · doi:10.1103/physrevd.71.043006
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 71(4) (American Physical Society) · 14 pages, 2 figures, expanded discussion, matches published version
openalex publication_date 2005/02/28 · arxiv created 2005/03/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A primordial cosmological magnetic field induces Faraday rotation of the cosmic microwave background polarization. This rotation produces a curl-type polarization component even when the unrotated polarization possesses only gradient-type polarization, as expected from scalar density perturbations. We compute the angular power spectrum of curl-type polarization arising from small Faraday rotation due to a weak stochastic primordial magnetic field with a power-law power spectrum. The induced polarization power spectrum peaks at arc minute angular scales. Faraday rotation is one of the few cosmological sources of curl-type polarization, along with primordial tensor perturbations, gravitational lensing, and the vector and tensor perturbations induced by magnetic fields; the Faraday rotation signal peaks on significantly smaller angular scales than any of these, with a power spectrum amplitude which can be comparable to that from gravitational lensing. Prospects for detection are briefly discussed.