Probing primordial magnetism with off-diagonal correlators of CMB polarization

Amit Yadav, Levon Pogosian, Tanmay Vachaspati

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Primordial magnetic fields (PMF) can create polarization B-modes in the cosmic microwave background (CMB) through Faraday rotation (FR), leading to nontrivial two-point and four-point correlators of the CMB temperature and polarization. We discuss the detectability of primordial magnetic fields using different correlators and evaluate their relative merits. We have fully accounted for the contamination by weak lensing, which contributes to the variance, but whose contribution to the four-point correlations is orthogonal to that of FR. We show that a Planck-like experiment can detect scale-invariant PMF of nG strength using the FR diagnostic at 90GHz, while realistic future experiments at the same frequency can detect 10-10G. Utilizing multiple frequencies will improve on these prospects, making FR of CMB a powerful probe of scale-invariant PMF.

Original languageEnglish (US)
Article number123009
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number12
StatePublished - Dec 12 2012

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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