Related Experiment Video
Updated: Jun 19, 2026

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures
Published on: November 21, 2019
Cosmic microwave background bispectrum from primordial magnetic fields on large angular scales
T R Seshadri1, Kandaswamy Subramanian
1Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India. trs@physics.du.ac.in
Abstract:
Primordial magnetic fields lead to non-Gaussian signals in the cosmic microwave background (CMB) even at the lowest order, as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. In contrast, CMB non-Gaussianity due to inflationary scalar perturbations arises only as a higher-order effect. We propose a novel probe of stochastic primordial magnetic fields that exploits the characteristic CMB non-Gaussianity that they induce. We compute the CMB bispectrum (b(l1l2l3)) induced by such fields on large angular scales. We find a typical value of l1(l1 + 1)l3(l3 + 1)b(l1l2l3) approximately 10(-22), for magnetic fields of strength B0 approximately 3 nG and with a nearly scale invariant magnetic spectrum. Observational limits on the bispectrum allow us to set upper limits on B0 approximately 35 nG.
Related Concept Videos
Plane Electromagnetic Waves II
Divergence and Curl of Magnetic Field
Magnetic Fields
A magnetic field is defined by the force that a charged particle experiences...
Atomic Nuclei: Larmor Precession Frequency
Atomic Nuclei: Nuclear Relaxation Processes
Atomic Nuclei: Magnetic Resonance
