Magnetic fields from inflation: The CMB temperature anisotropies

Abstract

The cosmic microwave background (CMB) temperature anisotropies from primordial magnetic fields are studied. In addition to the known passive and the compensated mode we discuss an inflationary magnetic mode in the curvature perturbation, present when magnetic fields are generated during inflation. This mode is absent if the generation mechanism is causal, e.g. a phase transition. We compute and discuss the effect of this mode on the observed CMB anisotropy spectrum, in comparison with the passive and compensated ones. We find that it dominates the CMB anisotropy, and consequently leads to stronger constraints on the amplitude $B_{1\mathrm{Mpc}}$ and spectral index $n_B$ of the magnetic field than what usually found in CMB analyses from the compensated mode. This happens in particular for spectral indexes $n_B>-3$: the inflationary magnetic mode is always scale invariant, therefore through this mode even a magnetic field with a spectrum which is not scale invariant can leave a detectable signal in the CMB at large scales.

15 pages, 4 figures; v2 minor changes, matches published version

References in corpus (19)

• Generation of Large-Scale Magnetic Fields in Single-Field Inflation
• Magnetic fields from inflation?
• N-flationary magnetic fields
• CMB anisotropies from primordial inhomogeneous magnetic fields
• Observable non-gaussianity from gauge field production in slow roll inflation, and a challenging connection with magnetogenesis
• CMB bispectrum from primordial magnetic fields on large angular scales
• The cosmic microwave background temperature bispectrum from scalar perturbations induced by primordial magnetic fields
• The Impact of Stochastic Primordial Magnetic Fields on the Scalar Contribution to Cosmic Microwave Background Anisotropies
• The Search for a Primordial Magnetic Field
• Optimal limits on primordial magnetic fields from CMB temperature bispectrum of passive modes
• Cosmic Magnetic Fields and the CMB
• Magnetic fields from inflation: the transition to the radiation era
• CMB anisotropies in the presence of a stochastic magnetic field
• Cosmic microwave background bispectrum of vector modes induced from primordial magnetic fields
• Probing Primordial Magnetism with Off-Diagonal Correlators of CMB Polarization
• Reheating constraints in inflationary magnetogenesis
• Generalized CMB initial conditions with pre-equality magnetic fields
• Primordial Magnetic Field Effects on the CMB and Large Scale Structure
• Magnetogenesis and the primordial non-gaussianity

Cited by in corpus (30)

• The origin, evolution and signatures of primordial magnetic fields
• Planck 2015 results. XIX. Constraints on primordial magnetic fields
• Adding helicity to inflationary magnetogenesis
• Stringent Limit on Primordial Magnetic Fields from the Cosmic Microwave Background Radiation
• Constraints on Primordial Magnetic Fields from Planck combined with the South Pole Telescope CMB B-mode polarization measurements
• Can primordial magnetic fields be the origin of the BICEP2 data?
• Introducing SPHINX-MHD: The Impact of Primordial Magnetic Fields on the First Galaxies, Reionization, and the Global 21cm Signal
• Primordial Magnetic Field Limits from CMB Trispectrum - Scalar Modes and Planck Constraints
• Future CMB constraints on cosmic birefringence and implications for fundamental physics
• A scenario for inflationary magnetogenesis without strong coupling problem
• Constraints on primordial magnetic fields from magnetically-induced perturbations: current status and future perspectives with LiteBIRD and future ground based experiments
• Constraints on Gauge Field Production during Inflation
• Primordial Magnetic Helicity Constraints from WMAP Nine-Year Data
• Schwinger effect impacting primordial magnetogenesis
• Searching for Primordial Magnetic Fields with CMB B-modes
• Generation of large-scale magnetic fields, non-Gaussianity, and primordial gravitational waves in inflationary cosmology
• Searching for primordial magnetism with multi-frequency CMB experiments
• Probing large-scale magnetism with the Cosmic Microwave Background
• Inflationary Magnetogenesis with Broken Local U(1) Symmetry
• Limits on primordial magnetic fields from primordial black hole abundance
• Primordial Magnetogenesis in a Bouncing Universe
• Narrowing the window of inflationary magnetogenesis
• Probing the primordial Universe with 21-cm line from cosmic dawn/epoch of reionization
• LiteBIRD Science Goals and Forecasts: Primordial Magnetic Fields
• Imprints of primordial magnetic fields on intrinsic alignments of galaxies
• The Impact of Primordial Magnetic Fields on Future CMB Bounds on Inflationary Gravitational Waves
• Circumventing the challenges in the choice of the non-conformal coupling function in inflationary magnetogenesis
• Evolution of the cosmic matter density field with a primordial magnetic field
• Magnetic fields and the Weyl tensor in the early universe
• Distinguishing Primordial Magnetic Fields from Inflationary Tensor Perturbations in the Cosmic Microwave Background