Pseudoscalar

Physics

Dark matter

Energy (signal processing)

Meson

Cosmic microwave background

Mathematics

Galaxy

Particle physics

Optics

Statistics

Spectral density

Dark energy

Cosmology

Astrophysics

Quantum mechanics

Anisotropy

Redshift

Reionization

Physical review. D/Physical review. D.

A pseudoscalar ``axionlike'' field, $\ensuremath{\phi}$, may explain the $3\ensuremath{\sigma}$ hint of cosmic birefringence observed in the $EB$ power spectrum of the cosmic microwave background polarization data. Is $\ensuremath{\phi}$ dark energy or dark matter? A tomographic approach can answer this question. The effective mass of dark energy field responsible for the accelerated expansion of the Universe today must be smaller than ${m}_{\ensuremath{\phi}}\ensuremath{\simeq}{10}^{\ensuremath{-}33}\text{ }\text{ }\mathrm{eV}$. If ${m}_{\ensuremath{\phi}}\ensuremath{\gtrsim}{10}^{\ensuremath{-}32}\text{ }\text{ }\mathrm{eV}$, $\ensuremath{\phi}$ starts evolving before the epoch of reionization and we should observe different amounts of birefringence from the $EB$ power spectrum at low ($l\ensuremath{\lesssim}10$) and high multipoles. Such an observation, which requires a full-sky satellite mission, would rule out $\ensuremath{\phi}$ being dark energy. If ${m}_{\ensuremath{\phi}}\ensuremath{\gtrsim}{10}^{\ensuremath{-}28}\text{ }\text{ }\mathrm{eV}$, $\ensuremath{\phi}$ starts oscillating during the epoch of recombination, leaving a distinct signature in the $EB$ power spectrum at high multipoles, which can be measured precisely by ground-based cosmic microwave background observations. Our tomographic approach relies on the shape of the $EB$ power spectrum and is less sensitive to miscalibration of polarization angles.

Is cosmic birefringence due to dark energy or dark matter? A tomographic approach