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

A pseudoscalar ???axionlike??? field, ??, may explain the 3?? hint of cosmic birefringence observed in the EB power spectrum of the cosmic microwave background polarization data. Is ?? 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?? ??? 10???33 eV. If m?? ??? 10???32 eV, ?? starts evolving before the epoch of reionization and we should observe different amounts of birefringence from the EB power spectrum at low (l ??? 10) and high multipoles. Such an observation, which requires a full-sky satellite mission, would rule out ?? being dark energy. If m?? ??? 10???28 eV, ?? 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.

Automated summary

This article investigates the possibility of a pseudoscalar field explaining the observed cosmic birefringence in the cosmic microwave background polarization data and proposes a tomographic approach to determine whether it is dark energy or dark matter. The study suggests that the shape and features of the EB power spectrum can be used to differentiate between these two possibilities based on different effective mass values.