Axion dark matter detection with CMB polarization

Abstract

We point out two ways to search for low-mass axion dark matter using cosmic microwave background (CMB) polarization measurements. These appear, in particular, to be some of the most promising ways to directly detect fuzzy dark matter. Axion dark matter causes rotation of the polarization of light passing through it. This gives rise to two novel phenomena in the CMB. First, the late-time oscillations of the axion field today cause the CMB polarization to oscillate in phase across the entire sky. Second, the early-time oscillations of the axion field wash out the polarization produced at last scattering, reducing the polarized fraction (TE and EE power spectra) compared to the standard prediction. Since the axion field is oscillating, the common (static) 'cosmic birefringence' search is not appropriate for axion dark matter. These two phenomena can be used to search for axion dark matter at the lighter end of the mass range, with a reach several orders of magnitude beyond current constraints. We set a limit from the washout effect using existing Planck results, and find significant future discovery potential for CMB detectors searching in particular for the oscillating effect.

Constraining the gravitational coupling of axion dark matter at LIGO

“…The parity violation in previous works are manifest in two ways: one is through the dispersion relation [16,28,[43][44][45][46][47] and the other through the enhancement [16,26]. For our case, the parity-dependent dispersion is absent because we consider the resonance regime (k ≈ m a =2), and the paritydependent enhancement is absent because we consider the forward propagation of waves (not stochastic waves).…”

Atacama Cosmology Telescope: Constraints on cosmic birefringence

“…Finally, cosmic birefringence can also be generated by primordial magnetic fields (PMFs) through Faraday rotation of the CMB polarization (e.g., [16][17][18][19][20][21]). The PMFsinduced cosmic birefringence has frequency dependence * Axion-like particles within a mass range of 10 −22 ma 10 −18 eV also introduce a time variation of the polarization angle rotation whose oscillation period is from hours to years, and can be tightly constrained by current and future CMB experiments as discussed in [11].…”

Signals of axion like dark matter in time dependent polarization of light

“…Now let us consider the possibility to use the data taken by CMB polarization experiments, whose primary purpose is to find the inflationary B-mode signals, to find ALPs. We consider the Fourier-space analysis of the time dependence of the polarization of the CMB; for earlier discussion about the time dependence of the CMB polarization due to the ALP DM, see [20,24]. We focus on the polarized foreground emission below, although the polarized CMB (induced by the Thomson scattering) may also be used as a probe of ALP as well.…”

“…In particular, if we consider the light from astrophysical sources, which travels a significant amount of distance before being observed, the effects of the ALP condensation may be accumulated in the polarization plane of the light; such an effect may be experimentally detectable. The ALP search using the polarization of light from astrophysical sources have been considered in literatures, using the light from radio galaxies [14], protoplanetary disks [15], jets in active galaxies [16], pulsars [17,18], and the cosmic microwave background (CMB) [19][20][21][22][23][24]. Even if the ALP is not DM, the axion cloud may be formed around rotating black holes through the superradiance [25], and the effect on the polarization of light passing through such axion cloud was discussed in [26,27].…”