String theory predicts an axiverse of ultralight axions whose effects on CMB polarization, matter power spectrum, and black hole superradiance can be probed by future astrophysical experiments.
Pseudoscalar perturbations and polarization of the cosmic microwave background
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
We show that models of new particle physics containing massless pseudoscalar fields super-weakly coupled to photons can be very efficiently probed with CMB polarization anisotropies. The stochastic pseudoscalar fluctuations generated during inflation provide a mechanism for converting E-mode polarization to B-mode during photon propagation from the surface of last scattering. The efficiency of this conversion process is controlled by the dimensionless ratio H/(2\pi f_a), where H is the Hubble scale during inflation, and f_a^{-1} is the strength of the pseudoscalar coupling to photons. The current observational limits on the B-mode constrain this ratio to be less than 0.07, which in many models of inflation translates to a sensitivity to values of f_a in excess of 10^{14} GeV, surpassing the sensitivity of other tests.
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CMB polarization rotation emerges as a Pancharatnam phase localized at dark sector vacuum interfaces, independent of redshift, frequency, and the presence of light axions.
Presents the science case, reference design, and project plan for the CMB-S4 ground-based CMB experiment.
citing papers explorer
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String Axiverse
String theory predicts an axiverse of ultralight axions whose effects on CMB polarization, matter power spectrum, and black hole superradiance can be probed by future astrophysical experiments.
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CMB Birefringence from Vacuum Interfaces
CMB polarization rotation emerges as a Pancharatnam phase localized at dark sector vacuum interfaces, independent of redshift, frequency, and the presence of light axions.
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CMB-S4 Science Case, Reference Design, and Project Plan
Presents the science case, reference design, and project plan for the CMB-S4 ground-based CMB experiment.