Speaker
Description
In this talk, I will give an overview of the cosmic birefringence effect, from its theoretical foundations to its imprint on the polarized Cosmic Microwave Background. Cosmic birefringence, the rotation of the linear polarization plane of photons as they travel across the universe, would be a direct manifestation of parity violation in the Universe. It arises naturally when a pseudoscalar field, such as an axion-like particle coupled to electromagnetism through a Chern-Simons term, evolves over cosmic time, and as such it provides a unique observational window onto physics beyond the standard model, including dark matter and dark energy candidates.
I will discuss how the rotation of the linear polarization plane of the CMB generates observable signatures, in particular non-zero TB and EB correlations, that are otherwise forbidden in a parity-conserving universe. I will also review the current observational status, including the intriguing hints of a non-zero isotropic birefringence angle at the 2.4–3.6σ level from Planck data, the latest results from more recent searches, and outline the prospects for a detection with current and planned experiments.
| Parallel session | Astrophysical Probes of Dark Matter and Dark Energy |
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