PIRSA:12120019

CMB as a Probe of New Physics: The Story of Cosmic Birefringence

(2012). CMB as a Probe of New Physics: The Story of Cosmic Birefringence. Perimeter Institute. https://pirsa.org/12120019

CMB as a Probe of New Physics: The Story of Cosmic Birefringence. Perimeter Institute, Dec. 06, 2012, https://pirsa.org/12120019 

          @misc{ pirsa_PIRSA:12120019,
            doi = {10.48660/12120019},
            url = {https://pirsa.org/12120019},
            author = {},
            keywords = {Cosmology},
            language = {en},
            title = {CMB as a Probe of New Physics: The Story of Cosmic Birefringence},
            publisher = {Perimeter Institute},
            year = {2012},
            month = {dec},
            note = {PIRSA:12120019 see, \url{https://pirsa.org}}
          }
Talk number
PIRSA:12120019
Collection
Talk Type
Subject
Abstract
Cosmological birefringence is a postulated rotation of the linear polarization of photons that arises due to a Chern-Simons coupling of a new scalar field to electromagnetism. In particular, it appears as a generic feature of simple quintessence models for Dark Energy, and therefore, should it be detected, could provide insight into the microphysics of cosmic acceleration. Prior work has sought this rotation, assuming the rotation angle to be uniform across the sky, by looking for the parity-violating TB and EB correlations in the CMB temperature/polarization. However, if the scalar field that gives rise to cosmological birefringence has spatial fluctuations, then the rotation angle may vary across the sky. In this talk, I will present the results of the first CMB-based search for direction-dependent cosmological birefringence, using WMAP-7 data, and report the constraint on the rotation-angle power spectrum for all multipoles up to the resolution of the instrument. I will discuss the implications for a specific models for rotation, and show forecasts for Planck and future experiments. I will then conclude with a brief discussion of other exotic physical models, such as chiral gravity, and astrophysical scenarios, such as inhomogeneous reionization, that can be probed using the same analysis.