Speaker
Description
Precise polarization measurements of the Cosmic Microwave Background (CMB) provide an opportunity to rigorously test the standard cosmological model. The correlation between E and B modes, indicative of cosmic birefringence, is expected to arise from parity-violating physics in the Universe. However, detecting these EB correlations remains extremely challenging as it demands exceptionally precise polarization calibration of observational instruments. In this talk, I will present a novel calibration method for CMB polarimeters that circumvents the need for external polarized sources or self-calibration techniques. By cross-correlating data from two instruments observing the same region of the sky, we demonstrate that the difference between their misalignment angles can be resolved with data only, in a model independent-way. Using the flagship of calibration implemented in the Small Aperture Telescope (SAT) of Simons, we can precisely calibrate a wide range of experiment. As a proof of concept, we show that using this new calibration methods allows us to calibrate the Large Aperture Telescope (LAT) and Planck. This can be then be used to constrain parity-violation, whether it be cosmic birefringence or primordial EB power spectrum.