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.