Impact of half-wave plate systematics on the measurement of cosmic birefringence from CMB polarization

Understand

Polarization of the cosmic microwave background (CMB) can probe new parity-violating physics such as cosmic birefringence (CB), which requires exquisite control over instrumental systematics.

• The non-idealities of the half-wave plate (HWP) represent a source of systematics when used as a polarization modulator.
• We study their impact on the CMB angular power spectra, which is partially degenerate with CB and miscalibration of the polarization angle.
• We use full-sky beam convolution simulations including HWP to generate mock noiseless time-ordered data, process them through a bin averaging map-maker, and calculate the power spectra including $TB$ and $EB$ correlations.