New method separates cosmic birefringence from calibration errors

Researchers at UC San Diego developed a technique to distinguish a real twist in cosmic microwave background polarization from detector calibration errors. Tested on eight Planck polarization maps, it reproduced a birefringence angle of 0.37 ± 0.12 degrees, matching the Minami-Komatsu analysis.

• Method compares polarization maps from different detector groups in one telescope
• Eight Planck maps yielded a birefringence angle of 0.37 ± 0.12 degrees
• Results matched the Minami-Komatsu analysis despite different assumptions
• Approach helps validate primordial B-mode signals from gravitational waves