English

Forecasts of constraining isotropic cosmic birefringence on AliCPT-1

Cosmology and Nongalactic Astrophysics 2026-03-03 v2

Abstract

Cosmic birefringence (CB) is a promising probe of parity-violating physics beyond the Standard Model, characterized by the rotation of the linear polarization plane of cosmic microwave background (CMB) photons. This effect, quantified by the birefringence angle β\beta, generates non-zero EBEB and TBTB correlations that are otherwise absent in standard cosmology. However, instrumental miscalibration angles α\alpha can mimic this signal, necessitating a joint estimation approach. In this work, we forecast the sensitivity of the AliCPT experiment, combined with Planck HFI data, on constraining the isotropic CB angle using a semi-analytical maximum-likelihood method. We simulate observations under various foreground complexities, rotation angles, and scanning strategies, and demonstrate that AliCPT can achieve an uncertainty of σ(β)=0.09\sigma(\beta)=0.09^\circ with one-year data, which will improve to 0.0260.026^\circ after four years' observations. We also find that neglecting or mismodeling the foreground EBEB correlation will introduce significant biases, which can be alleviated under a clean but small sky patch.

Keywords

Cite

@article{arxiv.2510.21221,
  title  = {Forecasts of constraining isotropic cosmic birefringence on AliCPT-1},
  author = {Jiazheng Dou and Wen Zhao},
  journal= {arXiv preprint arXiv:2510.21221},
  year   = {2026}
}

Comments

Matches version accepted by JCAP; 22 pages, 9 figures, 7 tables; Major revision: adding Appendix D