We perform a comprehensive study of the signatures of Lorentz violation in electrodynamics on the Cosmic Microwave Background (CMB) anisotropies. In the framework of the minimal Standard Model Extension (SME), we consider effects generated by renormalizable operators, both CPT-odd and CPT-even. These operators are responsible for sourcing, respectively, cosmic birefringence and circular polarization. We propagate jointly the effects of all the relevant Lorentz-violating parameters to CMB observables and provide constraints with the most recent CMB datasets. We bound the CPT-even coefficient to $k_{F,E+B} < 2.31 \times 10^{-31}$ at 95\% CL. This improves previous CMB bounds by one order of magnitude. The limits we obtain on the CPT-odd coefficients, i.e. $|k_{(V)00}^{(3)}| < 1.54 \times 10^{-44} \; {\rm GeV}$ and $|\mathbf{k_{AF}}| < 0.74 \times 10^{-44} \; {\rm GeV}$ at 95\% CL, are respectively one and two orders of magnitude stronger than previous CMB-based limits, superseding also bounds from non-CMB searches. This analysis provides the strongest constraints to date on CPT-violating coefficients in the minimal SME from CMB searches.
In this paper we study in detail the effect of our recently proposed model of parity and charge-parity (PCP) violating varying alpha on the Cosmic Microwave Background (CMB) photon passing through the intra galaxy-cluster medium (ICM). The ICM is well known to be composed of magnetized plasma. According to our model, the polarization and intensity of the CMB would be affected when traversing through the ICM due to non-trivial scalar photon interactions. We have calculated the evolution of such polarization and intensity collectively, known as the stokes parameters of the CMB photon during its …
Parity-violating extensions of Maxwell electromagnetism induce a rotation of the linear polarization plane of photons during propagation. This effect, known as cosmic birefringence, impacts on the Cosmic Microwave Background (CMB) observations producing a mixing of $E$ and $B$ polarization modes which is otherwise null in the standard scenario. Such an effect is naturally parametrized by a rotation angle which can be written as the sum of an isotropic component $α_0$ and an anisotropic one $δα(\hat{\mathbf{n}})$. In this paper we compute angular power spectra and bispectra involving $δα$ and t…
Flavor violating axion couplings can be in action before recombination, and they can fill the early universe with an additional radiation component. Working within a model-independent framework, we consider an effective field theory for the axion field and quantify axion production. Current cosmological data exclude already a fraction of the available parameter space, and the bounds will improve significantly with future CMB-S4 surveys. Remarkably, we find that future cosmological bounds will be comparable or even stronger than the ones obtained in our terrestrial laboratories.
Calibration of CMB Polarisation Using Cross-Experiment Correlations
Laboratory for Theoretical Particle Physics and Cosmology, King’s College London（伦敦国王学院理论粒子物理与宇宙学实验室）；Joseph Henry Laboratories of Physics, Princeton University（普林斯顿大学约瑟夫·亨利物理实验室）
Precision Tests of Parity Violation Over Cosmological Distances
最近通过BICEP 2和POLARBEAR实验对宇宙微波背景$B$模式偏振功率谱的测量已经展示了用于探测基础物理的新的精确工具。不管起源如何，我们能够检测到亚$μ$ K CMB偏振的事实代表了巨大的技术突破。然而，更多的信息可能隐藏在CMB的极化模式中。由于它的张量性质，CMB偏振也可以通过检测宇宙偏振旋转来揭示宇称违反物理学。虽然目前的CMB偏振仪是足够灵敏的测量一个度级偏振旋转与$>5σ$统计意义，他们缺乏区分这种效果从一个系统的仪器偏振旋转的能力。在这里，我们激励从目前的CMB数据以及独立的射电星系和类星体的偏振测量宇宙偏振旋转的搜索。我们认为，校准精度的提高将允许精确测量的奇偶性和洛伦兹违反效果。我们描述了CalSat天基偏振校准器，该校准器将为$0.05^\circ$提供系统偏振角校准不确定性的严格控制--比当前CMB偏振校准器有一个数量级的改进。基于CalSat-based校准可以与当前的CMB偏振仪一起使用，以搜索$B$模式偏振，有效地将它们变成宇宙宇称违反的探测器，即不需要建立专用仪器。
Cosmic Birefringence (CB) is the in-vacuo rotation of the linear polarization direction of photons during propagation, caused by parity-violating extensions of Maxwell electromagnetism. We build low resolution CB angle maps using Planck Legacy and NPIPE products and provide for the first time estimates of the cross-correlation spectra $C_L^{αE}$ and $C_L^{αB}$ between the CB and the CMB polarization fields. We also provide updated CB auto-correlation spectra $C_L^{αα}$ as well as the cross-correlation $C_L^{αT}$ with the CMB temperature field. We report constraints by defining the scale-invari…
Cosmic polarization rotation, which may result from parity-violating new physics or the presence of primordial magnetic fields, converts $E$-mode polarization of the cosmic microwave background (CMB) into $B$-mode polarization. Anisotropic cosmic polarization rotation leads to statistical anisotropy in CMB polarization and can be reconstructed with quadratic estimator techniques similar to those designed for gravitational lensing of the CMB. At the sensitivity of upcoming CMB surveys, lensing-induced $B$-mode polarization will act as a limiting factor in the search for anisotropic cosmic polar…
