论文标题
各向异性双折射对测量宇宙微波背景镜头的影响
Impact of Anisotropic Birefringence on Measuring Cosmic Microwave Background Lensing
论文作者
论文摘要
宇宙微波背景镜头的功率谱是限制基本物理（例如中微子质量和状态的暗能量方程）的强大工具。当前的镜头测量值主要来自微波背景温度场，但是偏振镜头信号将占主导地位，以更高的灵敏度主导实验。宇宙双向反射是指从最后一个散射表面传播到我们的微波光子的线性极化方向的旋转，这可以通过奇偶校验的物理（例如轴突样暗物质或原始磁场）引起。我们发现，对于即将进行的类似CMB-S4的实验，如果存在比例不变的各向异性双折射，幅度对应于当前$ 95 \％$上限的幅度，则测得的镜头功率谱可能会在小规模上偏出几个因素，$ L \ l \ gtrsim $ 1000 $ 1000 $ 1000 $。我们表明，偏置与比例不变的双折射谱的幅度线性缩放。即使双重振幅降低到当前上限的$ \ sim 5 \％$，各向异性双折射的贡献的信噪比也大于统一。我们的结果表明，各向异性双折射的测量和表征对于未来的低噪声极化实验中的镜头分析很重要。
The power spectrum of cosmic microwave background lensing is a powerful tool for constraining fundamental physics such as the sum of neutrino masses and the dark energy equation of state. Current lensing measurements primarily come from distortions to the microwave background temperature field, but the polarization lensing signal will dominate upcoming experiments with greater sensitivity. Cosmic birefringence refers to the rotation of the linear polarization direction of microwave photons propagating from the last scattering surface to us, which can be induced by parity-violating physics such as axion-like dark matter or primordial magnetic fields. We find that, for an upcoming CMB-S4-like experiment, if there exists the scale-invariant anisotropic birefringence with an amplitude corresponding to the current $95\%$ upper bound, the measured lensing power spectrum could be biased by up to a factor of few at small scales, $L\gtrsim 1000$. We show that the bias scales linearly with the amplitude of the scale-invariant birefringence spectrum. The signal-to-noise of the contribution from anisotropic birefringence is larger than unity even if the birefringence amplitude decreases to $\sim 5\%$ of the current upper bound. Our results indicate that a measurement and characterization of the anisotropic birefringence is important for lensing analysis in future low-noise polarization experiments.
