标题： CMB三功率谱中来自标量部分的宇称破坏 显示英文标题

标题： Parity violation in the CMB trispectrum from the scalar sector

摘要： 在膨胀期间存在手征非高斯源的情况下，原始曲率扰动的四点函数可以打破宇称。 我们检查了由此诱导的宇宙微波背景（CMB）各向异性四点函数的特征。 通过谐波空间分析确认，作为宇称破缺的结果，这种CMB四点函数在$\ell_1 + \ell_2 + \ell_3 + \ell_4 = \text{odd}$域中有非零信号，而在协调宇宙学中这是被禁止的。 当曲率四点函数用勒让德多项式参数化时，由于勒让德偶极项，在$\ell$空间中的拉伸构型下CMB信号增强，导致信噪比高。 费舍尔矩阵计算得出，在宇宙方差受限级别的温度调查中，偶极子系数的最小可探测大小为$d_1^{\rm odd} = 640$。 在一个膨胀模型中，其中膨胀场通过$f(\phi)(F^2 + F\tilde{F})$相互作用与规范场耦合，曲率四点函数包含这样的奇数宇称偶极子项。 我们发现，在此模型中，CMB四点函数相对于CMB功率谱或三阶谱具有更高的信噪比。 因此，$\ell_1 + \ell_2 + \ell_3 + \ell_4 = \text{odd}$信号可能是宇宙宇称破缺的一个有前景的可观测量。 显示英文摘要

摘要： Under the existence of chiral non-Gaussian sources during inflation, the trispectrum of primordial curvature perturbations can break parity. We examine signatures of the induced trispectrum of the cosmic microwave background (CMB) anisotropies. It is confirmed via a harmonic-space analysis that, as a consequence of parity violation, such a CMB trispectrum has nonvanishing signal in the $\ell_1 + \ell_2 + \ell_3 + \ell_4 = \text{odd}$ domain, which is prohibited in the concordance cosmology. When the curvature trispectrum is parametrized with Legendre polynomials, the CMB signal due to the Legendre dipolar term is enhanced at the squeezed configurations in $\ell$ space, yielding a high signal-to-noise ratio. A Fisher matrix computation results in a minimum detectable size of the dipolar coefficient in a cosmic-variance-limited-level temperature survey as $d_1^{\rm odd} = 640$. In an inflationary model where the inflaton field couples to the gauge field via an $f(\phi)(F^2 + F\tilde{F})$ interaction, the curvature trispectrum contains such a parity-odd dipolar term. We find that, in this model, the CMB trispectrum yields a high signal-to-noise ratio compared with the CMB power spectrum or bispectrum. Therefore, the $\ell_1 + \ell_2 + \ell_3 + \ell_4 = \text{odd}$ signal could be a promising observable of cosmological parity violation.