论文标题
Bianchi I的观察后果在循环量子宇宙学中
Observational consequences of Bianchi I spacetimes in loop quantum cosmology
论文作者
论文摘要
各向异性始终占主导地位的均匀宇宙的最早阶段。它们在弹跳模型中特别重要，因为剪切在宇宙的合同阶段生长，从而使各向同性情况不稳定。本文将环路量子宇宙学（LQC）中的宇宙学扰动扩展到各向异性的bianchi I模型，其中包含弹跳，然后是缓慢浮力的阶段。我们表明，尽管剪切张量稀释，而宇宙在弹跳后不久各向同性化，但宇宙扰动仍保留了这一短各向异性阶段的记忆。我们开发了描述各向异性，有效LQC的扰动所需的形式主义，并将其应用于对宇宙微波背景（CMB）的预测，同时尊重当前的观察性约束。 We show that the anisotropic bounce induces: (i) anisotropic features in all angular correlation functions in the CMB, and in particular a quadrupolar modulation that can account for a similar feature observed in the temperature map by the Planck satellite, and (ii) quantum entanglement between scalar and tensor modes, that manifests itself in temperature-polarization (T-B and E-B) correlations in the CMB。
Anisotropies generically dominate the earliest stages of expansion of a homogeneous universe. They are particularly relevant in bouncing models, since shears grow in the contracting phase of the cosmos, making the isotropic situation unstable. This paper extends the study of cosmological perturbations in loop quantum cosmology (LQC) to anisotropic Bianchi I models that contain a bounce followed by a phase of slow-roll inflation. We show that, although the shear tensor dilutes and the universe isotropizes soon after the bounce, cosmic perturbations retain memory of this short anisotropic phase. We develop the formalism needed to describe perturbations in anisotropic, effective LQC, and apply it to make predictions for the cosmic microwave background (CMB), while respecting current observational constraints. We show that the anisotropic bounce induces: (i) anisotropic features in all angular correlation functions in the CMB, and in particular a quadrupolar modulation that can account for a similar feature observed in the temperature map by the Planck satellite, and (ii) quantum entanglement between scalar and tensor modes, that manifests itself in temperature-polarization (T-B and E-B) correlations in the CMB.
