论文标题
明显的量学不变的宇宙学扰动理论来自全循环量子重力
Manifestly Gauge-Invariant Cosmological Perturbation Theory from Full Loop Quantum Gravity
论文作者
论文摘要
我们将环路量子重力（LQG）的完整理论应用于宇宙学，并提出了从量子重力中对规范不变宇宙学扰动理论的自上而下的推导。该派生采用LQG的减少相空间公式和ARXIV中定义的新离散路径积分公式：1910.03763。我们证明，在半经典近似和连续限制中，结果与例如在例如ARXIV：0711.0117。宇宙学扰动的时间演变是根据LQG的新宇宙学扰动理论计算得出的，并研究了各种功率谱以进行标量模式和张量模式扰动。将这些功率谱与经典理论的预测进行比较，表明在超长波长方向上进行了校正。这些校正是LQG中晶格离散化的结果。此外，张量模式在晚期的扰动证明了Spin-2 Gravitons作为LQG的低能量激发的出现。重力具有修饰的色散关系，并在长波长极限下还原为标准的重力。
We apply the full theory of Loop Quantum Gravity (LQG) to cosmology and present a top-down derivation of gauge-invariant cosmological perturbation theory from quantum gravity. The derivation employs the reduced phase space formulation of LQG and the new discrete path integral formulation defined in arXiv:1910.03763. We demonstrate that in the semiclassical approximation and continuum limit, the result coincides with the existing formulation of gauge-invariant cosmological perturbation theory in e.g. arXiv:0711.0117. Time evolution of cosmological perturbations is computed numerically from the new cosmological perturbation theory of LQG, and various power spectrums are studied for scalar mode and tensor mode perturbations. Comparing these power spectrums with predictions from the classical theory demonstrate corrections in the ultra-long wavelength regime. These corrections are results from the lattice discretization in LQG. In addition, tensor mode perturbations at late time demonstrate the emergence of spin-2 gravitons as low energy excitations from LQG. The graviton has a modified dispersion relation and reduces to the standard graviton in the long wavelength limit.
