论文标题
Bianchi中宇宙学理论的实施
xAct Implementation of the Theory of Cosmological Perturbation in Bianchi I Spacetimes
论文作者
论文摘要
本文提出了一种计算算法，以得出对Bianchi I类型的各向异性宇宙学空间的线性规格扰动理论。我们的代码基于在Mathematica编写的XACT计算基础架构中基于tensor代数XTENSOR和XPERT。该算法基于哈密顿量或相空间公式，它提供了一种有效且透明的方式，可以在扰动场中隔离仪表不变程度的自由度并获得汉密尔顿产生动力学的方法。限制弗里德曼 - 莱玛特（Robertson） - 步行者的空间很简单。
This paper presents a computational algorithm to derive the theory of linear gauge invariant perturbations on anisotropic cosmological spacetimes of the Bianchi I type. Our code is based on the tensor algebra packages xTensor and xPert, within the computational infrastructure of xAct written in Mathematica. The algorithm is based on a Hamiltonian, or phase space formulation, and it provides an efficient and transparent way of isolating the gauge invariant degrees of freedom in the perturbation fields and to obtain the Hamiltonian generating their dynamics. The restriction to Friedmann--Lemaître--Robertson--Walker spacetimes is straightforward.
