标题： 宇宙学建模与Regge微积分 显示英文标题

标题： Cosmological modelling with Regge calculus

摘要： 在晚期宇宙中，物质分布仅在最粗略的尺度上遵循哥白尼原理。 这种不均匀性的相对重要性仍然未被充分理解。 由于爱因斯坦场方程的非线性性质，一些人认为需要采用非微扰的方法来正确模拟不均匀性，这甚至可能消除对暗能量的任何需求。 我们将讨论一种基于Regge微分法的方法，这是广义相对论的一种离散近似：我们将讨论Regge微分法的Collins--Williams形式及其在两个玩具宇宙中的应用。 第一个是连续解已得到很好确立的宇宙，即$\Lambda$-FLRW 宇宙。 第二个是一个不均匀的宇宙，即“晶格宇宙”，其中物质仅由点质量的晶格构成，晶格之间为纯真空，这种分布比FLRW宇宙更类似于实际宇宙的分布。 我们将讨论规则晶格以及其中一个质量受到扰动的情况。 显示英文摘要

摘要： The late universe's matter distribution obeys the Copernican principle at only the coarsest of scales. The relative importance of such inhomogeneity is still not well understood. Because of the Einstein field equations' non-linear nature, some argue a non-perturbative approach is necessary to correctly model inhomogeneities and may even obviate any need for dark energy. We shall discuss an approach based on Regge calculus, a discrete approximation to general relativity: we shall discuss the Collins--Williams formulation of Regge calculus and its application to two toy universes. The first is a universe for which the continuum solution is well-established, the $\Lambda$-FLRW universe. The second is an inhomogeneous universe, the `lattice universe' wherein matter consists solely of a lattice of point masses with pure vacuum in between, a distribution more similar to that of the actual universe compared to FLRW universes. We shall discuss both regular lattices and one where one mass gets perturbed.