Dark Energy and the Cosmological Constant

暗能量是一种虚幻的物质，它驱动着观测到的宇宙加速，关于暗能量的一个未知之处是，它是由什么组成的？它是观测到的能量密度的一个真正的宇宙常数，还是像一个不断发展的标量场（Quintessence）一样的东西，或者是在大尺度上对爱因斯坦广义相对论的修改而产生的东西？最近，随着哈勃参数在局部和全球测量中出现的明显紧张，这一点受到了严峻的质疑。一种可能的解释是，我们可能看到了早期动态暗能量的证据，这些暗能量与物质辐射相等和重组之间的红移有关。通过动力系统分析暗能量演化的方法，以及利用遗传机器学习技术重建最佳拟合暗能量状态方程的补充方法，我们的目标是说一些比目前可能的更明确的关于宇宙中暗能量的本质的东西。

One of the unknowns about dark energy, the illusive substance driving the observed acceleration of the universe, is what it is composed of? Is it a genuine cosmological constant of the observed energy density, or is it something else like an evolving scalar field (Quintessence) or something that is arising from a modification of Einstein's General theory of relativity on large scales?This has come into stark question recently with the apparent tension arising in local and global measurements of the Hubble parameter today. One possible explanation is that we could be seeing evidence of early dynamical dark energy at a redshift linked to the region between matter radiation equality and recombination. Using a combination of analytical approaches to dark energy evolution through dynamical systems, and a complementary approach using genetic machine learning techniques to reconstruct the best fitting dark energy equation of state, we aim to say something more definitive than is currently possible about the nature of dark energy in the universe.