Cosmological probes of gravity

虽然我们知道广义相对论很好地描述了太阳系尺度上的引力相互作用，但在大得多(高能物理)和小得多(宇宙学)的能量尺度上，这一点还远未确定。这打开了令人着迷的发现窗口，以了解更多关于引力和宇宙中与其加速膨胀有关的暗成分的信息。在探索其中几个窗口时，该项目将跨越广泛的物理系统和方法，从从目前和即将到来的大量观测大尺度结构数据中得出观测界限(重点是DES和LSST调查)，到探索理论高能物理，以及对重力行为的限制。因此，作为这个项目的一部分，我们将在非常大的尺度上探索宇宙学对暗能量和修正重力的限制，在这些尺度上，物理足够线性，可以分析处理。例如，这将涉及理解、计算和结合来自星系透镜和星系团的新约束和来自宇宙微波背景的约束。我们将使用DES(暗能量调查)和一系列补充的河外主机星表的最新数据来得出引力物理的最新界限，并预测下一代调查的类似限制，特别是LSST(传统空间和时间调查)。此外，我们将用传统上在国内粒子物理中使用的技术得出的理论见解和约束来补充这些数据驱动的约束，例如，通过考虑基本粒子(如引力子)的散射来研究引力物理的新界限。通过将它们与直接从宇宙学获得的界限相结合，我们将能够获得定性的新见解，从而将焦点对准宇宙引力的性质。

While we know that General Relativity is an excellent description of gravitational interactions on solar system scales, at much larger (high energy physics) and much smaller (cosmology) energy scales this is far from certain. This opens up fascinating discovery windows to learn more about gravity and the dark components of the universe linked to its accelerated expansion. In exploring several of these windows, this project will span a wide range of physical systems and methods, from deriving observational bounds from the current and upcoming wealth of observational large scale structure data (with a focus on the DES and LSST surveys) to exploring theoretical high energy physicsconstraints on the behaviour of gravity. As part of this project, we will therefore explore cosmological constraints on dark energy and modified gravity on very large scales, where the physics is sufficiently linear to be analytically tractable. This will e.g. involve understanding, computing and combining novel constraints from the lensing and clustering of galaxies with those from the cosmic microwave background. We will use current data from DES (Dark Energy Survey) and a host of complementary extragalactic host catalogues to derive state-of-the-art bounds on gravitational physics and to forecast analogous constraints for the next generation of surveys, especially for LSST (Legacy Survey of Space and Time). Furthermore, we will complement these data-driven constraints with theoretical insights and constraints derived using techniques traditionally at home in particle physics, e.g. novel bounds on gravitational physics from considering the scattering of fundamental particles (such as gravitons). In combining them with bounds obtained directly from cosmology, we will be able to gain qualitatively new insights and thereby zero in on the nature of cosmological gravity.