Cosmological probes of gravity

虽然我们知道广义相对论是太阳系尺度上引力相互作用的一个很好的描述，但在更大（高能物理学）和更小（宇宙学）的能量尺度上，这还远远不能确定。这打开了迷人的发现窗口，以了解更多关于引力和宇宙中与其加速膨胀有关的黑暗成分。在探索这些窗口中的几个窗口时，该项目将跨越广泛的物理系统和方法，从从当前和即将到来的观测大尺度结构数据（重点是DES和LSST调查）中获得观测边界，以探索理论高能物理学对重力行为的约束。因此，作为这个项目的一部分，我们将探索宇宙学对暗能量的约束和非常大尺度上的修正引力，其中物理学是足够线性的，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与来自宇宙微波背景的约束。我们将使用来自DES（暗能量调查）的当前数据和大量补充的河外宿主目录来推导引力物理学的最新边界，并预测下一代调查的类似约束，特别是LSST（时空遗产调查）。此外，我们将用粒子物理学中传统的技术推导出的理论见解和约束来补充这些数据驱动的约束，例如考虑基本粒子（如引力子）散射的引力物理学的新边界。通过将它们与直接从宇宙学获得的边界相结合，我们将能够获得定性的新见解，从而将注意力集中在宇宙学引力的本质上。

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.