Extending the toolset for cosmological tests of gravity

引力是物理学家面临的最大挑战之一。我们不知道如何调和引力与量子物理，也不了解暗能量和暗物质。这些谜题激发了对新引力理论的广泛研究，以及使用天文观测来验证它们的方法。重力测试是国际资助的大规模宇宙学调查的主要科学驱动力之一，加拿大在其中发挥了主导作用。MGCAMB是由SFU宇宙学小组开发和维护的数字代码，已成为宇宙学引力测试的标准工具之一。拟议的合作将利用Kazuya Koyama教授（朴茨茅斯）和Claudia de Rham教授（帝国）的独特专业知识，扩展MGCAMB的能力，并帮助保持它作为宇宙学界的首选工具，使加拿大在引力测试领域保持领先地位。Koyama教授是修正引力非线性效应的全球领导者。SFU小组的成员将与他的小组合作，为MGCAMB增加对小距离宇宙结构进行预测的选项，大部分信息都存在于小距离上。de Rham教授是世界领先的大质量引力专家，这是一类重要的修正引力理论，可以解释宇宙加速的起源。SFU小组将与de Rham教授和Koyama的小组合作，确定大质量引力的宇宙学特征，并为MGCAMB增加相应的能力。

Gravity presents some of the hardest challenges to physicists. We do not know how to reconcile gravity with quantum physics, nor do we understand dark energy and dark matter. These puzzles motivate extensive studies of new theories of gravity, as well as ways of testing them using astronomical observations. Testing gravity is one of the main science drivers for the large-scale internationally funded cosmological surveys in which Canada plays a leading role. MGCAMB is a numerical code developed and maintained by the cosmology group at SFU that has become one of the standard tools for cosmological tests of gravity. The proposed collaboration will take advantage of the unique expertise of Profs Kazuya Koyama (Portsmouth) and Claudia de Rham (Imperial) to extend the capabilities of MGCAMB and help keep it as the go-to tool for the cosmological community, keeping Canada at the forefront of discovery in the field of testing gravity.Prof. Koyama is a global leader in nonlinear effects of modified gravity. Members of the SFU group will work with his group to add to MGCAMB the option of making predictions for cosmic structures on small distances, where most of the information resides. Prof. de Rham is the world leading expert on massive gravity, which is an important class of modified gravity theories that could explain the origin of cosmic acceleration. Working jointly with Profs de Rham and Koyama's groups, the SFU group will identify cosmological signatures of massive gravity and add the corresponding capabilities to MGCAMB.