General relativity is currently the standard theory to describe gravity. It has passed all the tests in our Solar System and has been positively supported by astronomy observations including electromagnetic waves from neutron stars and gravitational waves from coalescing compact binary systems. But fundamentally it is incompatible with quantum theory, and there are also the large-scale observational problems of galaxies' rotation curves and the accelerating expansion of the universe which cannot be resolved without the help of dark matter and dark energy. Various alternative theories of gravity has been proposed since the birth of general relativity. In this talk, I will give a brief introduction to two types alternative gravity theories that I have been working on, the vector-tensor theories and the theories with breaking of Lorentz symmetry. Then I will present predictions relevant to black holes and neutron stars in those theories, and talk about tests that we can do using the state-of-the-art multimessenger astronomy observations.
BIO
Rui Xu graduated from Nanjing University with a Bachelor of Science Degree in Astronomy and studied theoretical gravitational physics in Indiana University for his PhD program. He had the first postdoctoral work at the Kavli Institute for Astronomy and Astrophysics in Peking University in Professor Lijing Shao's group. Now he is in his second postdoctoral position working with Professor DanDan Xu at the Department of Astronomy in Tsinghua University. His research focuses on studying observable signals from neutron stars and black holes in general relativity as well as popular alternative gravitational theories, and testing the theories using astronomical and astrophysical observations.
References:
https://journals.aps.org/prd/abstract/10.1103/PhysRevD.103.084028
https://journals.aps.org/prd/abstract/10.1103/PhysRevD.107.024011
