title: Testing Einstein's Equivalence Principle With Fast Radio Bursts.
abstract: The accuracy of Einstein's equivalence principle (EEP) can be tested with the observed time delays between correlated particles or photons that are emitted from astronomical sources. Assuming as a lower limit that the time delays are caused mainly by the gravitational potential of the Milky Way, we prove that fast radio bursts (FRBs) of cosmological origin can be used to constrain the EEP with high accuracy. Taking FRB 110220 and two possible FRB/gamma-ray burst (GRB) association systems (FRB/GRB 101011A and FRB/GRB 100704A) as examples, we obtain a strict upper limit on the differences of the parametrized post-Newtonian parameter γ values as low as [γ(1.23  GHz)-γ(1.45  GHz)]<4.36×10(-9). This provides the most stringent limit up to date on the EEP through the relative differential variations of the γ parameter at radio energies, improving by 1 to 2 orders of magnitude the previous results at other energies based on supernova 1987A and GRBs.
authors.affiliation: Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Wei
authors.affiliation: Department of Astronomy, Beijing Normal University, Beijing 100875, China.
authors.forename: He
authors.initials: H
authors.lastname: Gao
authors.affiliation: Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China.|Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing University-Purple Mountain Observatory, Nanjing 210008, China.
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Wu
authors.affiliation: Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, Pennsylvania 16802, USA.|Department of Physics, Pennsylvania State University, 104 Davey Laboratory, University Park, Pennsylvania 16802, USA.|Center for Particle and Gravitational Astrophysics, Institute for Gravitation and the Cosmos, Pennsylvania State University, 525 Davey Laboratory, University Park, Pennsylvania 16802, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Mészáros