Testing gravitational redshift based on microwave frequency links onboard China Space Station

TL;DR

This paper proposes a method using high-precision microwave frequency links between the China Space Station and ground stations to test gravitational redshift with significantly improved accuracy over past experiments.

Contribution

It introduces a new simulation-based approach leveraging advanced atomic clocks on CSS for more precise gravitational redshift testing.

Findings

Potential to test GR at an accuracy of (0.27 ± 2.15) × 10^{-7}

Method surpasses previous experimental accuracy by over two orders of magnitude

Simulation results support feasibility of high-precision gravitational redshift tests

Abstract

In 2022 China Space Station (CSS) will be equipped with atomic clocks and optical clocks with stabilities of $2 \times 10^{-16}$ and $8 \times 10^{-18}$, respectively, which provides an excellent opportunity to test gravitational redshift (GR) with higher accuracy than previous results. Based on high-precise frequency links between CSS and a ground station, we formulated a model and provided simulation experiments to test GR. Simulation results suggest that this method could test the GR at the accuracy level of $(0.27 \pm 2.15) \times10^{-7}$, more than two orders in magnitude higher than the result of the experiment of a hydrogen clock on board a flying rocket more than 40 years ago.