Probing Dark Matter's Gravitational Effects Locally with TianQin

TL;DR

This paper investigates TianQin's potential to detect local dark matter density around Earth by analyzing gravitational effects through precise orbit measurements, achieving unprecedented sensitivity levels.

Contribution

It introduces a novel method using TianQin's orbit data to constrain Earth's nearby dark matter density with high sensitivity.

Findings

TianQin can detect dark matter density as low as 10^{-8} kg/m^3.

The method surpasses previous bounds by 7 to 14 orders of magnitude.

High-precision orbit determination enables new dark matter constraints.

Abstract

In this study, we explore the potential of using TianQin missions to probe the local gravitational effects of dark matter. The TianQin project plans to launch satellites at both low and high orbits. High-precision orbit determination is expected to aid in detecting Earth's gravity or gravitational waves. By comparing the derived masses in low and high orbits, it is possible to constrain the amount of dark matter between the two spheres, hence placing a local constraint on dark matter's gravitational effect. Our results show the capability of TianQin in detecting the density of dark matter around Earth, with an ultimate sensitivity to a value of $10^{-8}\,\,{\rm kg\,\,m^{-3}}$. This detection limit surpasses the estimated bounds for the solar system and the observation results for our Galaxy by approximately 7 and 14 orders of magnitude, respectively.