Testing Chern-Simons modified gravity with orbiting superconductive gravity gradiometers --- The non-dynamical formulation

TL;DR

This paper proposes using orbiting superconductive gravity gradiometers to detect signals of non-dynamical Chern-Simons modified gravity around Earth, enabling tests of parity violation and gravitomagnetism.

Contribution

It develops a method to isolate Chern-Simons signals in gravity gradient data and demonstrates the potential for simultaneous tests of different gravity theories.

Findings

Chern-Simons signals can be isolated with multi-axis SGGs.

Trace of the tidal matrix is rotation-invariant and axis-error free.

Method allows independent testing of parity violation and gravitomagnetism.

Abstract

High precision Superconductivity Gravity Gradiometers (SGG) are powerful tools for relativistic experiments. In this paper, we work out the tidal signals in non-dynamical Chern-Simons modified gravity, which could be measured by orbiting SGGs around Earth. We find that, with proper orientations of multi-axes SGGs, the tidal signals from the Chern-Simons modification can be isolated in the combined data of different axes. Furthermore, for three-axes SGGs, such combined data is the trace of the total tidal matrix, which is invariant under the rotations of SGG axes and thus free from axis pointing errors. Following nearly circular orbits, the tests of the parity-violating Chern-Simons modification and the measurements of the gravitomagnetic sector in parity-conserving metric theories can be carried out independently in the same time. A first step analysis on noise sources is also included.