Towards constraining parity-violations in gravity with satellite gradiometry

Abstract

Parity violation in gravity, if existed, could have important implications, and it is meaningful to search and test the possible observational effects. Chern–Simons modified gravity serves as a natural model for gravitational parity-violations. Especially, considering extensions to Einstein–Hilbert action up to second order curvature terms, it is known that theories of gravitational parity-violation will reduce to the dynamical Chern–Simons gravity. In this letter, we outline the theoretical principles of testing the dynamical Chern–Simons gravity with orbiting gravity gradiometers, which could be naturally incorporated into future satellite gravity missions. The secular gravity gradient signals, due to the Mashhoon–Theiss (anomaly) effect, in dynamical Chern–Simons gravity are worked out, which can improve the constraint of the corresponding Chern–Simons length scale ξcs14 obtained from such measurement scheme. For orbiting superconducting gradiometers or gradiometers with optical readout, a bound ξcs14≤106km (or even better) could in principle be obtained, which will be at least 2 orders of magnitude stronger than the current one based on the observations from the GP-B mission and the LAGEOS I, II satellites.