Proposed test of Lorentz Invariance using the Gravitational Wave Interferometers

Abstract

Current limits on violation of local Lorentz invariance in the photon sector are derived mainly from experiments that search for a spatial anisotropy in the speed of light. The presently operating gravitational wave detectors are Michelson interferometers with long effective arms, 4e5 m, and sensitive to a fringe shift 2e-9. Therefore they can be used to test for a difference in the speed of light in the two arms, as modulated bi-annualy by the orientation of the Earth's velocity with respect to the direction of motion of the local system. A limit can be set on the Robertson-Mansouri-Sexl parameter PMM < 10e-15, as compared to its present limit of PMM < 2e-10, an improvement of five orders of magnitude.