Ultrahigh-Sensitivity Bragg Atom Gravimeter and its Application in Testing Lorentz Violation

We have demonstrated a precision atom-interferometry gravimeter based on matter-wave Bragg diffraction. By decreasing the atom temperature and increasing the atom number with Raman sideband cooling, it is shown that our Bragg atom gravimeter can achieve a short-term sensitivity of 2.2 & mu;Gal/Hz1/2 (1 Gal = 1 cm/s2), improved by nearly a factor of 2 compared to that of a state-of-the-art atom gravimeter. The resolution of our atom gravimeter has reached 0.08 & mu;Gal after an integration time of 2000 s, comparable to a cryogenic superconducting gravimeter. Based on extremely sensitive and stable gravity measurements, a test of local Lorentz invariance in the gravity sector was performed, where the accuracy of the upper bound on the space-space component was improved by a factor of 4.