Academic Appointments

All Publications

  • Atom-Interferometric Test of the Equivalence Principle at the 10^{-12} Level. Physical review letters Asenbaum, P., Overstreet, C., Kim, M., Curti, J., Kasevich, M. A. 2020; 125 (19): 191101


    We use a dual-species atom interferometer with 2 s of free-fall time to measure the relative acceleration between ^{85}Rb and ^{87}Rb wave packets in the Earth's gravitational field. Systematic errors arising from kinematic differences between the isotopes are suppressed by calibrating the angles and frequencies of the interferometry beams. We find an Eötvös parameter of η=[1.6±1.8(stat)±3.4(syst)]×10^{-12}, consistent with zero violation of the equivalence principle. With a resolution of up to 1.4×10^{-11}  g per shot, we demonstrate a sensitivity to η of 5.4×10^{-11}/sqrt[Hz].

    View details for DOI 10.1103/PhysRevLett.125.191101

    View details for PubMedID 33216577

  • Effective Inertial Frame in an Atom Interferometric Test of the Equivalence Principle PHYSICAL REVIEW LETTERS Overstreet, C., Asenbaum, P., Kovachy, T., Notermans, R., Hogan, J. M., Kasevich, M. A. 2018; 120 (18): 183604


    In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. Here we demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species. Using this method, we suppress the gravity-gradient-induced dependence of the differential phase on initial kinematic differences by 2 orders of magnitude and precisely measure these differences. We realize a relative precision of Δg/g≈6×10^{-11} per shot, which improves on the best previous result for a dual-species atom interferometer by more than 3 orders of magnitude. By reducing gravity gradient systematic errors to one part in 10^{13}, these results pave the way for an atomic test of the equivalence principle at an accuracy comparable with state-of-the-art classical tests.

    View details for PubMedID 29775337

  • Phase Shift in an Atom Interferometer due to Spacetime Curvature across its Wave Function PHYSICAL REVIEW LETTERS Asenbaum, P., Overstreet, C., Kovachy, T., Brown, D. D., Hogan, J. M., Kasevich, M. A. 2017; 118 (18)


    Spacetime curvature induces tidal forces on the wave function of a single quantum system. Using a dual light-pulse atom interferometer, we measure a phase shift associated with such tidal forces. The macroscopic spatial superposition state in each interferometer (extending over 16 cm) acts as a nonlocal probe of the spacetime manifold. Additionally, we utilize the dual atom interferometer as a gradiometer for precise gravitational measurements.

    View details for DOI 10.1103/PhysRevLett.118.183602

    View details for Web of Science ID 000400672600002

    View details for PubMedID 28524681

  • Quantum superposition at the half-metre scale NATURE Kovachy, T., Asenbaum, P., Overstreet, C., Donnelly, C. A., Dickerson, S. M., Sugarbaker, A., Hogan, J. M., Kasevich, M. A. 2015; 528 (7583): 530-?

    View details for DOI 10.1038/nature16155

    View details for Web of Science ID 000366991900047

    View details for PubMedID 26701053