Absolute and ratio measurements of the polarizability of Na, K, and Rb with an atom interferometer

We measured the ground-state electric-dipole polarizability of sodium, potassium, and rubidium using a Mach-Zehnder atom interferometer with an electric-field gradient. We find αNa=24.11(2)stat(18)sys×10 ^-24cm3, αK=43.06(14)(33), and αRb=47.24(12)(42). Since these measurements were all performed in the same apparatus and subject to the same systematic errors, we can present polarizability ratios with 0.3% uncertainty. We find αRb/αNa=1.959(5), αK/αNa=1.786(6), and αRb/αK=1.097(5). We combine our ratio measurements with the higher-precision measurement of sodium polarizability by Ekstrom [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.51.3883 51, 3883 (1995)] to find αK=43.06(21) and αRb=47.24(21).