Characterization of a simultaneous dual-species atom interferometer for a quantum test of the weak equivalence principle

We present here the performance of a simultaneous dual-species matter-wave accelerometer for measuring the differential acceleration between two different atomic species (⁸⁷Rb and ⁸⁵Rb). We study the expression and the extraction of the differential phase from the interferometer output. The differential accelerometer reaches a short-term sensitivity of 1.23×10^-7g/√Hz limited by the detection noise and a resolution of 2×10^-9g after 11 000 s, a very high sensitivity using a dual-species atom interferometer. Thanks to the simultaneous measurement, such resolution levels can still be achieved even with vibration levels up to 3×10^-3g, corresponding to a common-mode vibration noise rejection ratio of 94 dB (rejection factor of 50 000). These results prove the ability of such atom sensors for realizing a quantum-based test of the weak equivalence principle at a level of η~10^-9 even with high vibration levels and a compact sensor.