The paper proposes a method for measuring gravitational acceleration using ultracold atoms in an atomic fountain. The technique relies on detecting shifts in Ramsey interference fringes that occur when atoms interact twice with a microwave field during their ballistic motion in the gravitational field.
Because the time of flight of the atoms depends on gravity, changes in gravitational acceleration cause a measurable shift of the Ramsey spectrum, allowing the system to function as a gravimeter. We estimate that such a device could achieve a sensitivity of about δg ≈ 2 × 10⁻⁶ g / √τ, reaching an accuracy of roughly 20 μGal after long integration times.
The proposed approach could allow a single atomic fountain instrument to measure both frequency and gravitational acceleration, which is useful for quantum sensing and precision measurements.
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