Rapid adiabatic passage of cold Rydberg atoms optically shuttled through quantized RF fields for a dark matter search*

Recent advances in laser spectroscopy and in the ability to prepare and trap Rydberg atoms have re-invigorated Rydberg-atom physics and have led to a variety of applications in electromagnetic-field (EM) sensing, quantum information and quantum simulation. These advances build, in part, on a decades-old awareness of the extraordinary sensitivity of Rydberg atoms to EM fields caused by the atoms' large electric-dipole moments for microwave transitions, which can range in thousands of Debye. Here we theoretically study the dynamics of Rydberg atoms that are shuttled with a moving optical guiding potential through a quantized single- or few-photon microwave field for a dark-matter (DM) search. The field is near-resonant with a strong electric-dipole transition of the Rydberg atoms. A rapid-adiabatic-passage approach is employed to enhance the atoms' single-photon pickup efficiency. Due to the low center-of-mass energies and potential depths involved, both the center-of-mass and the internal degrees of freedom of the atoms are treated quantum-mechanically. We will present the model, results on the single-photon detection efficiency, non-adiabatic imperfections, and possible deviations from semi-classical estimates based on the Landau-Zener formula. The results are portable to Rydberg micro-masers in high-Q superconducting cavities, a well-known cavity-QED platform in the strong coupling regime. We will discuss an application for detection of wave-like DM based on the Primakoff effect over a mass range of 15 to 400~$mu$eV. Sensitivity estimates for this DM search will be given.