Enhancing strontium clock atom interferometry using quantum optimal control

Abstract: Strontium clock atom interferometry is a promising new technique, with multiple experiments under development to explore its potential for dark matter and gravitational wave detection. In these detectors, large momentum transfer (LMT) using sequences of many laser pulses is necessary, and thus high fidelity of each pulse is important since small infidelities become magnified. Quantum Optimal Control (QOC) is a framework for developing control pulse waveforms that achieve high fidelity and are robust against experimental imperfections. Resonant single-photon transitions using the narrow clock transition of strontium involve significantly different quantum dynamics than more established atom interferometry methods based on far-detuned two-photon Raman or Bragg transitions, which leads to new opportunities and challenges when applying QOC. Here, we study QOC pulses for strontium clock interferometry and demonstrate their advantage over basic square pulses (primitive pulses) and composite pulses in terms of robustness against multiple noise channels. This could improve the scale of large momentum transfer in Sr clock interferometers, paving the way to achieve these scientific goals.