Robust Quantum Control via Multipath Interference for Thousandfold Phase Amplification in a Resonant Atom Interferometer.

We introduce a novel technique for enhancing the robustness of light-pulse atom interferometers against the pulse infidelities that typically limit their sensitivities. The technique uses quantum optimal control to favorably harness the multipath interference of the stray trajectories produced by imperfect atom-optics operations. We apply this method to a resonant atom interferometer and achieve thousandfold phase amplification, representing a 50-fold improvement over the performance observed without optimized control.

High-power, low-phase-noise, frequency-agile laser system for delivering fiber-noise-canceled pulses for strontium clock atom interferometry.

We present a laser system for performing single-photon atom interferometry on the 698 nm clock transition in ultracold strontium. We coherently combine the power of two titanium:sapphire lasers and demonstrate chirps of 200 MHz in 2.5 ms while phase-locked to an optical reference.