Quantum control of a Tractor Atom Interferometer

In this work, we discuss Tractor Atom Interferometry (TAI), in which 3D traps are employed to transport ultracold atoms on predetermined trajectories before recombining them for sensing purposes. Tight, uninterrupted confinement facilitates guaranteed recombination, avoids dispersion, and allows long holding times while keeping the device compact without sacrificing TAI sensitivity. The simplest way to program the TAI is to use slow trajectories that retain adiabaticity. However, to fully exploit the potential of TAI, it is crucial to speed up trajectories while maximizing sensitivity and robustness, i.e., suppressing detrimental nonadiabatic excitations and maximizing the available time for accumulating a differential phase. To do so, we employ novel optimal quantum control techniques to obtain optimal trajectories. We show that the splitting and recombination can be two orders of magnitude shorter by relaxing adiabaticity conditions for the case where the device functions as an accelerometer.