Motion-insensitive time-optimal control of optical qubits

Abstract

We derive new, fundamental insights into the dynamics of an optical qubit, revealing how this is influenced by the motion of the trapped particle. Leveraging these new insights, we show that photon-recoil heating can be suppressed at relatively high Rabi frequencies by modulating the phase of the driving laser field in time. This technique enables single-qubit gates that are up to 20 times faster than current state-of-the-art approaches while maintaining the same fidelity. Remarkably, even when photon recoil is eliminated (i.e. when occupation of Fock states is preserved), we find that the gate infidelity does not vanish, but is rather limited by a fundamental mechanism, which we identify as thermal motion-induced entanglement. To overcome this limitation and the effect of recoil, we derive motion-insensitive control pulses that enable the execution of fast, very high-fidelity gates with optical qubits.