Rotational Coherence Times of Polar Molecules in Optical Tweezers

Qubit coherence times are critical to the performance of any robust quantum computing platform. For quantum information processing using arrays of polar molecules, a key performance parameter is the molecular rotational coherence time. We report a 93(7) ms coherence time for rotational state qubits of laser cooled CaF molecules in optical tweezer traps, over an order of magnitude longer than previous systems. Inhomogeneous broadening due to the differential polarizability between the qubit states is suppressed by tuning the tweezer polarization and applied magnetic field to a magic angle. The coherence time is limited by the residual differential polarizability, implying improvement with further cooling. A single spin-echo pulse is able to extend the coherence time to nearly half a second. The measured coherence times demonstrate the potential of polar molecules as high fidelity qubits.

Automated summary

Coherence times of rotational state qubits of laser-cooled CaF molecules in optical tweezer traps are reported, demonstrating potential as high fidelity qubits. Improvement in coherence time is suggested through further cooling and suppression of inhomogeneous broadening by tuning tweezer polarization and applied magnetic field to a magic angle. A single spin-echo pulse can extend coherence time to nearly half a second.