In our recent experiments, we have realized a novel neutral atom qubit encoded in two metastable fine-structure states of single Strontium atoms trapped in an optical tweezer. This qubit is at the core of the QRydDemo project, where we are setting up a 500 qubit neutral atom quantum processor. One of its unique properties is the possibility to speed up single-qubit gate operations by orders of magnitude, to timescales on par with the fast Rydberg-mediated two-body gates.
As the first step towards this goal, we show preparation, read-out and coherent operations on the fine-structure qubit. We demonstrate Rabi oscillations via a two-photon Raman transition bridging a gap of 17 THz and perform Ramsey spectroscopy to measure the transverse coherence time. With a measured coherence time of 1.2 ms, our work lays the foundation for realizing fast single-qubit gates on the order of 100 ns, enabling more than 10000 gates within the qubit coherence time.
