Benchmarking the strontium fine-structure qubit under triple-magic trapping conditions

Long-lived optical clock states of alkaline earth and alkaline earth-like atoms have many applications in quantum computing, simulation, and metrology. Direct optical driving of the clock transition in bosonic isotopes requires large laser intensities and strong magnetic fields, which typically limits the achievable Rabi frequency on this transition. In this talk, I will present a fast all-optical qutrit based on the ground state 1S0 and clock states 3P0 and 3P2 with all-to-all connectivity implemented via two- and three-photon transitions. Using three phase-coherent light fields we demonstrate strong Rabi coupling from the ground state to both clock states.
Under triple-magic trapping conditions, we characterize a universal gate set for the meta-stable fine-structure qubit encoded in the two clock states and find a single-qubit gate fidelity of 0.993(1) and a loss-corrected two-qubit gate fidelity of 0.9945(6). We perform mid-circuit erasure detection via fast destructive imaging and present a spin-resolved detection scheme for the fine-structure states enabling a high-fidelity correction of qubit loss. Our work overcomes several limitations to using bosonic strontium for quantum simulation and quantum computing and establishes the strontium fine-structure qubit as a promising candidate for quantum computing applications.