Rydberg atom crosstalks for large-scale high-fidelity two-qubit quantum gates

Strong interactions between neutral atoms excited to Rydberg states enable high-fidelity two-qubit Controlled-Z (CZ) gates, but may also introduce crosstalk errors between distant atoms. In order to fully realize the potential of large-scale atom tweezer arrays, both the isolated gate fidelity and crosstalk errors need to be characterized. In this work, we design and implement a quantum circuit to precisely measure the anisotropic, long-range Rydberg interaction strength between ytterbium-171 atoms at a high magnetic field, and compare to calculations using multichannel quantum defect theory. Additionally, we present an updated measurement of our two-qubit gate achieving a 99.70(3)% fidelity, without post-selection for atom loss.