A two-species neutral atom qubit array with individual qubit addressing*

Infleqtion's Sqale Error Correction Testbed is a neutral atom quantum computer designed to enable error correcting codes via mid-circuit measurement. The system is comprised of a 2D array of Cs and Rb qubits, loaded stochastically and rearranged into deterministically loaded logical qubit plaquettes. Species-specific readout allows syndrome measurements on Rb while Cs data qubits are protected. Both Rb and Cs are fully addressable for local gates and pairwise Cs+Rb entangling gates. Local gates are achieved via a combination of differential light shift induced Rz, and global microwave Rx and Ry. Entangling gates are achieved via Rydberg interactions, with Cs excited to Rydberg levels via a 2-photon 459 nm + 1040 nm process, while Rb is excited via 421 nm + 1005 nm. We have demonstrated independent readout and CZ entangling gates on Cs + Rb pairs and are progressing toward logical qubit operations on this system.