A Rb-Cs Quantum Computing Testbed

Infleqtion has implemented a neutral-atom quantum computer using two atomic species. This approach allows the classification of each species into data or ancilla qubits, thereby eliminating crosstalk between these sets. This enables fast mid-circuit measurement without atom motion or state-based hiding, a key capability for error corrected operation. Furthermore, it eliminates crosstalk on nearest neighbors during addressed single qubit operations. In our implementation, rubidium and cesium are loaded into a 2D array with 5.5 μm spacing. We will present Rydberg blockade calculations at various quantum numbers for the Rb-Cs pair, the demonstration and benchmarking of an inter-species CZ gate with state-of-the-art fidelity above the threshold for entanglement distillation, and demonstration of error syndrome readout on a dual-species plaquette.