Fast measurements and multiqubit gates in dual-species atomic arrays

We propose and analyze an approach for fast syndrome measurements in an array of rubidium and cesium atomic qubits. The scheme works by implementing an interspecies controlled-not (cnot${}_{k}$) gate, entangling one cesium ancilla qubit with $k\ensuremath{\ge}1$ rubidium qubits which are then used for state measurement. Utilizing Rydberg states with different interspecies and intraspecies interaction strengths, the proposal provides a syndrome measurement fidelity of $\mathcal{F}>0.9999$ in less than $5\phantom{\rule{0.28em}{0ex}}\textmu{}\mathrm{s}$ of integration time.