Rapid High-fidelity Multiplexed Readout of Superconducting Qubits

Fast, high-fidelity readout of qubits is crucial in quantum computing. Quantum error correction in particular requires the repeated measurement of subsets of qubits without perturbing any others. Achieving this goal in a multiplexed readout architecture has been challenging, mainly due to the crosstalk of readout signals. In this work, individual Purcell filters are used for each readout resonator to protect the qubits from untargeted readout signals, and from radiative decay. By implementing this scheme, which could find broad use in near-term multiqubit devices, the authors demonstrate the $s{{0}{0ex}}i{{0}{0ex}}m{{0}{0ex}}u{{0}{0ex}}l{{0}{0ex}}t{{0}{0ex}}a{{0}{0ex}}n{{0}{0ex}}e{{0}{0ex}}o{{0}{0ex}}u{{0}{0ex}}s$ readout of up to five qubits.