2018/01/24 by Johannes Heinsoo, Christian Kraglund Andersen, Ants Remm +8 · 4 citations
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physrevapplied.10.034040
published as Phys. Rev. Applied 10, 034040 (2018) · 13 pages, 10 figures
arxiv created 2018/01/24 · arxiv updated 2018/09/26
The duration and fidelity of qubit readout is a critical factor for applications in quantum information processing as it limits the fidelity of algorithms which reuse qubits after measurement or apply feedback based on the measurement result. Here we present fast multiplexed readout of five qubits in a single 1.2 GHz wide readout channel. Using a readout pulse length of 80 ns and populating readout resonators for less than 250 ns we find an average correct assignment probability for the five measured qubits to be 97%. The differences between the individual readout errors and those found when measuring the qubits simultaneously are within 1%. We employ individual Purcell filters for each readout resonator to suppress off-resonant driving, which we characterize by the dephasing imposed on unintentionally measured qubits. We expect the here presented readout scheme to become particularly useful for the selective readout of individual qubits in multi-qubit quantum processors.