Characterizing Midcircuit Measurements on a Superconducting Qubit Using Gate Set Tomography

Key applications of quantum computing, including error correction, rely critically on the capability to measure (read out) state selected bits, without disturbing other qubits or terminating computation. Such $m\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}d\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}u\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t$ $m\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}s\phantom{\rule{0}{0ex}}u\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}s$ are now being implemented in a few cutting-edge platforms, but their development is hindered by lack means performance and characterize errors that they produce. The authors show how extend popular tomography method for precise characterization midcircuit measurements, using QILGST protocol discover pernicious kind non-Markovian error, which once identified can be handled.