Restless Tuneup of High-Fidelity Qubit Gates
de Jong, S.R.
de Sterke, J.C.
We present a tuneup protocol for qubit gates with tenfold speedup over traditional methods reliant on qubit initialization by energy relaxation. This speedup is achieved by constructing a cost function for Nelder-Mead optimization from real-time correlation of nondemolition measurements interleaving gate operations without pause. Applying the protocol on a transmon qubit achieves 0.999 average Clifford fidelity in one minute, as independently verified using randomized benchmarking and gate-set tomography. The adjustable sensitivity of the cost function allows the detection of fractional changes in the gate error with a nearly constant signal-to-noise ratio. The restless concept demonstrated can be readily extended to the tuneup of two-qubit gates and measurement operations.
Observation, Weapon & Protection Systems
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RT - Radar Technology
TS - Technical Sciences
High Tech Systems & Materials
American Physical Society
Physical Review Applied, 7 (4)