Martin Wood Complex, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Dr Ravi Naik, UC Berkeley
Dr. Mustafa Bakr
Abstract
A significant source of errors for superconducting qubits is due to interactions between qubits and the materials they are composed of. In particular, quantum two-level system (TLS) defects, which are prevalent on the interfaces of the qubits structure, can couple resonantly to qubits, causing excess decoherence and enhanced gate errors. Here, we present a scalable architecture for site-specific and in-situ manipulation of TLS frequencies out of the spectral vicinity of our qubits. Our method is resource efficient, combining TLS frequency tuning and universal single qubit control into a single on-chip control line per qubit. We independently control each qubit's dissipative environment to dynamically improve both qubit coherence times and single qubit gate fidelities -- with a constant time overhead that does not scale with the device size. Critically, we realize a 4-fold suppression in the occurrence of TLS-induced performance outliers, and a complete reduction of simultaneous outlier events. These results mark a significant step toward overcoming the challenges that TLS defects pose to scaling superconducting quantum processors.