Optimizing the Frequency Positioning of Tunable Couplers in a Circuit QED Processor to Mitigate Spectator Effects on Quantum Operations
Abstract
We experimentally optimize the frequency of flux-tunable couplers in a superconducting quantum processor to minimize the impact of spectator transmons during quantum operations (single-qubit gates, two-qubit gates, and readout) on other transmons. We adapt a popular transmonlike tunable-coupling element, achieving high-fidelity, low-leakage controlled-Z gates with unipolar, fast-adiabatic pulsing only on the coupler. We demonstrate the ability of the tunable coupler to null residual-ZZ coupling as well as exchange couplings in the one- and two-excitation manifolds. However, the nulling of these coherent interactions is not simultaneous, prompting the exploration of trade-offs. We present experiments pinpointing spectator effects on specific quantum operations. We also study the combined effect on the three types of operations using repeated quantum parity measurements.
Fields of Study & Subjects
Neural Networks and Reservoir Computing
Optical Network Technologies
Quantum Information and Cryptography
Publication details
- Journal / source
- Physical Review Letters
- Publisher
- American Physical Society (APS)
- Volume
- 136
- Issue
- 20
- Pages
- 200801–200801
- Publication date
- 2 April 2026
- Language
- EN