Enhancing Circuit Fidelity in Transmon Qubit Rings via Operation Duration Tuning under Strong Connectivity Noise

TL;DR

This paper demonstrates that tuning operation durations in superconducting transmon qubit rings can significantly improve quantum gate fidelity under strong connectivity noise, aided by machine learning predictions.

Contribution

It introduces a method of optimizing gate durations to enhance fidelity in noisy transmon circuits and develops a machine learning model for predicting optimal durations.

Findings

Fidelity exhibits local maxima at specific operation durations even under strong noise.

Fidelity improvements are consistent across different qubit numbers and circuit types.

A supervised machine learning model accurately predicts optimal operation durations.

Abstract

Superconducting transmon qubits are a promising platform for quantum computation, yet they face significant fidelity degradation due to connectivity noise, particularly in the intermediate coupling regime where noise levels are substantial. While prior works suggest that high fidelity requires operating in regimes with strongly suppressed noise, maintaining such conditions under practical experimental constraints remains challenging. To address this, we investigate quantum gate operations in fully connected transmon rings, examining both SWAP and general circuits. Our study reveals that fidelity can be significantly enhanced by tuning gate operation durations, with local maxima emerging even under strong noise conditions. These fidelity enhancements occur consistently across different qubit numbers and operation types, and for specific initial states -- particularly those with favorable symmetry or entanglement properties -- the achieved fidelities approach quantum error correction thresholds. Furthermore, we develop a supervised machine learning model that accurately predicts the optimal operation durations for new devices, enabling efficient optimization without extensive experimental simulations. These results provide a pathway toward robust quantum circuit design in noisy experimental environments.