Oral: Analysis of Charge Noise Effects on Exchange Interaction Using Extended Hund-Mulliken Method

Achieving high-fidelity two-qubit gates is a key requirement for realizing fault-tolerant quantum computation with semiconductor spin qubits. While advancements in fabrication and control techniques have enabled gate fidelities to exceed the error-correction threshold, charge noise remains a major impediment to further enhancing fidelity. The exchange interaction, a fundamental mechanism for implementing two-qubit gates, is particularly sensitive to charge noise. Thus, understanding the relationship between charge noise and exchange interaction is important for developing strategies to mitigate this limitation.



In this study, we investigate the impact of various types of single noise sources, including dipole defects and single charges with their images, on the exchange interaction using an extended Hund-Mulliken approach. Although the Hund-Mulliken method was initially used for the examination of exchange interactions at constant barrier height potential, we extend this method using excited-state hybridization to improve the accuracy for arbitrary barrier heights and distortions caused by charge noise. This extension allows us to predict fluctuations in the exchange interaction due to different charge noise models and to identify the spatial position where charge noise has the greatest impact. In addition, the relationship between barrier height and the relative error of the exchange interaction is also examined. These results provide new insight into the exchange interaction in noisy environments.