Mitigating Residual Exchange Coupling in Resonant Singlet-Triplet Qubits

Abstract:We propose methods to mitigate single- and two-qubit control errors due to residual exchange coupling in systems of exchange-coupled resonant singlet-triplet qubits. Commensurate driving, where the pulse length is an integer multiple of the drive period, can mitigate errors from residual intra-qubit exchange, including effects from counter rotating terms and off-axis rotations, as well as leakage errors during two-qubit operations. Residual inter-qubit exchange creates crosstalk errors that reduce single-qubit control fidelities. We show that using a single-spin coupler between two resonant singlet-triplet qubits can reduce this crosstalk error by an order of magnitude. Assuming perfect coupler state preparation and realistic charge and hyperfine noise, we predict that coupler-assisted two-qubit gate errors can be below $3\times10^{-3}$ for gate times as short as $66~\text{ns}$, even in the presence of residual exchange levels exceeding several hundred kHz. Our results suggest the potential of utilizing coupler-based architectures for large scale fault-tolerant spin qubit processors based on resonant singlet-triplet qubits.

arXiv:2512.04846 [quant-ph]

(or arXiv:2512.04846v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2512.04846 Focus to learn more arXiv-issued DOI via DataCite

Physical Review Applied 26.1 (2026): 014087

https://doi.org/10.1103/gjn5-kc41 Focus to learn more DOI(s) linking to related resources

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