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arXiv · 2512.04846

Mitigating Residual Exchange Coupling in Resonant Singlet-Triplet Qubits

Jiheng Duan·Fernando Torres-Leal·John M. Nichol
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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.

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Jiheng Duan, Fernando Torres-Leal, John M. Nichol. 2025-12-04. Mitigating Residual Exchange Coupling in Resonant Singlet-Triplet Qubits. https://arxiv.org/abs/2512.04846

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