Erasure conversion for singlet-triplet spin qubits enables high-performance shuttling-based quantum error correction

TL;DR

This paper introduces a fault-tolerant quantum error correction framework using singlet-triplet spin qubits, enabling high-fidelity shuttling and significantly improving logical error rates in semiconductor quantum devices.

Contribution

It presents a novel leakage-detection protocol and demonstrates enhanced error correction thresholds with the XZZX surface code for singlet-triplet qubits.

Findings

Twofold increase in error correction threshold

Orders-of-magnitude reduction in logical error rates

Practical implementation of high-fidelity shuttling in semiconductor qubits

Abstract

Fast and high fidelity shuttling of spin qubits has been demonstrated in semiconductor quantum dot devices. Several architectures based on shuttling have been proposed; it has been suggested that singlet-triplet (dual-spin) qubits could be optimal for the highest shuttling fidelities. Here we present a fault-tolerant framework for quantum error correction based on such dual-spin qubits, establishing them as a natural realisation of erasure qubits within semiconductor architectures. We introduce a hardware-efficient leakage-detection protocol that automatically projects leaked qubits back onto the computational subspace, without the need for measurement feedback or increased classical control overheads. When combined with the XZZX surface code and leakage-aware decoding, we demonstrate a twofold increase in the error correction threshold and achieve orders-of-magnitude reductions in logical error rates. This establishes the singlet-triplet encoding as a practical route toward high-fidelity shuttling and erasure-based, fault-tolerant quantum computation in semiconductor devices.