Improve coherence and establish additional shuttling-mediated connections

Investigate whether additional tuning can improve coherence for currently inaccessible or low-fidelity shuttling links in the 6×6 merged-barrier quantum-dot array, thereby enabling additional qubit-qubit connections beyond the four pairs demonstrated.

Background

The paper demonstrates exchange-mediated interactions for four pairs of qubits, but additional connections were not established because of coherence loss on certain shuttling paths, including the inaccessible QD5D site and the low-fidelity QD3C–QD4C connection. The authors suggest that further device tuning might improve the coherence of these links, which would enlarge the connected interaction graph and increase the flexibility of shuttling paths in sparsely occupied arrays.

Whether such tuning can recover coherent shuttling and enable reliable two-qubit interactions on these links is left unresolved. Determining this would clarify the extent to which the merged-barrier architecture can provide scalable connectivity across the full two-dimensional array.

References

More connections have not been established, largely due to coherence loss for certain links, for example the inaccessibility of QD\textsubscript{5D} or the low fidelity connection between QD\textsubscript{3C}-QD\textsubscript{4C} (see the SEDs in main Figure~\ref{fig:figure1}c). This coherence may be improved with additional tuning, but this remains to be studied.

— Sparse qubit operation in a 6$\times$6 quantum dot array  (2610.07683 - Ivlev et al., 6 Oct 2026) in Supplementary Material, Section 8, “Two Qubit interaction,” subsection “Other interacting qubits”