{"paper":{"title":"Using a spin-triplet encoding to enhance shuttling fidelities in Si/SiGe quantum wells","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Two-electron valley-singlet encoding makes shuttling fidelity improve with smaller valley splittings in Si/SiGe wells.","cross_cats":[],"primary_cat":"cond-mat.mes-hall","authors_text":"Mark Friesen, Merritt P. R. Losert, S. N. Coppersmith","submitted_at":"2026-05-12T19:35:29Z","abstract_excerpt":"Spatial variations of the valley splitting in a quantum well present a key challenge for conveyor-mode shuttling of electron spins in Si/SiGe, giving rise to Landau-Zener-like excitations that cause leakage outside the qubit subspace. Here, we propose an unconventional two-electron qubit encoding, based on valley-singlet states, that is largely immune to Landau-Zener leakage processes. In contrast to single-electron spins, the shuttling fidelity actually improves for small valley splittings, in this case. We show that high fidelities can be achieved without applying any special procedures, suc"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We propose an unconventional two-electron qubit encoding, based on valley-singlet states, that is largely immune to Landau-Zener leakage processes. In contrast to single-electron spins, the shuttling fidelity actually improves for small valley splittings.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The model assumes that valley-singlet states can be prepared and maintained as stable qubits during shuttling without introducing new decoherence or control errors from two-electron interactions or gate operations.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A spin-triplet encoding based on valley-singlet states makes shuttling fidelities in Si/SiGe quantum wells higher and more robust to small valley splittings by suppressing Landau-Zener excitations.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Two-electron valley-singlet encoding makes shuttling fidelity improve with smaller valley splittings in Si/SiGe wells.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"c19644517eff85cd13baa484495308654e03b1730e3d8f387df5746ca7b1d513"},"source":{"id":"2605.12687","kind":"arxiv","version":1},"verdict":{"id":"4c564924-3fc3-445a-9b07-fc9c9552bafd","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-14T20:05:48.289825Z","strongest_claim":"We propose an unconventional two-electron qubit encoding, based on valley-singlet states, that is largely immune to Landau-Zener leakage processes. In contrast to single-electron spins, the shuttling fidelity actually improves for small valley splittings.","one_line_summary":"A spin-triplet encoding based on valley-singlet states makes shuttling fidelities in Si/SiGe quantum wells higher and more robust to small valley splittings by suppressing Landau-Zener excitations.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The model assumes that valley-singlet states can be prepared and maintained as stable qubits during shuttling without introducing new decoherence or control errors from two-electron interactions or gate operations.","pith_extraction_headline":"Two-electron valley-singlet encoding makes shuttling fidelity improve with smaller valley splittings in Si/SiGe wells."},"references":{"count":103,"sample":[{"doi":"","year":null,"title":"We see that average infidelities are well below10 −4 in all cases","work_id":"4c36055c-f213-4422-b0b0-b8b01c03f55c","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1998,"title":"D. Loss and D. P. DiVincenzo, Quantum computation with quantum dots, Phys. Rev. A57, 120 (1998)","work_id":"a28db5a9-b390-43ef-97bb-4f1603181c25","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2013,"title":"F. A. Zwanenburg, A. S. Dzurak, A. Morello, M. Y. Simmons, L. C. L. Hollenberg, G. Klimeck, S. Rogge, S. N. Copper- smith, and M. A. Eriksson, Silicon quantum electronics, Rev. Mod. Phys.85, 961 (2013","work_id":"77f0adf1-f16b-40c1-b0c5-d08c0d055fef","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"G. Burkard, T. D. Ladd, A. Pan, J. M. Nichol, and J. R. Petta, Semiconductor spin qubits, Rev. Mod. Phys.95, 025003 (2023)","work_id":"d0cc7c23-537c-40d6-8dd3-4af3127b1865","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2018,"title":"J. Yoneda, K. Takeda, T. Otsuka, T. Nakajima, M. R. Delbecq, G. Allison, T. Honda, T. Kodera, S. Oda, Y. Hoshi, N. Usami, K. M. Itoh, and S. Tarucha, A quantum-dot spin qubit with coherence limited by","work_id":"6f33b918-f37c-45ba-adbe-7eac421b8307","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":103,"snapshot_sha256":"f278262597c471fa648d611bf8502b6937eef3b4b913d5e0fc1bd98cbae6a58c","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"f0c609c47b3edcea6c4d9532c1f95d4f2387ec027d21462a90fb0d2e5ebe3c88"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}