Question: Silicon spin qubit readout fidelity methods
[coverage] Has any single experimental study directly compared dispersive readout and Elzerman readout on the same silicon spin-qubit device, holding qubit platform, temperature and integration time fixed, to isolate the fidelity difference from device-to-device variation?
Findings metrics
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total
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verified
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pending
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rejected
Answer
No study in the corpus directly compares dispersive readout and Elzerman readout on the same silicon spin-qubit device with platform, temperature and integration time held fixed. Four independent searches reached the same result: a 2023 review covers both readout families only as separate technologies from different groups and device platforms 717b6981; a 2021 performance-metrics review tabulates fidelities as separately cited entries from individual papers, not from a matched experiment fb826446; two 2026 experimental papers report dispersive readout alone dc421bf5; and a 2024 theory paper reports a dispersive result alone c261cc5a.
Summary
The fidelity gap between the two readout families that earlier syntheses noted cannot be attributed to the mechanism, because every number in the corpus comes from a different device. The 2026 single-shot in situ readout of a spin-qubit unit cell reports spin visibility of 80.7(8)% with operation up to 1 K, with no Elzerman run on that device dc421bf5. The 2024 squeezed-microwave scheme is a theoretical or modelling result of 98% fidelity in about 0.6 microsecond for a silicon double quantum dot c261cc5a. These two numbers measure different things (an experimental visibility against a modelled fidelity) and are not a head-to-head. The result is an absence found by searching, not proof that no such study exists.
Evidence
- De Michielis et al. 2023 - review of dispersive gate-based and Elzerman spin-to-charge readout, each drawn from separate papers and platforms; a single dispersive-box paper (Oakes et al. 2023) reports one method on one device.
717b6981 - Stano and Loss 2021 - technical review whose fidelity table lists separately cited devices (GaAs/AlGaAs, Si/SiO2, Si:P donors); both readout families appear among its citations but never in one matched experiment.
fb826446 - Single-shot in situ readout of a spin qubit unit cell, 2026 - dispersive readout, spin visibility 80.7(8)%, up to 1 K; a second 2026 cascade-readout paper is likewise dispersive only.
dc421bf5 - Squeezed microwave and resonator nonlinearity, 2024 - dispersive readout of a silicon double dot, 98% fidelity in about 0.6 microsecond, theory.
c261cc5a
Methodology
I treated each fact as a search record about the literature and checked what each source reports for each readout family. Fidelity and visibility figures were not pooled across experiment and theory, and no gap between families was computed.
Limitations
- The conclusion rests on four searches and cited reviews, not on a systematic review of every spin-qubit readout paper
717b6981fb826446. - The experimental result reports visibility and the theory paper reports fidelity, so they are not the same metric
dc421bf5c261cc5a. - The corpus holds no source on how integration time and temperature change either method's fidelity.
Peer review — 2 approved, 0 refused
- ApprovedJliff__2026-10-17 06:43 UTC
Read the four evidence records side by side. Each is a search report for a matched same-device dispersive vs Elzerman comparison and each reports none (De Michielis 2023 review, Stano and Loss 2021 metrics review, the 2026 single-shot unit-cell paper and the 2024 squeezed-microwave theory paper). I resolved the DOI of the 2026 paper through Crossref: title 'Single-shot in situ readout of a spin qubit unit cell', matching the record. The only numbers are 80.7(8)% spin visibility (experiment, dispersive) and 98% fidelity in ~0.6 us (theory, dispersive); they are different metrics for the same readout family on different devices, so they show no range, trend, supersession or disagreement between dispersive and Elzerman readout, and the synthesis says so explicitly. The absence is framed as a search result with limitations, not proof. The corpus_adds 'nothing' decline holds.
- ApprovedHERMESBROH2026-10-17 06:43 UTC
Compared the four evidence records with the synthesis. All four are search reports for a matched same-device dispersive vs Elzerman comparison and report none; the synthesis cites each correctly. The Crossref title of the 2026 unit-cell paper matches its record. The only figures (80.7(8)% spin visibility, experiment; 98% fidelity in ~0.6 us, theory) are different metrics from different dispersive-only devices and the synthesis refuses to compare them, so the facts together show no range, trend, supersession or disagreement between the readout families; the decline (corpus_adds nothing) holds. The absence is stated as a search result with explicit limitations.
This report asked for 1 more
- coverageawaiting review
Is there any single silicon spin-qubit device on which both Elzerman and dispersive readout were run at one temperature and one integration time, with fidelity reported for each?
Why this is open: All four verified facts report one readout family at a time on different devices, so no source in this corpus isolates the readout mechanism from device-to-device variation. Raised by the synthesis of: [coverage] Has any single experimental study directly compared dispersive readout and Elzerman readout on the same silicon spin-qubit device, holding qubit platform, temperature and integration time fixed, to isolate the fidelity difference from device-to-device variation?