Table 1 Experiment and cosmic-ray rate model parameters
From: Synchronous detection of cosmic rays and correlated errors in superconducting qubit arrays
Symbol | Value | Description | Evaluation | Reference |
|---|---|---|---|---|
Δtcycle | 15.274 μs | measurement cycle duration | measured | Supplementary Note 2 |
δtQS | 45.821 μs | coincidence window | 3 ⋅ Δtcycle | Supplementary Note 3 |
ncycles | 62.82 ⋅ 109 | total number of cycles | defined | Supplementary Note 2 |
T | 266.531 h | total duration of data | ncycles ⋅ Δtcycle | Supplementary Note 2 |
σQ | 0.131 cm2 | qubit array (Q) cross-section | numerical sampling | Methods |
σQS | 0.0189 cm2 | qubit-detector (QS) cross-section | numerical sampling | Methods |
σQS,ϵ | 0.0187 cm2 | QS effective cross-section | Eq. 16 | Methods |
\({\epsilon }_{{\delta t}_{{\rm{QS}}}}\) | 94 ± 1% | QS identification efficiency | simulated and measured | Supplementary Note 3 |
ϵS | 98.7 % | efficiency of detectors collectively (S) | σQS,ϵ/σQS | Methods |
ϵ | 92 % | net efficiency of QS detection | \({\epsilon }_{{\rm{S}}}{\epsilon }_{{\delta t}_{{\rm{QS}}}}\) | Methods |
CQS | 13.3 ± 0.4 % | Coverage of the qubit array | \({\epsilon }_{{\delta t}_{{\rm{QS}}}}{\epsilon }_{{\rm{S}}}{\sigma }_{{\rm{QS}}}/{\sigma }_{{\rm{Q}}}\) | Methods |
NQ | 9, 460 | qubit array (Q) event count | measured | Supplementary Note 1 |
NS | 14, 403, 488 | collective detector (S) pulse count | measured | Methods |
NQS | 222 | QS coincidence count | measured | Supplementary Note 3 |
rQ | 1/(101 ± 1) s−1 | qubit array (Q) event rate | NQ/T | Supplementary Note 4 |
rS | 1/66.6 ms−1 | collective detector (S) pulse rate | NS/T | Supplementary Note 4 |
rQS | \(1/(72\pm 5)\,{\min }^{-1}\) | QS coincidence rate | NQS/T | Supplementary Note 4 |
\({r}_{{\rm{QS}}}^{{\rm{acc}}.}\) | 1/(41.9 ± 0.9) h−1 | QS accidental coincidence rate | \(({r}_{{\rm{Q}}}-{r}_{{\rm{QS}}})({e}^{{r}_{{\rm{S}}}{\delta t}_{{\rm{QS}}}}-1)\) | Supplementary Note 5 |
\({r}_{{\rm{QS}}}^{\mu }\) | \(1/(7{4}_{-5}^{+6})\,{\min }^{-1}\) | QS cosmic-ray coincidence rate | \({r}_{{\rm{QS}}}-{r}_{{\rm{QS}}}^{{\rm{acc}}.}\) | Supplementary Note 3 |
\({r}_{{\rm{Q}}}^{\mu }\) | \(1/(59{2}_{-41}^{+48})\,{{\rm{s}}}^{-1}\) | Q rate from cosmogenic sources | \({r}_{{\rm{QS}}}^{\mu }/{C}_{{\rm{QS}}}\) | Results and Methods |
\({r}_{{\rm{Q}}}^{{\rm{other}}}\) | 1/(120 ± 2) s−1 | Q rate from non-cosmogenic sources | \({r}_{{\rm{Q}}}-{r}_{{\rm{Q}}}^{\mu }\) | Results |
Φ | 0.0133(8) s−1cm−2 | muon flux | fitted detector-only data | Supplementary Note 9 |
\({r}_{{\rm{Q}}}^{\mu,\exp .}\) | \(1/(57{4}_{-33}^{+38})\,{{\rm{s}}}^{-1}{{\rm{cm}}}^{-2}\) | expected Q rate from cosmic rays | σQΦ | Results and Methods |
