Error Signals

Separate Error Budgets

do not call every mismatch decoherence

Bit labels and readout labels are different classical error models. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Bit-flip and readout budgets are separate

The bit-flip channel over 80 shots predicts 57 zero labels.

Nbit zero=57N_{\text{bit zero}}=57
Bit-flip budgetThis is a classical label channel.true probabilitieszero 3/4one 1/4assignmentobserved probszero 57/80one 23/80over 80 shots57 zero reads23 one readserror -> read

The two models use different denominators

The scan compares zero-label fractions without merging the bit-channel and readout-channel models.

modelpzero labelrolebit5780label channelreadout2940assignmentgap180do not merge\begin{array}{c|c|c}\text{model}&p_{\text{zero label}}&\text{role}\\\text{bit}&\frac{57}{80}&\text{label channel}\\\text{readout}&\frac{29}{40}&\text{assignment}\\\text{gap}&\frac{1}{80}&\text{do not merge}\\\end{array}
Separate-budget scanThe readout model is not renamed as bit flip.true probabilitieszero 3/4one 1/4assignmentobserved probszero 29/40one 11/40over 40 shots29 zero reads11 one reads

Readout assignment is a different model

The readout model over 40 shots predicts 29 zero reads.

Nread zero=29N_{\text{read zero}}=29
Readout budgetThis is calibrated readout, not decoherence.true probabilitieszero 3/4one 1/4assignmentobserved probszero 29/40one 11/40over 40 shots29 zero reads11 one reads