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Equation 23 · Part 1 · Error Correction Is the Whole Problem in Quantum Computing

Symbol p_th

pthp_{\mathrm{th}}
pthp_{\mathrm{th}}

What this part means

ptp_th is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

ptp_th is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

It does not promise that operating below threshold is sufficient. Below threshold, increasing d suppresses logical error. The suppression is exponential in d but the prefactor matters enormously in practice, and the useful regime is reached only when p is well below pthp_{\mathrm{th}} , not marginally below it. Near threshold, the exponent is small and the overhead explodes.

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A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the article section

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