subscript

The passage around this formula

where $E_{\text{core}}$ is the energy of the operation itself — the multiply-accumulate, the interference pattern, the qubit gate — and $E_{\text{periphery}}$ and $E_{\text{I/O}}$ are the data-converter, laser-and-detector, cryogenic, or spike-routing overhead surrounding it. A headline figure reporting only $E_{\text{core}}$ , which vendor materials frequently do, looks dramatically better than one reporting the whole sum, and each approach hides a different fraction of its true cost: analog crossbars in $E_{\text{periphery}}$ 's data converters, photonics in $E_{\text{I/O}}$ 's laser budget, quantum processors in $E_{\text{periphery}}$ 's dilution-refrigerator overhead. A single tera-operations-per-watt…

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