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Equation 86 · Part 1 · The Atlas That Refuses to Close

Symbol X_NW

XNW\mathbf X_{\mathrm{NW}}
XNWX_{\mathrm{NW}}

What this part means

XNX_NW 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

XNX_NW 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

…to Hegerfeldt’s obstruction that has actually held up is to stop asking for a sharp position operator at all. Werner’s screen observables replace the eigenvalue-and-projector structure of x^\hat{\mathbf x} or XNW\mathbf X_{\mathrm{NW}} with a positive-operator-valued measure: a family of positive operators, one for each region of a detection screen, that sum to the identity and assign a probability to “a click registered in this region” without ever claiming the particle possessed a definite position immediately…

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