From a physical analogy to an operational question

The Galactic positron problem motivates questions about sources, transport, and annihilation observables. Actual analyses of the 511\,keV signal involve instrumental backgrounds, spatial models, spectra, and component-dependent inference Siegert2016. None of those structures is supplied by the four-dimensional data Hilbert space used here.

The present question is consequently narrower:

Given a declared finite preparation family and a declared finite channel, what does destructive readout return, and what may a separately declared statistical procedure infer from its records?

The words “bulge” and “disk” label two basis values. They do not identify those values with regions of the Milky Way.

The term antiqubit is motivated by the platform-specific unitary-inversion construction of Song and collaborators Song2025. Their work distinguishes an inverse unitary response from the ordinary response of a qubit. Here that distinction is installed as a mathematical input. We do not construct their transmon controls or import their experimental metrological performance.