Scope, target, and declared external inputs

The construction follows

Its target is one effect, not the two-memory apparatus of Em03-C Em03C. For a normalized outgoing packet $h$, set

Since the real part of a unitary has spectrum in $[-1,1]$,

We prove a state-class comparison of the form

Here $R$ is a spatial approximation parameter and $ϵ>0$ is a coupling parameter. The probe state, coupling profile, and readout test are specified below.

The scheme uses a full spherical shell. For each finite $R$ its coupling is compactly supported strictly outside the horizon. No fixed shell is claimed to realize arbitrary packet accuracy.