Note
Occupancy, radiation, and the greybody channel
Short Interior Skin Code. Working set 20 September 2026.
SISC is a channel grammar. An occupiable interior ρA (Hayden–Preskill diary) is coupled to a bath / reference σ by a joint unitary U. A greybody NΓ(w), with w the interoceptive precision / arousal, filters which bands of that joint evolution are allowed out. The outgoing state is radiation ρR.
The residual of the joint evolution is booked in ρR. Charging it back onto occupancy (backreaction onto dA) is illegal: occupancy is not the radiation account. Availability of radiation does not imply reconstructibility of the diary (Page; Hayden–Preskill). Helstrom-class recovery of ρR is not dynamical fidelity of the old generator H★ on that radiation.
A biological rhyme is general anesthesia as a tunable greybody: reportability can collapse (PCI as an availability meter) while residual hierarchical dynamics remain (Suzuki & Larkum 2020; Casali-class PCI).
Example 1. Imbalance under pinched greybody
Held point A0 = 1, σ = 0.8, w = 0.7. A pinched pass-band plus backreaction bills the mismatch onto occupancy. Opening Γ while backreaction remains is incomplete. Open NΓ with no backreaction leaves occupancy intact and books the residual as radiation.
| Condition | Γ | δ | I | A_after | ρ_R |
|---|---|---|---|---|---|
| Pinched Γ + backreaction | 0.25 | 0.85 | 0.56 | 0.44 | occupancy charged |
| Open Γ, backreaction remains | 1 | 0.85 | 0.29 | 0.71 | incomplete |
| Open N_Γ, no backreaction | 1 | 0 | 0 | 1 | 0.46 |
Example 2. XXZ new pair, no-crossing
4-site XXZ lattice. Seed 20260917, t = 0.7, Δ = 1. After Haar, a declared late pair (W′ = X3, K′ = H23) walks itself and does not reconstruct the old diary X0. The new pair is not continuation of X0.
| Quantity | Value | Reading |
|---|---|---|
| FA(K′, W′) | 1.0000 | declared late pair self-walks |
| FA(K′, X0) | 0.0581 | same generator does not walk the old diary |