Installed registers and schedule

Choose two regular ports $A,B$, separated by a straight developed distance $\ell >0$ in the existing tube. Let the available developed time window have length $D>0$. Choose $\beta >0$ and $\ell >0$ small enough that

and the whole segment and waiting worldlines lie inside the retained reserve.

Install:

• $p$-qubit payload slots $A_0$ at $A$ and $A_1$ at $B$, with $p\ge 1$;

• one clock qubit $C_1$ at $A$;

• a different clock qubit $C_2$ at $B$;

• four classical bits: the first record at $A$, its delivered copy at $B$, the second record at $B$, and the success/failure flag at $B$.

Prepare $A_1$ in $\omega$. The two clock qubits are initially supplied; neither is reused after measurement.

Use the following schedule:

1. read $C_1$ destructively in the computational basis during a local slot of duration $\beta$, returning $k$;

2. wait $\beta$, then SWAP the payload from $A$ to $B$ over duration $2\ell$; deliver a classical copy of $k$ along a parallel declared causal wire over the same duration;

3. at $B$, after both arrivals, apply $H^k$ to $C_2$ during duration $\beta$;

4. destructively read $C_2$ during duration $\beta$, returning $l$;

5. during duration $\beta$, apply

   $$W_{kl}={Z_1}^{k(1-l)}$$

   to the payload, where $Z_1$ acts on its first qubit; append the failure flag $f=l$;

6. wait $\beta$, then SWAP the payload back to $A$ over duration $2\ell$.

The route speed is $1/2$ in developed units. All cross-port paths are timelike.

The final quantum payload is at $A$. The first record remains at $A$; its copy and the other records remain at $B$. A later operation at $A$ depending on $l$ would require another classical delivery, which is not silently included.