A half-full array loads by chance.
Plan it defect-free — provably, at minimum cost.
A neutral-atom processor loads atoms stochastically into a grid of optical traps — each site fills with probability about a half — then mobile tweezers rearrange them into a defect-free target register before the computation. Which atom moves to which site is a combinatorial optimization: the linear sum assignment problem — give every target site a distinct atom, minimizing total move distance — solved exactly by the Hungarian algorithm.
Here it is in pure integer Rust, byte-identical on every machine, turning a low-yield load into
a defect-free block and sealing the plan into a signed wai.quantum.rearrange
receipt. The success verdict — every target site covered by a valid bijection of atoms
actually present — is re-checkable from the bound configurations, and the same check rejects a
tampered plan. Honest boundary: a geometric/combinatorial model — the solver and its optimality are
exact; tweezer transport, loss, and AOD parallelization are out of scope.
Rearrange to a defect-free register · Hungarian / LSAP
Yield transformation · the certificate is real
The combinatorial solver that prepares the register — signed, budgeted, verifiable
The plan panel loads a trap array at random and solves the assignment: every site of a centered
defect-free block is matched to a distinct loaded atom minimizing the total Manhattan move
distance (the Hungarian algorithm, proven optimal in the tests against brute force), and the
arrows show the atoms converging on the target. The receipt binds
(initial occupancy, target sites, move plan) → success plus the plan's cost. The yield
panel shows the point of it: the target region fills only partway by chance, and
completely after the plan — and dropping a single move makes the same deterministic check
report not defect-free, so the certificate can say no. A register-preparation plan you can put
in an auditor's hands, reproduce from the git repo, and verify with a public key. Reference solver +
spec in the open-standards repo, Apache-2.0.