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The contract rack released its training module before the chamber schedule advanced to the next task. Four channel lamps faced Tala at shoulder height. Through the glass behind them, matching cables ran outward along the truss toward four timing cavities.

The channels inherited the names of Sable's lost equatorial camps. Dawn had traveled the sunward rim, and Evening kept the opposing side. Cross maintained the surface road. Deep ended its migration in lava-tube shelter.

The camps were gone. Their names remained in maintenance speech, beside a collapsed antenna field and debts the cooperative still honored. Charter companies had abandoned both during the Withdrawal; Sable accepted the debts it could trace to real labor and rejected the ownership notices that arrived without maintenance. Nobody saying Deep has drifted needed to remember the people who once carried clocks there. The name remembered for them.

The training oracle phase-marked exactly one channel as faulty without exposing its identity directly.

Mara proposed opening the channel account. Osei reached for a physical probe. Iona agreed that either ordinary method would finish thirty minutes earlier.

The training case used four channels so every amplitude would remain visible.

A two-qubit register supplied four basis states, and Hadamards assigned them equal initial amplitude.

Each of four amplitude magnitudes was 1/2. Their squared magnitudes summed to one, establishing normalization.

4 * (1/2)^2 = 1

Iona selected state 3, and the oracle negated only that state's phase. Sana sealed the selection before execution, preventing any later relocation of the answer.

Tala committed 3 to old paper before viewing the trace, denying her future memory room to improve the prediction.

Immediate measurement would still assign probability 1/4 to each outcome because phase negation preserved magnitude. Another operation had to bring the exceptional sign into interference.

They used the blank side of an obsolete maintenance card. Tala summed the amplitudes. Osei verified the arithmetic, rotated the card, and verified it from the opposite side.

After the phase mark, the mean of the four amplitudes was 1/4.

(1/2 + 1/2 + 1/2 - 1/2) / 4 = 1/4

The diffusion operation reflected each amplitude across the mean, mapping amplitude a to 2 * average - a.

unmarked: 2*(1/4) - 1/2  = 0
marked:   2*(1/4) - (-1/2) = 1

Reflection sent all three unmarked amplitudes to zero and the marked amplitude to one.

Interference had converted the phase mark into outcome certainty.

Mara finally approved of an algorithm rack. The answer had never been extracted and inserted into output. Its phase had altered how every alternative combined.

"That requires one iteration?"

"For this four-state space," Iona said.

"Measurement returns three with certainty?"

"Inside the stated oracle promise."

Mara indicated Sana. "I could hear that qualification approaching."

"Implication has no authority on my watch," Sana said.

Tala translated the arithmetic into gates.

quantum class GroverFour {
  state long measured = 0;
  qreg q = new qreg(2);

  unitary void markThree() {
    CZ(q[0], q[1]);
  }

  unitary void diffuse() {
    H(q[0]);
    H(q[1]);
    X(q[0]);
    X(q[1]);
    CZ(q[0], q[1]);
    X(q[0]);
    X(q[1]);
    H(q[0]);
    H(q[1]);
  }

  entry void main() {
    prepare(q, 0);
    H(q[0]);
    H(q[1]);
    markThree();
    diffuse();
    measured = measure(q);
    assert(measured == 3);
  }
}

The schedule permitted one ideal execution before cooling. The rack's four channel lamps remained alike while the simulator state followed the maintenance-card calculation.

after preparation  [+0.5, +0.5, +0.5, +0.5]
after mark         [+0.5, +0.5, +0.5, -0.5]
after diffusion    [ 0.0,  0.0,  0.0, -1.0]
measurement        3

The gate sequence produced a global minus absent from their hand result. It left every measurement prediction unchanged.

Tala exposed the 3 written before execution. Its age mattered more than its correctness.

Then Mara took Osei's probe and inspected the actual channels. All were healthy. State 3 had been marked in the training oracle. No fault had been discovered in the timing cavity. Faulty belonged to the problem, not the hardware.

Compared with direct inspection, the training execution spent thirty-three additional minutes. Mara charged every one to the maintenance account.

A delayed traffic notice arrived while she was signing it.

RETUNING RESERVE       one chamber window
NEXT CONTACT           full manifest or legacy profile
LEGACY CONSEQUENCE     widened approach intervals

Venn had signed before the training run began. She did not know which minutes Sable would spend. She had made clear that Catenary would spend them too.

They had performed one complete Grover iteration over four states. It demonstrated no practical speedup: the search space and oracle were tiny, chamber overhead dominated, and an ordinary probe could identify a physical channel fault.

"We spent half an hour proving that a future machine may avoid spending it," Mara said.

Iona reclaimed the probe. "You have understood the research calendar."

Any advantage claim would need larger spaces, accounted oracle construction, repeated iterations, state-preparation cost, and error correction. The two-qubit execution established none of those conditions.

Sable distrusted demonstrations promoted into industries. Machines in the abandoned camps had been sold through extrapolations from cleaner laboratories. Financing vanished long before their pressure shells finished failing.

Sana recorded the result at its demonstrated scale. In the ideal model, one oracle call phase-marked a state and diffusion made its outcome certain. She attached source, trace, assertion, and agreement without an advantage claim.

The main array required a transform over structured phase patterns. Hadamard supplied its one-qubit form. Larger forms added controlled phase, and Vela carried a three-qubit source ready for qualification.

Three qubits permitted complete inspection and sufficient room for a significant error.

Shutters crossed the outer truss beyond the rack-room glass, covering Dawn, then Cross, Evening, and Deep.

The central array alone remained open to the sky. Sable redirected years of maintained distance toward the coming comparison.

Iona bound the inherited source to the Far Instrument.