Quanticious | New quantum papers, explained

This week’s lead paper: A trapped-ion processor runs error correction well below threshold

Slide 1: Bigger error protection, twelve times fewer errors. Measured on Quantinuum’s Helios, preprint. Each step up in size cut errors about twelvefold, decoded afterwards on a computer. A triangle of seven qubits with one flipped qubit and the two tiles touching it raising flags.

Slide 2: Every qubit is fragile. A row of seven qubits, one flipped by a disturbance.

Slide 3: So one qubit is spread over seven. Coloured tiles check the qubits at their corners. The two tiles touching the flipped qubit raise a flag.

Slide 4: Bigger patch, fewer errors. Errors per round, measured on Helios, decoded offline. Distance 7: 5 (+4/−2) in a million. Values read from Figure 1c and rounded: about 5 in 10,000 with 7 qubits, about 4 in 100,000 with 19 and about 5 in a million with 37, labelled about ÷12 per step.

Slide 5: But only if every qubit is good enough. Schematic: adding qubits leads to more errors above a threshold (too noisy) and to fewer errors below it (good enough).

Slide 6: Helios is well below the threshold. About twelvefold fewer errors with each step up in size, with the best offline decoder. The three measured colour codes drawn as triangles of 7, 19 and 37 qubits with their check tiles, errors per round read from Figure 1c and rounded: about 5 in 10,000, 4 in 100,000 and 5 in a million. Link to quanticious.com.

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Issue 1 | 22 October 2026

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