Quanticious | New quantum papers, explained

This week’s lead paper: Two quantum chips, joined by a cable you could hold

Slide 1: Two quantum chips, joined by a cable you could hold. Measured at IBM on superconducting qubits: two 120-qubit chips, four cables of about 80 cm. Two dark squares with a grid of qubits, joined by four orange cables. Source: Sundaresan et al., arXiv 2610.29986, preprint, measured.

Slide 2: One chip will not be enough. Large quantum computers will be built from many chips that work as one machine. Six chips in two rows of three, joined by dotted orange links.

Slide 3: The cable hands a qubit’s state across. Chip 1 and chip 2, each with a white qubit and a blue end qubit, joined by a cable carrying an orange microwave.

Slide 4: Handovers reach 99 % fidelity. Average over the four cables 99.00 %, best cable 99.29 ± 0.07 %, a perfect copy would be 100 %. A schematic grid of 100 dots, 99 blue and 1 red, one red dot per percent missing.

Slide 5: A full gate between chips: about 95 % fidelity. Average 94.75 %, best 96.42 ± 0.28 %. In the authors' error budget the two handovers inside each gate are the largest part. A schematic grid of 100 dots, 95 blue and 5 red, rounded from 5.25 % missing.

Slide 6: The cables survived three cool-downs untouched. In the authors' model most handover loss comes from end qubits built without the usual quality steps, and with better ones it allows 99.68 to 99.77 %. Three circular arrows with check marks for cool-downs 1 to 3. New quantum papers, explained every Monday. Link to quanticious.com.

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Issue 2 | 2 November 2026

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Earlier issues

Issue 1 | 22 October 2026A trapped-ion processor runs error correction well below thresholdand 4 more