Reading a quantum bit without breaking it: a supercurrent does the listening

Quantum computers are powerful and fragile in equal measure: the act of reading a quantum bit usually destroys the information it holds. A team led by José Carlos Egues at the University of São Paulo, with Yugui Yao in Beijing, has shown in simulation a gentler way — an 'Andreev qubit' that can be read through the rhythm of its own oscillating supercurrent, an electric current that flows without resistance, with no helper qubits needed. Their simulations reached readout accuracies of 99.5% to 99.9%, inside the range quantum error correction requires. Published in Physical Review B, it is theory for now — but theory that removes one of the field's practical roadblocks.

SDG 9 · Industry, innovation and infrastructure — Mechanism: tech innovation