Low-overhead fault-tolerant quantum computation by gauging logical operators

Understand

Quantum computation must be performed in a fault-tolerant manner to be useful in practice.

• Recent progress has established quantum error-correcting codes with sparse connectivity requirements and constant qubit overhead suitable for quantum memory.
• However, existing schemes that include fault-tolerant logical measurement on such quantum memories do not always achieve low qubit overhead.
• Here we present a low-overhead method to implement fault-tolerant logical measurement on a quantum error-correcting code by treating the logical operator as a physical symmetry and gauging it so that it is enforced by a product of local symmetries.