Quantum error correction reduces measurements and qudits needed for recovery

Simultaneous Reduction of Observables and Measured Qudits in Entanglement-Assisted Quantum Local Recovery

Information Theory

Summary

Quantum computers need to fix mistakes caused by noise, and this requires measuring certain parts of their data and using specific qudits (quantum bits). The authors found a way to identify the smallest number of measurements and qudits necessary to recover the data after some are lost or erased. Their approach uses linear algebra and works efficiently for large sets of qudits. They also provide special formulas for certain types of quantum codes and relate their findings to ideas from classical data recovery.

What this means in practice

Authors

Ryutaroh Matsumoto

Abstract

For a general entanglement-assisted or unassisted quantum error-correcting code, a set of erasures, and an associated repair group, we propose a linear algebraic procedure to compute a reduced set of observables and a reduced repair group of codeword qudits for correcting the given erasures. The procedure has cubic complexity in the repair group size and the computed set of observables has the smallest possible size for correcting the given erasures. We specialize the general procedure to quantum codes constructed from Euclidean and Hermitian orthogonality, and provide closed-form upper bounds on the size of reduced repair groups for those special cases. Based on these closed-form bounds, we propose quantum counterparts of the information locality of classical local recovery.