Quantum Journal

Asymmetric Entanglement-Assisted Quantum Locally Recoverable Codes

Locally recoverable codes (LRCs) permit reconstruction of a lost coordinate from a small subset of the remaining coordinates, a property that is a fundamental coding technique for distributed storage and, more recently, for fault-tolerant quantum memories and distributed storage systems. Existing constructions of quantum locally recoverable codes (qLRCs) and their entanglement-assisted generalizations (EA-qLRCs) impose a single locality paramete...

Designing Robust Quantum Gates

For given control channels, quantum control theory determines whether quantum gates can be realized, but not their resilience to errors. We address this problem by establishing existence criteria for robust gate implementation in $d$-level systems. Our criteria reveal that implementability of all gates is not enough: a universal family of robust gates exists if and only if the driven Hamiltonians share no common symmetry. When these criteria hol...

Quantum error correction well below the color code threshold

Quantum error correction enables scalable fault-tolerant quantum computation by suppressing logical errors exponentially with code distance once physical error rates fall below a critical threshold. Here we demonstrate below-threshold operation of triangular color codes with distances $d=3,5,$ and $7$ on Quantinuum's Helios trapped-ion quantum processor. Leveraging both circuit- and hardware- level leakage reduction schemes, we achieve logical e...

Researchers Achieve Fundamental Quantum Limits on Surface Dynamics

A team of scientists has successfully reached the ultimate quantum limits on a surface, marking a milestone in precision physics. This achievement provides critical insights into the fundamental behavior of matter at the smallest scales.