Few Single-Qubit Measurements Suffice to Certify Any Quantum State
Abstract
A fundamental task in quantum information science is state certification: testing whether a lab-prepared n-qubit state is close to a given hypothesis state. In this work, we show that every pure hypothesis state can be certified using only O(n^2) single-qubit measurements applied to O(n) copies of the lab state. Prior to our work, it was not known whether even subexponentially many single-qubit measurements could suffice to certify arbitrary states. This resolves the main open question of Huang, Preskill, and Soleimanifar (FOCS 2024, QIP 2024).
Fields of Study & Subjects
Quantum Mechanics and Applications
Publication details
- Journal / source
- Proceedings of the 58th Annual ACM Symposium on Theory of Computing
- Publisher
- ACM
- Pages
- 54–60
- Publication date
- 9 June 2026
- Language
- EN