Certifying Quantum States with Uniform Measurements

Qubit-resolved operations and measurements are required for most current quantum information processing schemes. However, these operations can be experimentally costly due to the need for local addressing, demanding significant classical control. A more resource-effcient alternative to extract information is uniform measurement, where a site-independent rotation of qubits is performed before measuring in the computational basis. This operation can be performed in parallel, or globally, in atom- and ion-based platforms, reducing resource cost and increasing fidelity. In this work, we initiate the exploration of the utility of this operation in quantum information processing. In particular, we demonstrate that uniform measurements can certify certain graph states, a family of highly entangled and broadly useful quantum states. We provide a sample-effcient certification algorithm with a proved performance guarantee, together with an experimental scheme based on analog-mode Rydberg atom arrays. Uniform measurements, therefore, allow direct and effcient characterization of quantum states on quantum platforms in a hitherto unexplored manner. More broadly, our work establishes “uniformity” as a meaningful and practically motivated resource rubric for quantum information processing, and offers new insights into the architectural design of quantum computing devices.