Optimal quantum overlapping tomography: Theory and experiment

Quantum overlapping tomography (QOT), which focuses on reconstructing subsystems of quantum systems, has emerged as a promising approach for quantum state learning, especially when full-state tomography is infeasible. QOT has attracted considerable interest and seen substantial development, but has not yet reached its ultimate limit. The authors introduce a unified framework for optimal QOT by mapping the problem to the ``clique cover'' model from graph theory. This framework provides superlative efficiency and experimental feasibility in measurement strategies. This validation of QOT's utility paves the way for advanced quantum system characterization and state-property learning.