Kim, YosepYong-Siah, TeoDaekun, AhnIm, Dong GilCho, Young WookLeuchs, GerdSánchez Soto, Luis LorenzoHynseok, JeongKim, Yoon-Ho2023-06-162023-06-162020-05-270031-900710.1103/PhysRevLett.124.210401https://hdl.handle.net/20.500.14352/6324© 2020 American Physical Society. National Research Foundation of Korea (NRF)National Research Foundation of Korea [2019R1A2C3004812, 2019M3E4A1080074, 2019R1H1A3079890, 2020R1A2C1008609, 2019R1A6A1A10073437]; KIST institutional programKorea Institute of Science & Technology (KIST) [2E30620]; Spanish MINECO [FIS201567963-P, PGC2018-099183-B-I00]; Global Ph.D. Fellowship by the NRF [2015H1A2A1033028].Recent quantum technologies utilize complex multidimensional processes that govern the dynamics of quantum systems. We develop an adaptive diagonal-element-probing compression technique that feasibly characterizes any unknown quantum processes using much fewer measurements compared to conventional methods. This technique utilizes compressive projective measurements that are generalizable to an arbitrary number of subsystems. Both numerical analysis and experimental results with unitary gates demonstrate low measurement costs, of order O(d(2)) for d-dimensional systems, and robustness against statistical noise. Our work potentially paves the way for a reliable and highly compressive characterization of general quantum devices.engjournal articlehttp://dx.doi.org/10.1103/PhysRevLett.124.210401https://journals.aps.orgopen access535Signal recoveryEntanglementÓptica (Física)2209.19 Óptica Física