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(d2) 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.
Bibliographical noteFunding Information:
This work was supported in part by the National Research Foundation of Korea (NRF) (Grants No. 2019R1A2C3004812, No. 2019M3E4A1080074, No. 2019R1H1A3079890, No. 2020R1A2C1008609, and No. 2019R1A6A1A10073437), KIST institutional program (Project No. 2E30620), and the Spanish MINECO (Grants No. FIS201567963-P and No. PGC2018-099183-B-I00). Y. K. acknowledges support from the Global Ph.D. Fellowship by the NRF (Grant No. 2015H1A2A1033028).
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)