[ Prof. Kim, Yoon-Ho]Universal Compressive Characterization of Quantum…

Caption: (Left) Experimental schematic of adaptive compressive quantum process tomography (ACQPT). (Right) The outcome comparison between a standard quantum process tomography with 256 measurements and ACQPT with 39 measurements. 

Universal Compressive Characterization of Quantum Dynamics 

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.