Robust certification of arbitrary outcome quantum measure-ments from temporal correlations

Certification of quantum devices received from unknown providers is a primary requirement before utilizing the devices for any information processing task. Here, we establish a protocol for certification of a particular set of d-outcome quantum measurements (with d being arbitrary) in a setup comprising of a preparation followed by two measurements in sequence. We propose a set of temporal inequalities pertaining to different d involving correlation functions corresponding to successive measurement outcomes, that are not satisfied by quantum devices. Using quantum violations of these inequalities, we certify specific d-outcome quantum measurements under some minimal assumptions which can be met in an experiment efficiently. Our certification protocol neither requires entanglement, nor any prior knowledge about the dimension of the system under consideration. We further show that our protocol is robust against practical non-ideal realizations. Finally, as an offshoot of our protocol, we present a scheme for secure certification of genuine quantum randomness.

Automated summary

Certification of quantum devices is crucial before utilizing them for information processing tasks. This paper presents a certification protocol for a particular set of d-outcome quantum measurements, using a setup comprising of preparation and two sequential measurements. The protocol involves a set of temporal inequalities involving correlation functions and quantum violations of these inequalities are used to certify specific d-outcome measurements efficiently in an experiment. The protocol is robust against practical non-ideal realizations and does not require prior knowledge about the system dimension. Additionally, a scheme for secure certification of quantum randomness is presented as an offshoot of the protocol.