Experimentally Robust Self-testing for Bipartite and Tripartite Entangled States

Abstract

Self-testing refers to a method with which a classical user can certify the state and measurements of quantum systems in a device-independent way. Especially, the self-testing of entangled states is of great importance in quantum information process. A comprehensible example is that violating the CHSH inequality maximally necessarily implies the bipartite shares a singlet. One essential question in self-testing is that, when one observes a non-maximum violation, how close is the tested state to the target state (which maximally violates certain Bell inequality)? The answer to this question describes the robustness of the used self-testing criterion, which is highly important in a practical sense. Recently, J. Kaniewski predicts two analytic self-testing bounds for bipartite and tripartite systems. In this work, we experimentally investigate these two bounds with high quality two-qubit and three-qubit entanglement sources. The results show that these bounds are valid for various of entangled states we prepared, and thus, we implement robust self-testing processes which improve the previous results significantly.

Direct characterization of coherence of quantum detectors by sequential measurements

“…33 The quantum detectors can also be self-tested with certain quantum states in the absence of prior knowledge of the apparatus. [34][35][36][37] The emerging data-pattern approach realizes the operational tomography of quantum states through fitting the detector response, which is robust to imperfections of the experimental setup. 38,39 Though QDT is a generic protocol to acquire entire measurement operators, it does not have the direct access to the singlematrix components of the measurement operator.…”

Directly Characterizing the Coherence of Quantum Detectors by Sequential Measurement

“…33 The quantum detectors can also be self-tested with certain quantum states in the absence of the prior knowledge of the apparatus. [34][35][36][37] The emerging data-pattern approach realizes the operational tomography of quantum states through fitting the detector response, which is robust to imperfections of the experimental setup. 38,39 Though QDT is a generic protocol to acquire the entire measurement operators, it does not have the direct access to the single matrix entries of the measurement operator.…”

Experimental self-testing for photonic graph states

“…However, due to the imperfect experimental systems, one cannot achieve the ideal self-testing results, i.e., the most self-testing methods are still only theoretical recipe. To realize the self-testing task in laboratory, many robust self-testing protocols have been developed to tolerate certain noise, in particular, some of them have also been successfully demonstrated in optical experiment [39,[43][44][45][46][47]. However, the experimental realization of self-testing for multipartite entanglement states has not been demonstrated yet.…”