Experimental comparison of tomography and self-testing in certifying entanglement
arXiv:1901.10127 · doi:10.1103/PhysRevA.100.022305
The paper compares standard quantum state tomography with device‑independent self‑testing methods for certifying entanglement of two‑qubit states, showing that self‑testing can achieve nearly the same fidelity as tomography even when detection and locality loopholes are present.
Abstract
We assess the quality of a source of allegedly pure two-qubit states using both standard tomography and methods inspired by device-independent self-testing. Even when the detection and locality loopholes are open, the latter methods can dispense with modelling of the system and the measurements. However, due to finite sample fluctuations, the estimated probability distribution usually does not satisfy the no-signaling conditions exactly. We implement data analysis that is robust against these fluctuations. We demonstrate a high ratio $f_s/f_t\approx 0.988$ between the fidelity estimated from self-testing and that estimated from full tomography, proving high performance of self-testing methods.
9 pages, 6 figures