Experimentally Robust Selftesting for Bipartite and Tripartite Entangled States
Abstract
Selftesting is a method with which a classical user can certify the state and measurements of quantum systems in a deviceindependent way. In particular, selftesting of entangled states is of great importance in quantum information processing. An understandable example is that the maximal violation of the ClauserHorneShimonyHolt inequality necessarily implies that the bipartite system shares a singlet. One essential question in selftesting is that, when one observes a nonmaximum violation, how far is the tested state from the target state (which maximally violates a certain Bell inequality)? The answer to this question describes the robustness of the used selftesting criterion, which is highly important in a practical sense. Recently, J. Kaniewski derived two analytic selftesting bounds for bipartite and tripartite systems. In this Letter, we experimentally investigate these two bounds with highquality twoqubit and threequbit entanglement sources. The results show that these bounds are valid for various entangled states that we prepared. Thereby, a proofofconcept demonstration of robust selftesting is achieved, which improves on the previous results significantly.
 Publication:

Physical Review Letters
 Pub Date:
 December 2018
 DOI:
 10.1103/PhysRevLett.121.240402
 arXiv:
 arXiv:1804.01375
 Bibcode:
 2018PhRvL.121x0402Z
 Keywords:

 Quantum Physics
 EPrint:
 Phys. Rev. Lett. 121, 240402 (2018)