Simulation Scheme For Post-quantum Correlation And Its Distillation In Optical System

Nonlocal correlation is an important physical resource.Quantum nonlocality is the essential characteristic of the quantum world.Bell inequality is the basic criterion to distinguish quantum theory and hidden variable model,and in the recent experimental verification of Bell inequality,people have been able to close three main experimental loopholes simultaneously.However,Bell inequality is not a sufficient and necessary criterion,and its theoretical research is still a hot topic in current international academic research.At the same time,the study of super-quantum correlation(or post-quantum correlation)will also deepen people's understanding of quantum theory and may lead to the emergence of new information processing methods.In this thesis,we mainly study how to simulate post-quantum correlation and its distillation in optical system.The research contents and achievements of this thesis include three aspects as follows:First,we design a physical scheme for simulating the Popescu-Rohrlich(PR)box in optical system.The probability distribution of the PR box can lead to the maximal violation of the CHSH(Clauser-Horne-Shimony-Holt)inequality,that is,its CHSH value reaches the maximum value of 4,which is far beyond the observed maximum CHSH value 2(?)in quantum mechanics.As we all know,by selecting the states to be tested,we can open the fair sampling loophole in Bell test,and thus it will lead to post-quantum correlations.In this thesis,we will select the measurement results after measurement,which opens the fair-sampling loophole and thus simulates the post-quantum correlations.Because the post-selection process violates the information causality,it opens the locality loophole too,which means that this kind of results selection leads to both fair-sampling loophole and locality loophole,so we call it a comprehensive loophole in Bell test.The comprehensive loophole opened by the results selection may be another possible explanation of why post-quantum correlations are incompatible with quantum mechanics and seem not to exist in nature.Second,an optical scheme for simulating nonlocality distillation is proposed in post-quantum regime.The nonlocal boxes are simulated by measurements on appropriately pre-and post-selected polarization entangled photon pairs.We can obtain a strong post-quantum nonlocal box from two weak post-quantum nonlocal boxes by implementing a beamsplitter-based mod 2 addition operation on the outputs of the simulated boxes with suitable pre-selected and post-selected polarization entangled photons.The success probability of the distillation process is unit,and the practical non-unit efficiency of the detectors will only slightly affect the quality of the output box.Lastly,an optical scheme for simulating adaptive nonlocality distillation is proposed.The adaptive property of the nonlocal distillation scheme means that the inputs of the second nonlocal box are dependent on the outputs of the first nonlocal box.Finally,the outputs of the two boxes will be combined via modulo-2 addition operation,whose results are regarded as the outputs of the distilled box.In the asymptotic limit,arbitrary correlated nonlocal boxes can be distilled to the maximally non-local one,i.e.PR box.The main obstacle to the simulation of adaptive nonlocal distillation is how to simulate the nonlocal box in quantum systems and get the outputs of each box without destroying the quantum state simulating it.Here the appropriately pre-and post-selected polarized entangled photons are used to simulate the nonlocal boxes,and with the quantum nondestructive measurement(QND)based on the standard quantum teleportation process we can get the outputs of the first box without destroying the corresponding quantum state.The schemes proposed in this thesis provide feasible tools for the experimental study on the manipulation of nonlocality in post-quantum regime and the exact physical principle precisely distinguishing physically realizable correlations from nonphysical ones.