Cabello non-locality principle and experimental test of High dimensional setup system

The liquid crystal spatial light modulator is mainly composed of liquid crystal light valve, driving board and control software. Its working principle mainly uses the photoelectric effect of the liquid crystal, under the control of the driving signal, changes the voltage loaded on the liquid crystal molecule in the box, the liquid crystal molecule deflects, and the birefringence changes, thus changing the amplitude, phase or polarization state of the spatial distribution of the read light. The liquid crystal spatial light modulator can realize different modulation modes through software programming, and this programmability makes it flexible to use in different application scenarios and adapt to different optical requirements. Due to the advantages of flexibility, high-dimensional regulation and high-precision measurement, the liquid crystal spatial light modulator can effectively improve the operability of the experiment and the accuracy of the data, and provide a strong tool support for the study of quantum non-localization.

Thesis information:

Recent advances have extended Hardy's non-locality principle to multi-setups and multi-dimensional systems to enhance quantum correlation. Compared with Hardy's non-locality principle, Cabello's non-locality Principle (CNA) can explain the non-locality characteristics of quantum better. However, it remains an open question as to whether CNA is possible to scale to arbitrary (k, d) scenarios. This paper answers this question theoretically and experimentally. In theory, a new logical framework for high-dimensional setting CNA is constructed using compatibility graph, which proves that the probability of non-local events will increase with the increase of setting number k and dimension d. Experimentally, the reconfigurable property of a spatial light modulator (SLM) is used to achieve entanglement concentration and measurement. Specifically, by adjusting the diffraction efficiency of the blazed phase grating loaded on SLM, the weight of OAM mode with high probability amplitude in the initial state is reduced, so that the prepared state is preserved consistent with the optimal quantum state, and the measurement of entanglement concentration and OAM superposition state is realized at the same time. Through this measurement scheme, the experimental results show that the probability of non-local events is 20.29% in scenario (2,4) and 28.72% in scenario (6,2), which proves the high-dimensional set Cabello theorem. The work in this paper demonstrates an even sharper contradiction between quantum mechanics and classical theory, beyond the limits of the original Cabello theorem on the probability of non-locality.

The following are part of the experimental process and results:

A 355nm UV-mode-locked laser was used as the pumping source of a 3mm thick barium β-borate (BBO) crystal to generate 710nm photon pairs through a spontaneous parametric downconversion process. A long-pass filter (IF) is placed behind the crystal to block the pumping beam, and then a non-polarized beam splitter (BS) is used to separate the signal photons from the idle photons. In each lower converter arm, A 4f system consisting of twin lenses (L1, f1 = 200 mm and L2, f2 = 400 mm) imagines the output plane of the BBO onto two SLMS (SLM A and SLM B, FSLM-2K70-VIS). The designed holograms are loaded separately on the two SLMS for the preparation of the desired OAM measurement state and for the implementation of the entanglement concentration process. Subsequently, another 4f system (L3, f3 = 500 mm and L4, f4 = 4 mm) was used to re-image the SLM surface to the input surface of the single mode fiber (SMF) connected to the single photon counting module. In addition, two bandpass filters (BF) with a bandwidth of 10 nm and a central wavelength of 710 nm are placed in front of the SMF to reduce the detection of noisy photons. The outputs of the two single-photon counters are connected to a coincident counting circuit with a 25ns coincident time window.

FIG. 2 Experimental device (Phase spatial light modulator, model: FSLM-2K70-VIS).

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The parameters of the spatial light modulator used in this experiment are as follows: