Abstract
Dicke state is an widely used type of multi-particle entangled state in quantum information. However, very few works have been done on its nonlocality. Here we prepare a four-photon symmetric Dicke state, whose fidelity is as high as 0.904 ± 0.004, and devise a simple Bell-type inequality to demonstrate that it violates the local realism with 12 standard deviation.
Highlights
Multi-particle entanglement states provide an important resource in quantum information and computing
The violations of local hidden variable theory for multipartite entangled states become the criteria of some Device-Independent (DI) quantum information processing tasks, such as the security of quantum key distribution (QKD) [1,2], decreasing the computation complexity [3,4] and the validity of random number generation [5], etc
The explicit expressions of Bell inequalities are too complicate to be used to verify the violation of local realism
Summary
Multi-particle entanglement states provide an important resource in quantum information and computing. Observations of violations of local realism in the case of multipartite correlations are a challenging task because of the lack of handy Bell inequalities for multipartite systems,. As a kind of important multipartite states which naturally arise in symmetric systems [18], Dicke states are highly persistent against photon loss and projective mesurements [19]. These states possess high level multipartite entanglement. Recent researches demonstrate that they are optimal for quantum metrology [20, 21] and easy to quantify the entanglement depth for many-body systems [22] For these reasons, many works have been done on preparing the high quality Dicke states. It is more simple and easier to be realized in experiment than the one in [26]
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