Manipulation of Quantum Nonlocality of the Single-Photon Entangled State via Beam Splitter
Qingping Zhou, Mao-Fa Fang, Xiaojuan Liu · Chinese Physics Letters · 2004
Quantum nonlocality of the single-photon entangled state emerging from a beam splitter with arbitrary controlling parameters is investigated by means of the parity measurement. The condition of the maximal violation of the Bell-CHSH inequality is obtained for the single-photon entangled state. Under the condition of the small coherent intensity J ( J = 0.1) and the phase difference γ αβ of the two coherent displacements being opposite to the internal phase shift ϕ of the beam splitter (γ αβ = −ϕ), we find that the quantum nonlocality depends only on the reflection coefficient R of the beam splitter, while ϕ plays an important role for selecting γ αβ . The strongest quantum nonlocality can be observed for a 50:50 beam splitter. If R deviates from the intermediate value 0.5, the quantum nonlocality decreases gradually, even vanishes. Our results provide a method to observe and manipulate the quantum nonlocality of the single-photon entangled state by adjusting the parameters of the coherent displacements and the beam splitter.