Abstract: Based on the theory of non-Kolmogorov atmospheric turbulence spectrum, a mathematical model of spatial two-qubit entangled states propagation in non-Kolmogorov atmospheric turbulence is established, the corresponding mathematical expression of entanglement degradation is obtained, and the influence of non-Kolmogorov turbulence on the entanglement of spatial two-qubit states is analyzed by numerical simulation. The results show that high entanglement of the spatial two-qubit entangled states can be maintained when the physical size and separation between each signal and the corresponding idler apertures is small. Moreover, it is found that when the long wavelength entangled photons propa- gate through non-Kolmogorov atmospheric turbulence with larger generalized refractive-index exponent parameter α and generalized refractive-index structure parameter ˜C2 n, the entanglement degradation is rel- atively weak. The proposed model can be used to quantitatively analyze the entanglement degradation, which is helpful for long distance self-adaption quantum communication with low bit error rate.

Key words: quantum optics, atmospheric optics, turbulence effect, non-Kolmogorov atmospheric turbu- lence, spatial entanglement, concurrence