Universal Decay of Quantumness for Photonic Qubits Carrying Orbital Angular Momentum Through Atmospheric Turbulence

We investigate the decay properties of the quantumness including quantum entanglement, quantum discord, and quantum coherence for two photonic qubits, which are partially entangled in their orbital angular momenta, through Kolmogorov turbulent atmosphere. It is found that the decay of quantum coherence and quantum discord may be qualitatively different from that of quantum entanglement when the initial state of two photons is not maximally entangled. We also derive two universal decay laws for quantum coherence and quantum discord, respectively, and show that the decay of quantum coherence is more robust than nonclassical correlations.