Single-photon scattering and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide system

We theoretically investigate coherent scattering of single photons and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide system. Using the real-space Hamiltonian, analytical expressions are derived for the transport spectra scattered by these two giant atoms with four azimuthal angles. Fano-like resonance can be exhibited in the scattering spectra by adjusting the azimuthal angle difference. High concurrence of the entangled state for two atoms can be implemented in a wide angle-difference range, and the entanglement of the atomic states can be switched on/off by modulating the additional azimuthal angle differences from the giant atoms. This suggests a novel handle to effectively control the single-photon scattering and quantum entanglement.