Quantum entanglement in plasmonic waveguides with near-zero mode indices

We investigate the quantum entanglement between two quantum dots (QDs) in a plasmonic waveguide with a near-zero mode index, considering the dependence of concurrence on interdot distance, QD waveguide frequency detuning, and coupling strength ratio. High concurrence is achieved for a wide range of interdot distances due to the near-zero mode index, which largely relaxes the strict requirement of interdot distance in conventional dielectric waveguides or metal nanowires. The proposed QD waveguide system with near-zero phase variation along the waveguide near the mode cutoff frequency shows very promising potential in quantum optics and quantum information processing.