Quantum phase flip gate based on plasmonic double-bar resonators

We demonstrate a quantum phase flip gate between two QDs that resonantly couple to plasmonic double-bar resonators with asymmetric coupling strengths. Large coupling strengths can be achieved due to the deep sub-wavelength mode volumes of the optical modes in plasmonic double-bar resonators. High fidelity (∼98%) and high success probability of the phase gate operation have been obtained when the coupling strength ratio (g₂/g₁) and resonant mode decay rate (κ/g₁) are optimized. The subwavelength-scale plasmonic structures provide tremendous potential for solid-state quantum information processing.