We investigate the long-range coupling of individual atoms coupled to plasmon modes of metallic nanostructures. Placing a
pair of emitters along a thin metallic wire, we observe a strong, wire- mediated long-range interaction between the emitters.
As a result, super- and subradiance can occur over distances large compared to the resonant wavelength. The states with
enhanced or suppressed decay rate are the symmetric or anti-symmetric single-excitation states. Coupling more atoms to a
wire network with a nontrivial coupling topology leads to interesting entangled subradiant states of the system. A similar
long-range superradiance effect can be observed when two emitters are coupled by a metamaterial slab (also known as a
perfect lens) having a refractive index n=-1. Besides the modification of decay rates, dipole-dipole shifts enter due to the
plasmon-mediated interaction. Based on the superradiance effect, we propose setups for building a two-qubit quantum
phase gate for quantum emitters coupled by a nanowire and a perfect lens, respectively, where the qubits are strongly
interacting and individually addressable at the same time.