We study cooperative behavior of quantum dipole emitters coupled to a
rectangular waveguide with dielectric core and silver cladding. We investigate
cooperative emission and inter-emitter entanglement generation phenomena for
emitters whose resonant frequencies are near the frequency cutoff of the
waveguide, where the waveguide effectively behaves as zero-index metamaterial.
We show that coupling emitters to a zero-index waveguide allows one to relax
the constraint on precision positioning of emitters for observing inter-emitter
entanglement generation and extend the spatial scale at which the superradiance
can be observed
