Title: Gain-loss-driven travelling waves in PT-symmetric nonlinear metamaterials,
Abstract: In this work we investigate a one-dimensional parity-time (PT)-symmetric
magnetic metamaterial consisting of split-ring dimers having gain or loss.
Employing a Melnikov analysis we study the existence of localized travelling
waves, i.e. homoclinic or heteroclinic solutions. We find conditions under
which the homoclinic or heteroclinic orbits persist. Our analytical results are
found to be in good agreement with direct numerical computations. For the
particular nonlinearity admitting travelling kinks, numerically we observe
homoclinic snaking in the bifurcation diagram. The Melnikov analysis yields a
good approximation to one of the boundaries of the snaking profile.