  Lattice models with non-hermitian, parity and time-reversal ($\mathcal{PT}$)
symmetric Hamiltonians, realized most readily in coupled optical systems, have
been intensely studied in the past few years. A $\mathcal{PT}$-symmetric dimer
lattice consists of dimers with intra-dimer coupling $\nu$, inter-dimer
coupling $\nu'$, and balanced gain and loss potentials $\pm i\gamma$ within
each dimer. This model undergoes two independent transitions, namely a
$\mathcal{PT}$-breaking transition and a topological transition. We numerically
and analytically investigate the signatures of these transitions in the
time-evolution of states that are initially localized on the gain-site or the
loss-site.
