  Recent experimental advance in creating dissipative couplings provides a new
route for engineering exotic lattice systems and exploring topological
dissipation. Using the spatial lattice of atomic spinwaves in a vacuum vapor
cell, where purely dissipative couplings arise from diffusion of atoms, we
experimentally realize a dissipative version of the Su-Schrieffer-Heeger (SSH)
model. We construct the dissipation spectrum of the topological or trivial
lattices via electromagnetically-induced-transparency (EIT) spectroscopy. The
topological dissipation spectrum is found to exhibit edge modes within a
dissipative gap. We validate chiral symmetry of the dissipative SSH couplings,
and also probe topological features of the generalized dissipative SSH model.
This work paves the way for realizing non-Hermitian topological quantum optics
via dissipative couplings.
