  In spite of decades of effort, it has not yet been possible to create
single-mode multiphoton states of light with high success probability and near
unity fidelity. Complex quantum states of propagating optical photons would be
an enabling resource for diverse protocols in quantum information science,
including for interconnecting quantum nodes in quantum networks. Here, we
propose several methods to generate heralded mutipartite entangled atomic and
photonic states by using the strong and long-range dissipative couplings
between atoms emerging in waveguide QED setups. Our theoretical analysis
demonstrates high success probabilities and fidelities are possible exploiting
waveguide QED properties.
