WaveguideQEDoffers the possibility of generating strong coherent atomic
interactions either through appropriate atomic configurations in the
dissipative regime or in the bandgap regime. In this work, we show how to
harness these interactions in order to herald the generation of highly
entangled atomic states, which afterwards can be mapped to generate single mode
multi-photonic states with high fidelities.Weintroduce two protocols for the
preparation of the atomic states, we discuss their performance and compare them
to previous proposals. In particular, we show that one of them reaches high
probability of success for systems with many atoms but low Purcell factors
