Bare-excitation ground state of a spinless-fermion — boson model and W-state engineering in an array of superconducting qubits and resonators

This work unravels an interesting property of a one-dimensional lattice model that describes a single itinerant spinless fermion (excitation) coupled to zero-dimensional (dispersionless) bosons through two different nonlocal-coupling mechanisms. Namely, below a critical value of the effective excitation-boson coupling strength the exact ground state of this model is the zero-quasimomentum Bloch state of a bare excitation. It is demonstrated here how this last property of the model under consideration can be exploited for a fast, deterministic preparation of multipartite W states in a readily realizable system of inductively-coupled superconducting qubits and microwave resonators.