Effective many-body Hamiltonians of qubit-photon bound states

Understand

Quantum emitters (QEs) coupled to structured baths can localize multiple photons around them and form qubit-photon bound states.

• In the Markovian or weak coupling regime, the interaction of QEs through these single-photon bound states is known to lead to effective many-body QE Hamiltonians with tuneable but yet perturbative interactions.
• In this work we study the emergence of such models in the non-Markovian or strong coupling regime in different excitation subspaces.
• The effective models for the non-Markovian regime with up to three excitations are characterized using analytical methods, uncovering the existence of doublons or triplon states.