Quantum Bath Synthesizer*

Photonic cavity arrays form the basis of one of the most promising paradigms for quantum simulation to study complex many-body physics. We developed a non-trivial structured photonic environment that could enable a multimode strong and ultra-strong coupling with quantum emitters. This platform consists of a unidimensional metamaterial implemented by an array of coupled superconducting microwave cavities made from thin Niobium Nitride (NbN) thin films. Such disordered superconductor allows to reach a very high kinetic inductance, which presents a two-fold advantage: a) It allows to reach ultra-strong coupling with an artificial atom as the capacitive coupling is proportional to the square root of the resonators' impedance, which can be highly increased thanks to the kinetic inductance; b) It allows to strongly reduce the resonator/metamaterial footprint. Furthermore, working with a metamaterial allows the engineering of a non-trivial photonic dispersion relation, where one can open bandgaps where it is possible to obtain states displaying symmetry protected topological (SPT) properties (SSH-states). In this work, we have been able to fabricate and characterize unidimensional metamaterials made of up to 64 ultra-compact resonators, in which we have engineered diverse band structures. To assess the quality of our metamaterials, we studied numerically and experimentally the evolution of the gap size between the hybridized SSH states, both in frequency and time domain. We are currently working on developing the platform for the study interacting atom-photon bound states in the giant-atom regime in these structured environments.