Tunneling spectroscopy in superconducting circuit lattices

Investigating the behavior of collective excitations in strongly correlated quantum materials is crucial for understanding many-body physics and advancing quantum technology. I will present our recent experiments on probing collective excitations in a superconducting circuit lattice quantum simulator. We demonstrate site-resolved tunneling spectroscopy by coupling the lattice to engineered driven-dissipative particle baths that serve as local tunneling probes. We extract quasi-hole and quasi-particle spectra and reconstruct the spatial structure of collective excitations. We perform spectroscopy of a strongly interacting Bose-Hubbard lattice at different lattice fillings, observing changes in energy gaps across the superfluid to Mott-insulator transition and the effects of three-body interactions. In addition, I will also discuss our ongoing effort to characterize the decoherence of these collective excitations and the potential to leverage it for entanglement generation in strongly interacting qubit arrays. Our results offer a novel toolset for characterizing many-body states and dynamics in analog quantum simulators.