Analog quantum simulation of a Kondo impurity with superconducting circuits

A particular quantum simulator can be used to access the many body properties of the Kondo problem [1]. We created the first experimental realization of this quantum simulator. The simulator is comprised of a high impedance Josephson junction waveguide connected to a fluxonium qubit at its end. The fluxonium hosts a fluxon mode that can be far detuned from any of the other transitions. It can thus be considered as a two level system that then acts as the spin in the simulated Kondo model. This spin couples to a continuum of modes in the waveguide, which acts as the bath, thus completing the model. We study the spectra of inelastic and elastic scattering of the waveguide photons which are expected to reveal the many body correlation functions of the Kondo model.
[1] Goldstein, M., Devoret, M. H., Houzet, M. & Glazman, L. I. Phys. Rev. Lett. 110, 1–5 (2013).