Advances in circuit quantum electrodynamics have enabled the generation of arbitrary nonclassical microwave states and paved the way for addressing novel physics questions. Here, we present a theoretical study of the electrical current in a Josephson tunnel junction interacting with a nonclassical electromagnetic environment. This allows us to generalize classical transport phenomena like photon-assisted tunneling and Shapiro steps to the quantum regime. We predict that the analysis of the supercurrent in such a setup enables the complete reconstruction of quantum states of the electromagnetic environment, something that is not possible with normal tunnel junctions.
@article{arxiv.2507.22662,
title = {Nonclassical Photon-Assisted Transport in Superconducting Tunnel Junctions},
author = {Matthias Hübler and Juan Carlos Cuevas and Wolfgang Belzig},
journal= {arXiv preprint arXiv:2507.22662},
year = {2025}
}