It is well known that superconducting waveguides strongly attenuate the propagation of electromagnetic waves with frequencies beyond the superconducting gap. In circuit QED, the interaction between non-linear charge qubits and superconducting resonators invariably involves the qubit coupling to a large set of resonator modes. So far, strong dispersion effects near and beyond the superconducting-gap have been ignored in quantization models. Rather, it is assumed that the superconducting resonator behaves ideally across the large frequency intervals. We present a quantization approach which includes the superconducting frequency-dependent surface impedance and demonstrate that superconducting dispersion plays a role in determining the effective light-matter interaction cut-off.
@article{arxiv.2505.09322,
title = {Light-Matter Interaction in dispersive Superconducting Circuit QED},
author = {Harsh Arora and Jay Deshmukh and Ansh Das and R. Vijay and Baladitya Suri},
journal= {arXiv preprint arXiv:2505.09322},
year = {2025}
}