Light-Matter Interaction in dispersive Superconducting Circuit QED

TL;DR

This paper introduces a quantization method for superconducting circuit QED that accounts for frequency-dependent dispersion effects, revealing their influence on light-matter interaction limits.

Contribution

It presents a novel quantization approach incorporating superconducting dispersion, addressing a gap in modeling high-frequency interactions in circuit QED.

Findings

Superconducting dispersion affects the effective light-matter interaction cutoff.

Traditional models neglecting dispersion may oversimplify high-frequency behavior.

The new approach improves understanding of mode coupling near the superconducting gap.

Abstract

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.