Direct detection of down-converted photons spontaneously produced at a single Josephson junction
Abstract
We study spontaneous photon decay into multiple photons triggered by strong non-linearities in a superconducting quantum simulator of the boundary sine-Gordon impurity model. Previously, spectroscopic signatures of photon-conversion were reported and evidenced as resonances in the many-body spectrum of these systems. Here, we report on the observation of multi-mode fluorescence of a small Josephson junction embedded in a high impedance superconducting transmission line. Measurement of the down-converted photons is achieved using state-of-the-art broadband parametric amplifiers. Photon triplet emission is explicitly demonstrated at a given frequency as the counterpart of inelastic photon decay at three-times the emission frequency. These results open exciting prospects for the burgeoning field of many-body quantum optics and offer a direct signature of the ultra-strong light-matter coupling.
Keywords
Cite
@article{arxiv.2405.00411,
title = {Direct detection of down-converted photons spontaneously produced at a single Josephson junction},
author = {Dorian Fraudet and Izak Snyman and Denis M. Basko and Sébastien Léger and Théo Sépulcre and Arpit Ranadive and Gwenael Le Gal and Alba Torras-Coloma and Serge Florens and Nicolas Roch},
journal= {arXiv preprint arXiv:2405.00411},
year = {2025}
}
Comments
16 pages including supplementary material, 8 figures