Photon bound state dynamics from a single artificial atom

authored by
Natasha Tomm, Sahand Mahmoodian, Nadia O. Antoniadis, Rüdiger Schott, Sascha R. Valentin, Andreas D. Wieck, Arne Ludwig, Alisa Javadi, Richard J. Warburton
Abstract

The interaction between photons and a single two-level atom constitutes a fundamental paradigm in quantum physics. The nonlinearity provided by the atom leads to a strong dependence of the light–matter interface on the number of photons interacting with the two-level system within its emission lifetime. This nonlinearity unveils strongly correlated quasiparticles known as photon bound states, giving rise to key physical processes such as stimulated emission and soliton propagation. Although signatures consistent with the existence of photon bound states have been measured in strongly interacting Rydberg gases, their hallmark excitation-number-dependent dispersion and propagation velocity have not yet been observed. Here we report the direct observation of a photon-number-dependent time delay in the scattering off a single artificial atom—a semiconductor quantum dot coupled to an optical cavity. By scattering a weak coherent pulse off the cavity–quantum electrodynamics system and measuring the time-dependent output power and correlation functions, we show that single photons and two- and three-photon bound states incur different time delays, becoming shorter for higher photon numbers. This reduced time delay is a fingerprint of stimulated emission, where the arrival of two photons within the lifetime of an emitter causes one photon to stimulate the emission of another.

Organisation(s)
Institute of Theoretical Physics
External Organisation(s)
University of Basel
University of Sydney
Ruhr-Universität Bochum
Type
Article
Journal
Nature physics
Volume
19
Pages
857-862
No. of pages
6
ISSN
1745-2473
Publication date
06.2023
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Physics and Astronomy(all)
Electronic version(s)
https://doi.org/10.48550/arXiv.2205.03309 (Access: Open)
https://doi.org/10.1038/s41567-023-01997-6 (Access: Open)