Humboldt-Universität zu Berlin - Faculty of Mathematics and Natural Sciences - Department of Physics

Photon Correlations and Quantum Nonlinearities: Insights from Atom-Light Interactions

Abstract

The interaction of photons with quantum emitters is a cornerstone of quantum optics and a foundation for many emerging quantum technologies. This talk will explore two recent advances in the understanding and harnessing of photon correlations through atom-light interactions. In the first part, I will examine the simultaneous scattering of two photons by a single two-level atom. While conventional wisdom states that such an emitter can only absorb and emit single photons, our experimental validation of a quantum interference-based description shows that photon anticorrelations arise from the interplay of coherent and incoherent two-photon scattering amplitudes. By isolating the incoherent component of the scattered light, we demonstrate the generation of photon pairs, providing a new way to generate highly non-classical light fields.  In the second part, I investigate the collective nonlinear response of weakly coupled atomic ensembles to optical fields. Here, photon correlations arise not from strong coupling, but from collective effects in the weak coupling regime combined with dissipation. These effect allows us to transform laser light  into strongly bunched or antibunched light, demonstrating a novel approach to the generation of correlated quantum states of light. Together, these studies provide new insights into fundamental light-matter interactions and open up promising avenues for quantum information science.

The Colloquium will be held in "hybrid" format, i.e., you can join the talk in the lecture hall or via zoom.

Zoom Link:
https://hu-berlin.zoom.us/j/64567336962?pwd=QjhyMW5SbFVBZWVNRWJrTFBFN2Rtdz09
Meeting-ID: 645 6733 6962
Passwort: 607723