Collective radiation effects in complex bosonic reservoirs

• Applicant: Professor Dr. Peter Rabl
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 561288511

Superradiance describes the collectively accelerated emission of multiple emitters that are coupled to a common photonic reservoir. Together with its counterpart, the subradiant inhibition of radiative decay, this effect is a prototypical example of the build-up of environment-induced correlations in open quantum systems and has been studied in atoms and solid-state systems in free space, cavities, and 1D photonic waveguides. In this project, we go beyond these conventional settings and investigate the collective radiation of ensembles of emitters coupled to complex bosonic reservoirs, including extended networks with non-Markovian propagation delays, photonic quantum Hall systems in the presence of synthetic magnetic fields, and chaotic cavities. These settings are motivated by recent experiments with nanophotonic structures, superconducting microwave resonators, and engineered phonon waveguides. A common feature of these environments is that the reservoir itself exhibits a highly complex dynamics, raising the intriguing question of how the collective correlations between the emitters, which are responsible for super- and subradiance, will emerge under such conditions. The key theoretical challenge in addressing this question arises from the fact that the reservoir's dynamics can no longer be eliminated, as is usually the case in conventional open quantum systems. In this binational project, we will therefore combine the expertise of our groups in Germany and Israel to develop more efficient numerical tools and novel analytical approaches to tackle this challenge and gain a deeper understanding of collective radiation effects in complex environments. Specifically, we will investigate super- and subradiant dynamics in photonic networks with propagation delays, topologically nontrivial and chaotic bosonic reservoirs, and reservoirs with preexisting photonic correlations. Special emphasis will be placed on potential experimental observations of the predicted effects, particularly in the context of circuit QED and solid-state spin qubits coupled to phononic nanostructures.

• DFG Programme: Research Grants
• International Connection: Israel
• Partner Organisation: The Israel Science Foundation
• Cooperation Partner: Professor Dr. Alexander Poddubny, Ph.D.