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Quantum Emitters and Cavity QED

Giulia Gualdi, Karim Murr

The modern physics of quantum emitters illuminates the most fundamental aspects of coherence and decoherence in quantum physics, where very rich theoretical models guide experiments to reveal intriguing aspects of reversible and dissipative quantum dynamics. It is remarkable that many avenues share the same concepts, whereas they explore different regimes with essentially different techniques. For instance, the recent years have brought the demonstration that the dynamics of single atoms strongly coupled to a quantized field can be well studied in a solid-state architecture, where now artificial atoms made of Josephson junctions are coupled to on-chip superconducting resonators. As a rule, quantum bits can consist of atoms, ions, electron spins in quantum dots, N-V centres in diamond, or any elementary system to be conceived in the future that couples to electromagnetic fields in the optical or microwave regime. In years to come, the importance of quantum emitters will grow as researchers build on a rich infrastructure to tackle open questions in micro- and mesoscopic physics. For instance, after a work started at the MPQ on the squeezing of single atoms coupled to an optical cavity, we studied the squeezing generated by a single atom coupled to a nanostructure in collaboration with the nano-optics group of Dr Mario Agio at Q*. Other research is concerned with the analysis of the mechanism of Rydberg Blockade under the strong coupling between 2 (and more) atoms and single photons in a cavity quantum electrodynamics setup.