报告人：Georg Engelhardt 副教授
报告人单位：南方科技大学
主持人：蒋士成
时间：2023年8月11日（周五）上午10:00
地点：华东师范大学光学大楼B325会议室
报告人简介：
Georg Engelhardt has received his PhD at the TU Berlin in 2017, after which he joint the Beijing Computational Science Research Center as a postdoctorial research fellow until 2021. At present, he works as an associate researcher at the Southern University of Science and Technology in the Shenzhen Institute of Quantum Science and Engineering. He has published 17 Nature Index articles, including five articles in Physical Review Letters. He investigates principles of light-matter interaction in the quantum optical and semiclassical regimes. In this context, he develops protocols for quantum control and quantum sensing. Besides others, his research has contributed to the understanding of the polariton dynamics and the quantum control of Floquet systems.
报告内容简介：
Floquet theory is frequently employed to describe the dynamics of atoms and artificial atoms interacting with intense electromagnetic fields. However, this semiclassical analysis can not account for quantum-optical phenomena that rely on the quantized nature of light. Here, we take a significant step to go beyond the semiclassical description of atom-photon coupled systems by unifying Floquet theory with quantum optics using the framework of Full-Counting Statistics. This is achieved by introducing counting fields that keep track of the photonic dynamics. This formalism, which is dubbed ``Photon-resolved Floquet theory (PRFT), predicts the generation of macroscopic light-matter entanglement when atoms interact with multimode electromagnetic fields, thereby leading to complete decoherence of the atomic subsystem in the basis of the Floquet states. This decoherence occurs rapidly in the optical frequency regime, but is negligible in the radio frequency regime. Our results thus pave the way for the design of efficient quantum memories and quantum operations. Employing the PRFT, we propose a quantum communication protocol that can significantly outperform the state-of-art few-photon protocols by two orders of magnitude or better. The PRFT potentially leads to new insights in various Floquet settings including spectroscopy, thermodynamics, quantum metrology, and quantum simulations.