RWTH Aachen University

报告人简介

Professor Dante Kennes is a condensed matter theorist at RWTH Aachen, where he leads the “OPTIMAL - Optical Control of Quantum Materials” research group. His research is dedicated to the ultrafast control of macroscopic properties of quantum materials through light-matter interaction.

报告摘要

Driving quantum materials is a promising route for potential future applications in the engineering of quantum properties, such as superconductivity and topologically protected edge states [1].

First, we are going to discuss some examples of how to control superconducting properties in ultrafast transient phenomena [2] by the transient steering of symmetries. Then we will switch gears and discuss potential routes to manipulate quantum properties in the emerging field of cavity quantum electrodynamics. The latter aims at controlling material properties via the coupling with the quantized photon modes in a cavity. Through the hybridization of light and matter we explore to which extent it is possible to tailor properties of extended solids, realizing what was coined “cavity quantum materials”[3, 4].

The entanglement entropy between light and matter is a direct measure of the degree of hybridization, but a clear understanding on what are the necessary conditions for this to be generated in the emergent field of cavity coupled band electrons [5, 6, 7] is still missing.

We consider a paradigmatic model of interacting spinless fermions coupled with the first resonant mode of a cavity. We derive an analytic expression, exact in the cavity high frequency limit, that relates the cavity-matter entanglement to the quantum fluctuations of the current operator.

This relation establishes that the presence of such fluctuations is a necessary condition for non-zero light-matter entanglement. Furthermore, we solve numerically exactly the model, showing that the qualitative behavior predicted by our analytic expansion holds in a wide range of parameters.

We also discuss problematic aspects of mean field approaches to this model.

Fig. 1.Cartoon picture of the mechanism generating light-matter entanglement, a superposition of Bloch states is responsible for the insurgence of entanglement between light and matter degrees of freedom.

The results presented in this work are expected to hold in more general settings than the particular model discussed, providing a first fundamental condition for the realization of true light-matter hybridized band electrons in a cavity [8].

References

[1] A. de la Torre et al, Rev. Mod. Phys. 93, 041002 (2021).

[2] M. Claassen et al, Nat. Phys. 15, 766-770 (2019).

[3] F. Schlawin et al, Applied Physics Reviews 9, 011312 (2022).

[4] A. Frisk Kockum et al, Nat Rev Phys 1, 19 (2019).

[5] F. Schlawin et al, Phys. Rev. Lett. 122, 133602 (2019).

[6] H. Gao et al, Phys. Rev. Lett. 125, 053602 (2020).

[7] A. Chakraborty et al, Phys. Rev. Lett. 127, 177002 (2021).

[8] G. Passetti et al, Phys. Rev. Lett. 131, 023601, (2023)

报告地点：中国科学院物理研究所M楼253会议室

腾讯视频会议号：676-971-635，会议密码：250709

邀请人：万源 研究员

联系人：万源 研究员

        汪非凡 副研究员

        田春璐 cltian@iphy.ac.cn

主办方：中国科学院物理研究所、松山湖材料实验室