181027 Mixed Quantum-Classical Electrodynamics: A New Route for Light-Matter Interactions

Title:
Mixed Quantum-Classical Electrodynamics: A New Route for Light-Matter Interactions

Speaker:
陳信達 (Hsing-Ta 'Theta' Chen), PhD, University of Pennsylvania

Time:
10/27 (Sat.) 6 pm PDT, 7 pm MDT, 8 pm CDT, 9 pm EDT
10/28 (Sun.) 9 am Taiwan

Keywords:
Chemistry, Chemical Physics

Abstract:

The conclusion of recent developments in novel spectroscopic techniques and optoelectronic devices are challenging to simulate with current theoretical approaches of quantum electrodynamics (QED). This challenge is attributed to the fact that the underlying dynamics involve many degrees of freedom rendering a full quantum treatment prohibitively difficult. This difficulty reveals a significant gap at the interface of chemical dynamics and QED and raises many open questions that need to be addressed to advance material science and device technology. To develop a feasible approach for these problems, we investigate mixed quantum-classical theories for the dynamics of an electronic system interacting with an electromagnetic field.

We first consider three flavors of existing mixed quantum-classical dynamics and find that certain quantum features of the photon field, such as spontaneous emission and fluorescence, cannot be captured qualitatively. Then we propose a new Ehrenfest+R method to recover spontaneous emission while also distinguishing between electromagnetic fluctuations and coherent emission. More importantly, we have shown that Ehrenfest+R dynamics can correctly describe Raman scattering, resonant energy transfer, and the fluorescence triplet. With these promising results, the proposed semiclassical approach provide a viable route for bridging the gap between chemical dynamics and QED.