Welakuh Davis M, Flick Johannes, Ruggenthaler Michael, Appel Heiko, Rubio Angel
Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science & Department of Physics, Luruper Chaussee 149, Hamburg 22761, Germany.
Harvard John A. Paulson School Of Engineering And Applied Sciences, Harvard University, Cambridge 02138, Massachusetts, United States.
J Chem Theory Comput. 2022 Jul 12;18(7):4354-4365. doi: 10.1021/acs.jctc.2c00076. Epub 2022 Jun 8.
The rapid progress in quantum-optical experiments, especially in the field of cavity quantum electrodynamics and nanoplasmonics, allows one to substantially modify and control chemical and physical properties of atoms, molecules, and solids by strongly coupling to the quantized field. Alongside such experimental advances has been the recent development of ab initio approaches such as quantum electrodynamical density-functional theory (QEDFT), which is capable of describing these strongly coupled systems from first principles. To investigate response properties of relatively large systems coupled to a wide range of photon modes, ab initio methods that scale well with system size become relevant. In light of this, we extend the linear-response Sternheimer approach within the framework of QEDFT to efficiently compute excited-state properties of strongly coupled light-matter systems. Using this method, we capture features of strong light-matter coupling both in the dispersion and absorption properties of a molecular system strongly coupled to the modes of a cavity. We exemplify the efficiency of the Sternheimer approach by coupling the matter system to the continuum of an electromagnetic field. We observe changes in the spectral features of the coupled system as Lorentzian line shapes turn into Fano resonances when the molecule interacts strongly with the continuum of modes. This work provides an alternative approach for computing efficiently excited-state properties of large molecular systems interacting with the quantized electromagnetic field.
量子光学实验的快速进展，特别是在腔量子电动力学和纳米等离子体学领域，使得人们能够通过与量子化场的强耦合来显著改变和控制原子、分子及固体的化学和物理性质。伴随着这些实验进展的是诸如量子电动力学密度泛函理论（QEDFT）等从头算方法的最新发展，该理论能够从第一性原理出发描述这些强耦合系统。为了研究与广泛的光子模式耦合的相对较大系统的响应特性，与系统大小具有良好缩放比例的从头算方法变得至关重要。有鉴于此，我们在QEDFT框架内扩展了线性响应斯特恩海默方法，以有效计算强耦合光 - 物质系统的激发态性质。使用这种方法，我们在与腔模式强耦合的分子系统的色散和吸收特性中捕捉到了强光 - 物质耦合的特征。我们通过将物质系统与电磁场的连续体耦合来例证斯特恩海默方法的效率。当分子与连续模式强烈相互作用时，我们观察到耦合系统的光谱特征发生变化，即洛伦兹线形转变为法诺共振。这项工作为有效计算与量子化电磁场相互作用的大分子系统的激发态性质提供了一种替代方法。
