Collective strong light-matter coupling provides a versatile means to manipulate physicochemical properties of molecules and materials. Understanding collective polaritonic dynamics is hindered by the macroscopic number of molecules interacting collectively with photonic modes. We develop a many-body theory to investigate the spectroscopy and dynamics of a molecular ensemble embedded in an optical cavity in the collective strong coupling regime. This theory is constructed by a pseudoparticle representation of the molecular Hamiltonian, which maps the polaritonic Hamiltonian into a coupled fermion-boson model under particle number constraints. The mapped model is then analyzed using the nonequilibrium Green’s function theory with the self-energy diagrams identified through a large N expansion. We demonstrate that in the thermodynamic limit, the necessary condition to have any collective effects is to have a macroscopic cavity field. Numerical illustrations are shown for the driven Tavis–Cummings model, which shows an excellent agreement with exact results.

中文翻译：

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迈向强光-物质耦合下的集体化学


集体强光-物质耦合提供了一种通用的方法来操纵分子和材料的物理化学性质。理解集体极化子动力学受到与光子模式集体相互作用的分子的宏观数量的阻碍。我们开发了一个多体理论来研究在集体强耦合状态下嵌入光腔中的分子系综的光谱和动力学。该理论由分子哈密顿量的伪粒子表示构建，该分子哈密顿量在粒子数约束下将极化子哈密顿量映射到耦合费米子-玻色子模型。然后使用非平衡格林函数理论分析映射模型，并通过大 N 展开确定自能图。我们证明，在热力学极限中，产生任何集体效应的必要条件是具有宏观腔场。图中显示了驱动 Tavis-Cummings 模型的数值图示，该模型与精确结果吻合极好。