Using an extended Tavis-Cummings model, we study the effect of the spin-orbit coupling between the singlet and the triplet molecular excitons in organic microcavities in the strong coupling regime. The model is solved in the single excitation space for polaritons, which contains the bright (permutation symmetric) singlet and triplet excitons, as well as the dark bands consisting of the nonsymmetric excitons of either type. We find that the spin-orbit coupling splits the lower polariton into two branches, and also creates a triplet polariton when the cavity mode is in resonance with the triplet excitons. The optical absorption spectrum of the system that can reveal this splitting in experiments is presented and the effect of disorder in exciton energies and couplings is explored. An important consequence of the disorder in the spin-orbit coupling -- a weak coupling between the otherwise decoupled bright and dark sectors -- is explored and detailed calculations of the squared transition matrix elements between the dark bands and polaritons are presented along with derivation of some approximate yet quite accurate analytical expressions. This relaxation channel for the dark states contains an interference between two transition paths that, for a given polariton state, suppresses the relaxation of one dark band and enhances it for the other.
Reanalysis of experimental determinations of polariton-polariton interactions in microcavities
极化激元-极化激元相互作用强度是利用极化激元的非线性特性进行光开关和单光子阻塞器件等各种应用的重要参数。本文回顾和比较了GaAs/Al $_x$ Ga $_{-1x}$ As微腔极化激元结构中极化激元-极化激元相互作用的一系列实验结果，并对这些实验进行了新的理论分析。我们发现，不仅是谱线的能量移动，而且极化激元散射率敏感的测量结果是重要的相互作用参数在低激发密度的校准。我们发现，当进行调整，以纠正新的理解的实验，在低密度的相互作用参数的值低于以前的报道，但仍然显着高于理论预测。
Estimating the conditions for polariton condensation in organic thin-film microcavities
我们研究了在有机量子阱中观察受限二维极化激元气体玻色凝聚的可能性。我们推导出一个合适的参数化模型哈密顿的基础上的腔的几何形状，双激子结合能，和类似的光谱和结构数据。通过转换的总和在$d$维相空间的半经典积分的状态，我们表明，虽然一个理想的2-D玻色气体将不会发生凝聚，与Bogoliubov色散$H(p)\approx s p$接近$p=0$的相互作用的气体将发生玻色凝聚在一个给定的临界密度和温度。我们发现，$T_c/\sqrt{ρ_c}$是敏感的腔的几何形状和双激子结合能。特别是对于强束缚的双激子，Gross-Pitaevskii方程中的非线性相互作用项变为负值，从而得到的基态将是定域孤子态而不是离域玻色凝聚态.
Quantum Droplets of Light in Semiconductor Microcavities
International School for Advanced Studies (SISSA)（高等研究院）；School of Physics and Astronomy, Monash University（蒙纳士大学物理与天文学学院）；Institüt für Theoretische Physik, Heidelberg University（海德堡大学理论物理研究所）；Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid（马德里自治大学凝聚态物质理论物理系）；Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid（马德里自治大学凝聚态物理中心）
