The strong coupling of excitons to optical cavities has provided new insights into cavity quantum electrodynamics as well as opportunities to engineer nanoscale light–matter interactions^1,2,3,4,5,6. Here we study the interaction between out-of-equilibrium cavity photons and both neutral and negatively charged excitons, by embedding a single layer of the atomically thin semiconductor molybdenum diselenide in a monolithic optical cavity based on distributed Bragg reflectors. The interactions lead to multiple cavity polariton resonances and anomalous band inversion for the lower, trion-derived, polariton branch—the central result of the present work. Our theoretical analysis reveals that many-body effects in an out-of-equilibrium setting result in an effective level attraction between the exciton-polariton and trion-polariton accounting for the experimentally observed inverted trion-polariton dispersion. Our results suggest a pathway for studying interesting regimes in quantum many-body physics yielding possible new phases of quantum matter^7,8,9,10,11 as well as fresh possibilities for polaritonic device architectures^12,13,14,15.

激子与光腔的强耦合为腔量子电动力学提供了新的见识，并提供了设计纳米级光-物质相互作用^{1,2,3,4,5,6的机会}。在这里，我们通过在基于分布式布拉格反射器的单片光学腔中嵌入单层原子薄的半导体二硒化钼，研究了非平衡腔光子与中性和带负电荷的激子之间的相互作用。相互作用会导致多重空腔极化子共振，并导致较低的，由Trion衍生的极化子分支的反常带反转-这是本研究的主要结果。我们的理论分析表明，在不平衡状态下的多体效应会导致激子-极化子和三子-极化子之间的有效能级吸引，这说明了实验观察到的倒三子-极化子色散。我们的研究结果为研究量子多体物理学中有趣的态势提供了可能产生量子物质新阶段的途径^7,8,9,10,11以及极化设备结构^{12,13,14,15的}新鲜可能性。