Understanding strong cooperative optical responses in dense and cold atomic ensembles is vital for fundamental science and emerging quantum technologies. Methodologies for characterizing light-induced quantum effects in such systems, however, are still lacking. Here we unambiguously identify significant quantum many-body effects, robust to position fluctuations and strong dipole–dipole interactions, in light scattered from planar atomic ensembles by comparing full quantum simulations with a semiclassical model neglecting quantum fluctuations. We find pronounced quantum effects at high atomic densities, light close to saturation intensity, and around subradiant resonances. Such conditions also maximize spin–spin correlations and entanglement between atoms, revealing the microscopic origin of light-induced quantum effects. In several regimes of interest, our approximate model reproduces light transmission remarkably well, permitting analysis of otherwise numerically inaccessible large ensembles, in which we observe many-body analogues of resonance power broadening, vacuum Rabi splitting, and significant suppression in cooperative reflection from atomic arrays.

对于基础科学和新兴的量子技术而言，了解密集和冷原子团簇中强大的合作光学响应至关重要。然而，仍然缺乏表征这种系统中光诱导量子效应的方法。在这里，我们通过将完整的量子模拟与忽略了量子波动的半经典模型进行比较，明确地确定了从平面原子团散射的光中对位置波动具有鲁棒性的强量子多体效应，对位置波动具有鲁棒性，并且强烈的偶极-偶极相互作用。我们发现在高原子密度，接近饱和强度的光以及亚辐射共振附近有明显的量子效应。这种条件还使自旋-自旋相关性和原子之间的纠缠最大化，从而揭示了光诱导量子效应的微观起源。