标题： 材料中的超强光物质耦合 显示英文标题

标题： Ultrastrong Light-Matter Coupling in Materials

摘要： 强光物质耦合传统上是在光学腔中研究的，在那里当光物质耦合强度达到跃迁频率的重要部分时会发生这种情况。 这个状态从根本上改变了粒子腔系统的基态和激发态，解锁了控制其物理和化学的新方法。 然而，在工程腔中实现强耦合仍然是一项重大挑战。 在这里，我们展示出超强和深强耦合自然发生在块状材料中，无需外部腔。 通过分析超过70种材料的实验数据，我们证明了许多固体中的声子、激子和平面极化子表现出超强耦合，系统地超越了基于腔的系统所实现的耦合强度。 为了解释这一现象，我们引入了一个基于广义Hopfield哈密顿量的偶极晶格模型，该模型统一了光子物质、物质间以及光子间的相互作用。 晶格中光子与集体偶极模式之间的完全重叠使得超强耦合成为可能，导致激发态混合、辐射衰减抑制以及潜在的进入集体基态的相变。 将我们的模型应用于真实材料，我们展示了它可以在广泛的材料类别中重现光物质耦合，并可能引起导致铁电性、绝缘体到金属转变以及激子凝聚等新兴现象的结构相变。 认识到强耦合是固体的固有属性，重塑了我们对光物质相互作用的理解，并开辟了探索量子材料和奇异物质相的新途径。 显示英文摘要

摘要： Ultrastrong light-matter coupling has traditionally been studied in optical cavities, where it occurs when the light-matter coupling strength reaches a significant fraction of the transition frequency. This regime fundamentally alters the ground and excited states of the particle-cavity system, unlocking new ways to control its physics and chemistry. However, achieving ultrastrong coupling in engineered cavities remains a major challenge. Here, we show that ultra- and deep-strong coupling naturally occur in bulk materials without the need for external cavities. By analyzing experimental data from over 70 materials, we demonstrate that phonon-, exciton-, and plasmon-polaritons in many solids exhibit ultrastrong coupling, systematically surpassing the coupling strengths achieved in cavity-based systems. To explain this phenomenon, we introduce a dipole lattice model based on a generalized Hopfield Hamiltonian, which unifies photon-matter, matter-matter, and photon-photon interactions. The complete overlap between the photonic and collective dipole modes in the lattice enables ultrastrong coupling, leading to excited-state mixing, radiative decay suppression, and potential phase transitions into collective ground states. Applying our model to real materials, we show that it reproduces light-matter coupling across broad material classes and may underlie structural phase transitions that give rise to emergent phenomena such as ferroelectricity, insulator-to-metal transitions, and exciton condensation. Recognizing ultrastrong coupling as an intrinsic property of solids reshapes our understanding of light-matter interactions and opens new avenues for exploring quantum materials and exotic phases of matter.