QLC: EAGER: Molecular harvesting of ultrastrong light-matter coupling

加州大学圣地亚哥分校的Joel Yuen Zhou获得了化学系的EAGER奖，以研究光学腔中分子与光之间超强耦合产生的奇异形式的物质。光学腔是形成用于光波的驻波腔谐振器的反射镜的布置。 当分子的集合体被放置在紧密间隔的镜子之间时，分子的能量状态与腔光子（光粒子）的能量状态混合，产生新的混合激发量子态。 这些状态部分是分子的，部分是光子的。如果光与物质之间的相互作用能量足够强，就会产生一种不寻常的物质相，称为超强耦合（USC）相。 在这个阶段，复合系统的基态包含宏观数量的光子。在室温下，分子嵌入光学微腔的背景下，USC刚刚成功地实现。这些奇异的分子光子系统的物理化学性质是什么？ Yuen及其同事使用理论方法来解决这个问题。 他们研究了这种相变的发生，作为可以外部调谐的系统参数的函数。 此类参数可 温度、分子浓度或其它量。 他们将探索USC如何影响化学反应以及能量转换和储存。 Yuen-Zhou团队致力于拓展活动，旨在扩大Yuen Zhou代表性不足的群体的参与，他的研究团队开创了理论和计算框架，以了解受限光和分子自由度之间分子USC的物理和化学。在这些系统中，分子基态原则上存储了非平凡数量的光子，如果光-物质耦合强于临界阈值，这些光子甚至可以与系统大小成比例。目前，人们对如何提取或使用这种能量知之甚少。这项研究解决了如何利用分子中的电子和振动自由度来存储和释放这种真空能量，并在此过程中同时实现新的化学反应性。该项目还提供了新的策略来探测改性真空的量子性质，并利用分子系统探索量子相变。该项目的相关性在于，它及时解决了量子电动力学和化学交叉点上一个尚未探索的前沿问题。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Joel Yuen Zhou of the University of California, San Diego, is supported by an EAGER award in the Division of Chemistry to study exotic forms of matter that arise from ultra-strong coupling between molecules and light in an optical cavity. An optical cavity is an arrangement of mirrors that forms a standing wave cavity resonator for light waves. When ensembles of molecules are placed between closely spaced mirrors, the energy states of the molecules mix with those of the cavity photons (light particles) to produce new hybrid excited quantum states. These states are partially molecular and partially photonic. If the energy of interaction between light and matter is sufficiently strong, an unusual phase of matter called the ultrastrong coupling (USC) phase is achieved. In this phase, the ground state of the composite system contains a macroscopic number of photons. USC has just been successfully attained in the context of molecules embedded in optical microcavities at room temperature. What are the physicochemical properties of these exotic molecular-photonic systems? Yuen and coworkers use theoretical approaches to address this question. They study the onset of this phase transition as a function of system parameters that can be externally tuned. Such parameters may be temperature, molecular concentration or other quantities. They will explore how USC affects chemical reactivity as well as energy conversion and storage. The Yuen-Zhou group engages in outreach activities aimed at broadening the participation of under-represented groups in Yuen Zhou and his research group pioneer the theoretical and computational frameworks to understand the physics and chemistry of molecular USC between confined light and molecular degrees of freedom. In these systems, the molecular ground state in principle stores a nontrivial number of photons that can even scale with system size if the light-matter coupling is stronger than a critical threshold. Currently, there is little understanding on how to extract or use this energy. This research addresses how to harness electronic and vibrational degrees of freedom in molecules to store and release this vacuum energy and in doing so, concomitantly achieve new flavors of chemical reactivity. This project also provides novel strategies to probe the quantum nature of the modified vacuum and explore quantum phase transitions using molecular systems. The relevance of this project is that it addresses a timely yet largely unexplored frontier at the intersection of quantum electrodynamics and chemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.