EAGER: Enabling Quantum Leap: Manipulating polariton entanglement for room-temperature quantum logic

量子计算比传统计算提供了巨大的优势，因为它利用量子力学现象，原则上可以比目前最好的计算机更快、更有效地执行逻辑任务。然而，量子计算仍处于起步阶段。量子计算利用了纠缠——量子粒子的一个关键特性——从根本上不可能区分两个相同粒子的性质，无论它们彼此相距多远。在室温下实现鲁棒纠缠仍然是实现量子计算机的最重要挑战之一。目前的项目克服了现有的室温纠缠的基本限制，通过设计和制造光学设备，产生纠缠的粒子，光和物质的混合物，称为极化子。通过对器件施加电压来操纵和控制纠缠的极化。极化子纠缠被设计成在足够长的时间内保持稳定，可以在室温下进行量子计算操作。除了这项研究所涉及的科技创新外，它还作为一个培训平台，为美国的智力资本和科学基础设施做出贡献，其中量子技术的重要性日益增加。技术描述：该项目的主要目标是演示在室温下工作的通用量子门，利用半导体微腔中的极化子纠缠，该微腔被设计为可被外电场寻址。激子极化子是由光子和激子的强（非微扰）耦合产生的半光半物质准粒子。由于它们的混合特性，激子极化子有望通过操纵物质中的纠缠来实现量子光学门，因为物质相互作用可以进化纠缠态。因此，一项重要的任务是证明将光子纠缠映射到微腔中的物质上的能力。在外加电场的作用下，双极子纠缠态可以独立地控制光子和物质组分。通过这种外部控制，对通用双量子比特量子门进行了测试。由于二维金属卤化物杂化钙钛矿具有高振子强度、高激子结合能和强多激子相互作用等特点，被选择作为活性材料。法布里-珀罗微腔是基于多种无机-有机杂化材料的组合而成的，这些材料可以通过组成和沉积后的程序轻松地进行指数调节，而金属氧化物可以通过溶胶-凝胶方法沉积。这个EAGER项目的成功成果需要一个通用量子门的演示，这为其在量子计算中的实现奠定了平台。除了展示通用量子门的主要成果之外，这一努力还需要在可寻址微腔方面进行创新，从而推进可扩展室温量子光电子学的材料处理协议知识。该奖项反映了美国国家科学基金会的法定使命，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。

Quantum computing offers a tremendous advantage over traditional computing because it exploits quantum mechanical phenomena that can in principle carry out logic tasks much faster and more efficiently than even the best computers at present. Nevertheless, quantum computing is still in its infancy. Quantum computation exploits entanglement - a key peculiarity of quantum particles - where it is fundamentally impossible to distinguish between the properties of two identical particles, regardless of how far they are from each other. Achieving robust entanglement at room temperature remains one of the most important challenges in realizing a quantum computer. The present project overcomes existing fundamental limitations to room-temperature entanglement by designing and fabricating optical devices that produce entangled particles that are hybrids of light and matter, termed polaritons. Entangled polaritons are manipulated and controlled by applying an electrical voltage to the device. Polariton entanglement is designed to be stable over sufficiently long time to perform quantum computing operations at room temperature. In addition to the scientific and technical innovations involved in this research, it serves as a training platform to contribute to the intellectual capital and scientific infrastructure of the US, in which quantum technologies is growing in significance. Technical description: The key objective of this project is to demonstrate a universal quantum gate operating at room temperature, harnessing polariton entanglement in semiconductor microcavities that are designed to be addressable by an external electric field. Exciton polaritons are half-light, half-matter quasiparticles that are produced by strong (non-perturbative) coupling of photons and excitons. Because of their hybrid identity, exciton polaritons promise opportunities for quantum-optical gates by manipulation of entanglement in matter, since matter interactions can evolve the entangled state. An important task is thus to demonstrate the ability to map photon entanglement onto matter in microcavities. The entangled bi-polariton state can be manipulated by an applied electric field to independently control both photon and matter components. By this external control, universal two-qubit quantum gates are tested. Two-dimensional metal-halide hybrid perovskites are chosen as the active material because of their high oscillator strength, high exciton binding energy, and strong multi-exciton interactions. Fabry-Perot microcavities are based on a combination of versatile inorganic-organic hybrid materials that are readily index-tunable via composition and post-deposition procedures, and metal oxides that can be deposited by sol-gel methods. The successful outcome of this EAGER project entails a demonstration of a universal quantum gate, which lays the platform to pursue its implementation in quantum computation. Beyond the primary outcome of demonstrating a universal quantum gate, this endeavor requires innovation in addressable microcavities and thus advances knowledge of materials processing protocols for scalable room-temperature quantum optoelectronics.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.