Engineering Photonic Quantum States for Quantum Information

单个光粒子或光子可以与另一个光子相关联，这样即使它们不在同一位置，测量一个光子的性质也会立即影响另一个光子的性质。这种相关性使得光子在创造新技术方面非常有用，这些新技术允许更快、更强大的计算和完全安全的通信，以及测试基本物理理论。然而，为这些应用创造具有正确相关性的光子仍然具有挑战性。这个研究项目通过创造和展示测量和控制单光子及其相互作用的物质的新技术来解决这些困难。通过调整产生光子的能量源和介质，产生的光子的相关性接近于新技术和物理原理基本测试的理想状态。研究表明，具有适合安全远距离通信特性的单光子可以存储在由原子气体构成的存储器中，并保持它们之间的相关性。在这个项目中，将研究光与环境本身的相互作用，例如光如何被吸收并在分子中不同形式的能量之间传递。单光子的相关性将被用来更深入地了解这些过程是如何发生的。扩展控制单光子的特性及其与物质的相互作用的能力，对基于量子力学定律的新型计算产生了影响，这种计算可以解决原本令人望而却步的数学问题，并模拟复杂的物理系统。它还使发送信息的方法完全安全，没有任何窃听的明确迹象，并提高了测试量子力学理论的能力。了解分子中光与物质的相互作用有助于新药的发明和利用这些分子的技术的改进。该研究项目还为学生提供量子光学和原子分子物理方面的培训，并通过演示、博物馆展览和公开讲座向公众介绍量子技术。这个研究项目扩展了我们的理解和能力，以控制量子态的空间和频谱-时间特性及其相关性。为了执行协议，利用光子量子态的量子应用通常对光子的空间和光谱-时间特性和相关性有特定的要求。通过这项工作，新技术将被开发和应用于以前所未有的速度和分辨率测量自发四波混频产生的光子量子态的联合相关。利用一种基于双泵浦自发四波混频的新方案，探索在人工结构材料中产生的光子对的光谱可调性。光子量子态将使用自相位和交叉相位调制，并通过调整两个不同泵之间的群速度差来设计，以创建完全不相关的光子对（除了一个指示另一个的存在）。量子存储器是量子信息处理应用的关键部件。在原子钡蒸气中使用非共振拉曼协议的电信波长光子的高带宽存储和检索将被演示。原子系统的内在相关性将被用来产生纯光子，这对依赖于高可见度双光子干涉的量子应用有用，并演示原子系综的纠缠。量子信息研究导致了测量光子量子态的空间、光谱和时间相关性的技术。这些技术将被扩展和应用于更好地理解和控制与光子相互作用的材料。基于单光子水平干涉和巧合检测的新光谱学将用于获得对分子液体的相干性和种群动力学的独特见解，包括振动状态之间复杂的能量再分配。通过扩展对超快光子量子态及其与材料系统相互作用的理解和控制能力，该研究对量子通信、量子计算和量子力学基础测试领域的量子信息研究目标做出了重大贡献。在光子、原子和分子量子态的光谱、时间和空间领域中展示的量子控制新技术有可能开辟令人兴奋的研究和技术发展的新途径。这项研究与外展组件相结合，向公众和K-12学生介绍单光子的惊人特性。PI准备了单光子在量子通信中应用的交互式演示，用于在伊利诺伊大学物理大楼展示，并在公共宣传讲座、工程开放日和当地儿童博物馆展出。该研究为量子光学和原子分子物理学的研究生提供了专业培训。

A single particle of light, or a photon, can be correlated with another photon such that measuring the properties of one instantaneously affects the properties of the other even if they are not in the same location. Such correlations make photons useful for creating new technologies that allow for faster and more powerful computing and completely secure communication as well as for testing fundamental physical theories. Yet creating photons with just the right correlations for such applications remains challenging. This research project addresses these difficulties by creating and demonstrating new techniques for measuring and controlling single photons and the matter with which they interact. By adjusting the energy source and medium in which photons are created, photons are created whose correlations are close to ideal for new technologies and fundamental tests of physics principles. It has been shown that single photons with properties suitable for secure long-distance communication can be stored in a memory made of a gas of atoms that preserves their correlations. In this project the interaction of light with the environment itself, such as how light is absorbed and transferred between different forms of energy in molecules, will be studied. The correlations of single photons will be used to gain more insight into how such processes occur. Extending the ability to control the properties of single photons and their interactions with matter has implications for creating new types of computing based on the laws of quantum mechanics that can solve otherwise prohibitive mathematical problems and simulate complex physical systems. It also enables methods of sending information completely securely, with clear indications of any eavesdropping, and improves the ability to test the theory of quantum mechanics. Understanding light-matter interaction in molecules supports the creation of new drugs and improvement of technologies that use such molecules. This research project also provides students training in quantum optics and atomic and molecular physics and informs the public about quantum technologies through demonstrations, museum exhibits and public lectures.This research project extends our understanding and ability to control the spatial and spectral-temporal properties of quantum states and their correlations. Quantum applications that utilize photonic quantum states often have specific requirements for the photons' spatial and spectral-temporal properties and correlations in order to perform protocols. Through this work new techniques will be developed and applied to measure with unprecedented speed and resolution the joint correlations of photonic quantum states produced via spontaneous four-wave mixing. The spectral tunability of photon-pairs created in artificially structured materials will be explored using a new scheme based on dual-pump spontaneous four-wave mixing. Photonic quantum states will be engineered using self- and cross-phase modulation and by tuning the group velocity difference between two distinct pumps, to create photon pairs that are completely uncorrelated (except for the existence of one indicating the other).Quantum memories, are critical components for quantum information processing applications. High-bandwidth storage and retrieval of telecom-wavelength photons using an off-resonant Raman protocol in atomic barium vapor will be demonstrated. The inherent correlations of the atomic system will be utilized to generate pure photons useful for quantum applications relying on high-visibility two-photon interference and demonstrate entanglement of atomic ensembles. Quantum information research has resulted in techniques to measure the spatial, spectral and temporal correlations of photonic quantum states. These techniques will be extended and applied to better understand and control the materials with which the photons interact. New spectroscopies based on single-photon level interference and coincidence detection will be used to gain unique insight into the coherence and population dynamics of molecular liquids, including the intricate redistribution of energy among vibrational states.By extending the understanding and ability to control ultrafast photonic quantum states and their interactions with material systems, the research contributes significantly to the goals of quantum information research in the areas of quantum communication, quantum computation, and fundamental tests of quantum mechanics. The new techniques demonstrated for quantum control in the spectral, temporal and spatial domains of photonic, atomic and molecular quantum states have the potential to open up exciting new avenues of research and technology development. The research is integrated with outreach components to inform the public and K-12 students about the amazing properties of single photons. The PI prepares interactive demonstrations of the applications of single photons in quantum communication for display in the University of Illinois physics building, and for presentation at public outreach lectures, engineering open houses, and for exhibit in a local children's museum. The research provides professional training to graduate students in quantum optics and atomic and molecular physics.