CAREER: Covert Quantum Sensing

量子信息处理在传感系统的精度方面提供了数量级的增强。同时，许多实际的感测场景需要主动探测传输和隐蔽（即，低检测/拦截概率-- LPD/LPI）操作，以防止对手检测到探测尝试。该项目的重点是量化量子信息处理提供的隐蔽测距和反射传感的安全性和准确性的根本改进，以及用于实现这些增益的系统和算法。 除了国防方面的明确应用外，该项目还提供了实施下一代隐私架构所需的技术，以及对传感和估计数学的广泛见解。 此外，该研究团队还指导参与该项目的研究生和本科生，并开展一项全面的教育计划，重点是通过吸引来自代表性不足群体的本科生来发展国家的量子劳动力。防止传输被对手检测到需要采用非常低功率的信号。 尽管这种信号在隐蔽通信中的应用是信息理论研究的一个活跃领域，但它们在传感应用中的基本限制几乎没有被探索过。 此外，虽然量子方法已被证明可以显著提高传感精度，但这些增益似乎仅在SNR低且噪声水平高时才明显。 这种机制在标准传感系统中是非常不寻常的;然而，它是隐蔽传感的自然状态。 因此，该项目采用量子视角来进行隐蔽传感。 它旨在确定隐蔽测距和反射传感的基本限制，以防止只受物理定律约束的对手。这个假设产生了对最强大的对手可能的可验证的隐蔽性。 从量子资源，如纠缠，光的量子态，和联合检测接收器的性能增强进行了探讨。此外，发射机和接收机的结构和算法，寻求实现这些改进。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Quantum information processing offers orders-of-magnitude enhancements in the precision of sensing systems. At the same time, many practical sensing scenarios require both active-probe transmission and covert (i.e., low probability of detection/intercept -- LPD/LPI) operation to prevent an adversary from detecting the probing attempt. This project focuses on quantifying the fundamental improvements to the security and accuracy of covert ranging and reflectance sensing offered by quantum information processing, as well as the systems and algorithms applied to achieve these gains. Aside from the clear applications for national defense, this project yields the technology necessary to implement next-generation privacy architectures, as well as broad insights into the mathematics of sensing and estimation. Additionally, the research team mentors graduate and undergraduate students involved in this project, and conducts a comprehensive educational program focused on growing the nation’s quantum workforce by engaging the undergraduate students from underrepresented groups.Preventing transmissions from being detected by the adversary requires employing very-low-power signals. Even though the application of such signals to covert communications is an active area of research in information theory, the fundamental limits of their use in sensing applications has barely been explored. Furthermore, while quantum methodology has been proven to yield significant improvements in sensing accuracy, these gains seem to be manifest only when SNR is low and noise level is high. This regime is highly unusual in standard sensing systems; however, it is a natural state for covert sensing. Thus, this project takes on the quantum perspective to covert sensing. It looks to determine the fundamental limits of covert ranging and reflectance sensing, secure against the adversary who is only subject to the laws of physics. This assumption yields mathematically-provable covertness against the most powerful adversary possible. Performance enhancements from quantum resources such as entanglement, quantum states of light, and joint-detection receivers are explored. Furthermore, transmitter and receiver structures and algorithms are sought to achieve these improvements.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.