CAREER: Covert Quantum Sensing

University Of Arizona, Tucson AZ

Investigators

Abstract

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.