Motivated by applications to covert quantum radar, we analyze a covert quantum sensing problem, in which a legitimate user aims at estimating an unknown parameter taking finitely many values by probing a quantum channel while remaining undetectable from an adversary receiving the probing signals through another quantum channel. When channels are classical-quantum, we characterize the optimal error exponent under a covertness constraint for sensing strategies in which probing signals do not depend on past observations. When the legitimate user's channel is a unitary depending on the unknown parameter, we provide achievability and converse results that show how one can significantly improve covertness using an entangled input state.
Multi-User Covert Communications via Intelligent Spectrum Control
State Key Laboratory of Integrated Services Networks, Xidian University（西安电子科技大学综合业务网理论及关键技术国家重点实验室）；College of Computing and Data Science, Nanyang Technological University（南洋理工大学计算与数据科学学院）
Variational Quantum Integrated Sensing and Communication
Signal Processing Systems Group, Department of Electrical Engineering, Eindhoven University of Technology（信号处理系统组，电气工程系，埃因霍温理工大学）；KCLIP lab, Center for Intelligent Information Processing Systems, Department of Engineering, King's College London（KCLIP实验室，智能信息处理系统中心，工程系，伦敦国王学院）
