NSF Award
2430953
Quantum inference is essential to unleashing full quantum advantage in sensing, communication, and computing. Quantum inference relies on measurements facilitated by quantum control; however, inference and control are traditionally treated separately in the design and analysis of quantum systems. This research puts forth a new vision and unifying framework, referred to as quantum information control, in which control of statistical information serves as a foundation for ultra-precise quantum inference. At the intersection of quantum information, statistical inference, and control theory, this research is a cross-pollination of traditionally disparate scientific fields, thus constituting a unique opportunity to capitalize on the strengths of each field and produce transformative theories and algorithms. This work will facilitate the maturation of emerging quantum information platforms.<br/><br/>Quantum information control centers on modeling and controlling statistical information (e.g., Fisher information) to improve inference capabilities (e.g., the accuracy of parameter estimation) in real-world open quantum systems, which are subject to environmental noise and practical design constraints. The goals of this project are to: (i) establish a framework for characterizing the time evolution of controlled statistical information; (ii) derive the ultimate performance limits of quantum information control; and (iii) develop control algorithms approaching these limits. Inspired by concepts in statistical inference, the notion of admissible controls-independent of the parameters they elicit-is introduced. A class of theorems will be developed to identify when information maximizing controls are admissible and hence realizable in practice. Moreover, near-optimal adaptive control algorithms will be designed for situations in which the admissibility conditions are not met. Central to this project is the concept of time-dependent reachable sets of measurement operators. Such reachable sets will be characterized and information extraction will be optimized over them to establish tight information inequalities. The multidisciplinary approach developed in this fundamental research will lay the foundations for quantum information control, paving the way to unparalleled capabilities for quantum sensing, communication, and computing.<br/><br/>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.
