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Ward, William

Publications and source records attributed to Ward, William.

Entanglement-Enhanced Neyman-Pearson Target Detection

Quantum illumination (QI) provides entanglement-enabled target-detection enhancement, despite operating in an entanglement-breaking environment. Existing experimental studies of QI have utilized a Bayesian approach, assuming that the target is equally likely to be present or absent before detection, to demonstrate an advantage over classical target detection. However, such a premise breaks down in practical operational scenarios in which the prior probability is unknown, thereby hindering QI's applicability to real-world target-detection scenarios. In this work, we adopt the Neyman-Pearson criterion in lieu of the error probability for equally likely target absence or presence as our figure of merit for QI. We demonstrate an unconditional quantum advantage over the optimal classical-illumination protocol as benchmarked by the receiver operating characteristic, which examines detection probability versus false-alarm probability without resorting to known prior probabilities. Our work represents a critical advancement in adapting quantum-enhanced sensing to practical operational settings.

Ward, William

Observations from a constant-altitude stratospheric balloon

The paper describes a constant-altitude stratospheric balloon system, called Earthwinds, designed for high-altitude atmospheric observations. Special attention is given to the balloon's variable ballast system for altitude control; reactions of the balloon system to air motions in a stratified atmosphere; instruments for locating the balloon position, controlling the altitude, and making observations of atmospheric movements; balloon dynamics; and the atmospheric phenomena that will be observed by the balloon instruments.

Mollo-Christensen, Erik