If a tree falls in a forest and no one is around to hear it, does its wavefunction collapse? The measurement problem is the dirty secret of quantum mechanics, which is otherwise a sound and self-contained theory of nature. During the early years of quantum theory, musings about the measurement problem were largely theoretical. In my PhD, I shed empirical light on this problem by making quantum measurements of quantum measurements. In my study of measurement disturbance, I demonstrated that carefully engineered disturbance can actually improve measurement precision. In a different experiment, I elucidated how disturbance can and cannot explain certain paradoxical quantum phenomena that seem classically absurd, yet my data prove demonstrably real. Finally, I synthesized my understanding of disturbance into a new theoretical framework that describes the flow of quantum information between advanced quantum artificial intelligences that sense each other and their surroundings.

# Final PhD Oral Exam, Public Seminar - Noah Lupu-Gladstein

Quantum Measurements are Disturbing: Experiments studying the role of disturbance in
postselected metrology, quantum pigeonholes, and entangled sheep

Host: Aephraim Steinberg