Nigel Cooper - Quantum Science and Engineering Seminar

Measuring Quantum Many-Body Systems in Phase Space

Abstract: Quantum gas microscopes offer unprecedented insight into many-body states of cold atomic gases, but conventionally resolve only density correlations in position space. We introduce protocols extending quantum gas microscopy into phase space, mapping momentum onto an auxiliary degree of freedom to realize a positive operator-valued measure. Two operational modes emerge: the Husimi-Q microscope jointly measures position and momentum in a single shot, with quantum noise distributed between them; the averaged-mode microscope instead extracts spatial averages of the momentum density and its moments at arbitrary spatial resolution. We show that the resulting $n$-body correlation functions in phase space determine, in principle, all $n$-body observables — making phase-space imaging a uniquely complete probe of strongly correlated matter. We discuss a range of applications of phase space microscopes to characterize quantum many body states.

Bio: Nigel Cooper is Professor of Theoretical Physics at the University of Cambridge, having previously been at the University of Birmingham, the Institut Laue-Langevin, Harvard University and Oxford University. His group investigates the theoretical physics of many-particle quantum systems, engaging with a broad range of experimental platforms, including electronic materials, ultracold gases, and other synthetic quantum systems.