Jul 17 – 22, 2022
Royal Conservatory of Music, Toronto
America/Toronto timezone

Observation of Stochastic Wavefunction Evolution from Dispersively Measured Bose-Einstein Condensates

Jul 19, 2022, 5:00 PM
1h 30m
Hart House (Hart House)

Hart House

Hart House

7 Hart House Cir, Toronto, ON M5S 3H3
Poster presentation Degenerate gases, many-body physics, and quantum simulation Poster session


A fundamental tenet of quantum mechanics is that measurements change a system's wavefunction to that most consistent with the measurement outcome, even if no observer is present. Weak measurements produce only limited information about the system, and as a result only minimally change the system state. In this context, the interaction of a nearly closed quantum system with its environment can be described as a continuous weak measurement process. Bose-Einstein condensates (BECs) offer multiple weak measurement techniques, that yield a controlled reservoir and consequently allow time-resolved study of the system evolution. We theoretically and experimentally characterize the quantum projection noise in atomic BECs weakly measured by the light scattered from a far-from resonant, i.e., dispersivly interacting, laser beam. We quantify the resulting wavefunction change with two observations: the contrast in a Ramsey interferometer, and the deposited energy. Next, we present a versatile high-resolution ultracold atom microscope: a combined hardware/software system that recovers near-diffraction limited performance and minimizes the information loss. Our high-fidelity digital correction technique reduces the contribution of photon shot noise to density-density correlation measurements, which would otherwise contaminate the quantum projection noise signal in weak measurements [1]. We demonstrate our aberration compensation technique using phase contrast imaging, a dispersive homodyne detection technique directly applicable to quantum back-action limited measurements.
[1] E. Altuntas, and I. B. Spielman, Physical Review Research, 3, 043087 (2021).

Presenter name Emine Altuntas
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Primary authors

Dr Emine Altuntas (Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland) Dr Ian Spielman (Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland)

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