PhD Defense: Mary Locke

ADVISOR: Dr. Yanhua Shih

TITLE: Two-Atom Interference

ABSTRACT: This dissertation presents the first demonstration of simultaneous, non-trivial 2D patiotemporal second-order atom-number correlations in a continuous thermal atom beam. Building upon the framework of the de Broglie wave packet as a coherent superposition of planewaves, and the thermal beam as an incoherent ensemble, non-local second-order interference is demonstrated to be a two-atom interference effect. Furthermore, it is shown that while first-order decoherence may occur due to path-dependent phase fluctuations leading to wave front disturbances, the second-order coherence or correlation is shown to be independent of these effects.

Advancements in laser cooling and trapping led to a series of experiments demonstrating two-atom correlation measurements. Each of those efforts have relied on pulsed releases from trapped atomic clouds in order to ensure high-density samples or single-point counting detectors to resolve single atom arrival times over a spatially extended detector. In the interest of advancing two-atom correlation measurements towards atomic sensor applications, it is necessary to extend into spatiotemporal correlation measurements for a truly continuous source. However, the elimination of 3D trapping leads to a loss of atomic density that makes the measurement uniquely challenging.

Through the collection of near-instantaneous atom-number density images, high-resolution 2D spatiotemporal atom-number fluctuation-correlations can be resolved. In addition toproviding a tool for studying the non-classical behavior of matter waves, this research lays the groundwork for realizing a continuous two-atom interferometer that can maintain operation in spite of common causes of first-order decoherence.