Dissertation/Thesis Abstract

Exploring Spontaneous Emission Phenomena Using Ultracold Atomic Matter Waves
by Krinner, Ludwig, Ph.D., State University of New York at Stony Brook, 2018, 154; 10929967
Abstract (Summary)

The controllability of ultracold quantum gases in optical lattices offers new perspectives on problems in various subfields of physics. In this dissertation, we study spontaneous emission, a fundamental concept in quantum electro-dynamics, using engineered emitters, realized with 87Rb atoms in a hyperfine ground state selective optical lattice (a lattice potential that confines one internal hyperfine ground state without confining the other), that send single atoms into one-dimensional matter-waveguides. On a fundamental level, each emitter is described by the Weisskopf-Wigner model. The system allows for easy tunability of the coupling strength and excited state energy, allowing the direct observation of how Markovian dynamics, giving rise to the usually observed exponential decay, transform into non-Markovian dynamics as the excited state energy approaches the coupling strength. This has allowed the first direct observation of a bound state, which was long predicted to exist for spontaneous emission in the context of photonic bandgap materials. We study its spatial characteristics in momentum-space and are able to infer its real-space extent.

The ability to carry out these experiments in our apparatus depends on two technical developments. First is the development of a technique which allows a precise characterization of magnetic fields at Gauss-level fields used in our apparatus. This is achieved by utilizing transitions to unused hyperfine states, which creates a ‘tag’ that characterizes the field at the position of the atoms at the time of the experiment to an accuracy of better than 100 µG for every single experimental repetition. This allows post-selection stabilization on a level which is comparable to state-of-the-art active stabilization techniques. The second development is an image analysis technique which allows for the removal of spurious unwanted fringes in our absorption images, which allows a reliable detection of small (on the order of several hundred) atom number.

The experimental work presented in this dissertation realizes a platform for future studies of dissipative many-body physics in ultraold atomic gases mirroring one of the current frontiers in quantum optics.

Indexing (document details)
Advisor: Schneble, Dominik A.
Commitee: Allen, Philip B., Daley, Andrew, Figueroa, Eden
School: State University of New York at Stony Brook
Department: Physics
School Location: United States -- New York
Source: DAI-B 80/03(E), Dissertation Abstracts International
Subjects: Physics, Atomic physics
Keywords: BEC, Quantum optics, Spontaneous emission, Ultracold, Weisskopf-Wigner model
Publication Number: 10929967
ISBN: 978-0-438-57225-6
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