This thesis presents a theoretical investigation into the creation and exploitation of quantum correlations and entanglement among ultracold atoms. Specifically, it focuses on these non-classical effects in two contexts: (i) tests of local realism with massive particles, e.g., violations of a Bell inequality and the EPR paradox, and (ii) realization of quantum technology by exploitation of entanglement, for example quantum-enhanced metrology. In particular, the work presented in this thesis emphasizes the possibility of demonstrating and characterizing entanglement in realistic experiments, beyond the simple "toy-models" often discussed in the literature. The importance and relevance of this thesis are reflected in a spate of recent publications regarding experimental demonstrations of the atomic Hong-Ou-Mandel effect, observation of EPR entanglement with massive particles and a demonstration of an atomic SU(1,1) interferometer. With a separate chapter on each of these systems, this thesis is at the forefront of current research in ultracold atomic physics.

Robert Lewis-Swan obtained his Bachelors degree in science from University of Queensland, Australia in 2011 and was consequently awarded a prestigious University Medal. He continued his education at University of Queensland, pursuing a PhD in ultracold atomic physics under the supervision of A/Prof. Karen Kheruntsyan and graduating in 2015. His research interests include the study of non-equilibrium many-body dynamics, specifically the novel physics currently being explored in analogue quantum simulators, along with the generation, characterization and exploitation of entanglement and non-classical correlations in developing quantum technology.