% ************************** Thesis Acknowledgements ************************** \begin{acknowledgements} First and foremost, I would like to thank my supervisor Dr. Igor Mekhov who has been an excellent mentor throughout my time at Oxford. It is primarily thanks to his brilliant insights and professionalism that I was able to reach my full potential during my doctoral studies. The work contained in this thesis would also not be possible without the help of the other members of the group, Gabriel Mazzucchi and Dr. Santiago Caballero-Benitez. Without our frequent casual discussions in the Old Library office I would have still been stuck on the third chapter. I would also like to acknowledge all members of Prof. Dieter Jaksch's and Prof. Christopher Foot's groups for various helpful discussions. I must also offer a special mention for Edward Owen who provided much needed reality checks on some of my wishful theoretical thinking. I would also like to express my gratitude to EPSRC, St. Catherine's College, the ALP sub-department, and the Institute of Physics for providing me with the financial means to live and study in Oxford as well as attend several conferences in the UK and abroad. On a personal note, I would like to thank my parents who provided me with all the skills necessary work towards any goals I set myself. Needless to say, without them I would have never been able to be where I am right now. I would like to thank all the new and old friends that have kept me company for the last four years. The time spent together provided a welcome respite from the sweat and toil of my DPhil. \vspace{2em} \raggedleft{Oxford, September 2016} \end{acknowledgements}