%0 Generic
%A Anantha Murthy, Puneet
%C Heidelberg
%D 2018
%F heidok:24730
%R 10.11588/heidok.00024730
%T Emergent phenomena in two-dimensional Fermi systems
%U https://archiv.ub.uni-heidelberg.de/volltextserver/24730/
%X In this thesis, I present the experimental exploration of emergent effects in a twodimensional gas of ultracold atoms. First, I describe a novel method to measure the momentum distribution of a strongly interacting gas. Using this technique, we map out the phase diagram of the 2D BEC-BCS crossover and measure the critical temperature for  superfluidity. We observe, for the first time, the Berezinskii–Kosterlitz–Thouless phase transition in a Fermi gas that is characterized by algebraic decay of phase correlations. In a second experiment, we investigate fermion pairing in the normal phase using radio-frequency spectroscopy. We observe a crossover from two-body to many-body pairing at remarkably high temperatures, thus answering  a long-standing question concerning the existence of a pseudogap in this system. In the next experiment, we address the question of scale-invariance breaking, also known as a quantum anomaly, in the dynamics of a 2D Fermi superfluid. We observe a striking manifestation of this quantum anomaly in the momentum-space dynamics of the system, which demonstrates that short-range fermionic interactions have a  strong influence on long-range coherence in the system. By revealing the intriguing effects emerging from the interplay between fermionic statistics, strong interactions and reduced dimensionality, this thesis advances our general understanding of many-body quantum systems.