TY  - GEN
A1  - Faigle-Cedzich, Bruno Maximilian
CY  - Heidelberg
ID  - heidok31885
TI  - Towards understanding the dimensional BCS-BEC crossover and its spectral properties
N2  - In this thesis we investigate several aspects of ultracold Fermi gases within the framework of the functional renormalisation group (fRG). The first part concerns the determination of the thermodynamics and the phase structure of a Fermi gas within a dimensional crossover from three to two dimensions over the whole BCS-BEC crossover. Particular focus is put on the determination of the finite temperature phase diagram for different confinement which is then compared to recent experimental observations. In the second part, we perform an analytical continuation of the two-point functions in Euclidean space to real times. This allows us to gain knowledge about the spectral functions within the three-dimensional BCS- BEC crossover en route to obtaining transport properties of ultracold quantum gases. The third part is devoted to the access to quantitative precision within the fRG approach. We employ an approach that utilises higher order density fluctuations as the fundamental building blocks which circumvents the fine-tuning problem of the density on the microscopic level. We primarily compute the equation of state and the gap over the whole range of BEC-BCS crossover at vanishing temperature. The very good quantitative agreement with recent experimental results, particularly at unitarity, thus shows the quantitative reliability of the fRG framework.
Y1  - 2022///
AV  - public
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/31885/
ER  -