TY  - GEN
ID  - heidok18107
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/18107/
N2  - This thesis reports on the preparation of a 2D Fermi gas in the BEC-BCS crossover and
the observation of the BKT transition into a quasi long-range ordered super?uid phase.
The pair momentum distribution of the gas is probed by means of a matter-wave
focusing technique which relies on time-of-?ight evolution in a weak harmonic potential.
This distribution holds the coherence properties of the gas.
The quasi long-range ordered phase manifests itself as a sharp low-momentum peak.
The temperature where it forms is identi?ed as the transition temperature. By tuning
the temperature and the interaction strength, the phase diagram of the 2D Fermi gas in
the BEC-BCS crossover is mapped out.
The phase coherence is investigated in a self-interference experiment. Furthermore,
algebraic decay of correlations is observed in the trap average of the ?rst order corre-
lation function, which is obtained from the Fourier transform of the pair momentum
distribution. This is in qualitative agreement with predictions of homogeneous theory
for the super?uid phase in a 2D gas.
The presented results provide a foundation for future experimental and theoretical
studies of strongly correlated 2D Fermi gases. They might thus help to elucidate complex
systems such as the electron gas in high-Tc superconductors.
Y1  - 2015///
TI  - A Two-Dimensional Fermi Gas in the BEC-BCS Crossover
A1  - Ries, Martin Gerhard
AV  - public
ER  -