ISBN 9783843933919

978-3-8439-3391-9, Reihe Physik

Klaus M. Hueck
A Homogeneous, Two-Dimensional Fermi Gas

225 Seiten, Dissertation Universität Hamburg (2017), Hardcover, B5

Zusammenfassung / Abstract

This thesis reports on the first experimental realization and study of homogeneous ultracold two-dimensional atomic Fermi gases.

The atoms are confined radially by a ring potential which is generated using a novel optical setup consisting of three axicons.

With the ability to imprint arbitrary potentials using a digital micromirror device, the 2D samples can be manipulated locally, allowing to measure the equation of state (EOS), and thus the temperature, of a homogeneous ideal Fermi gas.

For the measurement of the EOS the development of a new and robust method to calibrate high intensity absorption imaging was crucial.

The in-situ density measurements were complemented by investigating the momentum distribution of 6Li Fermi gases in the crossover ranging from the Berezinskii-Kosterlitz-Thouless-phase to Bardeen-Cooper-Schrieffer-superfluidity.

This was facilitated by the implementation of a procedure to map momentum-space to position-space for both, non-interacting and interacting gases, using matter wave focusing.

For a non-interacting Fermi gas, Pauli blocking was directly witnessed in the unity occupation of single particle momentum states, while a strongly interacting gas of bosonic 6Li2 dimers featured a macroscopic occupation of low momentum modes.

The ability to accurately measure both, the position- and the momentum-space distribution, represents an ideal starting point for further investigations such as the study of Cooper-pair correlations in momentum space.