Degenerate Fermi Gases

Degenerate Fermi Gases
The main topic of these lectures is the physics of quantum degenerate atomic Fermi gases both under uniform confinement and in harmonic traps. To begin with, a general introduction on ideal Fermi gases is proposed. This "academic" limit is relevant in experiments where ultracold fermionic atoms are all polarized in a single spin state: the low atom momenta together with the fermionic nature of the atoms forbid atomic scattering (s-wave scattering) and the atoms can be considered as free. Interactions will then be introduced. They become relevant in mixtures with at least two spin components for which the s-wave scattering channel is allowed. Interactions can be tuned via Feshbach resonances and control the microscopic features of the superfluid phase, ranging from the BCS limit (formation of Cooper pairs) to the BEC limit (Bose-Einstein condensation of dimers). Various theoretical approaches for the description of the BCS-BEC crossover and their predictions in comparison with the experimental results will be discussed.

The main topic of these lectures is the physics of quantum degenerate atomic Fermi gases both under uniform confinement and in harmonic traps.

To begin with, a general introduction on ideal Fermi gases is proposed. This "academic" limit is relevant in experiments where ultracold fermionic atoms are all polarized in a single spin state: the low atom momenta together with the fermionic nature of the atoms forbid atomic scattering (s-wave scattering) and the atoms can be considered as free. Interactions will then be introduced.

They become relevant in mixtures with at least two spin components for which the s-wave scattering channel is allowed. Interactions can be tuned via Feshbach resonances and control the microscopic features of the superfluid phase, ranging from the BCS limit (formation of Cooper pairs) to the BEC limit (Bose-Einstein condensation of dimers).

Various theoretical approaches for the description of the BCS-BEC crossover and their predictions in comparison with the experimental results will be discussed.