On the 100th anniversary of the birth of V.L. Ginzburg. Physics of our days
Cooling and thermometry of atomic Fermi gases
R. Onofrioa,b aDipartimento di Fisica ‘Galileo Galilei’, Universita di Padova, via F. Marzolo 8, Padova, 35131, Italy bDepartment of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire, USA
We review the status of cooling techniques aimed at achieving the deepest quantum degeneracy for atomic Fermi gases. We first discuss some physics motivations, providing a quantitative assessment of the need for deep quantum degeneracy in relevant physics cases, such as the search for unconventional superfluid states. The attention is then focused on the most widespread technique to reach deep quantum degeneracy for Fermi systems, sympathetic cooling of Bose—Fermi mixtures, organizing the discussion according to the specific species involved. Various proposals to circumvent some of the limitations to achieve deepest Fermi degeneracy, and their experimental realizations, are then reviewed. We finally discuss the extension of these techniques to optical lattices, and the implementation of precision thermometry crucial to understand the phase diagram of classical and quantum phase transitions in Fermi gases.