  Using an ultracold gas of atoms, we have realized a quasi-two-dimensional
Fermi system with widely tunable s-wave interactions nearly in a ground state.
Pressure and density are measured. The experiment covers physically different
regimes: weakly and strongly attractive Fermi gases and a Bose gas of tightly
bound pairs of fermions. In the Fermi regime of weak interactions, the pressure
is systematically above a Fermi-liquid-theory prediction, maybe due to
mesoscopic effects. In the opposite Bose regime, the pressure agrees with a
bosonic mean-field scaling in a range beyond simplest expectations. In the
strongly interacting regime, measurements disagree with a purely 2D model.
Reported data may serve for sensitive testing of theoretical methods applicable
across different quantum physics disciplines.
