  We study Fermi gases in two dimensions at low temperatures with attractive
interactions. Analytical results are derived for the equation of state and the
Kosterlitz-Thouless transition temperature as functions of the two-body binding
energy and the density of the gas. Our results for the equation of state
strongly deviate from the mean field predictions. However, they are in
reasonable agreement with Monte-Carlo calculations and recent experiments with
cold atomic gases.
