  We propose a scheme for generating two-mode squeezing in high-Q resonators
using a beam of atoms with random arrival times, which acts as a reservoir for
the field. The scheme is based on four-wave mixing processes leading to
emission into two cavity modes, which are resonant with the Rabi sidebands of
the atomic dipole transition, driven by a saturating classical field. At steady
state the cavity modes are in an Einstein-Podolski-Rosen (EPR) state, whose
degree of entanglement is controlled by the intensity and the frequency of the
transverse field. This scheme is robust against stochastic fluctuations in the
atomic beam, does not require atomic detection nor velocity selection, and can
be realized by presently available experimental setups with microwave
resonators.
