Collision-assisted Zeeman cooling of neutral atoms

We propose a new method to cool gaseous samples of neutral atoms. The gas is confined in a non dissipative optical trap in the presence of an homogeneous magnetic field. The method accumulates atoms in the $m_F=0$ Zeeman sub-level. Cooling occurs via collisions that produce atoms in $m_F\neq 0$ states. Thanks to the second order Zeeman effect kinetic energy is transformed into internal energy and recycling of atoms is ensured by optical pumping. This method may allow quantum degeneracy to be reached by purely optical means.