Density and phase-space compression of molecular gases in magneto-electrostatic traps

We introduce, analyze, and compare two methods of single-photon cooling that generically cool and compress molecular gases. The first method compresses the molecular gas density by 3 orders of magnitude and increases collision frequency in trapped samples. The second method compresses the phase-space density of the gas by at least 2 orders of magnitude. Designed with combinations of electric and magnetic fields, these methods cool the molecules from ∼100 to 1 mK using a single irreversible state change. They can be regarded as generic cooling schemes applicable to any molecule with a magnetic and electric dipole moment. The high efficiency calculated, compared to schemes involving cycling, is a result of cooling the molecules in a single step.