Cooling by Spontaneous Decay of Highly Excited Antihydrogen Atoms in Magnetic Traps

An efficient cooling mechanism of magnetically trapped, highly excited antihydrogen atoms is presented. This cooling, in addition to the expected evaporative cooling, results in trapping of a large number of atoms in the ground state, essential for future antihydrogen trapping experiments. In good agreement with our numerical simulations, we identify two different dynamical regimes - adiabatic cooling followed by sudden de-excitation. Moreover we derive expressions for the cooling efficiency, which may help to design trap geometries with optimized groundstate trapping.