Simulations of trapping anti-hydrogen atoms - theory and experiment

A study of anti-hydrogen atoms is very important for fundamental physics. In the experiments at CERN anti-hydrogen atoms are created by mixing of cold antiprotons and positrons in a magnetic trap. We have made theoretical studies of the relaxation processes in the presence of a strong magnetic field (1-3 Tesla) using molecular dynamics technique. The calculated deceleration rates are different for particles with velocities parallel or perpendicular to the applied magnetic field. The creation of anti-hydrogen atoms can occur under conditions when the parallel velocities of the particles are still high. It may limit the production of trapped anti-hydrogen atoms in the existing experimental arrangements. In order to increase the number of trapped anti-hydrogen atoms optical cooling methods can be used. We suggest to perform experimental simulations of anti-hydrogen trapping with a magneto-optical trap (MOT) for lithium atoms. As a first step we have studied highly excited states of ultra-cold lithium-7 atoms by using a tunable UV-laser. The diagnostics of Rydberg transitions of lithium atoms in a MOT is developed. In our work the results for different Rydberg states nS, nP, nD, nF with quantum number n from 38 to 161 will be presented. In the future, a modified trap for anti-hydrogen atoms will be assembled at the International Facility for Antiproton and Ion Research (FAIR). The work was supported by Research Center FAIR (FAIR, Russia).