Molecular Bose Einstein Condensate

ongoing

Generating a Bose Einstein Condensate (BEC) or Fermi gas of molecules is a long-standing goal of modern molecular science. Molecular BEC is a macroscopic millimeter-size quantum object with a large number of molecules occupying the lowest center-of-mass quantum state. In stark contrast to atoms, molecules possess internal degrees of freedom and stronger interactions that lead to the emergence of new phenomena. Strong dipole-dipole interactions give rise to new ordered states of matter, quantum crystals. Many-body effects start dominating collision dynamics where even molecular rotational excitations are dissipated as angular-momenta-carrying quasiparticles within the condensate. Despite intense experimental efforts, these fascinating ideas remain in the realm of theory. The main difficulty in turning theory into reality has been the absence of general molecular cooling methods. Recently, we have demonstrated the first experiment where collisions between cold molecules trapped in a 1 K deep superconducting magnetic trap are achieved without laser cooling [Segev et al. Nature, 572 (2019)], opening a clear path to molecular evaporation. We here propose to cool molecules by removing the fastest ones from the trap and letting the rest thermalize to lower temperatures via collisions. This method has been used to produce atomic BECs and we are the first group reaching identical initial conditions that are necessary for the successful application of the evaporative cooling. Generality of our approach is the key to successful search for a suitable molecular candidate. As an alternative to evaporation we suggest applying direct laser cooling on magnetically stopped NH radicals. We are confident that one of our approaches will lead to the long-sought generation of molecular quantum degenerate gas. Our proposal opens new fields and will find applications in areas ranging from quantum chemistry to quantum information science.