Dynamics of weakly bound dimers and trimers controlled by short laser fields*

Controlling the interactions between atoms with external fields opened up new branches in physics ranging from strongly correlated atomic systems to ideal Bose and Fermi gases and Efimov physics. Such control usually prepares samples that are stationary or evolve adiabatically in time. In contrast, in molecular physics, external ultrashort laser fields are used to create anisotropic potentials that launch ultrafast rotational wave packets and align molecules in free space. Here we combine these two regimes of ultrafast times and low energies. The helium dimer and trimer systems are weakly bound few-body quantum systems that support universal two-atom and Efimov bound states, respectively. In this talk, I will discuss the dynamics of the helium dimer, the tunability of the dimer interaction, and the dynamics of the helium trimer controlled by ultrashort laser fields. The agreement between theory and experiment will be presented for the dimer dynamics. This work paves the way for future tomography of wave-packet dynamics and provides the technique for studying exotic and otherwise hardly accessible quantum systems, such as halo and Efimov states.