Speaker
Description
The helium dimer in its metastable triplet state is a promising candidate to become the first homonuclear molecule ever laser-cooled. Nearly diagonal Franck-Condon factors are obtained, because the electron employed for optical cycling occupies a Rydberg orbital that doesn’t take part in the chemical bond. In addition, the general Pauli principle facilitates the closing of the cooling cycle for the rotational degree-of-freedom.
Laser cooling and trapping of the helium dimer would result in a controllable, simple 4-electron system at record low temperature, allowing quantum sensing and precision measurements to test quantum electrodynamics and the quantum nature of collisions with unprecedented accuracy - while being accessible to highly accurate ab initio computational methods.
The prospects for laser cooling He2 are discussed and the rovibronic level structure and transition moments in He2 are analyzed to identify the most suitable electronic transitions for laser cooling. By evaluating the number of scattered photons and the scattering force under different repumping schemes, we determine the optimal optical cycling strategies. Loss mechanisms such as spin-forbidden transitions, predissociation, and ionization processes are studied and found not to introduce significant challenges for cooling.
