From Nanoscale Systems to Ultracold Atoms and Molecules, and Back

Mathematisch-naturwissenschaftlichen Fakultät I, Heinrich-Heine-Universität Düsseldorf

Goulven Quéméner, N. Balakrishnan, Roman V. Krems

Subhadeep Gupta

Benedikt B. Brandt, Constantine Yannouleas, Uzi Landman

"Bottom-up" approaches to the many-body physics of fermions have recently demonstrated precise number and site-resolved preparations with tunability of interparticle interactions in single-well, SW, and double-well, DW, nanoscale confinements created by manipulating ultracold fermionic atoms with optical tweezers. These experiments emulate an analogue-simulator mapping onto the requisite microscopic Hamiltonian, approaching realization of Feynmans' vision of quantum simulators that "will do exactly the same as nature". Here we report on exact benchmark configuration-interaction computational microscopy solutions of the Hamiltonian, uncovering the spectral evolution, wave function anatomy, and entanglement properties of the interacting fermions in the entire parameter range, including crossover from an SW to a DW confinement and a controllable energy imbalance between the wells. We demonstrate attractive pairing and formation of repulsive, highly correlated, ultracold Wigner molecules, well-described in the natural orbital representation. The agreement with the measurements affirms the henceforth gained deep insights into ultracold molecules and opens access to the size-dependent evolution of nanoclustered and condensed-matter phases and ultracold-atoms quantum information.

Claude N. Cohen-Tannoudji

Meng Shao-ying

The generation of ultracold molecules has been a hot topic in cold atom-molecule physics.It is difficult to obtain ultracold molecules with laser cooling as in the atomic system,because there are more degrees of freedom in molecules,and the level structure is denser and more complicated. For the time being,the ultracold molecules are generally generated from the ultracold atoms coupled by the external fields.The stimulated Raman adiabatic passage process(STIRAP) as an effective method of generating ultracold molecules from its atomic counterparts has been widely studied.In this article,we mainly focus on the recent research progress of dynamics,adiabaticity and instability of the dark state in the atom-molecule STIRAP.