Quantum phases transitions of ultracold atoms in an atomic vortex lattice.

Abstract

The production of vortices and the emergence of turbulence in Bose-Einstein condensates (BEC) have been, along the last year, the flagship of researching Atomic and Molecular Physics in the Research Center for Optics and Photonics. In order to continue and extend these studies, a new experimental apparatus has been built to product a trapped two-species Bose-Einstein condensates of sodium (23Na) and potassium (41K). In this project we propose to implement a route to produce and study ultracold atoms immersed in a BEC vortex lattice, exploring different intraspecies interaction regimes.Initially, we will induce and characterize Feshbach resonances between the atomic species by applying a homogeneous magnetic field. For the succeeding experiments, the vortex lattice will be produced in the 23Na condensate using the stirring beam technique, without perturbing the potassium atomic cloud. By changing the interaction between the two species, we pretend to demonstrate that a vortex lattice is equivalent to an optical lattice to trap ultracold atoms. This study will be innovative in the ultracold atoms area, it will provide a new tool for simulating systems and models in condensed matter physics. Specifically, by using ultracold atoms immersed in an atomic vortex lattice we will experimentally simulate the Bose-Hubbard model for a static lattice and the extended Bose-Hubbard model for a out-of-equilibrium lattice. We will investigate the quantum phases transitions between superfluid and Mott insulation in each situation. Once we demonstrated that ultracold atoms can be trapped in the vortex core, we will study dynamics of massive vortices. The studies proposed in this project will be fundamental (and, in fact, the initial step) for the sequence of investigations planed to be done in the two-species BEC experiment, it will provide tools to analyze and better understand the phenomena involving vortices and quantum turbulence formation and dynamics.