Ultra-cold atom transport made simple (Vol. 45 No.4)

Schematic representation of the physical system consisting of a ring trap and two dipole waveguides for injecting neutral atoms into, extracting them from, and velocity filtering them in the ring waveguide. Credit: Loiko et al.

New study provides proof of the validity of a filtering device for ultra-cold neutral atoms based on tunnelling.

A new study gives a proof of principle, confirmed by numerical simulations, of the applicability to ultra-cold atoms of a very efficient and robust transport technique called spatial adiabatic passage (SAP). The authors have, for the first time, applied SAP to inject, extract, and filter the velocity of neutral atoms from and into a ring trap.

They focused on controlling the transfer of a single atom between the outermost waveguides of a system composed of two dipole waveguides and a ring trap, using the SAP technique. They calculated the explicit conditions for SAP tunnelling, which depend on two factors: the atomic velocity along the input waveguide and the initial atom population distribution among what physicists refer to as the transverse vibrational states.

To check the performance of the proposed approach, they relied on a numerical integration of the corresponding equation with parameter values for rubidium atoms and an optical dipole ring trap.

Y. Loiko, V. Ahufinger, R. Menchon-Enrich, G. Birkl and J. Mompart, “Coherent injecting, extracting, and velocity filtering of neutral atoms in a ring trap via spatial adiabatic passage”, Eur. Phys. J. D, 68, 147 (2014)