Cold matter trapping via slowly rotating helical potential

We consider the cold bosonic ensemble trapped by a helical interference pattern in the optical loop scheme. This rotating helical potential is produced by the two slightly detuned counter-propagating Laguerre-Gaussian laser beams with counter-directed orbital angular momenta +/- l (h) over bar. The detuning may occur due to rotational Doppler effect. The superfluid hydrodynamics is analyzed for the large number of trapped atoms in Thomas-Fermi approximation. For the highly elongated trap the Gross-Pitaevskii equation is solved in a slowly varying envelope approximation. The speed of axial translation and angular momenta of interacting atomic cloud are evaluated. In the T -> 0 limit the angular momentum of the helical cloud is expected to be zero while toroidal trapping geometry leads to 2l (h) over bar angular momentum per trapped atom. (C) 2011 Elsevier B.V. All rights reserved.