  The classical dynamics of a cold atom trapped inside a vertical rotating
helical optical tube (HOT) is investigated by taking also into account the
gravitational field. The resulting equations of motion are solved numerically.
The rotation induces a vertical motion for an atom initially at rest. The
motion is a result of the action of two inertial forces, namely the centrifugal
force and the Coriolis force. Both inertial forces force the atom to rotate in
a direction opposite to that of the angular velocity of the HOT. The frequency
and the turning points of the atom's global oscillation can be controlled by
the value and the direction of the angular velocity of the HOT. However, at
large values of the angular velocity of the HOT the atom can escape from the
global oscillation and be transported along the axis of the HOT. In this case,
the rotating HOT operates as an Optical Archimedes' Screw (OAS) for atoms.
