  We have designed interferometers that sort Bose-Einstein condensates into
their vortex components. The Bose-Einstein condensates in the two arms of the
interferometer are rotated with respect to each other through fixed angles;
different vortex components then exit the interferometer in different
directions. The method we use to rotate the Bose-Einstein condensates involves
asymmetric phase imprinting and is itself new. We have modelled rotation
through fixed angles and sorting into vortex components with even and odd
values of the topological charge of 2-dimensional Bose-Einstein condensates in
a number of states (pure or superposition vortex states for different values of
the scattering length). Our scheme may have applications for quantum
information processing.
