Metastable off-axis vortices in nonrotating Bose-Einstein condensates

Abstract

We propose a scenario for studying vortices confined by nonrotating traps. For this purpose we model a polynomial trapping potential that can sustain locally stable off-axis vortices. We also describe a simple numerical method for generating vortices without relying on rotating frames or centrifugal potential techniques. This method offers other advantages related to the control in the number of vortices to be generated and in their location. Finally, we compute the vortex energy as a function of its position using three approaches and discuss their validity. We show that a well-defined energy barrier between the vortex and the ground state is obtained. © 2008 IOP Publishing Ltd.