SIAM Journal on Applied Dynamical Systems
In this paper we consider the existence and spectral stability of excited states in two-species Bose-Einstein condensates in the case of a pancake magnetic trap. Each new excited state found in this paper is to leading order a linear combination of two one-species dipoles, each of which is a spectrally stable excited state for one-species condensates. The analysis is done via a Lyapunov-Schmidt reduction and is valid in the limit of weak nonlinear interactions. Some conclusions, however, can be made at this limit which remain true even when the interactions are large.
Kapitula, Todd; Law, Kody J. H.; and Kevrekidis, Panayotis G., "Interaction of excited states in two-species Bose-Einstein condensates: A case study" (2010). University Faculty Publications and Creative Works. 406.