Before revision: We study a special nonconvex optimization problem with a single spherical constraint to find a global minimizer of it. One important application of this problem is the discretized energy functional minimization problem of non-rotating Bose-Einstein condensate (BEC) .
After revision: We study a special nonconvex optimization problem with a single spherical constraint , which includes the discretized energy functional minimization problem of non-rotating Bose-Einstein condensate (BEC) .