文摘
In this paper we consider a two-dimensional attractive Bose–Einstein condensate with periodic potential, described by Gross–Pitaevskii (GP) functional. By concentration-compactness lemma we show that minimizers of this functional exist when the interaction strength a satisfies a⁎<a<a⁎a⁎<a<a⁎ for some constants a⁎≥0a⁎≥0, a⁎>0a⁎>0, and there is no minimizer for a≥a⁎a≥a⁎. When a approaches a⁎a⁎, using concentration-compactness arguments again we obtain an optimal energy estimate depending on the shape of periodic potential. Moreover, we analyze the mass concentration.