Attractive nonlinear Schrdinger equation and Bose-Einstein condensate in phase space;

Using the direct perturbation technique,a general unstable chaotic solution was obtained of the Bose-Einstein condensates trapped in one-dimensional tilted optical lattice potential.

This paper is concerned with a class of nonlinear Schrdinger equations with combined power nonlinearities under a harmonic potential,which describes the attractive Bose-Einstein condensate under a magnetic trap.

Bose-Einstein condensation is a new and peculiar matter-form, and has become one of the hotspots of research in contemporary physics.

Einstein made Bose’s methods spread particles whose quality is not zero further, and predicted if the temperature is low enough, the phase transition will occur, all boson particles will gather to the lowest level, this is the Bose-Einstein Condensation.

This paper focuses on the theoretical discussion about Bose-Einstein condensation,mainly including four parts:(1) the characteristic of chemical potential of Bose gas;(2) condensation phenomenon;(3) macroscopic nature of Bose gas after condensation;(4) the physical formation condition of condensation.