Dynamics of an entangled Bose-Einstein condensate with internal tunneling Jinlong Wang and Yu Shi Phys. Dept., Fudan Univ. Internal tunneling can be considered in a entangled system which contains two type of atoms and each atom with two components. We can see that when internal tunneling happened, the evolutions of atom number and psedo-spin have some periodical properties and in some special parameter there are some nonlinear effects with the vary of time. Basic system H0 is the original system, contains a and b two type of atoms, and Ke term represents that there are some entanglements of two type of atoms. H1 is the tunneling term. haSax is the internal tunneling of a atoms which represents spin-up a atom transfers to spin-down or down to up, the same as b atoms. Reference