Dynamics Of Dipolar Spinor Condensates In The External Magneticeld

Bose-Einstein condensation(BEC)is a ubiquitous phenomenon relating to many fields in physics,such as atomic and molecular physics,quantum optics,quantum statistical physics,condensate matter physics.Since BEC was observed in a remarkable series of experiments on vapors of ⁸⁷Rb,²³Na,⁷Li in 1995,physicists aimed at gaining a deep insight into the fascinating behavior of this matter.In this thesis,we mainly discuss the external magnetic field effects on the stationary and dynamic property of the spinor BEC.This thesis is divided into four chapters.The first chapter is a review main about the condition of Bose-Einstein condensation realization,the corresponding experiment,some important physical phenomenon about the BEC,at last we introduce the spinor BEC.The second chapter of this paper is collisional interaction,dipole-dipole interaction,second quantized hamiltonian for spin-1 condensate,single-mode approximation.In chapter 3,we investigate the equilibrium populations and the coherent offequilibrium spin mixing with dipole-dipole interaction dynamics in an external magnetic field.As a result of the conservation of atom numbers and total hyperfine spin of the condensates,the coupled spinor equations simplified as the equations of the populationsρ₀ and the relative phase,the equilibrium populations depends on the relative value of quadratic term of the Zeeman energy,the dipole-dipole interaction and on the spin-dependent term of atom-atom interaction.The magnetization of the ground state of can be controlled by adjusting the external field and the aspect ratio of the potential well.The initial population especially the relative phase strongly affect the dynamics of the spin mixing.The quadratic Zeeman effect and the nonlinear interaction inside an atomic condensate both affect the tunneling of the hyperfine components.By adjusting the external magnetic field,spin-exchange interaction and the aspect ratio of the potential well we can control the tunneling of the hyperfine components,the oscillation of the populations p0and the relative phase.In the final chapter,we summarize the main results and give an outlook of the future study in this field.