The Interaction Of Becs Containing A Dark Soliton With The Potential Barrier And Its Implications For The Physics Teaching In Middle Schools

In this thesis,we study the interaction between a Bose Einstein Condensate(BEC)with a potential barrier.By using this as an example,we discuss how to apply the ideas and methods in scientific research to physics teaching in middle schools.BEC is a state of matter that at ultracold temperatures a large number of bosons of dilute gas assemble in the same quantum state with the lowest energy.As a new state of matter,BEC opens a new research field in physics.Since BEC is achieved in alkali metals,a lot of work and great achievements have been done in both theory and experiments.With the development of the technique of atom chips,the interaction between condensates and solid surface turns to be a hot research topic.It is helpful for not only a better understanding of the nature of the rules of quantum mechanics,but also a guidance for developing quantum devices in nano and micron scales.The contents of the thesis are as follows:We conduct the research in five steps,which are determining the research topic,literature review,constructing the research plan,doing calculations and analyzing data and obtaining results.We employ the Crank-Nicolson method to solve the Gross-Pitaevskii equation which is actually a nonlinear Schr?dinger equation governing the dynamics of BEC systems.The dynamics between dark-solitons and a potential barrier is studied through numerical simulations.The reflection rates of the condensates as a function of time are given with respect to relevant parameters,such as the width and strength of the potential barrier,the incident angle of the BECs and the orientation of the dark-solitons.The influence of these parameters on the asymptotic reflection rate,and the excitation propertied in the reflected and transmitted condensate clouds are also discussed.The results show that the asymptotic value of the reflection probability is decreased by the existence of a dark-soliton,and is highly sensitive to the initial orientation of the dark-soliton which also affects the excitation properties during the process of condensate and barrier interaction.Through the study of the BEC with a dark-soliton scattered by a barrier potential,new knowledge about the way and the methods of doing scientific researches has been gained.With the the method and means of scientific research have gained a new understanding.With the deepening of the teaching reform,the traditional physics teaching in middle schools cannot satisfy the development of modern physical science.It is the trend of reform and development to integrate scientific research ideas into physics teaching.It is also an urgent requirement to train citizens with high scientific literacy in the new era.Based on my own scientific research experience,I will put forward some ideas and concrete methods to improve the effect of physics teaching in middle schools.