Coherent Control Of Quantum Tunneling In An Open Few-well System

As the quick development of science and technology, people’s interest is in-creasing about the unknown world, and exploring the scale of the things become further narrow, which is from the mm to microns, and to nano and with fine at present. For example, the development of biology is from cellular level to the genes level now:selected key reaction in chemical research, precision machinery of micro-nano scale, and so on. These areas without exception should consider the controlling of the atoms. The continuous development of laser technology and the decreasing of the laser’s bandwidth provide the technical support of manipulating atoms more meticulously. The relevant features of the interaction between light and matter provide a theoretical support for coherently controlling atoms, and controlling particles in experiments. Microscopic particles perform some charac-ters in quantum mechanics which did not exist in classical mechanics, such as, the quantum tunneling of particle, coherent superposition of wave function of particles. Using this feature, people made many research equipments, for example, scanning tunneling microscopy devices. However, particle’s coherent control is limited to an ideal system which did not take into account the effects of external environment parameters. In order to adapt to the needs of experiment further and provide theoretical guidance for experiments better, this paper has studied the coherent control of single atom in the open double-well system, and preliminary studied the coherent control of the single atoms in open triple-well. We hope this paper could provide guidance to experiment.Full text is divided into four chapters. The first chapter is the introduction section, which introduced the atom laser cooling and trapping, extension of quan-tum mechanics, and NooN state theory. In the second chapter, we studied coherent control of tunneling of a single-atom confining in double driven by a single-mode optical field. Through building the basic model, we got some of the more interesting solution of the system in the high frequency drive field. For example, by adjusting drive field amplitude and frequency, we can get the quasi-Noon state population. In this case, the popula-tion of particle in the double-well is1/2; Secondly, adjusting the field parameters, the partial tunneling of particle will be happen in this system; Of course, this system will also appear the decaying population also. The paper have systemati-cally studied coherent tunneling of single particle in open double-well, and found that the analysis solution and numerical solution is agreement well by comparing between them. However, we still hope that we can have some verification with the experiment to support the study results strongly.For better researching open three trap system, in chapter3, we obtained the exact solution of the system in the high frequency approximation. By adjusting the laser field amplitude and frequency we can get different solutions. Through the preliminary analysis, these solutions can be divided into three types:the diverging non-physics solution shall be cut out:the population of particle is a oscillatory solution, that is, the particle will coherently tunnel in the triple-well system; and the last is the decay solution. Although we analysis the system preliminarily here and it also provides guidance to us for understanding the macroscopic properties of the system.In chapter4, we summarized and induced this paper, and prospected briefly about the domain of coherent control of atom in laser field.