Dynamic Quantum Erasure Mediated By Electromagnetically Induced Transparency

We propose a scheme on control of the transition from quantum decoherence to coherence of a considered system S provided by the polarization degree of free-dom of a probe field coupled to its motional degrees of freedom representing the environment B. A magneto-optically manipulated atomic ensemble with a tripod configuration is used to enhance the coupling between systems S and B. It is found that the coherence of the system S can be maintained, lost or gained by properly choosing the incident positions of the probe field with respect to the center of the control laser field, and the two photon detuning for each components of the probe laser field. Paper is divided into seven chapters:The first chapter is an introduction that the importance of quantum entan-glement and quantum coherence, a brief history and the current status of electro-magnetically induced Transparency.The second chapter describes the relevant, knowledge of quantum coherence and quantum entanglement, such as entanglement concept, EPR paradox, and so on,The third Chapter wrote a quantum decoherence dynamics as well as its description, which focuses on several mechanisms of quantum decoherence caused by measurement, and a brief description of the dynamics of quantum decoherence approach.The fourth chapter describes the development of EIT in these years, by using the three-level system, the formation mechanism of the semi-classical single-atom EIT is detailed descripted.The main elements of the fifth chapter is quantum erasure and physical con-notation through a variant version of the double-slit experiment. Chapter VI is the most important work of this paper, we take use of EIT system to control the quantum decoherence of the probe light field:Select the polarization degree of the probe field as system S, the freedom of movement as the environment B, and then adjusting the system coherence by EIT, Keep its disappeared or strengthened. Here we used s atomic ensemble of a tripod structure level by magneto-optical manipulation to enhance coupling between the system S and the environment B.The spatial profile of the external fields induce a spatially varying potential for system B in the gas cell with identical and noninteracting atoms a,t different transverse points,which caused the decoherence of the system.Chapter VII that the last chapter of this article, which is a summary of the work and expectations.