量子点、量子点分子及耦合腔场的纠缠动力学  

Entanglement Dynamics of a Quantum Dot,a Quantum Dot Molecule and Coupled-cavitiy Fields

作　　者：周青春[1] 狄尊燕[1] 周昱[1] 

机构地区：[1]江苏科技大学物理系,江苏镇江212003

出　　处：《广东工业大学学报》2014年第2期7-13,共7页Journal of Guangdong University of Technology

基　　金：国家自然科学基金资助项目(11205071)

摘　　要：考虑了各含一个二能级的量子点和一个三能级隧穿量子点分子的两耦合腔系统,导出了量子点、量子点分子与腔场发生共振相互作用,量子点处于激发态,量子点分子处于基态,腔场均处于真空态的初始条件下系统的态矢量,运用Negativity度量子系统间的纠缠,采用数值计算的方法研究了量子点原子与量子点分子之间,腔中量子点(量子点分子)与腔场之间和两个腔场之间的纠缠特性,探讨了腔场间的耦合系数及量子点分子的隧穿强度对纠缠特性的影响.结果表明,与弱腔场耦合相比,在强腔场耦合情况下,量子点、隧穿量子点分子与腔场之间的纠缠及腔场之间的纠缠减弱,量子点分子与隧穿量子点分子之间纠缠增强;在腔场弱耦合或强耦合下,随着量子点分子隧穿强度的增加,量子点与量子点分子间及量子点与腔场间的纠缠强度受影响程度较小,只有量子点分子与腔场纠缠出现明显减弱.It studies a system of two coupled cavities,one containing a two-level quantum dot and the other containing a three-level tunneling quantum dot molecule.The state vector of the system was derived under the assumption of resonant interaction and the initial conditions that the quantum dot was in the excited state,the quantum dot molecule in the ground state,and the cavity fields were in a vacuum.The dot-molecule entanglement,cavity-cavity entanglement,dot-cavity entanglement and molecule-cavity entanglement were discussed.The influence of coupling coefficeint between cavities and tunneling strength of the quantum molecule on entanglement properties was explored with Negativity used to measure the entanglement between subsystems.Numerical results show that,compared with the weak cavity-coupling case,strong cavity coupling makes the entanglement between the quantum dot （or the tunneling quantum dot molecule） and the corresponding cavity field,and that between the fields reduce,while entanglement between the quantum dot atom and the tunneling quantum dot molecule increases.On the other hand,for either weak or strong coupling between the cavities,with quantum dot molecule tunneling strength increasing,entanglement between the quantum dot （or molecule）,and that between fields are slightly affected; only entanglement between the molecule and its cavity field is obviously reduced.

关 键 词：量子点 耦合腔 量子纠缠 NEGATIVITY 

分 类 号：O413[理学—理论物理]