两量子比特与谐振子相耦合系统中的量子纠缠演化特性  

Quantum evolution of entanglement property in two-qubit and oscillator coupling system

作　　者：夏建平[1] 任学藻[1] 丛红璐[2] 王旭文[1] 贺树[1] 

机构地区：[1]西南科技大学理学院,绵阳621010 [2]北京交通大学海滨学院,黄骅061100

出　　处：《物理学报》2012年第1期190-195,共6页Acta Physica Sinica

基　　金：西南科技大学研究生创新基金(批准号:10ycjj22)资助的课题~~

摘　　要：在非旋波近似下,利用相干态正交化展开方法,对两量子比特与谐振子相耦合系统中的量子纠缠演化特性进行了精确计算.讨论了在共振时,两量子比特和谐振子耦合系统基态的性质以及量子比特和谐振子之间的纠缠与量子比特一量子比特间的纠缠的不同.结果表明:当不考虑外场时,量子比特-量子比特间的纠缠随着耦合强度的增大从1迅速地减小到零,表明了量子比特一量子比特问的纠缠对耦合强度是非常敏感的;而量子比特和谐振子之问的纠缠随着耦合强度的增大从零迅速地增大,但不能达到理论上的最大值2;当初始时刻两量子比特没有纠缠时,在弱耦合强度下,真空场不能导致纠缠的产生;而强的耦合非旋波效应则可以导致纠缠的突然产生现象.Under the non-rotating wave approximation,the quantum evolution of entanglement property of a two-qubit and oscillator coupling system is accurately investigated by the method of coherent-state orthogonalization expansion.The property of the ground state for qubit-oscillator system and the difference between qubit-oscillator entanglement and qubit-qubit entanglement when resonant vibration occurs are discussed.The calculation results show that when the external field is not taken into consideration,the qubit-qubit entanglement reduces from 1 to 0 rapidly with the increase of coupling strength,indicating the strong sensitivity of the entanglement to the coupling strength.On the contrary,with the increase of the coupling the qubit-oscillator entanglement rises from 0,but does not reach the maximum value 2.At the beginning,when the two qubits do not entangle,the vacuum field does not lead to the entanglement in weak coupling.However,the strong coupling can induce the sudden appearance of the entanglement.

关 键 词：相干态正交化展开 非旋波近似 量子纠缠 

分 类 号：O431.2[机械工程—光学工程]