作　　者： ; ;

机构地区： 广东第二师范学院

出　　处： 《物理学报》 2012年第5期411-421,共11页

摘　　要： 在一维铁磁性织构介观环的基础上,计及电子-双声子相互作用,介入了三项非经典效应抑制电子-单声子相互作用引起的量子涨落效应:1)跳步电子-单声子相干态关联效应;2)由压缩相干态引起的声子压缩态-单声子相干态间过程关联效应;3)声子位移-声子压缩态的表象关联效应.从结果来看,电子-双声子相互作用明显加强了压缩效应(增大压缩参量),而跳步电子-单声子相干态关联效应引起本征能量大幅度下降,持续电流大幅度增加.特别是介入了声子压缩态-单声子相干态间过程关联效应后,声子压缩参量远大于理想压缩态相应的压缩参量,有效地抑制了Debye-Waller(D-W)效应.当声子压缩态-单声子相干态间过程关联与声子位移重整化效应结合在一起时,声子场的压缩将更大幅度地增加,D-W效应(参量ωph)将更大幅度地减小,ωph■ω_ph^((0)),从而极大幅度地抑制了电子-单声子相互作用导致的量子涨落效应.这样一来,非经典态本征能量E_n极大幅度地下降,E_n■E_n^((0)),与此同时,本征持续电流振幅I_n则极大幅度地增大,I_n■I_n^((0)). For the one-dimensional mesoscopic ring with the ferromagnetic texture, to restrain the quantum fluctuations caused by the electron-one-phonon interaction, the non-classical correlation effects are used in our research to solve this puzzling problem, i.e. 1） the hopping electron-displaced phonon state correlation; 2） the process correlation between the phonon squeezed state, and the one-phonon coherent state, originating from the squeezed coherent state of phonon; 3） the renormalization of the phonon displacement. It is found that due to the electron-two phonon interaction, the squeezing effect of phonon is enhanced significantly. Because of the effect of the electron-displaced phonon correlation the non-classical eigen state energy declines significantly and the amplitude of the persistent current increases substantially. Particularly the process correlation between the squeezed phonon state and the one-phonon coherent state is by far the most important contribution to these non-classical effects. First of all, this effect more greatly increases the squeezing effect of phonon field in contrast to the ideal squeezed state. As a result, it will restrain effectively the Debye-Waller effect （factor ωph） with ωph （ ωph. Furthermore, when we combine the effective renormalization of the phonon displacement with the effect of process correlation between the phonon squeezed state and the one-phonon coherent state, the phonon squeezing effect will increases substantially, at the same time, the D-W effect decreased more substantially （ωph （≤ωph）, thereby weakening the quantum fluctuation to a bigger degree. With these results, the non-classical eigen energy （En） is much lowered （En≤En^（0）））, while the amplitude of eigen persistent current is increased most significantly （In≤ In^（0））.

关 键 词： 非经典本征态 持续电流 电子 声子相互作用 压缩相干态

领　　域： [机械工程] [理学] [理学]