Abstract The interactions between a two-level atom and a field via two-photon transition without rotating wave approximation have been investigated. We emphasize the dynamic behaviors of the atomic population inversion, the field squeezing, and the atomic dipole squeezing numerically when the field frequency varies with time in the forms of sine and rectangle. Some interesting phenomena are discovered and discussed. The good periodic character of the atomic population inversion in the standard two-photon Jaynes--Cummings model is weakened by the influence of the sine field frequency modulation. The rectangular field frequency modulation can change the correlation among different oscillations suddenly and induce new collapse-revival processes of the atomic population inversion. The field squeezing increases at the beginning of time, but then decreases and loses as the time increases after it reaches the maximum due to the sine modulation. The effects of the rectangular modulation on the field squeezing depend mostly on the appearance time of the modulation. The atomic dipole squeezing is weakened under the influence of the sine or rectangular modulation. Our results indicate that it is possible to perform the dynamic controlling of the system properties by changing the parameters of the system with time. This implies that one can dynamically control a quantum information process by choosing the system modulation properly.
Received: 24 October 2008
Revised: 19 January 2009
Accepted manuscript online:
Fund: Project supported in part by the
National Natural Science Foundation of China (Grant No 10674103) and
the New Century Excellent Talent
Foundation of the Ministry of Education (Grant No NCET-06-0384).
Cite this article:
Jia Fei(贾飞), Xie Shuang-Yuan(谢双媛), Yang Ya-Ping(羊亚平) Controlling nonclassical properties of the two-photon process by a time-varying field 2009 Chin. Phys. B 18 3193
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