Abstract Quantum-state engineering, i.e. active manipulation over the coherent dynamics of suitable quantum-mechanical systems, has become a fascinating prospect of modern physics. Here we discuss the dynamics of two interacting electrons in a coupled quantum dot driven by an external electric field. The results show that the two quantum dots can be used to prepare a maximally entangled Bell state by changing the strength and duration of an oscillatory electric field. Different from the suggestion made by Loss et al (1998 Phys. Rev. A 57 120, the present entanglement involves the spatial degree of freedom for the two electrons. We also find that the coherent tunnelling suppression discussed by Grossmann et al (1991 Phys. Rev. Lett. 67 516 persists in the two-particle case: i.e. two electrons initially localized in one dot can remain dynamically localized, although the strong Coulomb repulsion prevents them from behaving so. Surprisingly, the interaction enhances the degree of localization to a large extent compared with that in the non-interacting case. This phenomenon is referred to as the Coulomb-enhanced dynamical localization.
Received: 28 February 2006
Revised: 15 May 2006
Accepted manuscript online:
(Semiconductor-device characterization, design, and modeling)
Fund: Project supported in part by
the National Natural Science Foundation of China (Grant Nos 10544004 and
10574017).
Cite this article:
Song Hong-Zhou(宋红州), Zhang Ping(张平), Duan Su-Qing(段素青), and Zhao Xian-Geng(赵宪庚) Quantum control of two interacting electrons in a coupled quantum dot 2006 Chinese Physics 15 2130
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