中国物理B ›› 2006, Vol. 15 ›› Issue (9): 2130-2141.doi: 10.1088/1009-1963/15/9/038

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Quantum control of two interacting electrons in a coupled quantum dot

宋红州, 张平, 段素青, 赵宪庚   

  1. Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
  • 收稿日期:2006-02-28 修回日期:2006-05-15 出版日期:2006-09-20 发布日期:2006-09-20
  • 基金资助:
    Project supported in part by the National Natural Science Foundation of China (Grant Nos 10544004 and 10574017).

Quantum control of two interacting electrons in a coupled quantum dot

Song Hong-Zhou(宋红州)†, Zhang Ping(张平)‡ger, Duan Su-Qing(段素青), and Zhao Xian-Geng(赵宪庚)   

  1. Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
  • Received:2006-02-28 Revised:2006-05-15 Online:2006-09-20 Published:2006-09-20
  • Supported by:
    Project supported in part by the National Natural Science Foundation of China (Grant Nos 10544004 and 10574017).

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摘要： 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 \textit 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 \textit 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.

关键词: coupled quantum dot, dynamical localization, entanglement

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.

Key words: coupled quantum dot, dynamical localization, entanglement

中图分类号:  (Tunneling)

  • 73.40.Gk
71.18.+y (Fermi surface: calculations and measurements; effective mass, g factor) 85.30.Mn (Junction breakdown and tunneling devices (including resonance tunneling devices)) 85.30.De (Semiconductor-device characterization, design, and modeling)