中国物理B ›› 2020, Vol. 29 ›› Issue (3): 30302-030302.doi: 10.1088/1674-1056/ab6963

• SPECIAL TOPIC—Recent advances in thermoelectric materials and devices • 上一篇    下一篇

Geometric phase of an open double-quantum-dot system detected by a quantum point contact

Qian Du(杜倩), Kang Lan(蓝康), Yan-Hui Zhang(张延惠), Lu-Jing Jiang(姜露静)   

  1. School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
  • 收稿日期:2019-11-01 修回日期:2019-12-26 出版日期:2020-03-05 发布日期:2020-03-05
  • 通讯作者: Yan-Hui Zhang E-mail:yhzhang@sdnu.edu.cn
  • 基金资助:
    Project supported by the Natural Science Foundation of Shandong Province, China (Grant No. ZR2014AM030).

Geometric phase of an open double-quantum-dot system detected by a quantum point contact

Qian Du(杜倩), Kang Lan(蓝康), Yan-Hui Zhang(张延惠), Lu-Jing Jiang(姜露静)   

  1. School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
  • Received:2019-11-01 Revised:2019-12-26 Online:2020-03-05 Published:2020-03-05
  • Contact: Yan-Hui Zhang E-mail:yhzhang@sdnu.edu.cn
  • Supported by:
    Project supported by the Natural Science Foundation of Shandong Province, China (Grant No. ZR2014AM030).

摘要: We study theoretically the geometric phase of a double-quantum-dot (DQD) system measured by a quantum point contact (QPC) in the pure dephasing and dissipative environments, respectively. The results show that in these two environments, the coupling strength between the quantum dots has an enhanced impact on the geometric phase during a quasiperiod. This is due to the fact that the expansion of the width of the tunneling channel connecting the two quantum dots accelerates the oscillations of the electron between the quantum dots and makes the length of the evolution path longer. In addition, there is a notable near-zero region in the geometric phase because the stronger coupling between the system and the QPC freezes the electron in one quantum dot and the solid angle enclosed by the evolution path is approximately zero, which is associated with the quantum Zeno effect. For the pure dephasing environment, the geometric phase is suppressed as the dephasing rate increases which is caused only by the phase damping of the system. In the dissipative environment, the geometric phase is reduced with the increase of the relaxation rate which results from both the energy dissipation and phase damping of the system. Our results are helpful for using the geometric phase to construct the fault-tolerant quantum devices based on quantum dot systems in quantum information.

关键词: geometric phase, decoherence, quantum transport

Abstract: We study theoretically the geometric phase of a double-quantum-dot (DQD) system measured by a quantum point contact (QPC) in the pure dephasing and dissipative environments, respectively. The results show that in these two environments, the coupling strength between the quantum dots has an enhanced impact on the geometric phase during a quasiperiod. This is due to the fact that the expansion of the width of the tunneling channel connecting the two quantum dots accelerates the oscillations of the electron between the quantum dots and makes the length of the evolution path longer. In addition, there is a notable near-zero region in the geometric phase because the stronger coupling between the system and the QPC freezes the electron in one quantum dot and the solid angle enclosed by the evolution path is approximately zero, which is associated with the quantum Zeno effect. For the pure dephasing environment, the geometric phase is suppressed as the dephasing rate increases which is caused only by the phase damping of the system. In the dissipative environment, the geometric phase is reduced with the increase of the relaxation rate which results from both the energy dissipation and phase damping of the system. Our results are helpful for using the geometric phase to construct the fault-tolerant quantum devices based on quantum dot systems in quantum information.

Key words: geometric phase, decoherence, quantum transport

中图分类号:  (Phases: geometric; dynamic or topological)

  • 03.65.Vf
03.65.Yz (Decoherence; open systems; quantum statistical methods) 05.60.Gg (Quantum transport)