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

Du, Qian; Lan, Kang; Zhang, Yanhui; Jiang, Lujing

doi:10.1088/1674-1056/ab6963

Cited by 4 publications

(5 citation statements)

References 82 publications

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“…通过结合 MT 与 ML 速度极限时间,给出了封闭系统量子速度极限时间统一界 .非马尔可夫效应已经被证实了可以加速系统的演化,为了提高演化速度,人们对各种量子体系的速度极限不等式展开了深入研究 [17][18][19][20][21] .2016 年，Cai 和 Zheng 采用迹距离度量推导了非平衡环境下的 MT 与 ML 时间界，证实了体系的非马尔可夫特性对加速系统演化的必要不充分性质 [22] .2019 年,Sun 和 Zheng 基于量子几何相位和几何相位变化率, 在量子态矢量于流形空间中平行传输的条件下得出不同于 MT 和 ML 类型的时间界,且通过化简可以回到 ML 的结果 [23,24] . 单量子点具有操作性强、易观测、可制备等优点,它涉及到量子力学基本原理在实际中的应用, 表现出独特的量子特性,比如量子隧道效应、库仑阻塞效应、局域化效应、表面效应等等.1997 年 Gurvitz 将其与量子点接触探测器结合,研究了在测量过程中孤立量子点系统内电子转移的动力学演化机制,并在 2003 年将量子点系统与耗散环境耦合,表明弛豫会破坏测量过程的芝诺效应 [25,26] .2010 年,Ouyang 和 You 通过占有态和本征态两种方法得到电子运动的主方程,分析了不同外界环境下量子点系统的输运特性 [27] .科学工作者们对量子点的转移与输运等特性做出了大量探索, 并对耗散环境中电子转移过程的量子速度极限开展了深刻的研究 [28][29][30][31][32][33][34][35][36] ,但开放量子点系统输运过…”

Section: 引言unclassified

Study of quantum speed limit of of transport process of single quantum dot system in dissipative environment

Tian¹,

Li²,

Zhang³

et al. 2023

Acta Phys. Sin.

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We theoretically study the quantum speed limit (QSL) of the single dot system in dissipative environment Based on quantum dot transport theory and Bures angle metric method. The theoretical results show that in the dissipative environment, Different tunneling probabilities have different effects. The increase of left tunneling probability has a weak effect on the accelerating ability of the system, due to the Coulomb blocking effect and quantum coherence .On the other hand, the right tunneling probability has a significant impact for the accelerating ability of the system , the accelerating ability is promoted with the increase of right tunneling probability because of the effect of channel blocking and co-tunneling. The increase of energy displacement promote the accelerating ability of the system and change the oscillation frequency of the system, owing to its taking longer time for the system to evolve to the target state. The effect of the relaxation rate for the system's accelerating ability is not monotonic ,there is an interesting turning point due to the change of electron layout number. When the relaxation rate is less than this point, the accelerating ability of the system will oscillate. When the relaxation rate is higher than this point, the change of accelerating ability is monotonically suppressed by the relaxation rate. In general, the increase of the relaxation rate weaken the acceleration ability of the system. Our results provide theoretical reference for study the QSL time in a semiconductor device affected by numerous factors.

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Section: 引言unclassified

Study of quantum speed limit of of transport process of single quantum dot system in dissipative environment

Tian¹,

Li²,

Zhang³

et al. 2023

Acta Phys. Sin.

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“…In other words, the interaction with the pure dephasing environment has stimulative effect on the oscillation of the electron during the evolution. [45] The enhancement of the CPS represents that the oscillation of the electron is slowed down and the probability of the electron's tunnelling in the DQD system would be reduced.…”

Section: The Qsl Time In Pure Dephasing Environmentmentioning

confidence: 99%

Quantum speed limit of the double quantum dot in pure dephasing environment under measurement

Lin¹,

Tian²,

Li³

et al. 2022

Chinese Phys. B

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The quantum speed limit(QSL) of the double quantum dot(DQD) system has been theoretically investigated by adopting the detecting of the quantum point contact(QPC) in the pure dephasing environment.The ML type of the QSL bound which is based on the trace distance has been extended to the DQD system for calculating the shortest evolving time.The increase of decoherence rate can weaken the capacity for potential speedup(CPS) and delay the evolving process due to the frequently measurement localizing the electron in the DQD system.The system need longer time to evolving to target state as the enhancment of dephasing rate,because the strong interaction between pure dephasing environment and the DQD system could vary the oscillation of the electron.Increasing the dephasing rate can sharp the QSL bound,but the decoherence rate would weaken the former effect and vice versa.Moreover,the CPS would be raised by increasing the energy displacement,while the enhancement of the coupling strength between two quantum dots can diminish it.It is interesting that there has an inflection point,when the coupling strength is less than the value of the point,the increasing effect of the CPS from the energy displacement is dominant,otherwise the decreasing tendency of the CPS is determined by the coupling strength and suppress the action of the energy displacement if the coupling strength is greater than the point.Our results provide theoretical reference for study the QSL time in a semiconductor device affected by numerous factors.

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“…[39] When the electron transfers from the left quantum dot to the right quantum dot, the tunneling barrier of the detector changes, resulting in the hopping amplitude changing from Ω l,r to Ω ′ l,r . By introducing a QPC, the dynamical evolution of the reduced density matrix of the system is given by [6] d dt…”

Section: Theoretical Frameworkmentioning

confidence: 99%

“…With the rapid development of quantum information technology, solid-state quantum computing based on semiconductor quantum dot system has become a research focus in quantum measurement and quantum information processing. [1][2][3][4][5][6][7][8][9] In the practical quantum computation, the system inevitably interacts with the surrounding environments, which leads to the loss of the coherence of the quantum system. [10][11][12][13][14] Recently, it has become an urgent problem to study the decoherence process caused by the coupling of the quantum system and the external environment, and research on the non-Markovian dynamics of the open quantum system has attracted extensive attention.…”

Section: Introductionmentioning

confidence: 99%

Electron transfer properties of double quantum dot system in a fluctuating environment*

Jiang¹,

Lan²,

Lin³

et al. 2021

Chinese Phys. B

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Using the innovative method of the additional Bloch vector, the electron transfer properties of a double quantum dot (DQD) system measured by a quantum point contact (QPC) in a fluctuating environment are investigated. The results show that the environmental noises in transverse and longitudinal directions play different roles in the dynamical evolution of the open quantum systems. Considering the DQD with symmetric energy level, the Fano factor exhibits a slight peak with the increase of transverse noise amplitude σ T, which provides a basis for distinguishing dynamical phenomena caused by different directional fluctuation noises in symmetric DQD structures by studying the detector output. In the case of asymmetric DQD, the dependence of a detector current involving the level displacement is distinct when increasing the transverse noise damping coefficient τ T and the longitudinal noise damping coefficient τε respectively. Meanwhile, the transverse noise damping coefficient τ T could significantly reduce the Fano factor and enhance the stability of the quantum system compared with the longitudinal one. The Fano factors with stable values as the enhancement of noise amplitudes show different external influences from the detector measurement, and provide a numerical reference for adjusting the noise amplitudes in both transverse and longitudinal directions appropriately in a microscopic experimental process to offset the decoherence effect caused by the measurements. Finally, the research of average waiting time provides unique insights to the development of single electron transfer theory in the short-time limit.

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

Cited by 4 publications

References 82 publications

Study of quantum speed limit of of transport process of single quantum dot system in dissipative environment

Study of quantum speed limit of of transport process of single quantum dot system in dissipative environment

Quantum speed limit of the double quantum dot in pure dephasing environment under measurement

Electron transfer properties of double quantum dot system in a fluctuating environment*

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