Manipulating quantum coherence of charge states in interacting double-dot Aharonov–Bohm interferometers

Abstract

We investigate the dynamics of charge-state coherence in a degenerate double-dot Aharonov-Bohm interferometer with finite inter-dot Coulomb interactions. The quantum coherence of the charge states is found to be sensitive to the transport setup configurations, involving both the single-electron impurity channels and the Coulomb-assisted ones. We numerically demonstrate the emergence of a complete coherence between the two charge states, with the relative phase being continuously controllable through the magnetic flux. Interestingly, a fully coherent charge qubit arises at the double-dots electron pair tunneling resonance condition, where the chemical potential of one electrode is tuned at the center between a single-electron impurity channel and the related Coulombassisted channel. This pure quantum state of charge qubit could be experimentally realized at the current-voltage characteristic turnover position, where differential conductance sign changes. We further elaborate the underlying mechanism for both the real-time and the stationary charge-states coherence in the double-dot systems of study.

Dynamic transport characteristics of side-coupled double-quantum-impurity systems

“…The Aharonov-Bohm oscillation, Fano resonance, Kondo effect, quantum phase transition, thermoelectric effect are a few of examples. [1][2][3][4][5][6][7][8][9][10] Research on transport properties of double-quantum-impurity systems not only provides a theoretical basis for the study of integrated circuits but also plays a vital role in the study of quantum bit, quantum regulation, and other aspects. [11] Although many studies have been made on the spatial coherence of the electron wave function in quantum-impurity systems, the temporal coherence of the same system remains to be studied due to the difficulties involved in dealing with the time phase coherence and time memory effect of the electrons.…”

Dynamic Transport Characteristics of Side-Coupled Double Quantum-Impurity Systems

“…Since the double quantum-impurity system possesses a variety of geometrical configurations, its tunneling path is more than that of the single quantum-impurity system, and thus there are more abundant physical properties belonging to the double quantum impurity systems. The Aharonov-Bohm oscillation, Fano resonance, Kondo effect, quantum phase transition, thermoelectric effect are a few examples [1][2][3][4][5][6][7][8][9][10] . The research on the transport properties of the double quantum-impurity systems not only provides a theoretical basis for the study of integrated circuits but also plays a vital role in the study of quantum bit, quantum regulation, and other aspects 11 .…”

Equilibrium and transient thermodynamics: A unified dissipaton-space approach

“…[19][20][21][22] Demonstrated examples beyond the HEOM evaluations include the Fano interference, [23] Herzberg-Teller vibronic coupling, [24] quantum transport shot noise spectrums. [25][26][27] The recently developed phase-space DEOM theory enables also the evaluations on various thermal transport problems, including the dynamical heat correlation functions. [22] This paper consists of two major and closely related topics.…”

“…[29] The unified DEOM theory would facilitate the evaluations on various systemand-bath entanglement properties of strongly correlated quantum impurity systems. [19][20][21][22][23][24][25][26][27] To complete this topic, we present the equilibrium DEOM solutions in Appendix A, and further the imaginary-time DEOM in Appendix B. While the imaginary-time formalism focuses on equilibrium thermodynamics only, the real-time DEOM accesses also nonequilibrium and/or transient analogues.…”