The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneli...The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneling and interdot tunneling in a non-Hermitian double quantum dots system. It is found that in the weak-coupling regime the Majorana tunneling has pronounced effects on the transport properties of such a system, manifested as splitting of the single peak into three and a reduced 1/4 peak in the transmission function. In the presence of the PT-symmetric complex potentials and interdot tunneling, the 1/4 central peak is robust against them, while the two side peaks are tuned by them. The interdot tunneling only induces asymmetry, instead of moving the conductance peak, due to the robustness of the Majorana modes. There is an exceptional point induced by the union of Majorana tunneling and interdot tunneling. With increased PT-symmetric complex potentials, the two side peaks will move towards each other. When the exceptional point is passed through, these two side peaks will disappear. In the strong-coupling regime, the Majorana fermion induces a 1/4 conductance dip instead of the three-peak structure. PT-symmetric complex potentials induce two conductance dips pinned at the exceptional point. These effects should be accessible in experiments.展开更多
We investigate the real-time dynamical properties of Rabi-type oscillation through strongly correlated quantum-dot systems by means of accurate hierarchical equations of motion.It is an extension of the hierarchical L...We investigate the real-time dynamical properties of Rabi-type oscillation through strongly correlated quantum-dot systems by means of accurate hierarchical equations of motion.It is an extension of the hierarchical Liouville-space approach for addressing strongly correlated quantum-dot systems.We study two paradigmatic models,the single quantum-dot system,and serial coupling double quantum-dot system.We calculate accurately the time-dependent occupancy of quantum-dot systems subject to a sudden change of gate voltage.The Rabi-type oscillation of the occupancy and distinct relaxation time of the quantum-dot systems with different factors are described.This is helpful to understand dissipation and decoherence in real-time dynamics through nanodevices and provides a theoretical frame to experimental investigation and manipulation of molecular electronic devices.展开更多
Recently,a superradiant phase transition first predicted theoretically in the quantum Rabi model(QRM)has been verified experimentally.This further stimulates the interest in the study of the process of phase transitio...Recently,a superradiant phase transition first predicted theoretically in the quantum Rabi model(QRM)has been verified experimentally.This further stimulates the interest in the study of the process of phase transition and the nature of the superradiant phase since the fundamental role of the QRM in describing the interaction of light and matter,and more importantly,the QRM contains rich physics deserving further exploration despite its simplicity.Here we propose a scheme consisting of two successive diagonalizations to accurately obtain the ground-state and excited states wavefunctions of the QRM in full parameter regime ranging from weak to deepstrong couplings.Thus,one is able to see how the phase transition occurs and how the photons populate in Fock space of the superradiant phase.We characterize the photon populations by borrowing the distribution concept in random matrix theory and find that the photon population follows a Poissonian-like distribution once the phase transition takes place and further exhibits the statistics of Gaussian unitary ensemble with increasing coupling strength.More interestingly,the photons in the excited states behave even like the statistics of Gaussian orthogonal ensemble.Our results not only deepen understanding on the superradiant phase transition but also provide an insight on the nature of the superradiant phase of the QRM and related models.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.11834005)。
文摘The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneling and interdot tunneling in a non-Hermitian double quantum dots system. It is found that in the weak-coupling regime the Majorana tunneling has pronounced effects on the transport properties of such a system, manifested as splitting of the single peak into three and a reduced 1/4 peak in the transmission function. In the presence of the PT-symmetric complex potentials and interdot tunneling, the 1/4 central peak is robust against them, while the two side peaks are tuned by them. The interdot tunneling only induces asymmetry, instead of moving the conductance peak, due to the robustness of the Majorana modes. There is an exceptional point induced by the union of Majorana tunneling and interdot tunneling. With increased PT-symmetric complex potentials, the two side peaks will move towards each other. When the exceptional point is passed through, these two side peaks will disappear. In the strong-coupling regime, the Majorana fermion induces a 1/4 conductance dip instead of the three-peak structure. PT-symmetric complex potentials induce two conductance dips pinned at the exceptional point. These effects should be accessible in experiments.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11804245,11747098,11774418,12247101,and 12047501)the Scientific and Technologial Innovation Programs of Higher Education Institutions of Shanxi Province,China (Grant No.2021L534)the Fund from the Ministry of Science and Technology of China (Grant No.2022YFA1402704)。
文摘We investigate the real-time dynamical properties of Rabi-type oscillation through strongly correlated quantum-dot systems by means of accurate hierarchical equations of motion.It is an extension of the hierarchical Liouville-space approach for addressing strongly correlated quantum-dot systems.We study two paradigmatic models,the single quantum-dot system,and serial coupling double quantum-dot system.We calculate accurately the time-dependent occupancy of quantum-dot systems subject to a sudden change of gate voltage.The Rabi-type oscillation of the occupancy and distinct relaxation time of the quantum-dot systems with different factors are described.This is helpful to understand dissipation and decoherence in real-time dynamics through nanodevices and provides a theoretical frame to experimental investigation and manipulation of molecular electronic devices.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1402704)the National Natural Science Foundation of China(Grant Nos.11834005,12047501,and 12247101)。
文摘Recently,a superradiant phase transition first predicted theoretically in the quantum Rabi model(QRM)has been verified experimentally.This further stimulates the interest in the study of the process of phase transition and the nature of the superradiant phase since the fundamental role of the QRM in describing the interaction of light and matter,and more importantly,the QRM contains rich physics deserving further exploration despite its simplicity.Here we propose a scheme consisting of two successive diagonalizations to accurately obtain the ground-state and excited states wavefunctions of the QRM in full parameter regime ranging from weak to deepstrong couplings.Thus,one is able to see how the phase transition occurs and how the photons populate in Fock space of the superradiant phase.We characterize the photon populations by borrowing the distribution concept in random matrix theory and find that the photon population follows a Poissonian-like distribution once the phase transition takes place and further exhibits the statistics of Gaussian unitary ensemble with increasing coupling strength.More interestingly,the photons in the excited states behave even like the statistics of Gaussian orthogonal ensemble.Our results not only deepen understanding on the superradiant phase transition but also provide an insight on the nature of the superradiant phase of the QRM and related models.
