Using the Keldysh-Green function,we present a theoretical study on the electron transport properties of two coupled quantum dots under optical pumping. Plateaus in the I-V curve and resonant peaks in the transmission ...Using the Keldysh-Green function,we present a theoretical study on the electron transport properties of two coupled quantum dots under optical pumping. Plateaus in the I-V curve and resonant peaks in the transmission coefficient occur and can be explained by the local electron density of states in the quantum dots. The effects of the optical pumping frequency and intensity on the transport properties of the system are also discussed. The electron dynamical localization phenomenon occurs when the optical pumping frequency is equal to the discrete hole energy level. This result can be used to realize optical control switches.展开更多
An experimentally feasible scheme for teleportation of an unknown two-atom entangled state is proposed. Our scheme uses a duster state as the quantum channel, where we do not need any joint Bell-state measurement. Mor...An experimentally feasible scheme for teleportation of an unknown two-atom entangled state is proposed. Our scheme uses a duster state as the quantum channel, where we do not need any joint Bell-state measurement. Moreover the successful probability and fidelity of teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology.展开更多
A scheme for approximately and conditionally teleporting an unknown atomic state in dissipative cavity QED is proposed. It is the extension of the scheme of [Phys. Rev. A 69 （2004） 064302], where the cavity mode dec...A scheme for approximately and conditionally teleporting an unknown atomic state in dissipative cavity QED is proposed. It is the extension of the scheme of [Phys. Rev. A 69 （2004） 064302], where the cavity mode decay has not been considered and only a time point of system evolution and the corresponding fidelity implementing the teleportation are given. In fact, the cavity mode decay exists really and must be delt with. In this paper, we investigate the influence from the cavity mode decay on the implementation of the approximate and conditional teleportation by means of the dissipative Jaynes Cummings model and then show the analytical expression of the fidelity of realization of the teleportation. Alternatively, our scheme does not involve an additional atom, only requiring two atoms and one single-mode cavity.展开更多
Fundamental quantum transport equation for impact-ionization processes in fusion plasmas is formulated in the actor-spectator description. The density-matrix formulism is adopted to treat both coherent and incoherent ...Fundamental quantum transport equation for impact-ionization processes in fusion plasmas is formulated in the actor-spectator description. The density-matrix formulism is adopted to treat both coherent and incoherent effects in a unified fashion. Quantum electrodynamic effects are also considered for high-temperature scenarios. Electron-impact ionization of uranium ion U91＋ and proton-impact ionization of hydrogen are given as examples.展开更多
We design a double quantum-dot （QD） shuttle （DQDS） model including two rigidly connected QDs that are softly linked to two leads via deformable organic materiaJs. Based on the full quantum mechanical approaches we...We design a double quantum-dot （QD） shuttle （DQDS） model including two rigidly connected QDs that are softly linked to two leads via deformable organic materiaJs. Based on the full quantum mechanical approaches we explore the influences on the electron transport induced by the electrical and mechanical degrees of freedom. First of a/l the modified rate equations of the DQDS are derived theoretically and then a numerical investigation on the quantum transport through the DQDS is performed. For the classical DQDS, the time-dependent evolutions of the electron- occupation probabilities and the currents flowing through the DQDS show the periodic oscillations with their periods determined by the oscillation period of the DQDS. Both the mechanical oscillation amplitude and the interdot coupling can play crucial roles in adjusting the peak shapes of the currents and the probabilities. For the quantum DQDS, the current and electron-occupation probabilities of the DQDS evolve into a stationary state as time goes on, with no periodical oscillations observed. As a consequence, the sharp differences of the time-dependent properties between the c/assica/ and quantum DQDS systems are clearly demonstrated, which should be greatly helpful in designing new nanoelectromechanical devices. Also, this work is of great significance to understanding the kind of rigidly connected QD shuttle systems that have more than two QDs.展开更多
文摘Using the Keldysh-Green function,we present a theoretical study on the electron transport properties of two coupled quantum dots under optical pumping. Plateaus in the I-V curve and resonant peaks in the transmission coefficient occur and can be explained by the local electron density of states in the quantum dots. The effects of the optical pumping frequency and intensity on the transport properties of the system are also discussed. The electron dynamical localization phenomenon occurs when the optical pumping frequency is equal to the discrete hole energy level. This result can be used to realize optical control switches.
基金National Natural Science Foundation of China under Grant Nos.60678022 and 1070400the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No.20060357008+3 种基金Natural Science Foundation of Anhui Province under Grant No.070412060the Key Program of the Education Department of Anhui Province under Grant No.2006KJ070AThe Talent Foundation of Anhui UniversityAnhui Key Laboratory of Information Materials and Devices (Anhui University)
文摘An experimentally feasible scheme for teleportation of an unknown two-atom entangled state is proposed. Our scheme uses a duster state as the quantum channel, where we do not need any joint Bell-state measurement. Moreover the successful probability and fidelity of teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology.
基金National Natural Science Foundation of China under Grant Nos.10774042 and 10474118the National Fundamental Research Program under Grant No.2001CB309309+2 种基金the Science Research Fund of Educational Department of Hunan Provincethe Science Research Fund of Hunan Institute of Humanity and Science and Technology under Grant No 2004A014the Natural Science Foundation of Hunan Province under Grant No.05JJ30005
文摘A scheme for approximately and conditionally teleporting an unknown atomic state in dissipative cavity QED is proposed. It is the extension of the scheme of [Phys. Rev. A 69 （2004） 064302], where the cavity mode decay has not been considered and only a time point of system evolution and the corresponding fidelity implementing the teleportation are given. In fact, the cavity mode decay exists really and must be delt with. In this paper, we investigate the influence from the cavity mode decay on the implementation of the approximate and conditional teleportation by means of the dissipative Jaynes Cummings model and then show the analytical expression of the fidelity of realization of the teleportation. Alternatively, our scheme does not involve an additional atom, only requiring two atoms and one single-mode cavity.
文摘Fundamental quantum transport equation for impact-ionization processes in fusion plasmas is formulated in the actor-spectator description. The density-matrix formulism is adopted to treat both coherent and incoherent effects in a unified fashion. Quantum electrodynamic effects are also considered for high-temperature scenarios. Electron-impact ionization of uranium ion U91＋ and proton-impact ionization of hydrogen are given as examples.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10974015,11174024,and 11274040the Program for New Century Excellent Talents in University under Grant No.NCET-08-0044the National Basic Research Program of China under Grant No.2013CB921903
文摘We design a double quantum-dot （QD） shuttle （DQDS） model including two rigidly connected QDs that are softly linked to two leads via deformable organic materiaJs. Based on the full quantum mechanical approaches we explore the influences on the electron transport induced by the electrical and mechanical degrees of freedom. First of a/l the modified rate equations of the DQDS are derived theoretically and then a numerical investigation on the quantum transport through the DQDS is performed. For the classical DQDS, the time-dependent evolutions of the electron- occupation probabilities and the currents flowing through the DQDS show the periodic oscillations with their periods determined by the oscillation period of the DQDS. Both the mechanical oscillation amplitude and the interdot coupling can play crucial roles in adjusting the peak shapes of the currents and the probabilities. For the quantum DQDS, the current and electron-occupation probabilities of the DQDS evolve into a stationary state as time goes on, with no periodical oscillations observed. As a consequence, the sharp differences of the time-dependent properties between the c/assica/ and quantum DQDS systems are clearly demonstrated, which should be greatly helpful in designing new nanoelectromechanical devices. Also, this work is of great significance to understanding the kind of rigidly connected QD shuttle systems that have more than two QDs.
