We study the transmission dynamics of a driven two-level system dissipated by the two leads.Using nonequilibrium Green function,we derive an analytical transmission formula for an electron incident from the left lead,...We study the transmission dynamics of a driven two-level system dissipated by the two leads.Using nonequilibrium Green function,we derive an analytical transmission formula for an electron incident from the left lead,through the double quantum dots,to the right lead.Landauer-type conductance and current are also given.A discussion of the internal tunneling dynamics reveals crucial effects of the localization and delocalization on the transport of the system.展开更多
We show how the two interacting electrons in a field-driven coupled quantum dot can be used to prepare maximally entangled Bell states. The time durations of the oscillatory electric field for producing and maintainin...We show how the two interacting electrons in a field-driven coupled quantum dot can be used to prepare maximally entangled Bell states. The time durations of the oscillatory electric field for producing and maintaining such highly entangled states are identified by both analytic and exact numerical solutions of the quantum dynamical equations.展开更多
We investigate the dynamical processes taking place in nanodevices by high-frequency dc-ac fields.We found that Rabi oscillations between minibands are clearly identified under theoretical resonant conditions derived ...We investigate the dynamical processes taking place in nanodevices by high-frequency dc-ac fields.We found that Rabi oscillations between minibands are clearly identified under theoretical resonant conditions derived by an ideal two bands superlattice model,the resonant conditions have broadened,and the amount of broadening is about four times of the Rabi oscillation frequency.We also want to elucidate the role of different mechanisms that could lead to loss of quantum coherence.Our results show how the dephasing effects of disorder of interface roughness and doping fluctuation that destroy after some periods coherent oscillations,such as Rabi oscillations,can be reduced dramatically if we apply a bias static electric field to the superlattice system.Doping fluctuation's dephasing effect is much stronger than that of interface roughness in coherent process of realistic superlattices.展开更多
基金Supported in part by the National Natural Science Foundation of China under Grant No.19725417the China Academy of Engineering Physics.
文摘We study the transmission dynamics of a driven two-level system dissipated by the two leads.Using nonequilibrium Green function,we derive an analytical transmission formula for an electron incident from the left lead,through the double quantum dots,to the right lead.Landauer-type conductance and current are also given.A discussion of the internal tunneling dynamics reveals crucial effects of the localization and delocalization on the transport of the system.
基金Supported in part by the National Natural Science Foundation of China under Grant No.19725417the China Academy of Engineering Physics.
文摘We show how the two interacting electrons in a field-driven coupled quantum dot can be used to prepare maximally entangled Bell states. The time durations of the oscillatory electric field for producing and maintaining such highly entangled states are identified by both analytic and exact numerical solutions of the quantum dynamical equations.
基金Supported in part by the National Natural Science Foundation of China under Grant No.19725417the National Climbing Project under Grant No.95-YU-41the China Academy of Engineering Physics.
文摘We investigate the dynamical processes taking place in nanodevices by high-frequency dc-ac fields.We found that Rabi oscillations between minibands are clearly identified under theoretical resonant conditions derived by an ideal two bands superlattice model,the resonant conditions have broadened,and the amount of broadening is about four times of the Rabi oscillation frequency.We also want to elucidate the role of different mechanisms that could lead to loss of quantum coherence.Our results show how the dephasing effects of disorder of interface roughness and doping fluctuation that destroy after some periods coherent oscillations,such as Rabi oscillations,can be reduced dramatically if we apply a bias static electric field to the superlattice system.Doping fluctuation's dephasing effect is much stronger than that of interface roughness in coherent process of realistic superlattices.
