In this paper, we consider the macroscopic quantum tunnelling and self-trapping phenomena of Bose-Einstein condensates （BECs） with three-body recombination losses and atoms feeding from thermal cloud in triple-well ...In this paper, we consider the macroscopic quantum tunnelling and self-trapping phenomena of Bose-Einstein condensates （BECs） with three-body recombination losses and atoms feeding from thermal cloud in triple-well potential. Using the three-mode approximation, three coupled Gross-Pitaevskii equations （GPEs）, which describe the dynamics of the system, are obtained. The corresponding numerical results reveal some interesting characteristics of BECs for different scattering lengths. The self-trapping and quantum tunnelling both are found in zero-phase and ：r-phase modes. Furthermore, we observe the quantum beating phenomenon and the resonance character during the self-trapping and quantum tunnelling. It is also shown that the initial phase has a significant effect on the dynamics of the system.展开更多
The atomic population oscillations between two Bose-Einstein condensates with time-dependent nonlinear interaction in a double-well potential are studied. We first analyse the stabilities of the system＇s steady-state...The atomic population oscillations between two Bose-Einstein condensates with time-dependent nonlinear interaction in a double-well potential are studied. We first analyse the stabilities of the system＇s steady-state solutions. And then in the perturbative regime, the Melnikov chaotic oscillation of atomic population imbalance is investigated and the Melnikov chaotic criterion is obtained. When the system is out of the perturbative regime, numerical calculations reveal that regulating the nonlinear parameter can lead the system to step into chaos via period doubling bifurcations. It is also numerically found that adjusting the nonlinear parameter and asymmetric trap potential can result in the running-phase macroscopic quantum self-trapping （MQST）. In the presence of a weak asymmetric trap potential, there exists the parametric resonance in the system.展开更多
This paper investigates the thermal energy effect on electron auto-localization. The polaron characteristics (self-action potential and effective mass) are observed to be expressed via the renormalized electron-phonon...This paper investigates the thermal energy effect on electron auto-localization. The polaron characteristics (self-action potential and effective mass) are observed to be expressed via the renormalized electron-phonon coupling constant tailored by the thermal energy. Low temperatures are observed to favour auto-localization of the carrier while high temperatures favour polaron undressing and subsequent quenching of the quantum behaviour thereby rendering the system classical. The critical (transition) temperature <em>τ<sub>c</sub></em> expressed via the critical coupling constant <span style="white-space:nowrap;">ϒ</span><em><sub>C</sub></em> is found to be the separating boundary between the quantum and the classical phases. Therefore, the polaron undergoes phase transition (from self-tapped to quasi free states) when the temperature of the medium is enhanced.展开更多
The variational effective mass with respect to the e-p coupling constant for different values of cutoff wave vector is performed in quantum dot. The self-trapping transition of acoustic polaron in quantum dot is recon...The variational effective mass with respect to the e-p coupling constant for different values of cutoff wave vector is performed in quantum dot. The self-trapping transition of acoustic polaron in quantum dot is reconsidered by character of the effective mass curve varying with the e-p coupling. The holes are determined to be self-trapped in AlN quantum dot systems.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos10774120and10475066)the Natural Science Foundation of Gansu Province,China(Grant No3ZS051-A25-013)the Natural Science Foundation of Northwest Normal University of China(Grant No NWNU-KJCXGC-03-17)
文摘In this paper, we consider the macroscopic quantum tunnelling and self-trapping phenomena of Bose-Einstein condensates （BECs） with three-body recombination losses and atoms feeding from thermal cloud in triple-well potential. Using the three-mode approximation, three coupled Gross-Pitaevskii equations （GPEs）, which describe the dynamics of the system, are obtained. The corresponding numerical results reveal some interesting characteristics of BECs for different scattering lengths. The self-trapping and quantum tunnelling both are found in zero-phase and ：r-phase modes. Furthermore, we observe the quantum beating phenomenon and the resonance character during the self-trapping and quantum tunnelling. It is also shown that the initial phase has a significant effect on the dynamics of the system.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10125521 and 10535010） and the Key Development Program for State Basic Research of China （Grant No G2000077400）.
文摘The atomic population oscillations between two Bose-Einstein condensates with time-dependent nonlinear interaction in a double-well potential are studied. We first analyse the stabilities of the system＇s steady-state solutions. And then in the perturbative regime, the Melnikov chaotic oscillation of atomic population imbalance is investigated and the Melnikov chaotic criterion is obtained. When the system is out of the perturbative regime, numerical calculations reveal that regulating the nonlinear parameter can lead the system to step into chaos via period doubling bifurcations. It is also numerically found that adjusting the nonlinear parameter and asymmetric trap potential can result in the running-phase macroscopic quantum self-trapping （MQST）. In the presence of a weak asymmetric trap potential, there exists the parametric resonance in the system.
文摘This paper investigates the thermal energy effect on electron auto-localization. The polaron characteristics (self-action potential and effective mass) are observed to be expressed via the renormalized electron-phonon coupling constant tailored by the thermal energy. Low temperatures are observed to favour auto-localization of the carrier while high temperatures favour polaron undressing and subsequent quenching of the quantum behaviour thereby rendering the system classical. The critical (transition) temperature <em>τ<sub>c</sub></em> expressed via the critical coupling constant <span style="white-space:nowrap;">ϒ</span><em><sub>C</sub></em> is found to be the separating boundary between the quantum and the classical phases. Therefore, the polaron undergoes phase transition (from self-tapped to quasi free states) when the temperature of the medium is enhanced.
文摘The variational effective mass with respect to the e-p coupling constant for different values of cutoff wave vector is performed in quantum dot. The self-trapping transition of acoustic polaron in quantum dot is reconsidered by character of the effective mass curve varying with the e-p coupling. The holes are determined to be self-trapped in AlN quantum dot systems.
