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arXiv 0808.3245cond-mat.str-el
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非平衡Falicov-Kimball模型的初始关联

Initial correlations in nonequilibrium Falicov-Kimball model

Minh-Tien Tran

摘要:

利用截断自洽微扰理论和动力学平均场论,研究了无限维非平衡Falicov-Kimball模型的Keldysh边值问题.在该模型中,系统从平衡态开始,然后在系统中加入均匀电场,导出了非平衡态格林函数的Kadanoff-Baym-Wagner方程,并进行了数值求解。通过对系统演化过程的监测,研究了初始关联对系统演化的贡献。研究发现,初始关联对于建立系统的全电子关联是必不可少的,并且与系统进入平衡态的开始时间无关。通过考察初始关联对电流和双占据的贡献,我们发现当相互作用较弱时,初始关联对电流和双占据的贡献相对于这些物理量的总值较小,而当相互作用较强时,初始关联对电流和双占据的贡献显著增大。忽略初始关联可能会导致系统的非平衡性质中的伪像,特别是在强相互作用的情况下。

英文摘要:

The Keldysh boundary problem in a nonequilibrium Falicov-Kimball model in infinite dimensions is studied within the truncated and self-consistent perturbation theories, and the dynamical mean-field theory. Within the model the system is started in equilibrium, and later a uniform electric field is turned on. The Kadanoff-Baym-Wagner equations for the nonequilibrium Green functions are derived, and numerically solved. The contributions of initial correlations are studied by monitoring the system evolution. It is found that the initial correlations are essential for establishing full electron correlations of the system and independent on the starting time of preparing the system in equilibrium. By examining the contributions of the initial correlations to the electric current and the double occupation, we find that the contributions are small in relation to the total value of those physical quantities when the interaction is weak, and significantly increase when the interaction is strong. The neglect of initial correlations may cause artifacts in the nonequilibrium properties of the system, especially in the strong interaction case.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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