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arXiv 0808.3483cond-mat.mes-hall
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含时量子输运中的守恒近似:初始关联和记忆效应

Conserving approximations in time-dependent quantum transport: Initial correlations and memory effects

Petri Myöhänen, Adrian Stan, Gianluca Stefanucci, Robert van Leeuwen

摘要:

利用非平衡多体格林函数的Kadanoff-Baym方程的时间传播方法研究了关联模型系统中的含时量子输运。我们考虑一个最初接触的平衡系统的相关中心区域耦合到紧束缚的铅。随后,打开依赖于时间的偏置,之后我们详细跟踪系统的时间演化。Kadanoff-Baym方法的重要特征是:1)研究瞬变和其他时间依赖机制的超快动力学的可能性; 2)在守恒近似方案中包含交换和相关效应。我们发现,由于多体相互作用的初始相关性和记忆项的瞬态电流有很大的影响。此外,稳态电流的值被发现是强烈依赖于用于治疗的电子相互作用的近似。

英文摘要:

We study time-dependent quantum transport in a correlated model system by means of time-propagation of the Kadanoff-Baym equations for the nonequilibrium many-body Green function. We consider an initially contacted equilibrium system of a correlated central region coupled to tight-binding leads. Subsequently a time-dependent bias is switched on after which we follow in detail the time-evolution of the system. Important features of the Kadanoff-Baym approach are 1) the possibility of studying the ultrafast dynamics of transients and other time-dependent regimes and 2) the inclusion of exchange and correlation effects in a conserving approximation scheme. We find that initial correlation and memory terms due to many-body interactions have a large effect on the transient currents. Furthermore the value of the steady state current is found to be strongly dependent on the approximation used to treat the electronic interactions.

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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