Abstract

We propose a scheme to describe dynamical correlations in finite fermion systems which are open in the sense that they can lose particles, electrons in the present case. It is built as an extension of recently developed schemes to describe dissipative dynamics in finite fermion systems, namely stochastic time-dependent adiabatic local-density approximation (STDLDA) and its averaged version, ASTDLDA, so far being applied only in closed systems. STDLDA and ASTDLDA are based on real-time real-space dynamics in terms of time-dependent density functional theory and add dynamical two-body collisions in a stochastic manner. The extension to systems that can emit electrons is achieved by complementing the complete (numerical) description of wave functions in “inner” space (inside the computation box) through a global description in “outer” space (outside the computation box) and a careful bookkeeping of flow between inner and outer regions. We test the method in a 1D model system, mimicking simple molecules or clusters. Two test cases are investigated: a metal-like system excited by an instantaneous dipole boost, and a covalent-like system excited by an instantaneous one-particle–one-hole transition. The dynamics is analyzed in terms of one-body observables (dipole moment, ionization, entropy). STDLDA and ASTDLDA exhibit clearly dissipative features at variance with mean-field dynamics. Unlike the pattern in closed systems, differences between STDLDA and ASTDLDA show up for ionization. They can be attributed to significantly larger fluctuations of the mean field in STDLDA.

Graphic Abstract

中文翻译：

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遥远平衡量子系统中的发射和碰撞相关

摘要

我们提出了一个描述有限费米子系统中动力学相关性的方案，该系统在某种意义上是开放的，因为它们可能会丢失粒子（在当前情况下为电子）。它是对最近开发的方案的扩展，用于描述有限费米子系统中的耗散动力学，即随机时变绝热局部密度近似（STDLDA）及其平均形式ASTDLDA，迄今为止仅在封闭系统中应用。STDLDA和ASTDLDA基于随时间变化的密度泛函理论，基于实时的实时空间动力学，并以随机方式添加动态的两体碰撞。通过在“外部”空间（在计算框外部）的全局描述和对“内部”空间（在计算框内部）的波函数的完整（数字）描述进行补充，可以扩展对可以发射电子的系统的描述。记录内部和外部区域之间的流动。我们在1D模型系统中测试该方法，模仿简单的分子或簇。研究了两个测试用例：瞬时偶极增强激发的类金属系统，以及瞬时单粒子-单孔跃迁激发的类共价系统。根据一个物体的可观察性（偶极矩，电离，熵）来分析动力学。STDLDA和ASTDLDA在平均场动力学方面表现出明显的耗散特征。与封闭系统中的模式不同，STDLDA和ASTDLDA之间的差异表现为电离。它们可以归因于STDLDA中平均场的明显更大的波动。

图形摘要