Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, FEW, Vrije Universiteit, De Boelelaan 1083, 1081HV Amsterdam, Netherlands.
Phys Rev Lett. 2013 Sep 20;111(12):126402. doi: 10.1103/PhysRevLett.111.126402. Epub 2013 Sep 18.
We generalize the exact strong-interaction limit of the exchange-correlation energy of Kohn-Sham density functional theory to open systems with fluctuating particle numbers. When used in the self-consistent Kohn-Sham procedure on strongly interacting systems, this functional yields exact features crucial for important applications such as quantum transport. In particular, the steplike structure of the highest-occupied Kohn-Sham eigenvalue is very well captured, with accurate quantitative agreement with exact many-body chemical potentials. While it can be shown that a sharp derivative discontinuity is present only in the infinitely strongly correlated limit, at finite correlation regimes we observe a slightly smoothened discontinuity, with qualitative and quantitative features that improve with increasing correlation. From the fundamental point of view, our results obtain the derivative discontinuity without making the assumptions used in its standard derivation, offering independent support for its existence.
我们将 Kohn-Sham 密度泛函理论的交换相关能量的精确强相互作用极限推广到具有粒子数涨落的开放系统。当在强相互作用系统上的自洽 Kohn-Sham 程序中使用时，该泛函产生了对于重要应用（如量子输运）至关重要的精确特征。特别是，最高占据 Kohn-Sham 本征值的阶跃结构得到了很好的捕捉，与精确的多体化学势具有准确的定量一致性。虽然可以证明只有在无限强相关极限下才存在尖锐的导数不连续性，但在有限相关范围内，我们观察到稍微平滑的不连续性，其定性和定量特征随着相关性的增加而改善。从根本的角度来看，我们的结果在不使用其标准推导中所做假设的情况下获得了导数不连续性，为其存在提供了独立的支持。
