Density functional theory

Density functional theory (DFT) is an essential building block for modern theoretical physics, chemistry, and engineering, especially those concerning electronic properties. Through decades of development, various program packages for first-principles electronic structure calculation are now available. Their sophisticated interfaces allow users to apply DFT to actual systems, even without knowing the theory. It is hence becoming more and more important to recall the fundamentals of how DFT enables accurate calculations. This article attempts to provide such knowledge with a minimal overview of DFT -- its basic foundation, relations to observable electronic and nuclear dynamical properties, and some of its cutting-edge applications.