Analysis of Floquet formulation of time-dependent density-functional theory

TL;DR

This paper defends the Floquet formulation of time-dependent density-functional theory, demonstrating its validity and addressing recent criticisms by clarifying foundational aspects and providing supporting examples.

Contribution

It clarifies the theoretical foundations of Floquet TDDFT and counters recent criticisms, reaffirming its validity in quantum physics.

Findings

Floquet theory is well founded for TDDFT.

Criticisms overlooked key aspects of the formalism.

Examples support the validity of Floquet formulation.

Abstract

Floquet formulation of time-dependent density-functional theory is revisited in light of its recent criticism [Maitra and Burke, Chem. Phys. Lett. 359 (2002), 237]. It is shown that Floquet theory is well founded and its criticism has overlooked important points of both the Runge-Gross formalism and Floquet formulation itself. We substantiate our analysis by examples similar to that considered by Maitra and Burke.