ABSTRACT
General formalism for linear responses is one of the most estab-
lished theoretical framework in physics, given by using response
function χ :
P(r, t) = ∫
dr′ ∫ t
−∞ dt′χ(r, r′, t, t′)Fext(r′, t′) (2.1)
where P denotes response field (or polarization), which is generally vector, and Fext applied external field. When F is electric field, P is electric polarization; when F is magnetic field, P is magnetic polarization (Wooten, 1972; Landau et al., 1984).
