Kramers-Kronig relations for the dielectric function and the static conductivity of Coulomb systems
Joint Institute for High Temperatures, Russian Academy of Sciences - 13/19, Izhorskaia Str., Moscow 125412, Russia
2 Eindhoven University of Technology - P.O. Box 513, MB 5600 Eindhoven, The Netherlands, EU
Accepted: 30 March 2010
The mutual influence of singularities of the dielectric permittivity ε (q, ω) in a Coulomb system in two limiting cases ω 0, q 0 and q 0, ω 0 is established. It is shown that the dielectric permittivity ε (q 0, ω) satisfies the Kramers-Kronig relations, which possesses the singularity due to a finite value of the static conductivity. This singularity is associated with the “long tails” of the time correlation functions.
PACS: 05.20.Dd – Kinetic theory / 05.30.Fk – Fermion systems and electron gas / 52.25.Mq – Dielectric properties
© EPLA, 2010