Abstract Along the lines of the nonlinear response theory developed by Ruelle, in a previous paper we have proved under rather general conditions that Kramers-Kronig dispersion relations and sum rules apply for a class of susceptibilities describing at any order of perturbation the response of Axiom A non equilibrium steady state systems to weak monochromatic forcings. We present here the first...

In this paper we show that the standard causality condition for attenuated waves, i.e. the Kramers-Kronig relation that relates the attenuation law and the phase speed of the wave, is necessary but not sufficient for causality of a wave. By causality of a wave we understand the property that its wave front speed is bounded. Although this condition is not new, the consequences for wave attenuati...

Particle-in-cell (PIC) methods allow the study of plasma behavior by computing the trajectories of finite-size particles under the action of external and self-consistent electric and magnetic fields defined in a grid of points. In this work, the Finite Element Method (FEM) is used in order to obtain the self-consistent fields. An electrostatic PIC-FEM computational code for simulation of one-di...

Electronic and phononic states and their interactions in one-dimensional arrays of Si quantum dots interconnected with thin oxide layers is theoretically investigated. Electronic states under low electric field condition are obtained in the Kronig-Penny potential. Approximate expression for phonon wave functions is developed and numerically calculated using the linear atomic chain model. Simula...

The infrared reflectance of the transition-metal chalcogenide 1T-TaS2 has been measured at temperatures from 30 K to 360 K over 30–45 000 cm ~4 meV–5.5 eV!. The optical conductivity was obtained by Kramers-Kronig analysis. At 360 K only modest traces of the phonon lines are noticeable. The phonon modes are followed by a pseudo-gap-like increase of the optical conductivity, with direct optical t...

Explicitly based on causality, linearity (superposition) and stability (time invariance) and implicit on continuity (consistency), finiteness (convergence) and uniqueness (single valuedness) in the time domain, Kramers-Kronig (KK) integral transform (KKT) relations for immittances are derived as pure mathematical constructs in the complex frequency domain using the two-sided (bilateral) Laplace...

We investigate the modulational instability of nonlinear Schrödinger equations with periodic variation of their coefficients. In particular, we focus on the case of the recently proposed, experimentally realizable protocol of Feshbach Resonance Management for Bose-Einstein condensates. We derive the corresponding linear stability equation analytically and we show that it can be reduced to a Kro...

The properties of Dirac electrons in a magnetic superlattice (SL) on graphene consisting of very high and thin (δ-function) barriers are investigated. We obtain the energy spectrum analytically and study the transmission through a finite number of barriers. The results are contrasted with those for electrons described by the Schrödinger equation. In addition, a collimation of an incident beam o...

We study the localization properties of the eigenstates in the KronigPenney model with weak compositional and structural disorder. The main result is an expression for the localization length that is valid for any kind of selfand inter-correlations of the two types of disorder. We show that the interplay between compositional and structural disorder can result in anomalous localization. Pacs nu...