Dispersion relations for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-order nonlinear phenomena

Abstract

Through a method using a change of variables for frequencies occurring in nonlinear phenomena, we show that no dispersion relation can be established between different phenomena and that the only dispersion relation for a well-defined phenomenon is a relation of Kramers-Kronig type.