The general purpose of this paper is to develop a linear response formalism for stochastic multiperiodic systems; these systems being obtained by letting some stochastic perturbation act on deterministic multiperiodic systems. Such a formalism is then applied to the absorption coefficient of the...

Recently it has been proposed a modification of the Wigner function which consists in smoothing it by convolution with a phase-space gaussian function; this smoothed Wigner function is non-negative if the gaussian parameters Δ and δ satisfy the condition Δδ ⩾ ħ. We analyze in this paper...