Linear response at criticality

Adam Svenkeson, Mauro Bologna, Paolo Grigolini
2012 Physical Review E  
We study a set of cooperatively interacting units at criticality, and we prove with analytical and numerical arguments that they generate the same renewal non-Poisson intermittency as that produced by blinking quantum dots, thereby giving a stronger support to the results of earlier investigation. By analyzing how this out-ofequilibrium system responds to harmonic perturbations, we find that the response can be described only using a new form of linear response theory that accounts for aging
more » ... the nonergodic behavior of the underlying process. We connect the undamped response of the system at criticality to the decaying response predicted by the recently established nonergodic fluctuation-dissipation theorem for dichotomous processes using information about the second moment of the fluctuations. We demonstrate that over a wide range of perturbation frequencies the response of the cooperative system is greatest when at criticality.
doi:10.1103/physreve.86.041145 pmid:23214567 fatcat:fdf6ocpworcnnnpvu47d2rnbdq