Fluctuation-dissipation theorem and quantum decoherence

Eric A. B. Cole

C. Di Castro, Roberto Raimondi

Achille Giacometti, Amos Maritan, Flavio Toigo +1 more

Dmitry S. Golubev, Andrei D. Zaikin

We point out that the low temperature saturation of the electron phase decoherence time in a disordered conductor can be explained within the existing theory of weak localization provided the effect of quantum (high frequency) fluctuations is taken into account. Making use of the fluctuation-dissipation theorem we evaluate the quantum decoherence time, the crossover temperature below which thermal effects become unimportant, and the weak localization correction $\ensuremath{\delta}\ensuremath{\sigma}$ at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$. For 1D systems the latter is found to be $\ensuremath{\delta}\ensuremath{\sigma}/\ensuremath{\sigma}\ensuremath{\propto}1/\sqrt{N}$, where $N$ is the number of conducting channels.

No¨elle Pottier, A. Mauger

Ludovico Silvestri, Leone Fronzoni, Angelo Gemignani +3 more

We illustrate a theoretical approach to derive generalized master equations, in both quantum and classical physics, compatible with the occurrence of crucial events. We show how to derive out of it a new Fluctuation-Dissipation Theorem (FDT), called phenomenological FDT. We fail deriving from the same approach another FDT form, called dynamic FDT, which is proved by us to drive the response of liquid crystals to external perturbations. We argue that this experimental effect is incompatible with the adoption of a density approach, in the same way as the decoherence theory fails explaining the wave function collapse, if this corresponds to crucial events. We also argue that the same perspective applies to the brain, according to the tenets of the integration theory of consciousness.