Ergodic Regime Research Articles

Scaling approach to ergodic-nonergodic transitions

In the framework of a model which associates a hierarchical criterion to space renormalization we find nonexponential relaxations of the characteristic length scale ( s( t) ∼ t 1 zv at T = T c) and a transition from an ergodic regime at T> T c where equilibrium is reached at s = ξ in a finite time τ to a nonergodic regime at T< T c where s varies logarithmically in the long time limit.

Ergodic Theory of Stochastic Petri Networks

Stochastic Petri nets are a general formalism for describing the dynamics of discrete event systems. The present paper focuses on a subclass of stochastic Petri nets called stochastic event graphs. Under the assumption that the variables used for the timing of an event graph form stationary and ergodic sequences of random variables, we make use of an associated stochastic recursive equation in order to construct its stationary and ergodic regime. In particular, we determine the conditions under which the existence of this regime is guaranteed.

Breaking of ergodicity in high-T c superconductor YBa 2Cu 3O 7

We report on magnetic measurements on a high-T c oxide superconductor YBa 2Cu 3O 7. Below a characteristic temperature, glassy features are revealed by the diamagnetic susceptibility which splits in two separate branches corresponding to zero field cooling (ZFC) and field cooling (FC) the sample. The metastable ZFC susceptibility is considerably larger than the completely reversible FC susceptibility. The temperature which marks the onset of the irreversibility effects depends on the applied field and the line separating ergodic and non-ergodic regimes in the H-T plane closely resembles those found in spin glasses.

A spectral analysis method of obtaining molecular spectra from classical trajectories

Vibrational classical trajectories of anharmonic molecules are used here to obtain the classical vibrational autocorrelation function and, via a Fourier transform, the power (or infrared) spectrum of the dynamical variables. In the vibrationally quasiperiodic regime the spectrum consists of sharp lines, for any given initial amplitude. The initial amplitudes are chosen semiclassically. The spectral lines are compared with quantum mechanical calculations for systems with two and three coordinates, with excellent agreement. The method is also useful for obtaining a classical spectrum in the ergodic regime; the spectral lines are then ’’broad’’ rather than narrow. The method can be used in the analysis of trajectories for unimolecular reactions, infrared multiphoton dissociations, and for obtaining molecular spectra from force fields. The spectral analysis itself has implications for the theory of unimolecular reactions.