Noise induced transitions in some socio-economic systems

The paper proposes the use of some stochastic methods in order to explain the presence of the critical points in macroeconomic time series, starting from the classical linear model input-output elaborated by W. Leontief. The development of the model (N. GeorgescuRoegen, 1971) yields the set of the linear differential equations describing the dynamics of a system containing two or more interdependent production processes. In order to describe the nonlinear economic growth, a feedback mechanism is introduced, improving in this way the one-dimensional variant of the model. We study further the influence of the noise on a control parameter and the conditions in which noise induced transitions arise. The economic data illustrating such transition refer to a country evolving to the market economy (Romania), whose evolution proves a lot of instabilities that are interesting to study from physical point of view.