Statistical Physics

Multiscaling and non-universality in fluctuations of driven complex systems

For many externally driven complex systems neither the noisy driving force, nor the internal dynamics are a priori known. Here we focus on systems for which the timedependent activity of a large number of components can be monitored, allowing us to separate each signal into a component attributed to the external driving force and one to the internal dynamics. We propose a formalism to capture the potential multiscaling in the fluctuations and apply it to the high-frequency trading records of the New York Stock Exchange. We find that on the time scale of minutes the dynamics is governed by internal processes, while on a daily or longer scale the external factors dominate. This transition from internal to external dynamics induces systematic changes in the scaling exponents, offering direct evidence of non-universality in the system.


More publications
A.-L. Barabási, E. Ravasz, T. Vicsek

Physica A 299, 559–564 (2001)

Z. Dezso, Z. N. Oltvai, A.-L. Barabási

Genome Research 13, 2450-2454 (2003)

A.-L. Barabási, E. Bonabeau

Scientific American 288, 50-59 (2003)