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
Z. N. Oltvai, A.-L. Barabási

Science 298, 763-764 (2002)

N. Schwartz, R. Cohen, D. ben-Avraham, A.-L. Barabási, S. Havlin

Physical Review E 66, 015104 (2002)

Z. Dezso, A.-L. Barabási

Physical Review E 65, 055103 (2002)