Econophysics: can physicists contribute to the science of economics?

How can computational physicists contribute to the search for solutions to the puzzles posed by modern economics that economists themselves cannot solve? An approach-not very commonly used in economics-is to begin empirically, with real data that you can analyze in some detail, but without prior models. In economics, a great deal of real data is available. If you, moreover, have at your disposal the tools of computational physics and the computing power to carry out any number of approaches, this abundance of data is a great advantage. A careful analysis of any system involves studying the propagation of correlations from one unit of the system to the next. We learned that these correlations propagate both directly and indirectly. At one time, it was imagined that scale-free phenomena are relevant to only a fairly narrow slice of physical phenomena. However, the range of systems that apparently display power-law and hence scale-invariant correlations has increased dramatically in recent years. Such systems range from base-pair correlations in noncoding DNA, lung inflation, and interbeat intervals of the human heart, to complex systems involving large numbers of interacting subunits that display free will. In particular, economic time series, e.g., stock market indices or currency exchange rates, depend on the evolution of a large number of strongly interacting systems far from equilibrium, and belong to the class of complex evolving systems. Thus, the statistical properties of economic time series have attracted the interests of many physicists.