as long as the particle density is finite. Therefore capital in international trade may be considered as being at the edge of the fluid phase. Comparing with the empirical data, we found that the period 1962-2000 covered in the dataset corresponds to a transient period in the model. We were able to determine the time scale and the range of the particle density with which the model predictions match the empirical annual variation and distribution of product share. The estimated particle density turns out to be larger than the critical density, suggesting that a large fraction of trade volumes will concentrate on few product categories in the future. The model simulations show how the share distribution will change with time and predict the time scale of such condensation by using the estimated parameters. The model also makes baseline predictions for the evolution of various industrial sectors, and by comparison, allows us to find other factors such as intrinsic economic fitness [@safarzynska2010evolutionary] at work in addition to the endogenous dynamics represented by our model.

While our model can serve as a simple framework for analyzing the kinetics of capital in the space of products, it could be extended by allowing for 