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SOE: Fachverband Physik sozio-ökonomischer Systeme
SOE 20: Economic models III
SOE 20.3: Vortrag
Mittwoch, 9. März 2016, 18:00–18:15, H36
Phase transitions and relaxations in an agent-based macroeconomic model — •Wenzhi Zheng1 and Yu Chen2 — 1Teasic137@gmail.com — 2Chen@k.u-tokyo.ac.jp
An economic system can give rise to very rich and complex phenomena which often puzzle theorists and policy makers. In economic history, although periods of prosperity, recession and depression can be identified in hindsight, it is difficult for us to confirm whether those economies have reached, or are approaching the equilibrium. In other words, the large fluctuations suffered by these economies might be only a transient regime. In this research, we construct a minimal agent-based macroeconomic model to study the equilibrium states and the relaxation towards the equilibrium. We find that there exists a phase transition between a sustainable economy, characterized by high production, long-term profitability of firms and wealthy households, and a bankrupt economy, characterized by low production, short-term profitability of firms and poor households. The phase transition is controlled by the combination of the profitability of firms and the welfare indicator. Furthermore, we find that the heterogeneity of firms strongly influences the relaxation towards the equilibrium. In the model economy consisting of heterogeneous firms, the relaxation near the critical point is featured with stronger fluctuations and longer relaxation time. Under the circumstances, policy makers and stakeholders may miss the forest for the trees: being unable to perceive the global trends while desperately trying to deal with the small scale fluctuations or to catch up with the local trends.