Tao Yong
Economy, Industry and Business Management Institute, Chongqing University, Chongqing 400044, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Sep;82(3 Pt 2):036118. doi: 10.1103/PhysRevE.82.036118. Epub 2010 Sep 28.
The origin of economic crises is a key problem for economics. We present a model of long-run competitive markets to show that the multiplicity of behaviors in an economic system, over a long time scale, emerge as statistical regularities (perfectly competitive markets obey Bose-Einstein statistics and purely monopolistic-competitive markets obey Boltzmann statistics) and that how interaction among firms influences the evolutionary of competitive markets. It has been widely accepted that perfect competition is most efficient. Our study shows that the perfectly competitive system, as an extreme case of competitive markets, is most efficient but not stable, and gives rise to economic crises as society reaches full employment. In the economic crisis revealed by our model, many firms condense (collapse) into the lowest supply level (zero supply, namely, bankruptcy status), in analogy to Bose-Einstein condensation. This curious phenomenon arises because perfect competition (homogeneous competitions) equals symmetric (indistinguishable) investment direction, a fact abhorred by nature. Therefore, we urge the promotion of monopolistic competition (heterogeneous competitions) rather than perfect competition. To provide early warning of economic crises, we introduce a resolving index of investment, which approaches zero in the run-up to an economic crisis. On the other hand, our model discloses, as a profound conclusion, that the technological level for a long-run social or economic system is proportional to the freedom (disorder) of this system; in other words, technology equals the entropy of system. As an application of this concept, we give a possible answer to the Needham question: "Why was it that despite the immense achievements of traditional China it had been in Europe and not in China that the scientific and industrial revolutions occurred?"
经济危机的起源是经济学的一个关键问题。我们提出了一个长期竞争市场模型，以表明经济系统中多种行为模式在长时间尺度上会呈现为统计规律（完全竞争市场遵循玻色 - 爱因斯坦统计，纯垄断竞争市场遵循玻尔兹曼统计），以及企业间的相互作用如何影响竞争市场的演化。人们普遍认为完全竞争是最有效率的。我们的研究表明，完全竞争系统作为竞争市场的一种极端情况，虽然效率最高但并不稳定，并且当社会达到充分就业时会引发经济危机。在我们模型揭示的经济危机中，许多企业会凝聚（倒闭）到最低供给水平（零供给，即破产状态），这类似于玻色 - 爱因斯坦凝聚。这种奇特现象的出现是因为完全竞争（同质化竞争）等同于对称（不可区分）的投资方向，而这是自然所厌恶的。因此，我们主张促进垄断竞争（异质化竞争）而非完全竞争。为了提供经济危机的早期预警，我们引入了一个投资化解指数，该指数在经济危机来临前会趋近于零。另一方面，我们的模型作为一个深刻结论揭示，长期社会或经济系统的技术水平与其自由度（无序度）成正比；换句话说，技术等同于系统的熵。作为这一概念的应用，我们对李约瑟问题给出了一个可能的答案：“为什么尽管中国传统上有巨大成就，但科学和工业革命却发生在欧洲而非中国？”
