instanton fluidとは 意味・読み方・使い方

In quantum chromodynamics, the instanton fluid model is a model of Wick rotated Euclidean quantum chromodynamics. If we examine the path integral of the action, we find that it has infinitely many local minima, corresponding to varying instanton numbers. It turns out that the dominant contribution to the path integral comes from configurations with consisting of a pool of instantons and antiinstantons. The exponential suppression coming from the increased action is compensated by the increased phase space factor coming from all the instantons. In other words, the "Euclidean" free energy is minimized by a pool of instantons.