谁来讲十分钟：Nearly perfect fluidity

Thomas Schäfer

Is there a fundamental lower bound on viscosity? To answer this question, we can look at the coldest and hottest fluids that laboratories are able to produce.

From everyday experience, we have an intuitive feel for how a “good” fluid behaves. A good fluid, such as water, supports complicated flow patterns that decay slowly over time. In contrast, in a “poor” fluid, like honey or tar, we cannot observe waves or eddies, and flow processes decay quickly. Far beyond the realm of the everyday, experiments on ultracold gases and the extremely hot quark-gluon plasma are now allowing us to explore fundamental aspects of fluid mechanics. This article explores how results from studying such seemingly different systems are helping us address the question: Can there be such a thing as a perfect fluid?