Improving the theory of phase transitions with supercomputers
When water molecules evaporate from a liquid phase into a gaseous phase, they alter their aggregate state. The mathematical description of such a phase transition harbours pitfalls as nucleation is needed for the change to take place. The theory behind this, classical nucleation theory (CNT), however, is deemed highly inaccurate. Earlier studies suggest that the rate of the bubble nucleation determined with the CNT is underestimated. The research team headed by physicist Jürg Diemand, a professor at the University of Zurich, enlisted the aid of the CSCS supercomputers to scrutinise the process in which liquid vaporises. They revealed that, to some extent, the theory actually reflects the reality. The nucleation theory only underestimates the formation rate of the gas bubbles at very low temperatures. The simulations also gave the researchers an insight into possible causes of the deviations.