Non-Gaussian particle number fluctuations in vicinity of the critical point for van der Waals equation of state

Understand

The non-Gaussian measures of the particle number fluctuations -- skewness $S\sigma$ and kurtosis $\kappa \sigma^2$ -- are calculated in a vicinity of the critical point.

• This point corresponds to the end point of the first-order liquid-gas phase transition.
• The gaseous phase is characterized by the positive values of skewness while the liquid phase has negative skew.
• The kurtosis appears to be significantly negative at the critical density and supercritical temperatures.