Density functional study on bubble nucleation in liquid hydrogen as a quantum fluid

Bubble nucleation in a classical fluid such as liquid argon or standard Lennard-Jones fluid has been widely studied using classical nucleation theory (CNT), density functional theory (DFT), some statistical mechanical approaches, or molecular simulations. However, that of quantum fluid such as liquid hydrogen or liquid helium has hardly been studied from a molecular point of view, compared with classical fluid without quantum nature. In this study, we employed a phenomenological DFT, which is based on an equation of state (EOS) of liquid hydrogen, and evaluated the energy barrier height in the bubble nucleation. Also, we applied the same kind of DFT to classical liquid hydrogen without quantum nature, whose DFT is based on an EOS for standard Lennard-Jones fluid. As a result, the nucleation barrier in liquid hydrogen shows a similar tendency to that in classical hydrogen if those barriers are compared at the same temperature reduced by critical temperature and the same reduced superheat ratio, which is defined by the chemical potential at the saturation point and that at the spinodal. It shows that a principle of corresponding state for energy barrier in bubble nucleation may be satisfied between quantum fluid and classical fluid, which is a new insight in this field.