Effective Free Energy for Solidification of Superfluid 4He Under Pressure

Effective free energy for the solidification of the superfluid ⁴He under pressure is presented. Since this free energy is a function of two parameters, the density change and the translational symmetry breaking parameter , it is expected to describe over both the superfluid phase and the solid phase.The experimentally established values below and equal to the melting pressure P_m are successfully reproducible by the free energy. For P>P_m, where the superfluid is metastable, the free energy predicts that the instability for should occur first and then accompanies. That is, -nucleation is essential for the solid nucleation in the superfluid ⁴He.