The boson-defined thermodynamics at the liquid-solid transition

Abstract

Experimental evidence from rare gas (RG) solids, Ne, Ar, Kr and Xe, shows that a boson field orders at the liquid-solid transition. Upon ordering, all bosons condense in the lowest energy state (Bose-Einstein condensation). This is the highest possible thermodynamic order and provides an entropy argument for the surprising exclusion of the interatomic van der Waals interactions from performing the liquid-solid transition. Since the ordered boson field interacts with the atomic system, it defines the observed long-range coherent order of the crystalline state. This order is more perfect than can be expected if the locally anisotropic interatomic interactions would cause the ordering transition. Boson dynamics is evidenced by the observed universal temperature dependence of heat capacity and thermal length changes, ΔL/L₀, in the critical range below the melting temperature, T_m. It is argued that the bosons are elastic quadrupole radiation. Upon ordering, boson fields confine themselves to the finite volume of a stationary unit, such as a domain or a mosaic block, and compress the ordered unit increasingly with decreasing temperature. This compression ensures the cohesion of the solids up to T_m. The low-temperature lattice parameters, therefore, are rather short and the calculated van der Waals cohesive energies are larger by a factor of ten compared to the melting temperatures, T_m. In analogy to the term magnetostriction, the thermal lattice contractions below T_m could be termed “elastostriction”.