Thermodynamic properties of a one-dimensional system of charged bosons.

Abstract

A large but finite one-dimensional neutral system containing two types of locally (and weakly) interacting ``charged'' bosons is examined for its thermodynamic behavior at finite temperatures. It is found that the system can have a length ${\mathit{L}}_{0}$ at which it will achieve thermodynamic stability provided the temperature is below a finite temperature ${\mathit{T}}_{\mathit{d}}$. If the temperature ${\mathit{T}}_{\mathit{d}}$ is exceeded, the system disassociates in the sense that it no longer has a stable size. ${\mathit{T}}_{\mathit{d}}$ is a function of the interaction strengths between the bosons as well as the number of bosons N present in the system. Although the system has an a priori dependence on a set of five parameters, when N and L are large scaling is present. Interestingly, if one of the interaction parameters is zero, making the interactions ``Coulomb-like,'' the system will collapse if periodic boundary conditions are used. The introduction of Dirichlet boundary conditions does not prevent this collapse for large N and L but will do so otherwise. Moreover, without the collapse, the effect of N on the stability length is strikingly different from the nonzero parameter case, where periodic boundary conditions are used. This effect has been noted before in the ground-state energy, but now it is shown that the effect persists for finite temperatures.