Approximate calculation of the free energy of Fermi systems with topological solitons: soliton creation energy of polyacetylene

Abstract

The authors investigate an approximate technique for the calculation of the free energy of fermionic systems that are coupled to topological solitons. They apply this to a solvable one-dimensional model field theory: polyacetylene in the static dimerization approximation. They estimate the free energy of solitons with various scales of spatial extension and make comparisons with exact results. In an appendix, the authors make the connection between the high-temperature limit of their work and Ginzburg-Landau theory.