Physical review. B, Condensed matter
Variational Gaussian wave functional and the (1+1)-dimensional sine-Gordon model
Yumei Zhang, Bo-Wei Xu, Wen-Fa Lu
Abstract
The (1+1)-dimensional sine-Gordon model is studied in the framework of the variational Gaussian wave functionals. The renormalized mass depends on two dimensionless parameters. In the phase diagram a first-order phase transition will replace the second-order phase transition for large bare mass. The spectrum of the two-particle states consists of a continuum of scattering states and the isolated values connected to the excitonlike bound states. The energy of the bound states and the phase shifts of the scattering states are explicitly calculated.