arXiv:cond-mat/0310471 · Physical review. B, Condensed matter
Variational description of the dimensional crossover in an array of coupled one-dimensional conductors
A. V. Rozhkov
Abstract
Variational wave function is proposed to describe electronic properties of an array of one-dimensional conductors coupled by transverse hopping and interaction. For weak or intermediate in-chain interaction the wave function has the following structure: Tomonaga-Luttinger bosons with momentum higher than some variational quantity $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\Lambda}}$ are in their ground state while other bosons (with $|k|<\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\Lambda}})$ form kinks --- fermionlike excitations of the Tomonaga-Luttinger boson field. The nature of the ground state for these quasiparticles can be determined by solving a three-dimensional effective Hamiltonian. Since the anisotropy of the effective Hamiltonian is small the use of mean-field theory is justified. For repulsive interaction possible phases are density wave and p-wave superconductivity. Our method allows us to calculate the low-energy part of different electronic Green's functions. In order to do this it is sufficient to apply standard perturbation theory technique to the effective Hamiltonian. When the in-chain interaction is strong $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\Lambda}}$ vanishes and no fermionic excitation is present in the system. In this regime the dynamics is described by transversally coupled Tomonaga-Luttinger bosons.