Effects of interactions on dynamic correlations of hard-core bosons at finite temperatures

Article

关键词: MULTIPARTICLE EXCITATIONS;    RENORMALIZATION-GROUP;    MAGNETIC EXCITATIONS;    PERTURBATION-THEORY;    FLOW-EQUATIONS;    EXPANSIONS;    SPECTRUM;   

DOI  :  10.1103/PhysRevB.96.115150

来源: SCIE

【 摘 要 】

We investigate how dynamic correlations of hard-core bosonic excitation at finite temperature are affected by additional interactions besides the hard-core repulsion which prevents them from occupying the same site. We focus especially on dimerized spin systems, where these additional interactions between the elementary excitations, triplons, lead to the formation of bound states, relevant for the correct description of scattering processes. In order to include these effects quantitatively, we extend the previously developed Bruckner approach to include also nearest-neighbor (NN) and next-nearest neighbor (NNN) interactions correctly in a low-temperature expansion. This leads to the extension of the scalar Bethe-Salpeter equation to a matrix-valued equation. As an example, we consider the Heisenberg spin ladder to illustrate the significance of the additional interactions on the spectral functions at finite temperature, which are proportional to inelastic neutron scattering rates.

【 授权许可】

Free