Dynamical spin correlations in Heisenberg ladder under magnetic field and correlation functions in SO(5) ladder

TL;DR

This paper calculates the zero-temperature dynamical spin-spin correlation functions for a spin-1/2 two-leg Heisenberg ladder in a magnetic field, revealing massless and massive excitations and their implications for correlation functions and SO(5) symmetry.

Contribution

It provides detailed dynamical structure factors for the Heisenberg ladder under magnetic field, including excitations and singularities, and discusses applications to spin-1 chains and SO(5) models.

Findings

Identification of massless and massive excitations in the structure factors

Power-law singularities at the edges of the support

Applicability to spin-1 Heisenberg chains and SO(5) symmetric models

Abstract

The zero-temperature dynamical spin-spin correlation functions are calculated for the spin-1/2 two-leg Heisenberg ladder in a magnetic field above the lower critical field Hc1. The dynamical structure factors are calculated which exhibit both massless and massive excitations. These modes appear in different sectors characterized by the parity in the rung direction and by the momentum in the direction of the chains. The structure factors have power-law singularities at the lower edges of their support. The results are also applicable to spin-1 Heisenberg chain. The implications are briefly discussed for various correlation functions and the pi-resonance in the SO(5) symmetric ladder model.