Abstract
We use quantum Monte Carlo simulations and numerical analytic continuation to study high-energy spin excitations in the two-dimensional Heisenberg antiferromagnet at low temperature. We present results for both the transverse and longitudinal dynamic spin structure factors at and . Linear spin-wave theory predicts no dispersion on the line connecting these momenta. Our calculations show that in fact the magnon energy at is lower than at . We also discuss the transverse and longitudinal multimagnon continua and their relevance to neutron scattering experiments.
- Received 1 June 2000
DOI:https://doi.org/10.1103/PhysRevLett.86.528
©2001 American Physical Society