2000/06/01 by Anders W. Sandvik, Rajiv R. P. Singh · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.86.528
published as Phys. Rev. Lett. 86, 528 (2001) · 4 pages
arxiv created 2000/06/01 · arxiv updated 2009/11/30
We use quantum Monte Carlo simulations and numerical analytic continuation to study high-energy spin excitations in the two-dimensional S=1/2 Heisenberg antiferromagnet at low temperature. We present results for both the transverse and longitudinal dynamic spin structure factor S(q,w) at q=(pi,0) and (pi/2,pi/2). Linear spin-wave theory predicts no dispersion on the line connecting these momenta. Our calculations show that in fact the magnon energy at (pi,0) is 10% lower than at (pi/2,pi/2). We also discuss the transverse and longitudinal multi-magnon continua and their relevance to neutron scattering experiments.