We derive the exact expression of the four-spinon contribution S 4 to the dynamical correlation function S of the spin 1/2 isotropic (XXX) He isenberg model in the antiferromagnetic regime using the quantum group symmetry of the model. We first give the exact expression for the n-spinon contribution in the form of contour integrals and display known results regarding the two-spinon contribution S 2. Then we specialize the n-spinon formula to the case n = 4 and compute three sum rules for S 4 that the total S is known to satisfy exactly. These are: the total integrated intensity, the first frequency moment and the nearest-neighbor correlation function. We find that S 4 corrects only by a small amount the contribution from S 2.
- Antiferromagnetic Heisenberg spin chain exact dynamic structure function sum rules
ASJC Scopus subject areas
- Physics and Astronomy(all)