Figure 2: The spin dynamical structure factor S(q, ω) calculated using DQMC for the Hubbard model.

(a) False colour plots of the spectra along high symmetry directions in the Brillouin zone for different electron concentrations n. The calculations are done with the same Hubbard model parameters as in Fig. 1. (b) Dispersion relations of the spin response peak in S(q, ω) along these high symmetry directions for different n. (c) Comparison of the calculated and observed energies of the spectral peaks at selected momenta as a function of n (t=400 meV has been used for the comparison). YBa₂Cu₃O_6+x, YBa₂Cu₄O₈ and Nd_1.2Ba_1.8Cu₃O_6+x RIXS experimental data are taken from ref. 3; La_2−xSr_xCuO₄ RIXS experimental data are taken from ref. 6. Error bars on the experimental data have been taken from the corresponding references.