Exploring Spin Dynamics in One-Dimensional Spin Chains under Driven Conditions

One-dimensional (1D) quantum spin chains realized in quasi–1D magnets provide an ideal platform to probe entangled many-body dynamics. We investigate their spin dynamics under local energy-absorbing drives that mimic site-selective excitations and quantify their impact on the dynamical spin-structure factor S(q, ω), measurable via inelastic neutron scattering (INS). Using numerically exact time-evolution simulations on large chains, we track the emergence, broadening, and momentum-selective shifts of the S(q, ω) continua, identifying drive-induced pathways that amplify multi-spin-flip correlations and relax the restrictive INS selection rules. We further relate these driven responses to multi–spin-flip excitations observed in resonant inelastic X-ray scattering (RIXS) on chain compounds, clarifying when equilibrium RIXS intensities can serve as a proxy for driven spin dynamics. Our results provide testable predictions for spectral shifts and broadenings in S(q, ω), drive-strength-dependent thresholds, and drive-specific enhancements that can guide future RIXS and INS experiments on candidate 1D magnets.