Emulation of quantum correlations by classical dynamics in a spin-1/2 Heisenberg chain

We simulate the dynamical spin structure factor (DSSF) of the spin-1/2 Heisenberg antiferromagnetic chain using classical simulations. By employing Landau-Lifshitz Dynamics, we emulate quantum correlations through temperature-dependent corrections, including rescaling of magnetic dipoles and renormalization of exchange interactions. Our results closely match Quantum Monte-Carlo calculations for kT/J>1, extending the applicability of classical dynamics to the challenging case of gapless excitations. At higher temperatures, our simulations comply with general predictions for uncorrelated paramagnetic fluctuations in the infinite temperature limit. Sum-rules derived from the quantum-equivalent DSSF act as sensitive diagnostics for the quantum-to-classical crossover. Our framework also reproduces transverse spin correlations in finite magnetic fields, in agreement with quantum simulations. Together, our results show quantum-corrected classical dynamics as a useful tool for interpreting scattering experiments and exploring quantum correlations.