Fig. 1: Scattering and Van Hove correlations.
From: Quantum wake dynamics in Heisenberg antiferromagnetic chains
Finite temperature neutron scattering data for KCuF3 from the MAPS and SEQUOIA (SEQ) instruments (left column: a, d, g, j) and their transformation to real-space correlations, with the real G(r, t) (center column: b, e, h, k) and imaginary G(r, t) (right column: c, f, i, l). Red indicates ferromagnetic spin correlation, blue indicates antiferromagnetic spin correlation. At low temperatures, the real G(r, t) wavefront at the light cone is antiferromagnetic, and by 200 K it becomes ferromagnetic. Meanwhile, the imaginary G(r, t) is restricted in space and time at higher temperatures, showing loss of quantum coherence.
