Spin dynamics of the E8 particles

Abstract

In this article, we report on inelastic neutron scattering measurements on a quasi-1D antiferromagnet BaCo2V2O8 under a transverse magnetic field applied along the (0,1,0) direction.Combining results of inelastic neutron scattering experiments, analytical analysis, and numerical simulations, we precisely studied the E8 excitations appearing in the whole Brillouin zone at B 1D c ≈ 4.7 T. The energy scan at Q = (0, 0, 2) reveals a match between the data and the theoretical prediction of energies of multiple E8 excitations.Furthermore, dispersions of the lightest three E8 particles have been clearly observed, confirming the existence of the E8 particles in BaCo2V2O8.Our results lay down a concrete ground to systematically study the physics of the exotic E8 particles.