Quantum solids, liquids, and gases program:Bound states with E8 symmetry in quantum Ising-like chains

by Jonas Kjäll (UC Berkeley)

Tuesday 17 Aug 2010, 15:15 → 16:15 Europe/Stockholm

In a recent experiment on CoNb2O6, Coldea et. al. found for the first time experimental evidence of the exceptional Lie algebra E8. The emergence of this symmetry was theoretically predicted long ago for the transverse quantum Ising chain in the presence of a weak longitudinal field. We consider an accurate microscopic model of CoNb2O6 and calculate numerically the dynamical structure function using a recently developed matrix-product state based method. Then excitation spectra contain bound states which are characteristic to the E8 symmetry. We furthermore compare the observed bound states to the ones found in the transverse Ising chain in a longitudinal field.