A tensor-network (time-dependent variational principle) computation of the charge-neutral excitation spectra of fractional Chern insulators on the Haldane honeycomb lattice. It resolves the magnetoroton mode from the dynamic density structure factor - showing it softens and sharpens into a quasiparticle as the system approaches a charge-density-wave instability while the single-particle gap stays open - and resolves the spin-2 chiral graviton mode near the Brillouin-zone center, demonstrating for the first time that FCIs with opposite-sign Hall conductance carry gravitons of opposite chirality.
This condensed-matter theory letter computes the spectra of charge-neutral excitations in fractional Chern insulators (FCIs) - the nu=1/2 bosonic and nu=1/3 fermionic FCIs on the Haldane honeycomb la…