Exact Many Body Ground States of Vortexable Bands with Higher Chern Number: Applications to Moire Multilayer Graphene

Vortexable Chern bands, or bands with "ideal quantum geometry," enable analytic understanding of fractional Chern insulator ground states in systems distinct from the lowest Landau level, including with inhomogeneous charge density and Berry curvature. In this work, we derive exact many body ground states of vortexable higher Chern bands, which have recently been predicted in various moire graphene structures. We begin by showing how to decompose ideal higher Chern bands into separate ideal bands with Chern number 1 that are intertwined through translation and rotation symmetry. The decomposed bands admit an SU(C) action that combines real space and momentum space translations. Remarkably, they also allow for analytic construction of exact many-body ground states, such as generalized quantum Hall ferromagnets and FCIs, including flavor-singlet Halperin states and Laughlin ferromagnets in the limit of short-range interactions. In this limit, the SU(C) action is promoted to a symmetry on the ground-state subspace. While flavor singlet states are translation symmetric, the flavor ferromagnets correspond to translation broken states and admit charged skyrmion excitations corresponding to a spatially varying density wave pattern. We confirm our analytic predictions with numerical simulations of ideal bands of twisted chiral multilayers of graphene, and discuss consequences for experimentally accessible systems such as monolayer graphene twisted relative to a Bernal bilayer.