Quantum Many-Body Scars, Magnon-Pair Condensation, and Hilbert Space Fragmentation in an Anisotropic Heisenberg Model
We investigate a spin-$1/2$ anisotropic Heisenberg model on a lattice consisting of two identical bipartite sublattices. A family of exact eigenstates generated by the restricted spectrum generating algebra (RSGA) constitutes quantum many-body scar states, characterized by subextensive entanglement entropy and supporti...