New exact quantum many-body scars in the 1D PXP model

In the context of understanding non-ergodic phenomena in non-integrable quantum systems, the PXP model has received much attention thanks to its effectiveness in representing Rydberg atom chains in the strong Rydberg blockade regime. By generalizing the previously known results, we find a new family of exact quantum many-body scar states in the 1D PXP model. Unlike the exact scars discovered in earlier works, these new states exhibit a striking similarity to the primary members of scar towers characterized by high initial Z2 state overlap. This similarity is manifest in the overall structure as well as system size dependence of bipartite entanglement entropy and amplitude of the Z2 component. We study the mechanisms which give rise to the old and new exact scar states through the lens of the recent theoretical frameworks and discuss further properties of the new scars and insights from them about the scar physics in the enigmatic 1D PXP model.