Quantum many-body scars in bipartite Rydberg arrays originating from hidden projector embedding
Keita Omiya, Markus Müller
Abstract
We study the nature of the ergodicity-breaking ``quantum many-body scar'' states that appear in the PXP model describing constrained Rabi oscillations. For a wide class of bipartite lattices of Rydberg atoms, we reveal that the nearly energy-equidistant tower of these states arises from the Hamiltonian's close proximity to a generalized projector-embedding form in Phys. Rev. Lett. 119, 030601 (2017), a structure common to many models hosting quantum many-body scars. We construct a non-Hermitian but strictly local extension of the PXP model hosting exact quantum scars and show how various Hermitian scar-stabilizing extensions from the literature can be naturally understood within this framework. The exact scar states are obtained analytically as large spin states of explicitly constructed pseudospins. The quasiperiodic motion ensuing from the N\'eel state is finally shown to be the projection onto the Rydberg-constrained subspace of the precession of the large pseudospin.