Fragmented quantum phases in the antiblockade regime of a Rydberg atom array
Phys. Rev. B 113, 014317 – Published 27 January, 2026
DOI: https://doi.org/10.1103/bnr2-77yc
Abstract
Hilbert space fragmentation induced by dynamical constraints has emerged as a novel mechanism underlying nonergodic behavior in quantum many-body systems. Focusing on this phenomenon, we report a parameter-dependent Hilbert space fragmentation of the one-dimensional Rydberg atom array in the antiblockade regime. We explicitly identify and classify a set of distinct nonequilibrium dynamical phases in the parameter space and analyze their dynamical characteristics. We point out that their quasiperiodic behavior is jointly governed by multipath excitation interference and multiphoton cascaded excitation structures, further revealing fundamental differences in the state connectivity structure and effective dimensionality of the corresponding subspaces. By constructing a complete fragmented quantum phase diagram, we clearly delineate the transition of the Hilbert space from global thermalization to fragmented behavior. Furthermore, we demonstrate the process of secondary fragmentation that enables additional control over the accessible subspaces through local constraints. This work demonstrates the potential of realizing highly programmable nonthermal dynamics through antiblockade mechanisms, providing a theoretical foundation for the exploration and control of exotic nonequilibrium quantum phases in many-body systems.
