Quantum Hilbert Space Fragmentation and Entangled Frozen States
Published in arXiv preprint, 2026
We studied the generic physical mechnanism behind quantum Hilbert space fragmentation, with is HSF in an entangled basis. We identify the core mechanism for qHSF as the presence of entangled frozen states that emerge in the classical Krylov subspaces. This explains the previously known qHSF in the Temperley-Lieb model, quantum East model, and quantum breakdown model; we also propose two new models with qHSF, the triplet flip model and the cyclic qutrit model.