Topological protection of quantum many-body scars

Determine whether quantum many-body scar states embedded in the middle of the spectrum can possess topological protection, despite the failure of the ground-state protection mechanisms to apply directly to finite-energy scarred states.

Background

The paper studies quantum many-body scars in the family of scarred k-chain models and examines how symmetry defects, duality transformations, and half-gauging affect scarred subspaces. Its constructions demonstrate symmetry-protected degeneracies associated with anomalous interface algebras, but they do not establish a general form of topological protection for scar states.

The authors emphasize that ground-state topological protection mechanisms may not survive when states are embedded at finite energy density in the spectrum. Establishing whether genuinely topological protection can nevertheless occur for quantum many-body scars is therefore left unresolved and is proposed as a direction for future work, potentially through interfaces generated by half-gauging p-form symmetries in higher-dimensional systems.

References

For instance, the topological protection of quantum many-body scars remains an open question , as the mechanisms ensuring protection in the ground state no longer hold for states embedded in the middle of the spectrum.

— Symmetry protected quantum many body scars through half-gauging  (2610.08304 - Fontana et al., 6 Oct 2026) in Section V, “Final remarks”