Year: 2026
Type: preprint
Abstract: Chaotic many-body spectra are expected to densely fill their energy window. We show that constrained spin chains with chiral symmetry evade this expectation by hosting an exponentially large manifold of symmetry-protected exact zero modes separated from the surrounding spectrum by a sharp gap at zero energy. The gap is generated by chaotic level repulsion, with width set by the number of zero modes times the mean level spacing. We verify this mechanism in an East-West kinetically constrained chain, develop a minimal random-matrix description, and show how the gap can be detected through linear-response spectroscopy.
Source: arXiv (Cornell University)
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1520943153, G1605908383, G1768993395, G1848969253, Programmable Atomic Large-scale Quantum Simulation 2 - SGA1, FOR 5522: Quantenthermalisierung, Lokalisierung und eingeschränkte Dynamik mit wechselwirkenden ultrakalten Atomen, G2744928646, G4710139657, G4856404060, G526456201, G5987792135, TRR 360: Eingeschränkte Quantenmaterie, EXC 2111: Munich Center for Quantum Science and Technology (MCQST), G8908719260
OpenAlex ID: W7168142965