Breakdown of Quantum Chaos in the Staggered-Field XXZ Chain: Confinement and Meson Formation
This research investigates how local interactions in a quantum spin chain create 'mesons' through confinement, leading to nonergodic behavior and spectral chaos breakdown. By studying a staggered-field XXZ chain, the authors show that this confinement causes Hilbert space fragmentation and organizes eigenstates into structured bands linked to quasi-conserved quantities like the domain-wall number.