Breakdown of Quantum Chaos in the Staggered-Field XXZ Chain: Confinement and Meson Formation
Fuente:
arXiv
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866909911987781632 |
|---|---|
| author | Wildeboer, Julia Lajer, Marton Konik, Robert M. |
| author_facet | Wildeboer, Julia Lajer, Marton Konik, Robert M. |
| contents | Confinement of fractionalized excitations can strongly restructure many-body spectra. We investigate this phenomenon in the gapped spin-$\frac{1}{2}$ XXZ chain subject to a staggered field, where spinons bind into domain-wall ``mesons'' deep in the antiferromagnetic phase. We present evidence that this non-integrable model exhibits both Hilbert space fractionalization and quantum scar formation as controlled by the anisotropy parameter $Δ$. Exact diagonalization across symmetry-resolved sectors reveals a crossover from Gaussian-orthogonal (chaotic) level statistics at weak anisotropy $Δ\sim 1$ to non-ergodic behavior deep in the antiferromagnetic regime $Δ\gg 1$ through scrutinizing the adjacent gap ratios, accompanied by a striking banding of eigenstates by domain-wall number in correlation and entanglement measures. The Page-like entanglement dome characteristic of chaotic spectra gives way to suppressed, band-resolved entanglement consistent with emergent quasi-conservation of domain walls. To investigate further the formation mechanism of mesonic scar states, we carry out meson spectroscopy near the two-spinon threshold and compare with the analytic ladder predicted by Rutkevich [Phys. Rev. B 106, 134405 (2022)]. We test the theory through continuum-relative bindings, an offset-removed Airy scaling collapse, and explicit two-meson thresholds that determine the number of stable meson levels. The low-lying spectrum shows close quantitative agreement, while deviations at higher energies are consistent with finite-size and subleading corrections. These results establish a unified account of confinement-induced nonergodicity and provide a template for quantitative meson spectroscopy in quantum spin chains. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_14847 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Breakdown of Quantum Chaos in the Staggered-Field XXZ Chain: Confinement and Meson Formation Wildeboer, Julia Lajer, Marton Konik, Robert M. Strongly Correlated Electrons Confinement of fractionalized excitations can strongly restructure many-body spectra. We investigate this phenomenon in the gapped spin-$\frac{1}{2}$ XXZ chain subject to a staggered field, where spinons bind into domain-wall ``mesons'' deep in the antiferromagnetic phase. We present evidence that this non-integrable model exhibits both Hilbert space fractionalization and quantum scar formation as controlled by the anisotropy parameter $Δ$. Exact diagonalization across symmetry-resolved sectors reveals a crossover from Gaussian-orthogonal (chaotic) level statistics at weak anisotropy $Δ\sim 1$ to non-ergodic behavior deep in the antiferromagnetic regime $Δ\gg 1$ through scrutinizing the adjacent gap ratios, accompanied by a striking banding of eigenstates by domain-wall number in correlation and entanglement measures. The Page-like entanglement dome characteristic of chaotic spectra gives way to suppressed, band-resolved entanglement consistent with emergent quasi-conservation of domain walls. To investigate further the formation mechanism of mesonic scar states, we carry out meson spectroscopy near the two-spinon threshold and compare with the analytic ladder predicted by Rutkevich [Phys. Rev. B 106, 134405 (2022)]. We test the theory through continuum-relative bindings, an offset-removed Airy scaling collapse, and explicit two-meson thresholds that determine the number of stable meson levels. The low-lying spectrum shows close quantitative agreement, while deviations at higher energies are consistent with finite-size and subleading corrections. These results establish a unified account of confinement-induced nonergodicity and provide a template for quantitative meson spectroscopy in quantum spin chains. |
| title | Breakdown of Quantum Chaos in the Staggered-Field XXZ Chain: Confinement and Meson Formation |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2511.14847 |