Long-range resonances on the many-body localized side of XXZ chains

See also : JC, FA & NL, PRB 110, 214210 (2024)

1. We study rare events with large correlations at maximal distance in the many-body spectrum of the random-field  and quasi-periodic XXZ chains, where the many-body localized regime has been the topic of much debate.


These rare events arise in pairs...

2. ...revealing a broad region deep into the MBL regime where long-range cat-like states occur

3. An analytical description gives the main observables supporting a detailed characterization.

\mathcal{H} = \sum_{i} \frac{J}{2}\left({\color{lightgreen}S_i^{+} S_{i+1}^{-} + S_i^{-} S_{i+1}^{+}} + {\color{cyan} 2\Delta S_i^z S_{i+1}^z}\right) - \sum_{i} {\color{orange} h_i S_i^z}

3. An analytical description gives the main observables supporting a detailed characterization.

JC, FA & NL, PRB 110, (2024), NL, JC & FA, PRB 112 (2025), AP, JC, FA & NL, PRL 136 (2026)

Jeanne Colbois, Ashirbad Padhan, Fabien Alet, and Nicolas Laflorencie

LPT Toulouse (Univ. Toulouse & CNRS) & Institut Néel (UGA, Grenoble INP & CNRS)