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Long-Range Resonances in Quasiperiodic Many-Body Localization.
Ashirbad Padhan1, Jeanne Colbois2, Fabien Alet1
1Laboratoire de Physique Théorique, CNRS, Univ. Toulouse, Toulouse, France.
Physical Review Letters
|May 29, 2026
Summary
We found atypical eigenstates with long-range correlations in quasiperiodic many-body localized (MBL) systems. These resonant cat states challenge standard MBL diagnostics and suggest new experimental probes.
Area of Science:
- Condensed Matter Physics
- Quantum Many-Body Systems
- Disordered Systems
Background:
- Many-body localized (MBL) systems avoid thermalization due to disorder.
- Quasiperiodic potentials can also induce MBL, but their transitions are expected to be sharp.
- Standard diagnostics for MBL include energy level statistics and entanglement entropy.
Purpose of the Study:
- Investigate long-range resonances in quasiperiodic MBL systems.
- Analyze pairwise correlations in the Heisenberg chain within an Aubry-André potential.
- Identify the nature of eigenstates in unconventional regimes.
Main Methods:
- Focus on the Heisenberg chain model with a deterministic Aubry-André potential.
- Analyze long-distance pairwise correlations at high energy.
- Complement standard MBL diagnostics with correlation function analysis.
Main Results:
- Uncovered a broad unconventional regime at strong quasiperiodic potential.
- Observed fat-tailed distributions of longitudinal correlations at long distances.
- Identified anomalous eigenstates as quasidegenerate pairs of resonant cat states with long-range entanglement.
Conclusions:
- Atypical eigenstates with strong long-range correlations exist in a regime that appears MBL by standard diagnostics.
- These findings challenge the expected sharpness of the ergodic-MBL transition in quasiperiodic systems.
- Density-correlation measurements in ultracold atoms can probe these long-range resonances.
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