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arXiv · 2412.14280

Many-body spectral transitions through the lens of the variable-range SYK2 model

Andrea Legramandi·Soumik Bandyopadhyay·Philipp Hauke
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Abstract

The Sachdev-Ye-Kitaev (SYK) model is a cornerstone in the study of quantum chaos and holographic quantum matter. Real-world implementations, however, deviate from the idealized all-to-all connectivity, raising questions about the robustness of its chaotic properties. In this work, we investigate a quadratic SYK model with distance-dependent interactions governed by a power-law decay. By analytically and numerically studying the spectral form factor (SFF), we uncover how transitions present in the single-particle limit carry over to the many-body system. Non-trivial cancellations in the one-loop contributions lead to a robustness of the SFF under a considerable reduction of the interaction range. Further suppression leads to a breakdown of perturbation theory around the infinite-range path-integral saddle and the appearance of new spectral regimes, marked by a higher dip and the emergence of a secondary plateau. Our results highlight the interplay between single-particle criticality and many-body dynamics, offering new insights into the quantum chaos-to-localization transition and its reflection in spectral statistics.

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Andrea Legramandi, Soumik Bandyopadhyay, Philipp Hauke. 2024-12-18. Many-body spectral transitions through the lens of the variable-range SYK2 model. https://doi.org/10.1103/49yw-h27c

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