Information scrambling in all-to-all interacting models

Abhik Kumar Saha; Tanay Pathak; Masaki Tezuka

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arXiv · 2606.02207

Information scrambling in all-to-all interacting models

Abhik Kumar Saha·Tanay Pathak·Masaki Tezuka

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Abstract

Information scrambling is a hallmark of quantum chaos and thermalization in isolated quantum many-body systems. We investigate scrambling dynamics in the all-to-all interacting spin Sachdev-Ye-Kitaev (SYK)-$q$ model using both pure- and mixed-state entanglement measures. We show that von-Neumann and R\'enyi entropies exhibit rapid growth followed by saturation near Haar-random values, signaling efficient scrambling. The scrambling rate reveals a nontrivial dependence on the interaction order, system size, and Hamiltonian scaling. We further employ mixed-state entanglement as a powerful probe of information scrambling. We numerically find a universal relation between the R\'enyi-1/2 mutual information and entanglement negativity for minimal interaction order in the early growth regime. Furthermore, entanglement negativity displays a Page-curve-like behavior under unequal subsystem partitioning, characterized by the birth, spread, and eventual death of quantum correlations. Our results provide a generic description of information scrambling using entanglement dynamics in all-to-all interacting spin systems with multi-body interactions.

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Abhik Kumar Saha, Tanay Pathak, Masaki Tezuka. 2026-06-01. Information scrambling in all-to-all interacting models. https://arxiv.org/abs/2606.02207

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