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arXiv · 2602.09665

Tunable many-body burst in isolated quantum systems

Shozo Yamada·Akihiro Hokkyo·Masahito Ueda
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Abstract

Thermalization in isolated quantum many-body systems can be nonmonotonic, with its process dependent on an initial state. We propose a numerical method to construct a low-entangled initial state that creates a "burst" -- a transient deviation of an observable from its thermal equilibrium value -- at a designated time. We apply this method to demonstrate that a burst of magnetization can be realized for a nonintegrable mixed-field Ising chain on a timescale comparable to the onset of quantum scrambling. Contrary to the typical spreading of information in this regime, the created burst is accompanied by a slow or even negative entanglement growth. Analytically, we show that a burst becomes probabilistically rare after a long time. Our results suggest that a nonequilibrium state is maintained for an appropriately chosen initial state until scrambling becomes dominant. These predictions can be tested with programmable quantum simulators.

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Shozo Yamada, Akihiro Hokkyo, Masahito Ueda. 2026-02-10. Tunable many-body burst in isolated quantum systems. https://arxiv.org/abs/2602.09665

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