2026/02/10 by Shozo Yamada, Akihiro Hokkyo, Masahito Ueda · 1 voice
Physics and Astronomy · #quant-ph #cond-mat.stat-mech
arxiv published 2026/02/10 · arxiv updated 2026/02/18
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.