https://doi.org/10.1140/epjc/s10052-025-14451-z
Regular Article - Theoretical Physics
Krylov complexity as a probe for chaos
1
School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran
2
Institut für Theoretische Physik und Astrophysik, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
3
Würzburg-Dresden Cluster of Excellence ct.qmat, Würzburg, Germany
4
Department of Physics, University of Guilan, P.O. Box 41335-1914, Rasht, Iran
Received:
6
April
2025
Accepted:
18
June
2025
Published online:
7
July
2025
In this work, we explore in detail, the time evolution of Krylov complexity. We demonstrate, through analytical computations, that in finite many-body systems, while ramp and plateau are two generic features of Krylov complexity, the manner in which complexity saturates reveals the chaotic nature of the system. In particular, we show that the dynamics towards saturation precisely distinguish between chaotic and integrable systems. For chaotic models, the saturation value of complexity reaches its infinite time average at a finite saturation time. In this case, depending on the initial state, it may also exhibit a peak before saturation. In contrast, in integrable models, complexity approaches the infinite time average value from below at a much longer timescale. We confirm this distinction using numerical results for specific spin models.
© The Author(s) 2025
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