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Main Authors: Wang, Cheng, Yang, Zhi-Cheng, Zhou, Tianci, Chen, Xiao
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.10688
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author Wang, Cheng
Yang, Zhi-Cheng
Zhou, Tianci
Chen, Xiao
author_facet Wang, Cheng
Yang, Zhi-Cheng
Zhou, Tianci
Chen, Xiao
contents We investigate magic and its connection to entanglement in 1+1 dimensional random free fermion circuits, with a focus on hybrid free fermion dynamics that can exhibit an entanglement phase transition. To quantify magic, we use the Stabilizer Rényi Entropy (SRE), which we compute numerically via a perfect sampling algorithm. We show that although the SRE remains extensive as the system transitions from a critical phase to an area-law (disentangled) phase, the structure of magic itself undergoes a delocalization phase transition. This transition is characterized using the bipartite stabilizer mutual information, which exhibits the same scaling behavior as entanglement entropy: logarithmic scaling in the critical phase and a finite constant in the area-law phase. Additionally, we explore the dynamics of SRE. While the total SRE becomes extensive in $O(1)$ time, we find that in the critical phase, the relaxation time to the steady-state value is parameterically longer than that in generic random circuits. The relaxation follows a universal form, with a relaxation time that grows linearly with the system size, providing further evidence for the critical nature of the phase.
format Preprint
id arxiv_https___arxiv_org_abs_2507_10688
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Magic transition in monitored free fermion dynamics
Wang, Cheng
Yang, Zhi-Cheng
Zhou, Tianci
Chen, Xiao
Quantum Physics
Statistical Mechanics
We investigate magic and its connection to entanglement in 1+1 dimensional random free fermion circuits, with a focus on hybrid free fermion dynamics that can exhibit an entanglement phase transition. To quantify magic, we use the Stabilizer Rényi Entropy (SRE), which we compute numerically via a perfect sampling algorithm. We show that although the SRE remains extensive as the system transitions from a critical phase to an area-law (disentangled) phase, the structure of magic itself undergoes a delocalization phase transition. This transition is characterized using the bipartite stabilizer mutual information, which exhibits the same scaling behavior as entanglement entropy: logarithmic scaling in the critical phase and a finite constant in the area-law phase. Additionally, we explore the dynamics of SRE. While the total SRE becomes extensive in $O(1)$ time, we find that in the critical phase, the relaxation time to the steady-state value is parameterically longer than that in generic random circuits. The relaxation follows a universal form, with a relaxation time that grows linearly with the system size, providing further evidence for the critical nature of the phase.
title Magic transition in monitored free fermion dynamics
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2507.10688