Critical Entanglement Dynamics at Dynamical Quantum Phase Transitions

Quantum Physics [Submitted on 9 Apr 2026] Critical Entanglement Dynamics at Dynamical Quantum Phase Transitions Kaiyuan Cao, Mingzhi Li, Xiang-Ping Jiang, Shu Chen, Jian Wang We investigate the critical behavior of momentum-space entanglement entropy at dynamical quantum phase transitions (DQPTs) in translationally invariant two-band insulators and superconductors. By analyzing the Su-Schrieffer-Heeger model, the quantum XY chain, and the Haldane model, we establish that the geometric DQPT condition \hat{\textbf{d}}_{\textbf{k}}^{i} \cdot \hat{\textbf{d}}_{\textbf{k}}^{f} = 0 manifests as exact degeneracy p_{\textbf{k}^{*}}=1/2 in the entanglement spectrum defined with respect to the post-quench eigenbasis, yielding a maximal momentum-space entropy of \ln 2. In one dimension, critical momenta appear as isolated points, whereas in two dimensions they form continuous one-dimensional manifolds, reflecting the dimensional dependence of the underlying critical structure. Importantly, alternative bipartitions such as the sublattice basis produce qualitatively different behavior: the entropy becomes explicitly time-dependent and attains a minimum at DQPT critical times, underscoring the essential role of basis selection. Our results establish that momentum-space entanglement entropy, when evaluated in the appropriate eigenbasis, provides a robust, time-independent diagnostic of DQPTs and offers a unified geometric perspective linking entanglement, topology, and non-equilibrium criticality. Comments: 7 pages, 4 figures Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.07714 [quant-ph]   (or arXiv:2604.07714v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.07714 Focus to learn more Submission history From: Kaiyuan Cao [view email] [v1] Thu, 9 Apr 2026 01:58:39 UTC (3,890 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)