Quantum Information Dynamics of QED$_2$ in Expanding de Sitter Universe

High Energy Physics - Theory [Submitted on 3 Apr 2026] Quantum Information Dynamics of QED_2 in Expanding de Sitter Universe Kazuki Ikeda, Yaron Oz We study QED_2 in de Sitter space as a minimal interacting gauge theory in which cosmological expansion directly competes with quantum dynamics. In cosmic time, the hopping redshifts as 1/a(t) while the electric term grows as g^2 a(t), sweeping the spectrum through a moving narrow-gap region in the (\tau,m) plane. Exact diagonalization shows that this defines a pseudo-critical line governing the loss of adiabaticity, excitation growth, and redshifted response. Using matrix-product states at a fixed mass, we separate the fixed-cutoff thermodynamic limit from the continuum extrapolation. The late-time dip survives in the infinite physical box size limit, and shifts to later \tau as the lattice spacing goes to zero, with current data favoring \tau_* \approx 3.1, while the dip depth remains less controlled. For Gibbs initial states, the same mechanism produces an irreversibility front in the relative entropy that tracks the pseudo-critical line and is detectable via LOCC-accessible observables. These results identify de Sitter QED_2 as a controlled setting for linking curved-space gauge dynamics, near-critical spectral structure, and operational irreversibility. Comments: 23 pages, 3 figures Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Lattice (hep-lat); Nuclear Theory (nucl-th); Quantum Physics (quant-ph) Cite as: arXiv:2604.02777 [hep-th]   (or arXiv:2604.02777v1 [hep-th] for this version)   https://doi.org/10.48550/arXiv.2604.02777 Focus to learn more Submission history From: Kazuki Ikeda [view email] [v1] Fri, 3 Apr 2026 06:37:56 UTC (302 KB) Access Paper: HTML (experimental) view license Current browse context: hep-th < prev   |   next > new | recent | 2026-04 Change to browse by: gr-qc hep-lat nucl-th quant-ph 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?)