Real-time entanglement dynamics and information flux near black-hole horizons

Abstract We study real-time quantum information flow near black-hole horizons within an effective finite-capacity spacetime framework, in which local regions act as quantum memory registers coupled unitarily to infalling and outgoing field modes. Building on earlier information-preserving approaches to spacetime microstructure, we formulate the near-horizon dynamics as a reversible imprint-and-retrieval quantum channel and derive the corresponding entropy-flux relations. In the macroscopic limit, the resulting dynamics reproduce the Bekenstein–Hawking entropy balance, while finite local capacity introduces small, fully unitary corrections. Exact numerical simulations of the resulting channel dynamics, implemented without truncation for small systems, exhibit Page-curve-like behavior of the radiation entropy, echo-type modulations in correlation functions and single-mode spectra, and revivals of mutual information between early and late radiation. Parameter sweeps show that these features are robust and depend systematically on the horizon-register capacity, scrambling strength, and retrieval cadence. Together, the analytic construction and numerical results provide a concrete information-preserving model of near-horizon dynamics and motivate potential phenomenological signatures, such as delayed correlations and weak spectral structure, that could be explored in future observational or analog-gravity settings.