This record contains the preprint, supplemental material, source files, figures, and numerical data archive for the manuscript “Finite-time branch-record accumulation in one-dimensional baths: independent baselines, amplification, and nonredundant records”. Quantum Darwinism diagnoses objectivity through a redundancy plateau: many small, disjoint environment fragments independently reveal the same branch information. This manuscript studies finite-time branch-record accumulation in one-dimensional baths and separates the magnitude of the environmental record from the normalized shape with which that record is accessed locally. For weak uniform deposition, matched field-only controls with JX = 0 remain close to the analytic independent-site accumulation law, while the interacting bath increases the total environmental branch distinguishability. In a five-point matched scan at t = 3. 6 and gX = 0. 8, 0. 9, 1. 0, 1. 1, 1. 2, the interacting denominator is larger than the corresponding field-only denominator by factors 2. 56–3. 00. At the critical point, DE = 0. 266513 instead of 0. 090818, corresponding to a 2. 93-fold increase in trace-distance amplitude and an 8. 90-fold increase in the effective per-site signal. After matching the independent null to the interacting value of DE, the normalized fragment profile remains close to independent accumulation: bulk windows lie slightly above the homogeneous null while edge-attached windows lie below it. A solvable free-fermion benchmark with a local branch perturbation shows a complementary geometry: the record is locally detectable near the perturbation but is not broadcast to distant small fragments. The result is not a universal failure of Darwinism and not strong data hiding. It is a finite-time classification of independent accumulation, interaction-driven magnitude amplification, small geometry-dependent shape deviations, and local nonredundant records.
Samuele Garbati (Fri,) studied this question.