Screened Copy-Time Transport at Cosmic Dawn: A Microscopic Onsager Mechanism for Early Galaxy Compaction and Black-Hole Seed Growth

The earliest compact galaxies and black-hole candidates expose a supply problem at cosmic dawn: gas must reach the inner tens of parsecs on approximately a local dynamical time without altering the linear CMB/BAO sector, baryon conservation, or the standard radiation-hydrodynamic variables. We formulate screened copy-time transport as a projected Onsager current driven by a regularized Fisher likelihood ratio associated with radiative and chemical records. The logarithmic field is the additive coordinate of a Radon–Nikodym ratio between the retained record measure and the ordinary radiation-hydrodynamic measure, regularized by a finite receiver floor.

Onsager reciprocity fixes the baryonic cross coefficient L_{B\psi}^{(\ell)}=q_Q n_b D_B^{(\ell)}. The mobility D_B^{(\ell)} is evaluated from a filtered velocity power spectrum, and the structural Fisher coefficient is obtained from projected Poisson record channels with sub-grid clumping corrections. These ingredients define a closed push-forward from P(k,z), halo spin, and low-angular-momentum gas fraction to P(\mathcal K|z), the distribution of the compaction-feeding kernel. The upper tail predicts order-unity increases in central gas supply and obscuring column density, with a moderate reduction of effective radius and no modification of the Eddington law.

The characteristic prediction is finite-band rather than monotonic: compactness and black-hole feeding peak only when halo spin and the low-J reservoir overlap the receiver band. Reduced one- and two-dimensional conservative benchmarks test the operator, including a self-gravitating two-dimensional case that recomputes the potential at every step. A catalogue-level comparison with published JWST and X-ray systems shows that the predicted displacement is aligned with observed compactness, obscuration, and early black-hole feeding. The framework provides a quantitative and rejectable account of the supply-limited component of early galaxy compaction and black-hole seed growth.