Thermodynamic Coherence Limits of Hadronic Matter: Phenomenological Convergence between Lattice QCD, Relativistic Collisions, and Neutron Stars, and Theoretical Implications for the Infinite-Density Point

In this work, we propose a comparative synthesis of three independent families of physical results which, although arising from profoundly different methods, converge toward the same region of loss of coherence of hadronic matter. The first family is that of lattice QCD, which places the crossover of quantum chromodynamics around T_c = 156 ± 2 MeV and associates with the transition region an energy density of the order of 0.18 up to 0.5 GeV/fm^3.The second family is that of high-energy relativistic collisions, in which final observables allow the reconstruction of both extremely energetic local hotspots and much lower effective energy densities of the medium after expansion and dissipation.The third family is the astrophysical one, in which the masses, radii, and tidal deformabilities of massive neutron stars impose equations of state compatible with the presence of deconfined central regions.The central result is not the arbitrary introduction of a universal constant already directly demonstrated, but the identification of a phenomenological convergence toward an effective deconfinement window, of the order of a few tenths up to about 1 GeV/fm^3.This work rigorously distinguishes between direct observables, standard reconstructions, comparative phenomenological estimates, and theoretical extensions, and prepares the ground for a unified reading of the coherence limits of matter within the Multibubble framework.IntroductionOrdinary matter does not remain indefinitely identical to itself when brought into extreme regimes of temperature, energy density, or effective pressure. At a certain point, the description in terms of protons and neutrons as coherent hadronic states ceases to be sufficient. Taken alone, this statement may seem generic. However, if one carefully examines three distinct domains of contemporary physics, a more precise fact emerges: the signals of this change of regime, although obtained with different tools, tend to lie in the same physical region.