Exceptional-Point Stability Boundaries from Quantum Dissipation to Cosmological Acceleration

This Zenodo record provides the archived publication version of Exceptional-Point Stability Boundaries from Quantum Dissipation to Cosmological Acceleration, in Scientific Reports. It includes the revised and accepted main manuscript and supplementary information for persistent citation and open access preservation. Dissipative dynamics across physical systems exhibit organizing structural boundaries. The dimensionless damping ratio ( \chi \equiv \gamma/(2\omega) ) defines a stability architecture in which the critical threshold ( \chi = 1 ) marks a second-order non-Hermitian Exceptional Point (EP2). Within spatially flat ( \Lambda )CDM, an exact algebraic identity is demonstrated linking the onset of cosmic acceleration to critical damping of structure growth: ( \chi_\delta = 1 \Leftrightarrow q = 0 ). This identity is a structural reformulation of the standard Friedmann and growth equations, not a new physical law; its scientific value lies in recasting a known kinematic transition as a stability-phase transition and in generating the falsifiable prediction that departures from flat ( \Lambda )CDM produce a measurable, nonzero offset between the ( q = 0 ) and ( \chi_\delta = 1 ) transitions, identically zero under flat ( \Lambda )CDM and generically nonzero in extensions. A substrate inheritance relation is then proposed as a leading-order projection approximation, whereby emergent modes acquire effective parameters from substrate precursors. Within this framework, the observed particle distribution is consistent with stability organization: long-lived matter occupies localized stability basins at ( \chi \ll 1 ), while short-lived resonances occupy a secondary ( \chi \sim 0.1 )–(1) band whose sub-cluster evidence is suggestive rather than conclusive. The framework is presented as a structurally grounded classification with defined scope and testable consequences.