The Mutable Dark Sector And The Dynamic Balance Zone: Conditional Black Hole Recycling and the Cosmic Coincidence Problem

This preprint proposes a coupled fully mutable dark sector model in which a single scalar field shifts in response to local environmental conditions, expressing dark matter like behaviour (condensed form, supporting gravitational structure) or dark energy like behaviour (evaporated form, contributing to expansion pressure) depending on local circumstances. Because the total field content is conserved, the overall ratio between condensed and evaporated forms is naturally limited rather than arbitrary, addressing the cosmic coincidence problem without requiring fine tuning. A toy implementation across one thousand sampled parameter sets produces ratios within an order of magnitude of unity in over 99 percent of runs, compared to 32 percent in a null model treating the components as independent. Building on existing cosmological coupling work (Farrah et al. 2023, Croker et al. 2024), the model adds the proposal of full bidirectional reversibility. Where standard coupling treats the relationship between black hole mass and cosmic expansion as a one directional geometric effect, the present approach proposes that the field can transition in both directions according to local conditions. Supermassive black holes are proposed to participate as conditional recyclers, with activity modulated by local environmental conditions including baryonic gas supply, mass scale, accretion rate, and proximity to other dominant black holes. Quiescent black holes in matter poor environments, satellite black holes near a more active central, and black holes within cosmic voids are interpreted as expected outcomes of this conditional structure rather than as counterexamples. A Dynamic Balance Zone concept is introduced where the two field forms meet and interact, with mutual repulsion at the boundary contributing to local dynamics. A figure 8 topological architecture, in which the two forms exchange material through a crossing point, demonstrates stable lobe specialisation, exact mass conservation, and recovery from moderate perturbation in toy testing. Possible interpretations are offered for differences between cosmic voids and denser regions, between elliptical and spiral galaxies, and between active and quiescent black holes, with environmental conditions in each case determining the local balance between forms. A qualitative mechanism is offered by which patchy rebalancing, localised regional variations in field state across the universe, could contribute to differences between expansion rate measurements in different cosmic regions, though a quantitative account of the observed early universe versus late universe Hubble tension requires field theoretic development beyond the present scope. Long lived stellar populations such as red dwarfs in voids are interpreted as illustrating the long term preservation possible in condensed rich environments, with their stellar winds providing slow sustained baryonic input to central black holes consistent with observed underluminous accretion rates such as those of Sagittarius A*. Possible physical triggers for state transitions are explored, including plasma conditions, magnetic field strength, thermal environment, baryonic recycling, and gravitational gradient. Gravitational decoherence and ultralight scalar fields such as axion like particles are considered as candidate mechanisms and realisations. The work is presented at the toy model level. A complete field theoretic formulation, derivation of phenomenological coupling rates from a microphysical foundation, predictions for galaxy rotation curves and structure formation, and a full account of the temporal aspect of the Hubble tension are identified as open challenges requiring further work. Testable implications include environmental gradients in dark sector behaviour between voids, filaments, and cluster regions accessible to surveys such as DESI, systematic differences between elliptical and spiral galaxies in jet activity and black hole feeding rates, and signatures distinguishing dynamic balance zone contributions to AGN outflows from standard mechanisms in high resolution observations from facilities such as the Event Horizon Telescope and ALMA. Collaboration with theorists in cosmology and galaxy evolution is warmly invited to test, refine, formalise, or challenge these ideas.