Cosmic Elastic Theory II: Tension Decay Duality: The Singular Mode, Reversibility, and Entropic Structure of Spacetime

We present an extension of the Cosmic Elastic Theory (CET) that posits gravitation and dark energy arise as opposite polarities of the same thermodynamic process: the entropic cost of maintaining isotension within the medium — a process that, on large scales, manifests as the decay of cosmic tension. This decay represents a global statistical tendency rather than a universal rule: locally, the medium may reversibly relax or re–tension as curvature and energy exchange dynamically. In this framework, cosmic dynamics are not driven by an intrinsic expansion of space, but by the relaxation of a single, causal elastic field, which dispenses with independent mediating entities and is defined by non-asymptotic internal processes, acts as the universal determination of the material plane, where internal tension governs the metric’s capacity to propagate, store and dissipate energy. Gravitational attraction corresponds to the confining regime, where the elastic coupling is fully saturated and stability is attained. Conversely, dark energy represents the residual relaxation of the same field in its expansive polarity, where the effective coupling is suppressed. Cosmic inflation is interpreted as a singular event—the moment of maximal free-energy dis- charge during the initial tension decay—which sets the primordial baryon-antibaryon asymmetry and defines the thermodynamic arrow of the Universe. This concept of polarity unifies all elastic dynamics: from gravitational stability in large-scale struc- tures, where confinement dominates, to microphysical regimes where partial relaxation governs the binding of matter and the origin of quantum stochasticity. This unified description links gravitation, dark energy, and inflation as sequential states of a single cosmic tension-relaxation continuum.