A Universe as Inheritance: Phenomenological Interacting Dark Sector with Einstein--Cartan Torsion

We present a speculative cosmological scenario in which our Universe emerges as an inheritance from the gravitational collapse of a previous parent universe. We propose an effective interacting dark energy (IDE) model, phenomenologically motivated by torsion in Einstein–Cartan (EC) gravity, which avoids singularities at extreme densities and allows for non-singular bounces. At low redshift, the model reduces to an IDE framework with a coupling Q = 3ξHρde and a CPL dynamical equation of state w(a) = w0 +wa(1−a). We show that for ξ ∼ 0.01, w0 ≲ −1, and wa ∼ 0.1–0.2, the model reproduces H(z) within 1% of ΛCDM up to z ≤ 2, and predicts deviations of order 1–2% in the growth rate fσ8(z), testable with Euclid/DESI. We conclude that this framework is viable as a phenomenological hypothesis and deserves further exploration with full cosmological datasets.