Paper I of the RCD Hilltop Dark Energy Series. We investigate the cosmological dynamics of a scalar field model motivated by Radial Coherential Dynamics (RCD), in which a coherence parameter C ∈ (0, 1) evolves with a non-canonical kinetic coupling K (C) = (1−C) ² and a symmetric potential V (C) = vC (1−C). Working in the ghost-free convention with positive-definite kinetic energy, we establish that the model belongs to the class of k-essence theories linear in X, with sound speed c²ₛ = 1 identically. We demonstrate that C = 1/2 is an unstable equilibrium of the potential. For initial conditions C₀ ∈ 0. 42, 0. 51 near the hilltop, the model produces viable dark energy with w₀ ∈ −1. 00, −0. 81 and ΩDE ≈ 0. 685, placing it in the thawing quintessence class.
Arturo Cerezo (Mon,) studied this question.