Akademik Veri Yönetim Sistemi
Physics of the Dark Universe, cilt.52, 2026 (SCI-Expanded, Scopus)
We investigate a geometry-driven mechanism for causal bulk dissipation in teleparallel dark-energy cosmology and its implications for late-time growth and lensing phenomenology. Working within f (T, TG) gravity, we construct a causal bulk-viscous sector in which the effective pressure evolves through a hyperbolic relaxation law derived from a local Rayleigh–Onsager dissipation functional. The proposed geometry-driven causal closure extends the truncated Israel–Stewart framework by coupling the dissipative response to a dimensionless kernel built from the local teleparallel invariants, while recovering the standard causal hydrodynamic limit when the geometric coupling is switched off. In this construction, the viscous pressure is dynamically linked to the underlying torsional geometry rather than introduced through an instantaneous phenomenological prescription. For homogeneous cosmological backgrounds, we derive the modified evolution equations and identify regular trajectories compatible with the general-relativistic limit, non-negative entropy production, subluminal viscous propagation, and tensor-sector admissibility. At the level of linear scalar perturbations, the model separates the geometric modification of the Poisson and slip sectors from the relaxation-controlled viscous damping of matter growth. This leads to correlated diagnostic signatures in the effective Newton coupling, gravitational slip, fσ 8(z), and the lensing-growth statistic EG . The framework therefore provides a causal and geometrically motivated setting for studying late-time dark-energy phenomenology in teleparallel gravity, with testable channels in growth and weak-lensing probes.