Noether symmetric Yang–Mills cosmology with a Pontryagin coupling
Annals of Physics, cilt.495, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 495
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.aop.2026.170752
- Dergi Adı: Annals of Physics
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, INSPEC, MathSciNet, zbMATH, Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Earth, Atmospheric, & Aquatic Science Collection (ProQuest)
- Anahtar Kelimeler: Cosmic triad, de Sitter evolution, Exact cosmological solutions, Noether symmetry, Non-Abelian vector cosmology, Pontryagin coupling
- Akdeniz Üniversitesi Adresli: Evet
Özet
This work investigates a globally SU(2)-invariant vector–tensor cosmology with non-minimal Ricci and field-dependent kinetic couplings, a self-interaction potential, and a Pontryagin coupling. Dependence on the parity-even invariant ξ preserves global adjoint rotations, breaks local gauge symmetry, and turns the nonconstant Pontryagin coefficient into a parity-violating bulk interaction. A cosmic-triad ansatz reduces the theory on a flat FLRW background and yields the point-like Lagrangian, Hamiltonian constraint, effective-fluid variables, and criteria for quasi-de Sitter and constant-invariant configurations. Because the reduced Pontryagin term is linear in a minisuperspace velocity, the analysis applies the gauge Noether condition. In a power-law sector, this condition reconstructs the couplings and separates solutions into three branches. The generic sectors of Branches I and III are kinetically degenerate, whereas constrained Branch II admits a non-degenerate family and exact solutions in generic and logarithmic-coordinate sectors. Simultaneous positivity of the reconstructed gravitational and kinetic couplings excludes the real non-degenerate logarithmic-coordinate sector. It is shown that a regular generic trajectory evolves from radiation-like expansion to late-time acceleration and approaches a constant-invariant de Sitter state. The covariant constraint structure and perturbations are analysed on their respective regular domains. The scalar and tensor sectors have positive short-wavelength kinetic terms under the stated conditions, while the constant-invariant de Sitter state exhibits two longitudinal ghost modes.