We examine the observational viability and physical implications of the Gong-Zhang (GZ) dark--energy equation-of-state parametrizations using exclusively late-time cosmological probes. Two one-dimensional parametrization models, GZ-Type~I and GZ-Type~II, are constrained with Type~Ia supernovae (Union3, Pantheon+SH0ES, and DES-SN5YR), DESI baryon acoustic oscillations, and cosmic chronometer measurements of H(z). Bayesian inference combined with information-criteria diagnostics shows that both parametrizations provide competitive alternatives to ΛCDM, while the GZ-Type~II model is consistently favored, exhibiting reduced parameter degeneracy and stronger Jeffreys-scale support. Beyond background expansion tests, we employ configuration entropy as a thermodynamically motivated probe of structure formation. We demonstrate that the entropy-production rate sensitively traces the impact of dynamical dark energy on late-time gravitational clustering while preserving standard early-time behavior. Our results establish the Gong-Zhang framework as a physically transparent and observationally consistent extension of ΛCDM, with configuration entropy providing a complementary diagnostic of late-time cosmic acceleration.
@article{arxiv.2603.05009,
title = {Observational and Thermodynamic aspects of one-dimensional Dark Energy EoS parametrization models},
author = {Anirban Chatterjee and Yungui Gong},
journal= {arXiv preprint arXiv:2603.05009},
year = {2026}
}