Observational constraints on the modified cosmology inspired by string T-duality

We explore the cosmological consequences of a modified cosmology inspired by string T-duality. We incorporate the zero-point length correction, l 0 , into the gravitational potential and derive the modified Friedmann equations via thermodynamic approach at the apparent horizon of a Friedmann-Robertson-Walker (FRW) universe. The resulting framework introduces a dimensionless coupling parameter β ∼ l 0 2 H 0 2 quantifying deviations from the standard ΛCDM model. Using Bayesian inference with Cobaya and MCMC sampling, we constrain the model parameter against late-time observations, including PantheonPlus and Union3 Type Ia supernovae, cosmic chronometers, DESI DR2 BAO measurements, and Amati-calibrated GRBs. The joint analysis yields an upper bound β ≲ O ( 10 − 3 ) (68% C.L.), implying that any deviation from the standard ΛCDM scenario ( β = 0 ) is extremely small within the current observational precision. Model comparison through the Akaike Information Criterion shows that the ΛCDM and T-duality models provide statistically equivalent fits to the data, exhibiting only a marginal preference for ΛCDM. These results provide the first quantitative observational constraints on the cosmological imprint of string T-duality–inspired modifications and underscore the potential of future high-precision surveys to test possible residual effects of such corrections in the late-time Universe.