Modified Teleparallel $f(T)$ Gravity, DESI BAO and the $H_0$ Tension

TL;DR

This study explores if late-time modifications in $f(T)$ teleparallel gravity can influence the Hubble constant tension, analyzing three models against multiple cosmological data sets to assess their impact on $H_0$ and structure growth.

Contribution

It introduces three specific $f(T)$ models that deviate from General Relativity only at late times and evaluates their effects on the $H_0$ tension using diverse observational data.

Findings

Two models partially raise the $H_0$ value towards local measurements.

One model worsens the $H_0$ discrepancy.

Minimal $f(T)$ extensions are not favored over $\\Lambda$CDM by current data.

Abstract

We investigate whether late-time modifications of gravity in the teleparallel framework can impact the current tension in the Hubble constant $H_0$, focusing on $f(T)$ cosmology as a minimal and well-controlled extension of General Relativity. We consider three representative $f(T)$ parametrisations that recover the teleparallel equivalent of General Relativity at early times and deviate from it only at late epochs. The models are confronted with unanchored Pantheon+ Type~Ia supernovae, DESI DR2 baryon acoustic oscillations, compressed Planck cosmic microwave background distance priors, and redshift-space distortion data, allowing us to jointly probe the background expansion and the growth of cosmic structures. Two of the three models partially shift the inferred value of $H_0$ towards local measurements, while the third worsens the discrepancy. This behaviour is directly linked to the effective torsional dynamics, with phantom-like regimes favouring higher $H_0$ and quintessence-like regimes producing the opposite effect. A global statistical comparison shows that the minimal $f(T)$ extensions considered here are not favoured over $\Lambda$CDM by the combined data. Nevertheless, our results demonstrate that late-time torsional modifications can non-trivially redistribute current cosmological tensions among the background and growth sectors.