The Growth Index as a Survey Test of a Torsion-Regulated Bounce

This paper computes the growth index that links the growth rate to the matter density fraction for a cosmology whose early expansion passed through a torsion-regulated bounce, and compares the result with combined growth measurements spanning redshift 0.1 to 1.5 from several spectroscopic surveys. The background is the Planck 2018 fiducial cosmology; the bounce enters through a fractional sound-horizon shift of 0.0 and a growth index of 0.6 in place of the standard 0.55, with no parameter adjusted to the survey data. The full set of computed values, bin by bin, is deposited with the paper in machine-readable form. The comparison shows where current survey precision stands relative to the size of the offset a bounce predicts: in several bins the offset is smaller than the present uncertainty, so the framework is neither confirmed nor excluded by this statistic today, while the forecast precision of completed surveys reaches the level at which the two histories separate. This study is computed from stated assumptions and published summary statistics; it is not a measurement.