Parity Birefringence of Gravitational Waves from a Torsion Bounce: Left-Right Amplitude Splitting Computed from Axial Torsion

This study computes a specific gravitational-wave consequence of a torsion-regulated bounce in Einstein-Cartan gravity, taking the limiting density for neutron matter, 9.72e+54 grams per cubic centimetre under the stated prescription, as its single input scale. Torsion has a handedness, and a handed background can treat left- and right-circular gravitational waves differently; this study computes that splitting both in the base theory and in a clearly labelled extension, because the two answers differ categorically. The headline results of the computation are: EC_vacuum_splitting = 0.00e+00, fiducial_extension_splitting = 1.00e-03, fiducial_ratio_R_L = 1.0020. Each quantity is evaluated by the deposited script from the assumptions stated in the Methods, and the agreement or disagreement of each quantity with published observational bounds is reported at face value, including where the conclusion is that the channel examined is closed. The study is simulated and computed from stated assumptions; it is not a measurement, and no observational data were taken for it.