The Pulsar Timing Array Background and the Bounce Prediction

This paper converts the nanohertz stochastic background amplitude measured by pulsar timing arrays into an energy-density fraction, computes the contribution a bounced cosmology would make to that background as a function of the shear fraction at the turnaround, and derives the shear fraction the measurement permits. The headline results are as follows. Energy density fraction of the observed background at one cycle per year: 7.98e-09; Characteristic strain the bounce would produce today for a turnaround shear fraction of one part in a thousand: 8.5e-17; Turnaround shear fraction that would reproduce the observed amplitude: 0.0282; Ratio of the observed background energy density to the closure density in radiation-equivalent terms: 8.86e-05; Frequency at which a binary-driven background with the stated amplitude reaches a strain of ten to the minus fourteen: 0.118 per yr; Bounce background strain at the ceiling shear fraction of unity: 8.5e-14. All values are computed from the stated assumptions and published inputs; the study is simulated and computed, not measured.