Week 11: The Final Paper

This week I was finishing up the final paper. The headline result was the most significant change from last week’s value of 17% bound on validated events. Repeating the combination using only the 3 events that pass an automated quality rule gives a tighter bound on the fractional frequency and damping-time shift. I kept the historical-core combination as a continuity check against the earlier analysis, but the combination of the 3 events selected by the automated rule is now the one that appears as the main result.

I updated the theory section so it is now based on the comparison table from last week. In particular, higher-curvature modified gravity predicts shifts close to the 11.7% bound, so this is the only case that is starting to be constrained. Other theoretical frameworks like the soft hair, string fuzzballs, and loop-quantum-gravity polymer horizons all predict shifts well below the bound, so my analysis does not constrain them. These models all try to solve the black-hole information paradox by storing the information in tiny features right at the horizon. Unfortunately, my results cannot fully test them. As Cardoso, Franzin, and Pani showed in their 2016 paper, the early ringdown signal is set by the photon sphere, which sits outside the horizon, not by the horizon itself. Therefore, even if horizon-microstructure exists, it would not show up in the part of the signal current measurement looks at.

I also added a few sentences to the method section explaining the rules (uncertainty size, start-time stability, consistency of Kerr scale) used by the classifier so that the validation step is reproducible. In addition, I revised section 5 around the comparison table and added a subsection on what the bound can’t constrain. Then I regenerated Figure 2 to incorporate the new 0.117 bound in order to match the result.