Intro Blog: Where Theories Collide

I am drawn to black holes since they sit precisely where our current cosmological theories clash. General relativity paints a clean external picture: once a black hole settles, its spacetime is fully captured by just mass and spin. Meanwhile, quantum mechanics insists that information can never truly be destroyed. At the same time, black hole thermodynamics assigns an enormous entropy to these objects, hinting at countless hidden microstates lurking beneath the surface. Yet when taken together, these three frameworks still don’t mesh into a single coherent story about what actually happens at and beyond the horizon. That fundamental tension is what ultimately drew me to this project.

Gravitational waves, fortunately, offer a way to probe this problem with real observations. When two black holes merge, the resulting remnant doesn’t instantly settle. Instead, it oscillates and gradually decays in what we call the ringdown phase. According to classical general relativity, this pattern follows a precise structure encoded in quasinormal modes, which are essentially the black hole’s characteristic vibrations. Once we know the remnant’s mass and spin, those mode frequencies and damping times are completely determined. However, if quantum corrections or other novel structures exist near the horizon, they might reveal themselves as subtle shifts in these frequencies or in how quickly the oscillations decay. Rather than asking the grand question “which theory is correct,” I’m pursuing something more focused: how much deviation from Einstein’s predictions does the data allow, and what does that tell us about which quantum gravity models remain viable?

I want to learn how to turn that inquiry into a rigorous analysis. This involves working with public LIGO and Virgo datasets, isolating the ringdown portion of each signal, fitting straightforward models to the data, and then interpreting upper bounds rather than chasing big breakthroughs.