Not quite black holes at LIGO

          @misc{ pirsa_PIRSA:19090011,
            doi = {10.48660/19090011},
            url = {https://pirsa.org/19090011},
            author = {Holdom, Bob},
            keywords = {Cosmology, Particle Physics, Strong Gravity},
            language = {en},
            title = {Not quite black holes at LIGO},
            publisher = {Perimeter Institute},
            year = {2019},
            month = {sep},
            note = {PIRSA:19090011 see, \url{https://pirsa.org}}
          }
          

Abstract

The Einstein action has made us very accustomed to black holes and their “no drama” event horizons. But the Einstein action will eventually be subsumed into a UV complete theory of gravity, and in such a theory there can be a new class of solutions that are not quite black holes. Within a Planck length of the would-be horizon, strong gravity and high curvatures quickly turn on. These solutions are analogous to the hadrons and/or the quark matter states of QCD. They are very close to being completely black, but not quite. An ideal probe to test for not quite black holes are the low frequency gravitational waves that are excited in and around them when they are newly formed, as in the merger events observed by LIGO. There are some key features of waves that escape the interior of not quite black holes, and from this we describe our own search and search results using LIGO data.