2014

Discovering the QCD Axion with Black Holes and Gravitational Waves

Arvanitaki, Asimina, Baryakhtar, Masha, Huang, Xinlu

Understand

Advanced LIGO may be the first experiment to detect gravitational waves.

  • Through superradiance of stellar black holes, it may also be the first experiment to discover the QCD axion with decay constant above the GUT scale.
  • When an axion's Compton wavelength is comparable to the size of a black hole, the axion binds to the black hole, forming a "gravitational atom." Through the superradiance process, the number of axions occupying the bound levels grows exponentially, extracting energy and angular momentum from the black hole.
  • Axions transitioning between levels of the gravitational atom and axions annihilating to gravitons can produce observable gravitational wave signals.

Reading the bibliography…