American Physical Society Spotlight of Exceptional Research Highlights Work of Physics Professor Ratindranath Akhoury and Graduate Student Ryo Saotome
The absence of a consistent quantum theory of gravity continues to be the missing link between quantum mechanics and general relativity. One way to develop an effective theory of quantum gravity is to perturbatively quantize gravity, but this approach is known to create divergences (infinities) in the amplitudes that describe the scattering of gravitons—the particles that mediate gravity. There is, however, a useful mathematical connection between the structure of scattering amplitudes in perturbative quantum gravity and gauge theories of the standard model of particles. Theorists can therefore use a tool kit of methods developed for gauge theories to further develop perturbative quantum gravity.
Professor Akhoury and his collaborators show that the long distance properties of perturbative quantum gravity are very simple. A class of infinities (collinear divergences) that plague gauge theories at long distances, cancel to all orders and the soft divergences have a very simple structure.
This allows for a systematic study of gravitational scattering amplitudes at high energy with possible applications to black hole formations.