The study of how black holes evaporate is perhaps the most important outstanding problem in theoretical physics today. It requires that we understand the behavior of two of the pillars of modern physics, gravity and quantum field theory, in their most extreme regimes. Understanding how physical theories fit together in challenging regimes has in the past led to insights of spectacular consequences. An example of this could be Maxwell's understanding of how electricity and magnetism fit together led to the discovery of radio waves, with the ensuing transformational changes they induced in our society. A second very important objective of this type of work is the formation of human resources of very high quality. Physicists trained in these disciplines have proved valuable in industry and in finance.
This award supports studies of loop quantum gravity in spherically symmetric contexts with the ultimate goal of understanding black hole evaporation. This includes work on the back-reaction of quantum fields living on spherically symmetric quantum space-times. The discreteness of the quantum space-time naturally regularizes the infinities of quantum field theory. To study the back reaction will require quantum space-times more realistic than the ones considered so far, including dynamical evolution. The work will attempt to find the quantum space-time of a collapsing shell and compute the Hawking radiation produced and eventually the back reaction of fields living on it. In addition to this, the PI's group will study the structure of the quantum space-times, in particular their singularity structure in the case of extremal and super extremal charged black holes and the Cauchy horizons that appear in the solutions. Finally, the semiclassical collapse of a scalar field will be studied to understand how quantum effects change the universality and scaling first discovered by Choptuik.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
