Black holes were predicted by Einstein's theory of general relativity as solutions in which spacetime curved so much that even light became trapped. Per general relativity, it is possible that the fabric of spacetime bends an infinite amount. Such points with infinite curvature exist inside black holes and are called singularities. The curvature of spacetime is equivalent to the force of gravity rendering the singularity of a black hole with infinite gravity. For this reason, black holes provided an excellent theoretical ground for physicists to test the utility of string theory to explain the physics inside black holes. Within the EU-funded project QM-SING (Quantum resolution of gravitational singularities), physicists derived new solutions for supergravity equations – the limit at which string theory becomes a theory of gravity. Using advanced mathematical techniques of group theory, they constructed new supersymmetric and non-supersymmetric solutions. Importantly, the QM-SING team made a lot of progress in improving the current understanding of the physics of such smooth supergravity solutions as well as the corresponding black holes microstates. They also shed new light on how collapsing matter can form singularity-free microstates through a physical process known as quantum mechanical tunnelling. Armed with a better understanding of physical mechanisms behind black holes' microstates, physicists explored their implications on how the accelerated expansion of our universe could be described in string theory. Some of the research carried out is explained in a three-minute video from FameLab Netherlands, uploaded on Youtube.
Black holes, string theory, general relativity, QM-SING, supergravity