Research project Holographic spacetime from simple quantum systems
Gravitation governs cosmological expansion and mass motion on Earth and in the Universe. Quantum mechanics guides other forces and properties of matter. In "holographic" theories, gravitation and matter are parallel manifestations of quantum theory.
The project aims to increase the understanding of mysterious objects like black holes, from the perspective of holography. In principle, such a description should be complete, and able to solve any mysteries, but it is in practice extremely challenging technically. The idea of the project is instead to investigate simple models, which are rich enough to capture the qualitative features of black holes, but may deviate in details from observed black holes. The concrete results serve to inspire general conjectures and lessons.
In particular, black holes are known to obey rules similar to the laws of thermodynamics. In holography, the standard description of black holes starts from this thermodynamic perspective, while all other properties have to demonstrated by calculations. Many of the results in the projects confirm that this works, even in surprisingly simple models.
Project description
The primary simple model of the project is the so called O(N) model. It is studied on the sphere, because all physical spacetime processes can, by the "holographic principle", be encoded in a theory in the "boundary", which in this case is the sphere at infinity. Choosing this theory on the boundary to be the O(N) model – essentially the simplest possible free field theory replicated N times – one obtains an exotic gravity theory called Higher Spin Gravity in spacetime.
Early on, the project demonstrated that there are objects behaving much like thermal black holes in Higher Spin Gravity, by thermal field theory calculations in the O(N) model.
Current research in the project explores whether there are black holes that are even more similar to ordinary Schwarzschild black holes, so-called small black holes, in this theory, and whether the results can be sharpened to individual black hole states rather than thermal averages.
Project members
Project managers
Bo Sundborg
Professor
