University of California, Santa Barbara

Project Title

Information-theoretic foundations for quantum spacetime and gravity

Project Summary

All known physical phenomena are presently described via the framework of 'quantum field theory'. This framework is based on essential principles: quantum mechanics, special or general relativity, and locality. The latter, locality, states that information cannot propagate faster than the speed of light. This simple statement, combined with the existence of black holes, and the demonstration that they evaporate, has lead to a profound conflict. Specifically, Hawking predicted that since information cannot escape black holes, their evaporation destroys information - violating a basic tenet of quantum mechanics. There are strong indications that such violation of quantum mechanics is not sensible; basic principles of relativity likewise seem robust. However, locality is difficult to precisely formulate, when one accounts for the fact that, at the least, spacetime undergoes quantum fluctuations. The problem may go further than that, and indicate that space and time are not fundamental concepts but instead arise from a more fundamental mathematical structure. If quantum mechanics is taken as essential, this structure should involve a basic description of quantum information, the most basic 'stuff' of quantum mechanics, and how it transfers and interacts. These ideas can be tested in their ability to describe important gravitational systems: black holes and cosmology.

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