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Physical Society ColloquiumProgress in quantum gravity: theory and experimentLee SmolinPerimeter InstituteI describe recent progress in an approach to quantum gravity called loop quantum gravity. This includes the construction of a Hilbert space of quantum states, solutions to the quantum evolution equations, and the construction of a path integral formulation called spin foam models. The theory has been proved to be ultraviolet finite and infrared finite in the presence of a cosmological constant (which can be incorporated without difficulty), and can also incorporate all the standard matter fields and, if desired, supersymmetry. The theory passes a number of tests such as predicting the entropy of black holes. Most of the key results have been confirmed as theorems in a rigorous approach to diffeomorphism invariant quantum field theory.A number of predictions of the theory have been published, concerning Planck scale modifcations of energy-momentum relations as well as modifications in the cosmic microwave background spectrum. Some of these have already been compared to data, other key experimental tests will be coming in the next several years.
Friday, November 28th 2003, 15:30
Ernest Rutherford Physics Building, Keys Auditorium (room 112) |