On the square root of the Laplace-Beltrami operator as a Hamiltonian. (English) Zbl 0812.32009
Summary: The Einstein equations for a spacetime of the form \(T^ 2 \times \mathbb{R}\) can be reduced to a Hamiltonian system on the Teichmüller space. However, the resulting Hamiltonian is the square root of the quadratic form in the momenta. Trying to make sense of this as a quantum operator is problematic since the Hamiltonian operator would be non-polynomial and nonlocal. In the first half of this article, I examine the eigenfunctions of this operator. These go under the name of Maass functions and have been studied extensively by number theorists. In the second half, I show that the quantum evolution due to this Hamiltonian does not cause the spacetime to collapse in a finite lapse of mean curvature time. Because of the difficult number theory involved with the Maass functions, I actually perform the calculation for a simplified problem – a model of Teichmüller space – and argue that the answer should not be sensitive to the simplifications made in my model.
MSC:
32G81 | Applications of deformations of analytic structures to the sciences |
32G15 | Moduli of Riemann surfaces, Teichmüller theory (complex-analytic aspects in several variables) |
83C05 | Einstein’s equations (general structure, canonical formalism, Cauchy problems) |