Abstract
We expand on the idea that the spacetime signature should be treated as a dynamical degree of freedom in quantum field theory. It has been argued that the probability distribution for the signature, induced by massless free fields, is peaked at the Lorentzian value uniquely in dimensions. This argument is reviewed, and certain consistency constraints on the generalized signature (i.e., the tangent-space metric are derived. It is shown that only one dynamical "Wick angle" can be introduced in the generalized signature, and the magnitude of fluctuations away from the Lorentzian signature is estimated to be of order , where is the Planck length, and is the length scale of the Universe. For massless fields, the case of dimensions and the case of supersymmetry are degenerate, in the sense that no signature is preferred. Mass effects lift this degeneracy, and we show that a dynamical origin of the Lorentzian signature is also possible for (broken) supersymmetry theories in dimensions, in addition to the more general nonsupersymmetric case in dimensions.
- Received 25 August 1993
DOI:https://doi.org/10.1103/PhysRevD.49.866
©1994 American Physical Society