We have recently introduced a discrete model of Lorentzian quantum gravity,
given as a regularized non-perturbative state sum over simplicial Lorentzian spacetimes,
each possessing a uniqueWick rotation to Euclidean signature. We investigate
here the phase structure of the Wick-rotated path integral in three dimensions with
the aid of computer simulations. After fine-tuning the cosmological constant to
its critical value, we find a whole range of the gravitational coupling constant k0
for which the functional integral is dominated by non-degenerate three-dimensional
space-times. We therefore have a situation in which a well-defined ground state
of extended geometry is generated dynamically from a non-perturbative state sum
of fluctuating geometries. Remarkably, its macroscopic scaling properties resemble
those of a semi-classical spherical universe. Measurements so far indicate that k0
defines an overall scale in this extended phase, without affecting the physics of the
continuum limit. These findings provide further evidence that discrete Lorentzian
gravity is a promising candidate for a non-trivial theory of quantum gravity
Is data on this page outdated, violates copyrights or anything else? Report the problem now and we will take corresponding actions after reviewing your request.