It is one of the main open problems of physics to find a quantum theory
My contribution focused on quantum gravity defined
on simplicial lattices using the
Regge calculus . Some of my papers are listed below,
a complete list is available at hep-spires.
The main finding is the existence of a phase with well
defined expectation values .
However, an interesting continuum limit would require a 2nd order phase
but so far such a transition has not been found .
Recently, Seth Lloyd has proposed to
view our universe as a
quantum computer and this
approach leads to a variant of Regge
quantum gravity defined on simplicial lattices.
proposals have been suggested to solve the mysteries of quantum
the most promising being M-theory,
which is a
unified theory of superstrings.
One can only hope that new empirical
evidence will help us find the correct solution.
 The review talk of Des Johnston and
the living review of Renate
Loll provide for
overviews and an introduction to lattice quantum gravity.
 I should mention the work of Martin
Pilati [1,2,3]; He
found an exact solution for the
strong-coupling limit G -> infinity. The solution uses the fact that
in quantum gravity the
strong-coupling limit is equivalent to the limit c = 0, so that all
cones collapse and
different points in space decouple. Different lattice gravity models
exhibit a "well-defined"
phase for strong-coupling.
 Jacques Distler discussed the continuum limit of lattice gravity
models (in the context
of CDT) here
and the related issue of the UV fixed point here.
 The paper hep-lat/9407020
examines the Regge approach on non-regular triangulated
lattices and the results clearly indicate problems to find a continuum
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