  We calculate the spectral dimension for a nonperturbative lattice approach to
quantum gravity, known as causal dynamical triangulations (CDT), showing that
the dimension of spacetime smoothly decreases from approximately 4 on large
distance scales to approximately 3/2 on small distance scales. This novel
result may provide a possible resolution to a long-standing argument against
the asymptotic safety scenario. A method for determining the relative lattice
spacing within the physical phase of the CDT parameter space is also outlined,
which might prove useful when studying renormalization group flow in models of
lattice quantum gravity.
