Article

# General Covariance in Gravity at a Lifshitz Point

Classical and Quantum Gravity (Impact Factor: 3.56). 01/2011; 28(11). DOI:10.1088/0264-9381/28/11/114012
Source: arXiv

ABSTRACT This paper is based on the invited talks delivered by the author at GR 19:
the 19th International Conference on General Relativity and Gravitation, Ciudad
de M\'exico, M\'exico, July 2010. In Part 1, we briefly review some of the main
features of quantum gravity with anisotropic scaling, and comment on its
possible relation to the causal dynamical triangulations (CDT) approach to
lattice quantum gravity. Part 2 explains the construction of gravity with
anisotropic scaling with an extended gauge symmetry -- essentially a
nonrelativistic version of general covariance. This extra symmetry eliminates
the scalar graviton polarization, and thus brings the theory closer to general
relativity at long distances.

0 0
·
0 Bookmarks
·
38 Views
• Source
##### Article: The spectral dimension of the universe is scale dependent.
[hide abstract]
ABSTRACT: We measure the spectral dimension of universes emerging from nonperturbative quantum gravity, defined through state sums of causal triangulated geometries. While four dimensional on large scales, the quantum universe appears two dimensional at short distances. We conclude that quantum gravity may be "self-renormalizing" at the Planck scale, by virtue of a mechanism of dynamical dimensional reduction.
Physical Review Letters 11/2005; 95(17):171301. · 7.94 Impact Factor
• Source
##### Article: Spectral dimension of the universe in quantum gravity at a lifshitz point.
[hide abstract]
ABSTRACT: We extend the definition of "spectral dimension" d_{s} (usually defined for fractal and lattice geometries) to theories in spacetimes with anisotropic scaling. We show that in gravity with dynamical critical exponent z in D+1 dimensions, the spectral dimension of spacetime is d_{s}=1+D/z. In the case of gravity in 3+1 dimensions with z=3 in the UV which flows to z=1 in the IR, the spectral dimension changes from d_{s}=4 at large scales to d_{s}=2 at short distances. Remarkably, this is the behavior found numerically by Ambjørn et al. in their causal dynamical triangulations approach to quantum gravity.
Physical Review Letters 05/2009; 102(16):161301. · 7.94 Impact Factor