Quantum graphity: a model of emergent locality in quantum gravity Speaker(s): Fotini Markopoulou
Abstract: Quantum graphity is a background independent condensed matter model for emergent locality, spatial geometry and matter in quantum gravity. The states of the system are given by bosonic degrees of freedom on a dynamical graph on N vertices. At high energy, the graph is the complete graph on N vertices and the physics is invariant under the full symmetric group acting on the vertices and highly nonlocal. The ground state dynamically breaks the permutation symmetry to translations and rotations. In this phase the system is ordered, lowdimensional and local. The model gives rise to an emergent U(1) gauge theory in the ground state by the stringnet condensation mechanism of Levin and Wen. In addition, in such a model, observable effects of emergent locality such as its imprint on the CMB can be studied. Finding the right dynamics for the desired ground state is ongoing work and I will review some of the basic results with an emphasis on the use of methods from quantum information theory such as topological order and the use of the LiebRobinson bounds to find the speed of light in the system.
Date: 11/03/2009  2:00 pm
Series: Colloquium
