The goal of this review is to present an introduction to loop quantum gravity—a background-
independent, non-perturbative approach to the problem of unification of general relativity …

The problem of describing the quantum behavior of gravity, and thus understanding
quantum spacetime, is still open. Loop quantum gravity is a well-developed approach to this …

In this topical review, we review the present status of the spin foam formulation of non-
perturbative (background-independent) quantum gravity. The topical review is divided into …

Abstract Quantum General Relativity (QGR), sometimes called Loop Quantum Gravity, has
matured over the past fifteen years to a mathematically rigorous candidate quantum field …

Spin foam models are hoped to provide the dynamics of loop-quantum gravity. However, the
most popular of these, the Barrett-Crane model, does not have the good boundary state …

We study the semiclassical properties of the Riemannian spin foam models with Immirzi
parameter that are constructed via coherent states. We show that, in the semiclassical limit …

Group field theories can be approached from different angles, coming from different lines of
research in quantum gravity. Historically, their first appearance [2, 3] came as a development …

General relativity can be written as topological BF theory plus a set of second-class
constraints. Classically the constraints provide the geometric interpretation of the B variables …

Loop quantum gravity (LQG)[1–3] has become a serious competitor to string theory as a
candidate theory of quantum gravity. Its popularity is steadily growing because it has …

We study the action of diffeomorphisms on spin foam models. We prove that in 3
dimensions, there is a residual action of the diffeomorphisms that explains the naive …