Loop Quantum Gravity: A Demystified View

Abstract

An attempt is made to demystify loop quantum gravity (LQG) in a concise and lucid way. LQG is a background-independent as well as non-perturbative approach of the theory of quantum gravity. Since LQG is one of the supposed candidates of a theory of quantum gravity, firstly, prerequisite concepts that are needed for LQG are outlined. Since LQG belongs to the canonical quantization approach, the ADM formalism along with the metric formulation is introduced. Thereafter, other associated concepts regarding the connection formulation are given, such as tetrads, spin connection, and the Palatini action. Afterwards, a modification of the connection formulation, i.e., the Ashtekar formulation, a basis for the current framework of LQG, is presented. Thereafter, the kinematic and dynamical framework, i.e., spin network and spin foam, respectively, are explained; here, the geometrical observables such as area and volume are quantized. Applications of LQG, such as the black hole entropy problem and loop quantum cosmology, are also briefly introduced. This article targets on beginners and novice who wants to enter this research field.