String Theory For Dummies, 2nd Edition

Chapter 19

Loop Quantum Gravity: String Theory’s Biggest Competitor

IN THIS CHAPTER

Seeing how loop quantum gravity is more focused than string theory

Knowing what predictions loop quantum gravity makes

Evaluating the similarities between loop quantum gravity and string theory

Though string theory is often promoted as the “only consistent theory of quantum gravity” (or something along those lines), some would disagree with this categorization. Foremost among them are the researchers in a field known as loop quantum gravity (sometimes abbreviated LQG). We discuss other approaches to quantum gravity in Chapter 20.

In this chapter, we introduce you to loop quantum gravity, an alternative theory of quantum gravity. As string theory’s major competitor, loop quantum gravity hopes to answer many of the same questions by using a different approach. We start by describing the basic principles of loop quantum gravity and then present some of the major benefits of this approach over string theory. We lay out some of the preliminary predictions of loop quantum gravity, including possible ways to test it. Finally, we consider whether loop quantum gravity suffers from the same issues we discuss ...