ABSTRACT
This chapter is viewed as an introduction to the work of Einstein on general relativity where he used curvature of the three spatial and one time dimensions of the world in which we live to describe the theory of gravity. It explores what exactly are Goldstone bosons. Whenever a simple Lie group is broken spontaneously (smoothly and in an arbitrary “direction”) then a theorem by J. Goldstone tells that massless Goldstone bosons (scalar or pseudoscalar) are produced carrying the quantum numbers of the generator of the Lie group along the broken “directions.” The chapter shows how these bosons interact with each other, why they are massless, and how they interact with other(standard field) states of the system.
