ETD

• coset construction
• gravity
• spontaneous symmetry breaking

Symmetries and their spontaneous breaking play a foundational role in modern theoretical physics, natively leading to the formulation of Effective Field Theories (EFTs) via the Callan-Coleman-Wess-Zumino (CCWZ) coset construction. Concurrently, the modern perspective on gravity suggests that General Relativity (GR) should not be treated as a fundamental interaction, but rather as a low-energy EFT of an unknown ultraviolet completion. This thesis aims to reconcile these two paradigms by showing how gravitational theories can emerge dynamically from the spontaneous breaking of spacetime symmetries. Postulating the global affine group as the fundamental symmetry of the underlying UV theory, we apply the CCWZ construction to derive GR and its metric-affine modifications as EFTs associated with different symmetry breaking patterns. After a rigorous mathematical review of Spontaneous Symmetry Breaking and the geometric approach to gravity, the manuscript explores the exact geometric structures induced by the coset construction. Finally, these techniques are applied to the affine group, exploring different breaking patterns to its subgroups via a symmetry-breaking cascade down to the Lorentz group, which results in different emergent properties of spacetime. Through this mechanism, we derive General Relativity as well as teleparallel, Cartan gauge, and unimodular theories of gravity, providing new theoretical perspectives and filling a gap in the recent literature through a neat, unified geometrical interpretation.