Isolated Objects in Quadratic Gravity: From Action Principles to Observations

One of the main unanswered question of modern Physics is "How does gravity behave at small scales?". The aim of this thesis is to illustrate in a comprehensive but accessible way how to look for deviations from Einstein's theory of General Relativity in this regime, looking at the simplest celestial bodies: static and spherically symmetric ones.

With a conservative and bottom-up approach, at smaller scales the first corrections to the action of General Relativity are generally considered to ...