On the quantum description of the early universe

Abstract

Why is it interesting to try to understand the origin of the universe? Everything we observe today, including our existence, arose from that event. Although we still do not have a theory that allows us to describe the origin itself, the study of the very early era of the universe involves the ideal terrain to analyze the interface between two of today's most successful physical theories, General Relativity and Quantum physics. But it is also an area in which we have a large number of observational data to test our theoretical ideas. Two of the fathers of Quantum physics, Niels Bohr and Werner Heisenberg, shared some thoughts that could be described with these words: "Quantum physics tells us that there is a line between the observed and the observer, and therefore science should be limited to what is observed. We must give up a complete, objective and realistic theory of the world". This article will orbit around these ideas and summarizes how it is that today, from recent works, we are in a position to try to challenge them (at least in part) through cosmology, seeking the quantum description of the early universe.