Disappearance and emergence of space and time in quantum gravity

Understand

We discuss the hints for the disappearance of continuum space and time at microscopic scale.

• These include arguments for a discrete nature of them or for a fundamental non-locality, in a quantum theory of gravity.
• We discuss how these ideas are realized in specific quantum gravity approaches.
• Turning then the problem around, we consider the emergence of continuum space and time from the collective behaviour of discrete, pre-geometric atoms of quantum space, and for understanding spacetime as a kind of "condensate", and we present the case for this emergence process being the result of a phase transition, dubbed "geometrogenesis".