Quantum gravity

The most obvious ways of combining quantum mechanics and general relativity, without the use of gauge theories, such as treating gravity as simply another field of particles, quickly lead to what is known as the problem of renormalization (set of techniques used to obtain finite terms in perturbativo development).

The fundamental lesson of general relativity is that there is no fixed substrate of space-time, as it admitted in Newtonian mechanics and special relativity. Although easy to understand in principle, this is the most complicated idea on general relativity, and its consequences are profound and not fully explored yet at the classical level.

Quantum spacetime

Quantum physicists have depended on since her invention of a structure (no-dinamica) fixed as substrate. In the case of quantum mechanics, the time is that is given and is not dynamic, exactly as in Newtonian classical mechanics. While in relativistic quantum fields, as well as theory in classical field theory, the space is Minkowski time substrate fixed theory. Finally, the string theory, begun as a generalization of quantum field theory where, instead of point particles, are propagated in a fixed spacetime background objects like strings.

Problems of quantum gravity

A quantum theory of gravitation should be able to help us solve several unresolved physical problems such as:

• The problem of singularities, which explain which is the ultimate goal of a particle that falls into a black hole following a GEODESIC which ends in a spatiotemporal "singularity" and what is the physical nature of the singularities.
• The problem of the origin of the universe, which explains the process known as quantum inflation that apparently could also explain the cosmological horizon problem.