## Creatable Universes

##### Authors
Ferrando, Joan Josep
Lapiedra, Ramon
Morales, Juan Antonio
##### Description
We consider the question of properly defining energy and momenta for non asymptotic Minkowskian spaces in general relativity. Only spaces of this type, whose energy, linear 3-momentum, and intrinsic angular momentum vanish, would be candidates for creatable universes, that is, for universes which could have arisen from a vacuum quantum fluctuation. Given a universe, we completely characterize the family of coordinate systems for which one could sensibly say that this universe is a creatable universe.
Comment: 19 pages; v2: we have added an Appendix to make explicit the proof of the quasi-uniqueness of the defined energy and momenta of the Universe, for every space-like 3-surface
##### Keywords
General Relativity and Quantum Cosmology, Astrophysics