# Quantum cosmology

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Quantum cosmology [1] [2] is the attempt in theoretical physics to develop a quantum theory of the Universe. This approach attempts to answer open questions of classical physical cosmology, particularly those related to the first phases of the universe.

## Contents

Classical cosmology is based on Albert Einstein's general theory of relativity (GTR or simply GR) which describes the evolution of the universe very well, as long as you do not approach the Big Bang. It is the gravitational singularity and the Planck time where relativity theory fails to provide what must be demanded of a final theory of space and time. Therefore, a theory is needed that integrates relativity theory and quantum theory. [3] Such an approach is attempted for instance with loop quantum cosmology, loop quantum gravity, string theory and causal set theory. [4]

In quantum cosmology, the universe is treated as a wave function instead of classical spacetime. [5]

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## References

• Bojowald, Martin (2011). Quantum Cosmology. A Fundamental Description of the Universe. Lecture Notes in Physics. 835. Springer. ISBN   978-1-4419-8276-6.

### Notes

1. Stephen Hawking wrote 1999: So what the singularity theorems are really telling us, is that the universe had a quantum origin, and that we need a theory of quantum cosmology, if we are to predict the present state of the universe. "Archived copy". Archived from the original on 2015-02-14. Retrieved 2015-02-14.CS1 maint: archived copy as title (link)
2. Klebanov, Igor & Maldacena, Juan (2009). "Solving Quantum Field Theories via Curved Spacetimes" (PDF). Physics Today . 62 (1): 28. Bibcode:2009PhT....62a..28K. doi:. Archived from the original (PDF) on July 2, 2013. Retrieved 13 Feb 2015.
3. "arxiv.org" (PDF).