Gaussian and 1/N approximations in semiclassical cosmology
We study the 4 theory and the interacting O(N) model in a curved background using the Gaussian approximation for the former and the large-N approximation for the latter. We obtain the renormalized version of the semiclassical Einstein equations having in mind a future application of these models to...
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1989
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_05562821_v39_n8_p2234_Mazzitelli http://hdl.handle.net/20.500.12110/paper_05562821_v39_n8_p2234_Mazzitelli |
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paper:paper_05562821_v39_n8_p2234_Mazzitelli2023-06-08T15:42:06Z Gaussian and 1/N approximations in semiclassical cosmology We study the 4 theory and the interacting O(N) model in a curved background using the Gaussian approximation for the former and the large-N approximation for the latter. We obtain the renormalized version of the semiclassical Einstein equations having in mind a future application of these models to investigate the physics of the very early Universe. We show that, while the Gaussian approximation has two different phases, in the large-N limit only one is present. The different features of the two phases are analyzed at the level of the effective field equations. We discuss the initial-value problem and find the initial conditions that make the theory renormalizable. As an example, we study the de Sitter self-consistent solutions of the semiclassical Einstein equations. Finally, for an identically zero mean value of the field we find the evolution equations for the classical field 2 1/2 and the spacetime metric. They are very similar to the ones obtained by replacing the classical potential by the one-loop effective potential in the classical equations but do not have the drawbacks of the one-loop approximation. © 1989 The American Physical Society. 1989 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_05562821_v39_n8_p2234_Mazzitelli http://hdl.handle.net/20.500.12110/paper_05562821_v39_n8_p2234_Mazzitelli |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| description |
We study the 4 theory and the interacting O(N) model in a curved background using the Gaussian approximation for the former and the large-N approximation for the latter. We obtain the renormalized version of the semiclassical Einstein equations having in mind a future application of these models to investigate the physics of the very early Universe. We show that, while the Gaussian approximation has two different phases, in the large-N limit only one is present. The different features of the two phases are analyzed at the level of the effective field equations. We discuss the initial-value problem and find the initial conditions that make the theory renormalizable. As an example, we study the de Sitter self-consistent solutions of the semiclassical Einstein equations. Finally, for an identically zero mean value of the field we find the evolution equations for the classical field 2 1/2 and the spacetime metric. They are very similar to the ones obtained by replacing the classical potential by the one-loop effective potential in the classical equations but do not have the drawbacks of the one-loop approximation. © 1989 The American Physical Society. |
| title |
Gaussian and 1/N approximations in semiclassical cosmology |
| spellingShingle |
Gaussian and 1/N approximations in semiclassical cosmology |
| title_short |
Gaussian and 1/N approximations in semiclassical cosmology |
| title_full |
Gaussian and 1/N approximations in semiclassical cosmology |
| title_fullStr |
Gaussian and 1/N approximations in semiclassical cosmology |
| title_full_unstemmed |
Gaussian and 1/N approximations in semiclassical cosmology |
| title_sort |
gaussian and 1/n approximations in semiclassical cosmology |
| publishDate |
1989 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_05562821_v39_n8_p2234_Mazzitelli http://hdl.handle.net/20.500.12110/paper_05562821_v39_n8_p2234_Mazzitelli |
| _version_ |
1768542086196363264 |