2024-03-29T13:14:45Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1101222016-02-18T03:00:23Zcom_10261_135com_10261_4col_10261_388
DIGITAL.CSIC
author
Martín-Benito, Mercedes
author
Martín de Blas, Daniel
author
Mena Marugán, Guillermo A.
2015-02-03T11:18:14Z
2015-02-03T11:18:14Z
2014-11-28
Classical and Quantum Gravity, 31: 075022 (2014)
1361-6382
http://hdl.handle.net/10261/110122
10.1088/0264-9381/31/7/075022
We develop approximation methods in the hybrid quantization of the Gowdy model with linear polarization and a massless scalar field, for the case of three-torus spatial topology. The loop quantization of the homogeneous gravitational sector of the Gowdy model (according to the improved dynamics prescription) and the presence of inhomogeneities lead to a very complicated Hamiltonian constraint. Therefore, the extraction of physical results calls for the introduction of well justified approximations. We first show how to approximate the homogeneous part of the Hamiltonian constraint, corresponding to Bianchi I geometries, as if it described a Friedmann-Robertson-Walker (FRW) model corrected with anisotropies. This approximation is valid in the high-energy sector of the FRW geometry (concerning its contribution to the constraint) and for anisotropy profiles that are sufficiently smooth. In addition, for certain families of states associated to regimes of physical interest, with negligible effects of the anisotropies and small inhomogeneities, one can approximate the Hamiltonian constraint of the inhomogeneous system by that of an FRW geometry with a relatively simple matter content, and then obtain its solutions.
eng
openAccess
Approximation methods in Loop Quantum Cosmology: From Gowdy cosmologies to inhomogeneous models in Friedmann-Robertson-Walker geometries
preprint
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URL
https://digital.csic.es/bitstream/10261/110122/1/MMBenito.pdf
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MMBenito.pdf.txt
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MMBenito.pdf.txt