DeWitt Boundary Condition in One-Loop Quantum Cosmology

DeWitt’s suggestion that the wave function of the universe should vanish at the classical Big Bang singularity is considered here within the framework of one-loop quantum cosmology. For pure gravity at one loop about a flat four-dimensional background bounded by a 3-sphere, three choices of boundary...

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Main Author: Giampiero Esposito
Format: Article
Language:English
Published: MDPI AG 2023-04-01
Series:Universe
Subjects:
Online Access:https://www.mdpi.com/2218-1997/9/4/187
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author Giampiero Esposito
author_facet Giampiero Esposito
author_sort Giampiero Esposito
collection DOAJ
description DeWitt’s suggestion that the wave function of the universe should vanish at the classical Big Bang singularity is considered here within the framework of one-loop quantum cosmology. For pure gravity at one loop about a flat four-dimensional background bounded by a 3-sphere, three choices of boundary conditions are considered: vanishing of the linearized magnetic curvature when only transverse-traceless gravitational modes are quantized; a one-parameter family of mixed boundary conditions for gravitational and ghost modes; and diffeomorphism-invariant boundary conditions for metric perturbations and ghost modes. A positive <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ζ</mi><mo>(</mo><mn>0</mn><mo>)</mo></mrow></semantics></math></inline-formula> value in these cases ensures that, when the three-sphere boundary approaches zero, the resulting one-loop wave function approaches zero. This property may be interpreted by saying that, in the limit of small three-geometry, the resulting one-loop wave function describes a singularity-free universe. This property holds for one-loop functional integrals, which are not necessarily equivalent to solutions of the quantum constraint equations.
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spelling doaj.art-efb4cc7483a249ca91fa8397376918c72023-11-17T21:40:29ZengMDPI AGUniverse2218-19972023-04-019418710.3390/universe9040187DeWitt Boundary Condition in One-Loop Quantum CosmologyGiampiero Esposito0Dipartimento di Fisica “Ettore Pancini”, Complesso Universitario di Monte S. Angelo, Via Cintia Edificio 6, 80126 Napoli, ItalyDeWitt’s suggestion that the wave function of the universe should vanish at the classical Big Bang singularity is considered here within the framework of one-loop quantum cosmology. For pure gravity at one loop about a flat four-dimensional background bounded by a 3-sphere, three choices of boundary conditions are considered: vanishing of the linearized magnetic curvature when only transverse-traceless gravitational modes are quantized; a one-parameter family of mixed boundary conditions for gravitational and ghost modes; and diffeomorphism-invariant boundary conditions for metric perturbations and ghost modes. A positive <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ζ</mi><mo>(</mo><mn>0</mn><mo>)</mo></mrow></semantics></math></inline-formula> value in these cases ensures that, when the three-sphere boundary approaches zero, the resulting one-loop wave function approaches zero. This property may be interpreted by saying that, in the limit of small three-geometry, the resulting one-loop wave function describes a singularity-free universe. This property holds for one-loop functional integrals, which are not necessarily equivalent to solutions of the quantum constraint equations.https://www.mdpi.com/2218-1997/9/4/187quantum cosmologyboundary conditionsstrong ellipticityspectral ζ-function
spellingShingle Giampiero Esposito
DeWitt Boundary Condition in One-Loop Quantum Cosmology
Universe
quantum cosmology
boundary conditions
strong ellipticity
spectral ζ-function
title DeWitt Boundary Condition in One-Loop Quantum Cosmology
title_full DeWitt Boundary Condition in One-Loop Quantum Cosmology
title_fullStr DeWitt Boundary Condition in One-Loop Quantum Cosmology
title_full_unstemmed DeWitt Boundary Condition in One-Loop Quantum Cosmology
title_short DeWitt Boundary Condition in One-Loop Quantum Cosmology
title_sort dewitt boundary condition in one loop quantum cosmology
topic quantum cosmology
boundary conditions
strong ellipticity
spectral ζ-function
url https://www.mdpi.com/2218-1997/9/4/187
work_keys_str_mv AT giampieroesposito dewittboundaryconditioninoneloopquantumcosmology