Primordial perturbations in the Dapor-Liegener model of hybrid loop quantum cosmology

Gomar, Laura Castelló; García-Quismondo, Alejandro; Marugán, Guillermo A. Mena

doi:10.48550/arxiv.2002.01262

Cited by 5 publications

(24 citation statements)

References 59 publications

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“…(2) 0 of the densitized homogeneous Hamiltonian obtained with this prescription adopts the effective value [54]…”

Section: − 18 Hmentioning

confidence: 99%

“…(2.6) and (2.7)]. Actually, the way in which these objects are represented is intimately related to the structure of the quantum theory: we require that their action as quantum operators preserve the superselection sectors of the homogeneous Hamiltonian [32,54], so that the perturbative contributions do not alter them. In the first place,…”

Section: − 18 Hmentioning

confidence: 99%

“…This objective has inspired a number of studies (see, for instance, Refs. [47][48][49][50][51][52][53][54]), the aim of which was to explore the features of the model, how they compare to the standard ones, and the implementability of the procedure in more complicated scenarios, among others. It has been found that, although the big bang singularity is still resolved by a bouncing mechanism, the resulting bounce is quantitatively and qualitatively different from the standard one.…”

Section: Introductionmentioning

confidence: 99%

“…[50]. In a recent work [54], the particularization of the formalism of hybrid LQC to the Dapor-Liegener regularization of the FLRW cosmological background has been studied in detail, and two different admissible prescriptions have been put forward for the quantum definition of certain geometrical operators. At this point, it seems natural to wonder how the predictions of the hybrid and dressed metric formalisms compare to each other when the homogeneous geometry is regularized following the proposal of Ref.…”

Section: Introductionmentioning

confidence: 99%

“…II, we overview the most important elements of effective hybrid LQC and provide the expression of the time-dependent masses that govern the propagation of scalar and tensor perturbations, distinguishing between the two possible prescriptions discussed in Ref. [54] for the definition of the geometric operators that are necessary to determine these masses. Then, in Sec.…”

Section: Introductionmentioning

confidence: 99%

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The time-dependent mass of cosmological perturbations in loop quantum cosmology: Dapor-Liegener regularization

García-Quismondo,

Marugán,

Pérez

2020

Preprint

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In this work, we compute the time-dependent masses that govern the dynamics of scalar and tensor perturbations propagating on an effective flat, homogeneous, and isotropic background within the framework of loop quantum cosmology, regularized according to the procedure put forward by Dapor and Liegener. To do so, we follow the two main approaches that, in the field of loop quantum cosmology, lead to hyperbolic equations for the perturbations in the ultraviolet sector: the hybrid and dressed metric formalisms. This allows us to compare the masses resulting from both proposals and analyze their positivity in regimes of physical interest: the big bounce and the contracting de Sitter phase in the asymptotic past that is a defining feature of the model under consideration.

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“…(2) 0 of the densitized homogeneous Hamiltonian obtained with this prescription adopts the effective value [54]…”

Section: − 18 Hmentioning

confidence: 99%

Section: − 18 Hmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The time-dependent mass of cosmological perturbations in loop quantum cosmology: Dapor-Liegener regularization

García-Quismondo,

Marugán,

Pérez

2020

Preprint

Self Cite

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The time-dependent mass of cosmological perturbations in loop quantum cosmology: Dapor–Liegener regularization

García-Quismondo¹,

Marugán²,

Pérez³

2020

Class. Quantum Grav.

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In this work, we compute the time-dependent masses that govern the dynamics of scalar and tensor perturbations propagating on an effective flat, homogeneous, and isotropic background within the framework of loop quantum cosmology (LQC), regularized according to the procedure put forward by Dapor and Liegener. To do so, we follow the two main approaches that, in the field of LQC, lead to hyperbolic equations for the perturbations in the ultraviolet sector: the hybrid and dressed metric formalisms. This allows us to compare the masses resulting from both proposals and analyze their positivity in regimes of physical interest: the big bounce and the contracting de Sitter phase in the asymptotic past that is a defining feature of the model under consideration.

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A diffeomorphism invariant family of metric-affine actions for loop cosmologies

Delhom

Olmo

Singh

2023

J. Cosmol. Astropart. Phys.

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In loop quantum cosmology (LQC) the big bang singularity is generically resolved by a big bounce. This feature holds even when modified quantization prescriptions of the Hamiltonian constraint are used such as in mLQC-I and mLQC-II. While the later describes an effective description qualitatively similar to that of standard LQC, the former describes an asymmetric evolution with an emergent Planckian de-Sitter pre-bounce phase even in the absence of a potential. We consider the potential relation of these canonically quantized non-singular models with effective actions based on a geometric description. We find a 3-parameter family of metric-affine f(ℛ) theories which accurately approximate the effective dynamics of LQC and mLQC-II in all regimes and mLQC-I in the post-bounce phase. Two of the parameters are fixed by enforcing equivalence at the bounce, and the background evolution of the relevant observables can be fitted with only one free parameter. It is seen that the non-perturbative effects of these loop cosmologies are universally encoded by a logarithmic correction that only depends on the bounce curvature of the model. In addition, we find that the best fit value of the free parameter can be very approximately written in terms of fundamental parameters of the underlying quantum description for the three models. The values of the best fits can be written in terms of the bounce density in a simple manner, and the values for each model are related to one another by a proportionality relation involving only the Barbero-Immirzi parameter.

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Primordial perturbations in the Dapor-Liegener model of hybrid loop quantum cosmology

Cited by 5 publications

References 59 publications

The time-dependent mass of cosmological perturbations in loop quantum cosmology: Dapor-Liegener regularization

The time-dependent mass of cosmological perturbations in loop quantum cosmology: Dapor-Liegener regularization

The time-dependent mass of cosmological perturbations in loop quantum cosmology: Dapor–Liegener regularization

A diffeomorphism invariant family of metric-affine actions for loop cosmologies

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