Stability issues of nonlocal gravity during primordial inflation

Enis Belgacem; Giulia Cusin; Stefano Foffa; Michele Maggiore; Michele Mancarella

doi:10.48550/arXiv.1610.05664

Stability issues of nonlocal gravity during primordial inflation

Enis Belgacem, Giulia Cusin, Stefano Foffa, Michele Maggiore, Michele Mancarella

Research output: Working paper › Preprint › Academic

Abstract

We study the cosmological evolution of some nonlocal gravity models, when the initial conditions are set during a phase of primordial inflation. We examine in particular three models, the so-called RT, RR and $\Delta_4$ models, previously introduced by our group. We find that the RR and $\Delta_4$ models have a stable evolution also during inflation. The RT model has an apparent instability, but we show that, because of the smallness of the scale associated to the nonlocal term compared to the inflationary scale, this instability is innocuous and also the RT model has a viable evolution even when its initial conditions are set during a phase of primordial inflation.

Original language	English
Publisher	arXiv
Pages	1-21
DOIs	https://doi.org/10.48550/arXiv.1610.05664
Publication status	Published - 18 Oct 2016

Bibliographical note

v3: important error corrected, which changes a conclusion (RT model viable also when initial conditions are set during inflation); v4: corrected an error in the v3 submission (abstract in the arxiv form had not been changed)

Keywords

hep-th
astro-ph.CO

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1610.05664v4Submitted manuscript, 494 KB

https://arxiv.org/abs/1610.05664

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title = "Stability issues of nonlocal gravity during primordial inflation",

abstract = " We study the cosmological evolution of some nonlocal gravity models, when the initial conditions are set during a phase of primordial inflation. We examine in particular three models, the so-called RT, RR and $\Delta_4$ models, previously introduced by our group. We find that the RR and $\Delta_4$ models have a stable evolution also during inflation. The RT model has an apparent instability, but we show that, because of the smallness of the scale associated to the nonlocal term compared to the inflationary scale, this instability is innocuous and also the RT model has a viable evolution even when its initial conditions are set during a phase of primordial inflation. ",

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AU - Belgacem, Enis

AU - Cusin, Giulia

AU - Foffa, Stefano

AU - Maggiore, Michele

AU - Mancarella, Michele

N1 - v3: important error corrected, which changes a conclusion (RT model viable also when initial conditions are set during inflation); v4: corrected an error in the v3 submission (abstract in the arxiv form had not been changed)

PY - 2016/10/18

Y1 - 2016/10/18

N2 - We study the cosmological evolution of some nonlocal gravity models, when the initial conditions are set during a phase of primordial inflation. We examine in particular three models, the so-called RT, RR and $\Delta_4$ models, previously introduced by our group. We find that the RR and $\Delta_4$ models have a stable evolution also during inflation. The RT model has an apparent instability, but we show that, because of the smallness of the scale associated to the nonlocal term compared to the inflationary scale, this instability is innocuous and also the RT model has a viable evolution even when its initial conditions are set during a phase of primordial inflation.

AB - We study the cosmological evolution of some nonlocal gravity models, when the initial conditions are set during a phase of primordial inflation. We examine in particular three models, the so-called RT, RR and $\Delta_4$ models, previously introduced by our group. We find that the RR and $\Delta_4$ models have a stable evolution also during inflation. The RT model has an apparent instability, but we show that, because of the smallness of the scale associated to the nonlocal term compared to the inflationary scale, this instability is innocuous and also the RT model has a viable evolution even when its initial conditions are set during a phase of primordial inflation.

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DO - 10.48550/arXiv.1610.05664

M3 - Preprint

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EP - 21

BT - Stability issues of nonlocal gravity during primordial inflation

PB - arXiv

ER -

Stability issues of nonlocal gravity during primordial inflation

Abstract

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Keywords

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