Enhanced power on small scales and evolution of quantum state of perturbations in single and two field inflationary models

Raveendran, Rathul Nath; Parattu, Krishnamohan; Sriramkumar, L.

doi:10.1007/s10714-022-02974-9

Cited by 15 publications

(3 citation statements)

References 80 publications

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“…The influence of spectator fields during inflation has, of course, been explored in a variety of other contexts (e.g. [17][18][19][20][21][22][23]). One of the differences between our work and some other approaches is that we only consider gravitational interactions between the two sectors (coupling between the curvature perturbations and the perturbations in the spectator scalar field), rather than imposing a direct coupling term in the potential (i.e.…”

Section: Introductionmentioning

confidence: 99%

Entanglement masquerading in the CMB

Adil

Albrecht

Rose

et al. 2023

J. Cosmol. Astropart. Phys.

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The simplest single-field inflation models capture all the relevant contributions to the patterns in the Cosmic Microwave Background (CMB) observed today. A key assumption in these models is that the quantum inflationary fluctuations that source such patterns are generated by a particular quantum state — the Bunch-Davies (BD) state. While this is a well-motivated choice from a theoretical perspective, the question arises of whether current data can rule out other, also well motivated, choices of states. In particular, as we previously demonstrated in [1], entanglement is naturally and inevitably dynamically generated during inflation given the presence of a “rolling” spectator scalar field — and the resulting entangled state will yield a primordial power spectrum with potentially measurable deviations compared to the canonical BD result. For this work we developed a perturbative framework to allow a systematic exploration of constraints on (or detection of) entangled states with Planck CMB data using Monte Carlo techniques. We have found that most entangled states accessible with our framework are consistent with the data. One would have to expand the framework to allow a greater variety of entangled states in order to saturate the Planck constraints and more systematically explore any preferences the data may have among the different possibilities.

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Section: Introductionmentioning

confidence: 99%

Entanglement masquerading in the CMB

Adil

Albrecht

Rose

et al. 2023

J. Cosmol. Astropart. Phys.

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“…by a long-short splitting of the inflationary fluctuations). Among the works which adopted such choice, we find [50,51,71,72] (see also [73]), in addition to our current work. Such choice is motivated by the presence of more than one field in the early universe, at least, those populating radiation era.…”

Section: Introductionmentioning

confidence: 79%

Cosmic decoherence: primordial power spectra and non-Gaussianities

Hammou

Bartolo

2023

J. Cosmol. Astropart. Phys.

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We study the effect of quantum decoherence on the inflationary cosmological perturbations. This process might imprint specific observational signatures revealing the quantum nature of the inflationary mechanism being related to the longstanding issue of the quantum-to-classical transition of inflationary fluctuations. Several works have investigated the effect of quantum decoherence on the statistical properties of primordial fluctuations. In particular, it has been shown that cosmic decoherence leads to corrections to the curvature power spectrum predicted by standard slow-roll inflation. Equally interesting, a non zero curvature trispectrum has been shown to be purely induced by cosmic decoherence but, surprisingly, decoherence seems not to generate any bispectrum. We further develop such an analysis by adopting a generalized form of the pointer observable, showing that decoherence does induce a non vanishing curvature bispectrum and providing a specific underlying concrete physical process. Present constraints on primordial bispectra allow to put an upper bound on the strength of the environment-system interaction. In full generality, the decoherence-induced bispectrum can be scale dependent provided one imposes the corresponding correction to the power spectrum to be scale independent. Such scale dependence on the largest cosmological scales might represent a distinctive imprint of the quantum decoherence process taking place during inflation. We also provide a criterion that allows to understand when cosmic decoherence induces scale independent corrections, independently of the type of environment considered. As a final result, we study the effect of cosmic decoherence on tensor perturbations and we derive the decoherence corrected tensor-to-scalar perturbation ratio. In specific cases, decoherence induces a blue tilted correction to the standard tensor power spectrum.

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“…This contribution serves as a nice tribute, as not only Paddy would have followed these developments, but also Paddy would have been excited about profound challenges that this line of thinking poses. Other papers in this volume on the general theme of early universe cosmology include [15][16][17][18]. Especially noteworthy is the pedagogical review of Tirthankar Roy Choudhury [19].…”

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confidence: 99%

Topical collection: In memory of Professor T Padmanabhan

et al. 2022

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Professor Thanu Padmanabhan contributed significantly to a broad spectrum of topics in astrophysics, cosmology, and classical and quantum aspects of gravitation. In his memory, the Editorial Board of General Relativity and Gravitation invited us to edit a Topical Collection "In Memory of Professor T Padmanabhan". This collection gives a snapshot of ongoing research in the subjects he worked on.Professor Thanu Padmanabhan (affectionately known as Paddy) was an internationally acclaimed Indian Theoretical Physicist and Cosmologist, who passed away on 17 September 2021. He was a guiding light for all his students and younger colleagues who interacted with him [1]. We had the good fortune of discussing various aspects of physics with Paddy on several occasions. The Editors of General Relativity and Gravitation (GRG) invited us to organise a Topical Collection "In Memory of Professor T Padmanabhan". We have put together this volume in his fond memory and invited contributions in subjects Paddy had worked on.

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Enhanced power on small scales and evolution of quantum state of perturbations in single and two field inflationary models

Cited by 15 publications

References 80 publications

Entanglement masquerading in the CMB

Entanglement masquerading in the CMB

Cosmic decoherence: primordial power spectra and non-Gaussianities

Topical collection: In memory of Professor T Padmanabhan

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