String Inflation II: Inflation from Moduli

Burgess, C.P.

doi:10.1002/9783527628063.ch3

Cited by 3 publications

(16 citation statements)

References 38 publications

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“…Such details of the quantumness also motivate us to consider why they fit the classical description of cosmological perturbations, suggesting that there is a quantum-to-classical transition. The transition is often manifested with the environment-induced decoherence studied with various tools, including the mean field [17], the Schrödinger wave functional [18], the master equation [19][20][21][22][23][24][25], the related EFT [26,27] and the entropy increased by interactions [28], whereas there are also some early works arguing that the transition can happen without any environment [29][30][31][32] as well as the approaches with the non-equilibrium entropy [33][34][35]. Focusing on the minimal environment-induced decoherence for the cosmological perturbations, the process is accompanied by the entanglement between the environment and the system, represented by partitioning the scalar curvature modes ζ k based on their comoving momenta, and their couplings are dominated by gravitational interactions (at least by counting the slow-roll orders of the interactions).…”

Section: Jhep04(2023)092mentioning

confidence: 99%

“…One may consider the counterterms without time derivative on the boundary like ζ 2 , (∂iζ) 2 and (∂ 2 ζ)2 , but these only change the quadratic phase of the wave functional, and thus it cannot resolve the divergence in decoherence. Similarly, in[27], the UV divergence appears in the imaginary part of the Lindblad equation which is not related to decoherence.…”

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confidence: 99%

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Decoherence of cosmological perturbations from boundary terms and the non-classicality of gravity

Sou

Tran

Wang

2023

J. High Energ. Phys.

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We note that the decoherence of inflationary curvature perturbation ζ is dominated by a boundary term of the gravity action. Although this boundary term cannot affect cosmological correlators 〈ζn〉, it induces much faster decoherence for ζ than that of previous calculations. The gravitational origin of inflationary decoherence sheds light on the quantum (or non-classical) nature of gravity. By comparing with a Schrödinger-Newton toy model of classical gravity, we show that gravity theories of classical or quantum origins can be distinguished by comparing their different impacts on decoherence rate of ζ. Our calculation also indicates that density fluctuation δρ better preserves quantum information than ζ for the purpose of constructing cosmological Bell-like experiments.

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Section: Jhep04(2023)092mentioning

confidence: 99%

mentioning

confidence: 99%

Decoherence of cosmological perturbations from boundary terms and the non-classicality of gravity

Sou

Tran

Wang

2023

J. High Energ. Phys.

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“…In the literature, there are two definitions of tensor perturbations in the spatial metric h ij which are applied in the decoherence problems [44,45], and here we briefly discuss the difference. One is γ ij defined in the comoving gauge (ζ-gauge with δϕ = 0), e.g.…”

Section: The Setupmentioning

confidence: 99%

“…The environment-induced decoherence of scalar perturbations has been widely studied with various interactions and tools [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43], and some of the frameworks are also applicable to the decoherence of tensor perturbations. For the primordial gravitons, the possible sources of decoherence include the non-linear interaction between tensor modes [44], the scalar-tensor interaction [38,45], and the primordial magnetic field [46,47]. Focusing on the simplest single-field inflation, the decoherence effects of gravitons by scalar and tensor environments through the bulk interactions are comparable, and the quantum-to-classical transition happens at 7-9 e-folds after crossing the Hubble horizon, 2 proving the upper bound of the purity of the primordial squeezed gravitons.…”

Section: Introductionmentioning

confidence: 99%

On the decoherence of primordial gravitons

Ning

Sou

Wang

2023

J. High Energ. Phys.

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It is well-known that the primordial scalar curvature and tensor perturbations, ζ and γij, are conserved on super-horizon scales in minimal inflation models. However, their wave functional has a rapidly oscillating phase which is slow-roll unsuppressed, as can be seen either from boundary (total-derivative) terms of cosmological perturbations, or the WKB approximation of the Wheeler-DeWitt equation. Such an oscillatory phase involves gravitational non-linearity between scalar and tensor perturbations. By tracing out unobserved modes, the oscillatory phase causes faster decoherence of primordial gravitons compared to those by bulk interactions. Our results put a stronger lower bound of decoherence effect to the recent proposals probing squeezed primordial gravitons.

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“…In cosmic decoherence, there are two main choices of the environment which have been investigated so far. The first is to consider that super-horizon, or light, modes of fluctuations to be decohered by sub-horizon, or heavy, modes representing the environment 1 [32,34,35,46,53,70]. The second choice is to consider an external field, such that decoherence is caused by field-field interactions, rather than by self interactions of the same field as in first case (i.e.…”

Section: Introductionmentioning

confidence: 99%

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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String Inflation II: Inflation from Moduli

Cited by 3 publications

References 38 publications

Decoherence of cosmological perturbations from boundary terms and the non-classicality of gravity

Decoherence of cosmological perturbations from boundary terms and the non-classicality of gravity

On the decoherence of primordial gravitons

Cosmic decoherence: primordial power spectra and non-Gaussianities

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