Large-scale inhomogeneity of dark energy produced in the ancestor vacuum

Nan, Yue; Yamamoto, Kazuhiro; Aoki, Hajime; Iso, Satoshi; Yamauchi, Daisuke

doi:10.1103/physrevd.99.103512

Cited by 7 publications

(18 citation statements)

References 39 publications

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“…To put it the other way, a non-detection of such large tides can rule out the model that has no matter-radiation equality bump in the power spectrum. Related to this direction, the second one lies in exploring the large-scale anomaly such as the super-curvature fluctuation [47] and quintessential isocurvature [46]. To do so, we need to calibrate the response of small-scale perturbation to the large-scale fluctuation depending on each model.…”

Section: Discussionmentioning

confidence: 99%

Super-sample tidal modes on the celestial sphere

2019

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The super-sample tidal effect carries information on long-wavelength fluctuations that we cannot measure directly. It arises from the mode-coupling between short-wavelength and long-wavelength perturbations beyond a finite region of a galaxy survey and violates statistical isotropy of observed galaxy power spectra. In this paper, we propose the use of bipolar spherical harmonic (BipoSH) decomposition formalism to characterize statistically anisotropic power spectra. Using the BipoSH formalism, we perform a comprehensive study of the effect of the super-sample tides on measurements of other cosmological distortions such as the redshift-space distortion (RSD) and Alcock-Paczyński (AP) effects by means of the Fisher information matrix formalism. We find that the BipoSH formalism can break parameter degeneracies among the super-sample tidal, RSD and AP effects, indicating that the super-sample tides have little impact on the measurements of the RSD and AP effects. We also show that the super-sample tides are detectable with an accuracy better than the ΛCDM prediction without impairing the accuracy of measurements of other anisotropies assuming a SPHEREx-like galaxy survey.

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Section: Discussionmentioning

confidence: 99%

Super-sample tidal modes on the celestial sphere

2019

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“…As assumed in the previous works [23,24], we consider the model that the ultralight scalar field is varying at a very large spatial scale, much longer than the Hubble length in the present universe. Thus, they create large-scale inhomogeneities of the dark energy on superhorizon scales and break the cosmological principle, but the violation is small within the horizon of our universe at present.…”

Section: A Basic Equationsmentioning

confidence: 99%

“…The evolution of the superhorizon perturbations of φ was investigated in Ref. [23], which will be briefly reviewed in Sec. II D. In the present paper, we focus on investigating the effect of the superhorizon inhomogeneities on the LSS perturbations, which will be described by the perturbations of the order of O(κ ).…”

Section: B Perturbations In An Inhomogeneous Universementioning

confidence: 99%

“…To summarize this subsection, the evolution of superhorizon mode was expanded and represented by , which was investigated in Ref. [23]. In the following, after briefly reviewing the background equations and the superhorizon perturbations of the order κ, we will find the expression for the perturbation to the LSS of the order κ as an original work of the present paper.…”

Section: B Perturbations In An Inhomogeneous Universementioning

confidence: 99%

“…In recent years, cosmological models breaking the cosmological principle have been constructed to study various aspects of the accelerating universe [17][18][19][20][21][22]. In this paper, we consider a simplified version of the supercurvature mode dark energy model [23], which is a stochastic model of dark energy with large-scale inhomogeneity assuming an open universe associated with a specific inflationary scenario. The model introduces the potential energy of a scalar field with fluctuations of O(1) on a supercurvature scale sufficiently larger than the current horizon scale, which is responsible for the accelerated expansion.…”

Section: Introductionmentioning

confidence: 99%

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Large-scale structure with superhorizon isocurvature dark energy

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Hyperbolic field space and swampland conjecture for DBI scalar

Mizuno

Mukohyama

Zhang

2019

J. Cosmol. Astropart. Phys.

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We study a model of two scalar fields with a hyperbolic field space and show that it reduces to a single-field Dirac-Born-Infeld (DBI) model in the limit where the field space becomes infinitely curved. We apply the de Sitter swampland conjecture to the two-field model and take the same limit. It is shown that in the limit, all quantities appearing in the swampland conjecture remain well-defined within the single-field DBI model. Based on a consistency argument, we then speculate that the condition derived in this way can be considered as the de Sitter swampland conjecture for a DBI scalar field by its own. The condition differs from those proposed in the literature and only the one in the present paper passes the consistency argument. As a byproduct, we also point out that one of the inequalities in the swampland conjecture for a multi-field model with linear kinetic terms should involve the lowest mass squared for scalar perturbations and that this quantity can be significantly different from the lowest eigenvalue of the Hessian of the potential in the local orthonormal frame if the field space is highly curved. Finally, we propose an extension of the de Sitter swampland conjecture to a more general scalar field with the Lagrangian of the form P (X, ϕ), where X = −(∂ϕ) 2 /2.

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Large-scale inhomogeneity of dark energy produced in the ancestor vacuum

Cited by 7 publications

References 39 publications

Super-sample tidal modes on the celestial sphere

Super-sample tidal modes on the celestial sphere

Large-scale structure with superhorizon isocurvature dark energy

Hyperbolic field space and swampland conjecture for DBI scalar

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