Article
Astronomy & Astrophysics
Jaiyul Yoo, Nastassia Grimm, Ermis Mitsou
Summary: This study investigates the three-point correlation function of observed matter density fluctuations in a squeezed triangular configuration in a Lambda CDM universe under a single-field inflationary scenario. The study finds that the theoretical descriptions of galaxy bias in general relativity are incomplete due to ambiguities in spatial gauge choice, and a proper relativistic description of galaxy bias is needed for definitive conclusions in galaxy clustering. Additionally, it demonstrates that gauge-invariant calculations of cosmological observables are unaffected by extra coordinate transformations and that relativistic effects associated with light propagation cancel each other.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Amjad Ashoorioon, Ghazal Geshnizjani, Hyung J. Kim
Summary: In this paper, we study the validity and non-Gaussianity of Extended Effective Field Theory of Inflation (EEFToI) with initial conditions set with dispersion relations omega(2) a k(6). By computing the bispectrum and investigating the shape of triangles, we find interesting regions of parameter space where EEFToI with these initial conditions is sensible.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Fengge Zhang, Yungui Gong, Jiong Lin, Yizhou Lu, Zhu Yi
Summary: The study of non-Gaussianities of primordial curvature perturbations in G-inflation models reveals that even though f(NL) becomes large at certain scales, it remains to be small at peak scales. This suggests that the contributions of non-Gaussianity to scalar induced secondary gravitational waves and primordial black hole abundance are expected to be negligible.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Thomas Floss, Tim de Wild, P. Daniel Meerburg, Leon V. E. Koopmans
Summary: In this study, we investigate the possibility of using tomography of 21-cm brightness temperature fluctuations during the Dark Ages as a means to constrain primordial non-Gaussianity. We improve previous models by including the effect of the free electron fraction and derive the secondary bispectrum as well as the secondary trispectrum of 21-cm brightness temperature fluctuations. We find that although secondary non-Gaussianity dominates the signal, primordial non-Gaussianity can still be extracted with significantly higher signal-to-noise ratios than current and future CMB experiments.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Raphal van Laak, Sam Young
Summary: Primordial black holes are black holes that may have formed in high density regions in the early universe. The fluctuations in their formation rate can be used to constrain the amplitude of non-Gaussianity, especially if primordial black holes make up a significant fraction of dark matter. By extending the calculation to include peaks theory and considering the non-linearities between compaction C and curvature perturbation C, we find that the constraints on quadratic models of non-Gaussianity are largely unchanged, while the constraints on cubic models significantly worsen. If all of the dark matter is composed of primordial black holes, the parameters of non-Gaussianity are -2.9 & BULL; 10-4 < f < 3.8 & BULL; 10-4 and -1.5 & BULL; 10-3 < g < 1.9 & BULL; 10-3 for quadratic and cubic models respectively.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Emanuela Dimastrogiovanni, Matteo Fasiello, A. Emir Gumrukcuoglu
Summary: This paper investigates the possibility of extra spinning particles during inflation, focusing on the spin-2 case. The study explores the parameter space of the inflationary Lagrangian and identifies regions with signatures detectable by upcoming CMB probes. The analysis reveals the presence of a local-type non-Gaussianity in the gravitational wave spectrum and three-point function, which may be within the sensitivity range of both LiteBIRD and CMB-S4 experiments.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Sabino Matarrese, Luigi Pilo, Rocco Rollo
Summary: By carefully implementing gauge transformations involving long-wavelength modes, it is shown that effects involving squeezed bispectrum configurations cannot be gauged away, except for the unphysical exactly infinite-wavelength limit. This result is particularly relevant for the Maldacena consistency relation for single-field inflation and the f(NL)(GR) = -5/3 term appearing in dark matter bispectrum and halo bias, indicating their physical and observable nature in principle.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Jason Kristiano, Jun'ichi Yokoyama
Summary: By calculating the one-loop correction to the two-point functions of curvature perturbation in single-field inflation generated by cubic self-interaction, we find that the correction is finite and inversely proportional to the spectral tilt. Requiring the correction to be much smaller than the tree-level contribution leads to an upper bound on primordial non-Gaussianity. Observationally, the allowed region of non-Gaussian parameter space is entirely included by the region where the one-loop correction is smaller than the tree-level contribution, but there exists a significantly large region where the one-loop correction is larger than 1% or even 10% of the latter. If future observations confirm non-Gaussianity falling within such a region, it would be important to incorporate higher-order corrections to the spectrum in order to achieve precise cosmology. In some extreme cases, where the one-loop correction has a comparable magnitude to the tree-level contribution, it might indicate a breakdown of the cosmological perturbation theory in the context of single-field inflation.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Lucas Pinol
Summary: This article explores linear dynamics and cubic interactions for N-field scalar fields during inflation, using observable curvature perturbations and entropic fluctuations. It reveals rich geometrical effects beyond scalar curvature, particularly when the field space dimension is larger than two. The article also highlights potential instability in background dynamics when N-field is greater than or equal to 3, due to negative eigenvalues in the entropic mass matrix from fast rotation of local entropic basis.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Enrico Pajer
Summary: The study focuses on the three-point correlators of gravitons and scalar curvature perturbations around a quasi de Sitter space-time and establishes Bootstrap Rules that fully fix the form of these correlators in the asymptotic future at the boundary. The Boostless Bootstrap approach is shown to account for the breaking of de Sitter boosts caused by inflationary backgrounds. Derivations of bispectra involving gravitons in single-clock, canonical inflation are easily derived in this approach, as well as the scalar bispectrum in the Effective Field Theory of inflation to any order in derivatives. In many cases, the derivations are computationally simpler than the corresponding explicit calculations, emphasizing the implications of locality, vacuum choice, and underlying symmetries.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Yi-Fu Cai, Xiao-Han Ma, Misao Sasaki, Dong-Gang Wang, Zihan Zhoua
Summary: This paper investigates the relationship between deviations from Gaussian statistics in primordial perturbations and non-perturbative effects. It presents specific examples where the tail of the distribution becomes highly non-Gaussian despite remaining almost Gaussian in the perturbative regime. The study reveals the rich phenomenology of non-Gaussian tails, which has been overlooked in conventional analyses.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Daniel Baumann, Daniel Green
Summary: This paper discusses the impact of nonlinear structure formation on the study of primordial non-Gaussianity and proposes a method to measure non-Gaussianity in the position space maps of the large-scale structure. The study shows that map-level analysis can significantly improve the constraining power over non-Gaussianity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Sam Young
Summary: In this study, we reassess the impact of local-type non-Gaussianity on the abundance of primordial black holes (PBHs) and find that the effect is much less significant than previously believed. The non-Gaussianity parameters need to be significantly larger to have a similar effect as before, which weakens the constraints on PBH abundance and the primordial power spectrum dependence on non-Gaussianity parameters. Furthermore, we question the existing calculations of PBH abundance due to the correlation between curvature perturbation and compaction.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Azadeh Moradinezhad Dizgah, Matteo Biagetti, Emiliano Sefusatti, Vincent Desjacques, Jorge Norena
Summary: Upcoming galaxy redshift surveys are expected to improve limits on primordial non-Gaussianity (PNG) through measurements in Fourier space. A Monte-Carlo Markov Chain analysis was performed to confront perturbation theory predictions with N-body simulations, focusing on the local model of PNG parameterized by f(NL). Informative priors on the linear non-Gaussian bias parameter can significantly improve constraints on f(NL) in statistical inference.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Tingqi Cai, Jie Jiang, Yi Wang
Summary: This study presents the first lattice simulation to investigate the nature of multi-stream inflation. The simulation confirms the physical picture of multi-stream inflation and reveals new findings in parameter space and field behaviors. It shows that gradient energy plays a significant role in multi-stream inflation. The bifurcation probability in a double field potential with a shifted Gaussian barrier is controlled by the shift distance with an error function relation. The bubbles created by bifurcation tend to be more spherical as bifurcation probability decreases. Furthermore, bifurcation is more likely to introduce oscillations of field values inside the bubbles than outside.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Juan P. Beltran Almeida, Josue Motoa-Manzano, Jorge Norena, Thiago S. Pereira, Cesar A. Valenzuela-Toledo
Summary: The paper presents an effective Eulerian description of the growth of cosmological perturbations around a homogeneous but anisotropic Bianchi I spacetime background in the non-relativistic regime. It derives analytic solutions for linear dark matter density contrast and utilizes a formal perturbative approach to obtain a second-order (non-linear) solution. Analytic expressions for the power spectrum and the bispectrum of the dark matter density contrast are derived, showing various corrections due to anisotropy. The contribution of a late-time phase of anisotropic expansion to the growth of structure peaks at a finite redshift between CMB decoupling and today, although the exact redshift value depends on the model.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Editorial Material
Astronomy & Astrophysics
Luca Teodori, Kfir Blum, Emanuele Castorina, Marko Simonovic, Yotam Soreq
Summary: In this paper, we discuss the issue of modeling degeneracies in strong lensing measurements of the Hubble parameter H-0. We highlight the importance of considering weak lensing effects associated with different segments of the line of sight, and propose the inclusion of external convergence terms to avoid bias in the inferred value of H-0. We also show that the use of imaging data for multiple strongly-lensed sources cannot fully resolve the mass sheet degeneracy.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Giovanni Cabass, Mikhail M. Ivanov, Oliver H. E. Philcox, Marko Simonovi, Matias Zaldarriaga
Summary: This study presents constraints on nonlocal primordial non-Gaussianity using the redshift-space galaxy power spectra and bispectra of the BOSS data. The results yield joint limits on the amplitudes of equilateral and orthogonal shapes, and can be used to derive constraints on coefficients of the effective single-field inflationary Lagrangian.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
Matteo Biagetti, Juan Calles, Lina Castiblanco, Alex Cole, Jorge Norena
Summary: In this study, we investigate the information content of summary statistics constructed from the multi-scale topology of large-scale structures on the primordial non-Gaussianity of the local and equilateral type. By using halo catalogs derived from numerical simulations, we find that the uncertainties in redshift space are relatively small and are weakly affected by redshift errors.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Matteo Biagetti, Lina Castiblanco, Jorge Norena, Emiliano Sefusatti
Summary: The study of the halo bispectrum covariance shows a significant correlation between squeezed halo bispectrum configurations and the long-wavelength halo power spectrum. The diagonal Gaussian contribution fails to accurately describe the full covariance in these cases. The inclusion of non-Gaussian terms for squeezed configurations greatly improves the agreement between the numerical estimate and the model.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Paolo Creminelli, Oliver Janssen, Leonardo Senatore
Summary: We derive positivity bounds on EFT coefficients in theories where boosts are spontaneously broken, using the analytic properties of the retarded Green's function of conserved currents (or of the stress-energy tensor) and assuming the theory becomes conformal in the UV. This method is applicable to both cosmology and condensed matter systems. As a concrete example, we derive inequalities on the coefficients of the operators for the EFT of conformal superfluids, which describes the universal low-energy dynamics of CFT's at large chemical potential, in three dimensions at NLO and NNLO.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Giovanni Cabass, Mikhail M. Ivanov, Oliver H. E. Philcox, Marko Simonovic, Matias Zaldarriaga
Summary: We forecast the constraints on single-field inflation from the bispectrum of future high-redshift surveys such as MegaMapper. The current methods yield constraints of order sigma (fNLeq) N 23 and sigma (f orth NL) N 12 when varying both nuisance parameters and cosmology, and the limits tighten significantly to sigma (fNLeq) N 17 and sigma (forth NL) N 8 when fixing cosmological parameters and quadratic bias parameter relations. These constraints compare favorably with the forecasted bounds from CMB-S4 and are further improved with increased observational data and survey depth.
Article
Astronomy & Astrophysics
Giovanni Cabass, Mikhail M. Ivanov, Matthew Lewandowski, Mehrdad Mirbabayi, Marko Simonovic
Summary: This article summarizes the progress in studying small fluctuations around homogeneous and isotropic expanding backgrounds in cosmology, which are sensitive to the physical processes during inflation and in the late Universe and hold the key to answering many major open questions in cosmology.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Mikhail M. Ivanov, Oliver H. E. Philcox, Giovanni Cabass, Takahiro Nishimichi, Marko Simonovic, Matias Zaldarriaga
Summary: We propose a framework for analyzing the anisotropic bispectrum in cosmological studies, including the quadrupole and hexadecapole moments. We develop a new algorithm to extract the bispectrum multipoles and introduce a theoretical model for them. Through testing on mock data and analyzing real data from BOSS DR12, we show that our framework is accurate and can extract cosmological parameters.
Article
Astronomy & Astrophysics
Andrej Obuljen, Marko Simonovic, Aurel Schneider, Robert Feldmann
Summary: In this study, an analytical forward model based on perturbation theory is used to predict the neutral hydrogen (HI) overdensity maps at low redshifts. The model is compared to the simulated HI from the IllustrisTNG magneto-hydrodynamical simulation TNG300-1 to assess its performance. The results show that HI is a biased tracer of the underlying matter field and the model accurately describes the simulated HI power spectrum. The model also provides a simple and efficient way to generate accurate HI mock data.
Article
Astronomy & Astrophysics
Matteo Biagetti, Juan Calles, Lina Castiblanco, Alex Cole, Jorge Norena
Summary: This study investigates the impact of summary statistics built from multi-scale topology of large-scale structures on the information content of local and equilateral primordial non-Gaussianity. By using halo catalogs as a proxy for observed galaxies and considering realistic scenarios in redshift space, the reliability of this approach is assessed through various tests. The results show weak sensitivity of the constraints to redshift errors.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Giovanni Cabass, Mikhail M. Ivanov, Oliver H. E. Philcox, Marko Simonovic, Matias Zaldarriaga
Summary: This study uses redshift-space galaxy clustering data from the BOSS survey to constrain local primordial non-Gaussianity (LPNG). The results show no evidence for primordial non-Gaussianity. The addition of the bispectrum analysis tightens the constraints and breaks degeneracies with non-Gaussian galaxy bias.
Article
Astronomy & Astrophysics
Mikhail M. Ivanov, Oliver H. E. Philcox, Takahiro Nishimichi, Marko Simonovic, Masahiro Takada, Matias Zaldarriaga
Summary: We study the information content of the angle-averaged redshift space galaxy bispectrum using a systematic tree-level perturbation theory model. We find that our model is valid for a specific range of wave numbers and that including the bispectrum monopole improves constraints on cosmological parameters.
Article
Astronomy & Astrophysics
Mikhail M. Ivanov, Oliver H. E. Philcox, Marko Simonovic, Matias Zaldarriaga, Takahiro Nischimichi, Masahiro Takada
Summary: Nonlinear redshift-space distortions, also known as "fingers of God," pose challenges in analytical modeling. A new observable, Q(0), has been proposed to mitigate this issue and accurately described using perturbation theory. This new statistic yields noticeable improvements on cosmological parameters compared to standard power spectrum multipole analyses.
Article
Astronomy & Astrophysics
Oliver H. E. Philcox, Mikhail M. Ivanov, Giovanni Cabass, Marko Simonovic, Matias Zaldarriaga, Takahiro Nishimichi
Summary: The study shows that including one-loop corrections expands the range of scales over which the bispectrum can be modeled and tightens constraints on bias parameters, but does not lead to noticeable improvements in the sigma 8 error bar.