LSS constraints with controlled theoretical uncertainties

Baldauf, Tobias; Mirbabayi, Mehrdad; Simonović, Marko; Zaldarriaga, Matías

doi:10.48550/arxiv.1602.00674

Cited by 103 publications

(260 citation statements)

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“…Recently, precision tests of the one-loop bispectrum [44,45] have pointed out that the range of validity of the one-loop EFT is much more restricted than expected by initial studies. This is in line with findings for the two-loop power spectrum [46] and expectations based on theoretical errors [47]. In [44] it was also pointed out, that the common EdS approximation for the non-linear F 2 kernel leads to errors that exceed the size of the one-loop bispectrum on large scales.…”

supporting

confidence: 87%

“…In addition, we checked that the remaining differences are consistent with the expected theoretical uncertainty due to missing higher-order corrections (viz. three-loop for the EFT two-loop result), as indicated by the gray shaded area [47]. Furthermore, we indicate the remaining variance in the N-body result by the red shaded area.…”

Section: B Resultsmentioning

confidence: 99%

“…Difference between perturbative and N-body results, normalized to the tree-level bispectrum, for three different shapes: equilateral (k, k, k), squeezed (∆k, k, k) with ∆k = 0.02h Mpc −1 , and isosceles (k/2, k, k). The gray shaded region shows the expected theoretical uncertainty at tree-level, one-and two-loop, from light to dark gray, respectively [47]. The red shading indicates the error of the N-body simulation results.…”

Section: B Resultsmentioning

confidence: 99%

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The two-loop bispectrum of large-scale structure

Baldauf,

Garny,

Taule

et al. 2021

Preprint

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The bispectrum is the leading non-Gaussian statistic in large-scale structure, carrying valuable information on cosmology that is complementary to the power spectrum. To access this information, we need to model the bispectrum in the weakly non-linear regime. In this work we present the first two-loop, i.e., next-to-next-to-leading order perturbative description of the bispectrum within an effective field theory (EFT) framework. Using an analytic expansion of the perturbative kernels up to F6 we derive a renormalized bispectrum that is demonstrated to be independent of the UV cutoff. We show that the EFT parameters associated with the four independent second-order EFT operators known from the one-loop bispectrum are sufficient to absorb the UV sensitivity of the twoloop contributions in the double-hard region. In addition, we employ a simplified treatment of the single-hard region, introducing one extra EFT parameter at two-loop order. We compare our results to N-body simulations using the realization-based grid-PT method and find good agreement within the expected range, as well as consistent values for the EFT parameters. The two-loop terms start to become relevant at k ≈ 0.07h Mpc −1 . The range of wavenumbers with percent-level agreement, independently of the shape, extends from 0.08h Mpc −1 to 0.15h Mpc −1 when going from one to two loops at z = 0. In addition, we quantify the impact of using exact instead of Einstein-de-Sitter kernels for the one-loop bispectrum, and discuss in how far their impact can be absorbed into a shift of the EFT parameters.

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supporting

confidence: 87%

Section: B Resultsmentioning

confidence: 99%

Section: B Resultsmentioning

confidence: 99%

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The two-loop bispectrum of large-scale structure

Baldauf,

Garny,

Taule

et al. 2021

Preprint

Self Cite

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“…Similarly, in the case of perturbation theory, uncertainty can arise from the contribution of neglected orders, approximations in the equations of motions, and also from neglected physics such as galaxy formation (see eg. Baldauf et al 2016). Our hybrid model will suffer from both sources of uncertainties.…”

Section: Fitting Proceduresmentioning

confidence: 99%

Modelling galaxy clustering in redshift space with a Lagrangian bias formalism and $N$-body simulations

Pellejero-Ibanez,

Stuecker,

Angulo

et al. 2021

Preprint

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Improving the theoretical description of galaxy clustering on small scales is an important challenge in cosmology, as it can considerably increase the scientific return of forthcoming galaxy surveys -e.g. tightening the bounds on neutrino masses and deviations from general relativity. In this paper we propose and test a new model for the clustering of galaxies that is able to accurately describe redshift-space distortions even down to small scales. This model corresponds to a second-order perturbative Lagrangian bias expansion which is advected to Eulerian space employing a displacement field extracted from 𝑁-body simulations. Eulerian coordinates are then transformed into redshift space by directly employing simulated velocity fields augmented with nuisance parameters capturing various possible satellite fractions and intra-halo small-scale velocities. We quantify the accuracy of our approach against samples of physically-motivated mock galaxies selected according to either Stellar Mass (SM) or Star Formation Rate (SFR) at multiple abundances and at 𝑧 = 0 and 1. We find our model describes the monopole, quadrupole and hexadecapole of the galaxy-power spectra down to scales of 𝑘 ≈ 0.6[ℎ/Mpc] within the accuracy of our simulations. This approach could pave the way to significantly increase the amount of cosmological information to be extracted from future galaxy surveys.

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“…and the Gaussian covariance matrix between triangle configurations is [51,52] C T T = (2π) 3 V i πs 123 dk 1 dk 2 dk 3 P (k 1 ) P (k 2 ) P (k 3 )…”

Section: Preliminary Estimate Of Observabilitymentioning

confidence: 99%

Missing Scalars at the Cosmological Collider

Lu,

Reece,

Xianyu

2021

Preprint

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Light scalar fields typically develop spatially varying backgrounds during inflation. Very often they do not directly affect the density perturbations, but interact with other fields that do leave nontrivial signals in primordial perturbations. In this sense they become "missing scalars" at the cosmological collider. We study potentially observable signals of these missing scalars, focusing on a special example where a missing scalar distorts the usual oscillatory features in the squeezed bispectrum. The distortion is also a useful signal distinguishing the de Sitter background induced thermal mass from a constant intrinsic mass.

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LSS constraints with controlled theoretical uncertainties

Cited by 103 publications

References 0 publications

The two-loop bispectrum of large-scale structure

The two-loop bispectrum of large-scale structure

Modelling galaxy clustering in redshift space with a Lagrangian bias formalism and $N$-body simulations

Missing Scalars at the Cosmological Collider

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