GRAMSES: a new route to general relativistic <i>N</i>-body simulations in cosmology. Part II. Initial conditions

Barrera-Hinojosa, Cristian; Li, Baojiu

doi:10.1088/1475-7516/2020/04/056

Cited by 14 publications

(10 citation statements)

References 47 publications

(84 reference statements)

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“…As a final note, since our study is concerned only with large scales-and therefore small density contrasts-we expect our results to be well approximated in the weak-field limit of general relativity. Therefore, a re-analysis of the general observational effective parameters in the context of weak-field N-body cosmological simulations [i.e., gevolution, see [65][66][67] ], or simulations using the fullyconstrained formulation of GR i.e., GRAMSES, see [68,69] may produce similar results. This could also be investigated in the context of constrained cosmological simulations reconstructing the environment surrounding the local group, as done in [70].…”

Section: (B) Maximal Quadrupolar Anisotropies In the Effectivementioning

confidence: 99%

Luminosity distance and anisotropic sky-sampling at low redshifts: A numerical relativity study

MacPherson

Heinesen

2021

Phys. Rev. D

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Most cosmological data analysis today relies on the Friedmann-Lemaître-Robertson-Walker (FLRW) metric, providing the basis of the current standard cosmological model. Within this framework, interesting tensions between our increasingly precise data and theoretical predictions are coming to light. It is therefore reasonable to explore the potential for cosmological analysis outside of the exact FLRW cosmological framework. In this work we adopt the general luminosity-distance series expansion in redshift with no assumptions of homogeneity or isotropy. This framework will allow for a full model-independent analysis of near-future low-redshift cosmological surveys. We calculate the effective observational 'Hubble', 'deceleration', 'curvature' and 'jerk' parameters of the luminosity-distance series expansion in numerical relativity simulations of realistic structure formation, for observers located in different environments and with different levels of sky-coverage. With a 'fairly-sampled' sky, we find 2% and 15% cosmic variance in the 'Hubble' and 'deceleration' parameters for scales of 200 Mpc=h (corresponding to density contrasts of ∼0.1 in the simulated model universe), respectively. On top of this, we find that typical observers measure maximal sky-variance of 7% and 550% in the same parameters, as compared to their analogies in the large scale FLRW model. Our work suggests the inclusion of low-redshift anisotropy in cosmological analysis could be important for drawing correct conclusions about our Universe.

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Section: (B) Maximal Quadrupolar Anisotropies In the Effectivementioning

confidence: 99%

Luminosity distance and anisotropic sky-sampling at low redshifts: A numerical relativity study

MacPherson

Heinesen

2021

Phys. Rev. D

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“…The only danger through naming is to neglect correlations and covariances between different measurements 19. For cosmological N-body simulations, the readers might be interested to references[152][153][154].…”

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confidence: 99%

In the realm of the Hubble tension—a review of solutions ^*

Valentino

Mena²,

Pan³

et al. 2021

Class. Quantum Grav.

1,311

760

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The simplest ΛCDM model provides a good fit to a large span of cosmological data but harbors large areas of phenomenology and ignorance. With the improvement of the number and the accuracy of observations, discrepancies among key cosmological parameters of the model have emerged. The most statistically significant tension is the 4σ to 6σ disagreement between predictions of the Hubble constant, H 0, made by the early time probes in concert with the ‘vanilla’ ΛCDM cosmological model, and a number of late time, model-independent determinations of H 0 from local measurements of distances and redshifts. The high precision and consistency of the data at both ends present strong challenges to the possible solution space and demands a hypothesis with enough rigor to explain multiple observations—whether these invoke new physics, unexpected large-scale structures or multiple, unrelated errors. A thorough review of the problem including a discussion of recent Hubble constant estimates and a summary of the proposed theoretical solutions is presented here. We include more than 1000 references, indicating that the interest in this area has grown considerably just during the last few years. We classify the many proposals to resolve the tension in these categories: early dark energy, late dark energy, dark energy models with 6 degrees of freedom and their extensions, models with extra relativistic degrees of freedom, models with extra interactions, unified cosmologies, modified gravity, inflationary models, modified recombination history, physics of the critical phenomena, and alternative proposals. Some are formally successful, improving the fit to the data in light of their additional degrees of freedom, restoring agreement within 1–2σ between Planck 2018, using the cosmic microwave background power spectra data, baryon acoustic oscillations, Pantheon SN data, and R20, the latest SH0ES Team Riess, et al (2021 Astrophys. J. 908 L6) measurement of the Hubble constant (H 0 = 73.2 ± 1.3 km s−1 Mpc−1 at 68% confidence level). However, there are many more unsuccessful models which leave the discrepancy well above the 3σ disagreement level. In many cases, reduced tension comes not simply from a change in the value of H 0 but also due to an increase in its uncertainty due to degeneracy with additional physics, complicating the picture and pointing to the need for additional probes. While no specific proposal makes a strong case for being highly likely or far better than all others, solutions involving early or dynamical dark energy, neutrino interactions, interacting cosmologies, primordial magnetic fields, and modified gravity provide the best options until a better alternative comes along.

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“…The only danger through naming is to neglect correlations and covariances between different measurements. 7 For cosmological N-body simulations, the readers might be interested to Refs [150][151][152]…”

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confidence: 99%

In the Realm of the Hubble tension $-$ a Review of Solutions

Di Valentino,

Mena,

Pan

et al. 2021

Preprint

178

252

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The simplest ΛCDM model provides a good fit to a large span of cosmological data but harbors large areas of phenomenology and ignorance. With the improvement of the number and the accuracy of observations, discrepancies among key cosmological parameters of the model have emerged. The most statistically significant tension is the 4σ to 6σ disagreement between predictions of the Hubble constant, H 0 , made by the early time probes in concert with the "vanilla" ΛCDM Cosmological model, and a number of late time, model-independent determinations of H 0 from local measurements of distances and redshifts. The high precision and consistency of the data at both ends present strong challenges to the possible solution space and demands a hypothesis with enough rigor to explain multiple observations-whether these invoke new physics, unexpected large-scale structures or multiple, unrelated errors. A thorough review of the problem including a discussion of recent Hubble constant estimates and a summary of the proposed theoretical solutions is presented here. We include more than 850 references, indicating that the interest in this area has grown considerably just during the last few years. We classify the many proposals to resolve the tension in these categories: Early Dark Energy, Late Dark Energy, Dark energy models with 6 degrees of freedom and their extensions, Models with extra relativistic degrees of freedom, Models with Extra Interactions, Unified cosmologies, Modified gravity, Inflationary models, Modified recombination history, Physics of the critical Phenomena, and Alternative proposals. Some are formally successful, improving the fit to the data in light of their additional degrees of freedom, restoring agreement within 1 − 2σ between Planck 2018, using the Cosmic Microwave Background power spectra data, Baryon Acoustic Oscillations, Pantheon SN data, and R20, the latest SH0ES Team [2] measurement of the Hubble constant (H 0 = 73.2 ± 1.3 km s −1 Mpc −1 at 68% confidence level). However, there are many more unsuccessful models which leave the discrepancy well above the 3σ disagreement level. In many cases, reduced tension comes not simply from a change in the value of H 0 but also due to an increase in its uncertainty due to degeneracy with additional physics, complicating the picture and pointing to the need for additional probes. While no specific proposal makes a strong case for being highly likely or far better than all others, solutions involving early or dynamical dark energy, neutrino interactions, interacting cosmologies, primordial magnetic fields, and modified gravity provide the best options until a better alternative comes along.

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GRAMSES: a new route to general relativistic N-body simulations in cosmology. Part II. Initial conditions

Cited by 14 publications

References 47 publications

Luminosity distance and anisotropic sky-sampling at low redshifts: A numerical relativity study

Luminosity distance and anisotropic sky-sampling at low redshifts: A numerical relativity study

In the realm of the Hubble tension—a review of solutions ^*

In the Realm of the Hubble tension $-$ a Review of Solutions

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GRAMSES: a new route to general relativistic N-body simulations in cosmology. Part II. Initial conditions

Cited by 14 publications

References 47 publications

Luminosity distance and anisotropic sky-sampling at low redshifts: A numerical relativity study

Luminosity distance and anisotropic sky-sampling at low redshifts: A numerical relativity study

In the realm of the Hubble tension—a review of solutions *

In the Realm of the Hubble tension $-$ a Review of Solutions

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Product

Resources

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In the realm of the Hubble tension—a review of solutions ^*