Large-scale structure formation with massive neutrinos and dynamical dark energy

Upadhye, Amol; Biswas, Rahul; Pope, Adrian; Heitmann, Katrin; Habib, Salman; Finkel, Hal; Frontiere, Nicholas

doi:10.1103/physrevd.89.103515

Cited by 57 publications

(96 citation statements)

References 81 publications

(128 reference statements)

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“…We follow the approach discussed in detail in Heitmann et al (2015), applying a small correction to account for the scale dependence of the growth function as discussed in Upadhye et al (2014). We provide a short summary of our neutrino treatment here and show comparisons to results found by other groups in Section 4.…”

Section: Treatment Of Neutrinosmentioning

confidence: 99%

“…Meanwhile, at higher redshifts z 1, our use of the scale-independent CDM + baryon growth factor leads to an error at large scales where neutrinos cannot be neglected. Fortunately, these scales are linear, and Upadhye et al (2014) showed that the resulting error can be removed by multiplying the N-body power spectrum by the k-…”

Section: Treatment Of Neutrinosmentioning

confidence: 99%

“…As explained in Section 2.2.1, we treat the neutrinos not as a separate species but evolve them only in the background, and we add the linear neutrino power spectrum to the P cb -component obtained from the simulation rather than compute the nonlinear neutrino power spectrum. The validity of the first assumption was tested in Upadhye et al (2014) using TimeRG perturbation theory. In the regime that the perturbative approach is valid, the agreement was excellent.…”

Section: Range Of Validitymentioning

confidence: 99%

“…We first evaluate the power spectrum using the TimeRG perturbative approach (introduced in Pietroni 2008), as described in Upadhye et al (2014). This provides a smooth and very accurate prediction of the power spectrum on large scales (small k), out to k ∼ 0.04Mpc −1 for 0 ≤ z ≤ 1 and k ∼ 0.14Mpc −1 for z ≤ 2.…”

Section: Simulationsmentioning

confidence: 99%

“…The inclusion of a dynamical dark energy component and massive neutrinos is nontrivial -the approach to the simulations is described in more detail in Heitmann et al (2015). Several tests of the simulation methodology were carried out in Upadhye et al (2014), where results on large scales were compared to TimeRG perturbation theory. Discussions of the range of validity and methods for adding baryonic corrections are provided in Section 3.1.…”

mentioning

confidence: 99%

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The Mira-Titan Universe. II. Matter Power Spectrum Emulation

Lawrence

Heitmann

Kwan

et al. 2017

ApJ

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156

205

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We introduce a new cosmic emulator for the matter power spectrum covering eight cosmological parameters. Targeted at optical surveys, the emulator provides accurate predictions out to a wavenumber k ∼ 5Mpc −1 and redshift z ≤ 2. Besides covering the standard set of ΛCDM parameters, massive neutrinos and a dynamical dark energy of state are included. The emulator is built on a sample set of 36 cosmological models, carefully chosen to provide accurate predictions over the wide and large parameter space. For each model, we have performed a high-resolution simulation, augmented with sixteen medium-resolution simulations and TimeRG perturbation theory results to provide accurate coverage of a wide k-range; the dataset generated as part of this project is more than 1.2Pbyte. With the current set of simulated models, we achieve an accuracy of approximately 4%. Because the sampling approach used here has established convergence and error-control properties, follow-on results with more than a hundred cosmological models will soon achieve ∼ 1% accuracy. We compare our approach with other prediction schemes that are based on halo model ideas and remapping approaches. The new emulator code is publicly available. Subject headings: methods: statistical -cosmology: large-scale structure of the universe

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Section: Treatment Of Neutrinosmentioning

confidence: 99%

Section: Treatment Of Neutrinosmentioning

confidence: 99%

Section: Range Of Validitymentioning

confidence: 99%

Section: Simulationsmentioning

confidence: 99%

mentioning

confidence: 99%

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The Mira-Titan Universe. II. Matter Power Spectrum Emulation

Lawrence

Heitmann

Kwan

et al. 2017

ApJ

Self Cite

156

205

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Large-scale dark matter simulations

Angulo

Hahn

2022

Living Rev Comput Astrophys

111

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We review the field of collisionless numerical simulations for the large-scale structure of the Universe. We start by providing the main set of equations solved by these simulations and their connection with General Relativity. We then recap the relevant numerical approaches: discretization of the phase-space distribution (focusing on N-body but including alternatives, e.g., Lagrangian submanifold and Schrödinger–Poisson) and the respective techniques for their time evolution and force calculation (direct summation, mesh techniques, and hierarchical tree methods). We pay attention to the creation of initial conditions and the connection with Lagrangian Perturbation Theory. We then discuss the possible alternatives in terms of the micro-physical properties of dark matter (e.g., neutralinos, warm dark matter, QCD axions, Bose–Einstein condensates, and primordial black holes), and extensions to account for multiple fluids (baryons and neutrinos), primordial non-Gaussianity and modified gravity. We continue by discussing challenges involved in achieving highly accurate predictions. A key aspect of cosmological simulations is the connection to cosmological observables, we discuss various techniques in this regard: structure finding, galaxy formation and baryonic modelling, the creation of emulators and light-cones, and the role of machine learning. We finalise with a recount of state-of-the-art large-scale simulations and conclude with an outlook for the next decade.

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HACC: Simulating sky surveys on state-of-the-art supercomputing architectures

et al. 2016

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Current and future surveys of large-scale cosmic structure are associated with a massive and complex datastream to study, characterize, and ultimately understand the physics behind the two major components of the 'Dark Universe', dark energy and dark matter. In addition, the surveys also probe primordial perturbations and carry out fundamental measurements, such as determining the sum of neutrino masses. Large-scale simulations of structure formation in the Universe play a critical role in the interpretation of the data and extraction of the physics of interest. Just as survey instruments continue to grow in size and complexity, so do the supercomputers that enable these simulations. Here we report on HACC (Hardware/Hybrid Accelerated Cosmology Code), a recently developed and evolving cosmology N-body code framework, designed to run efficiently on diverse computing architectures and to scale to millions of cores and beyond. HACC can run on all current supercomputer architectures and supports a variety of programming models and algorithms. It has been demonstrated at scale on Cell-and GPU-accelerated systems, standard multicore node clusters, and Blue Gene systems. HACC's design allows for ease of portability, and at the same time, high levels of sustained performance on the fastest supercomputers available. We present a description of the design philosophy of HACC, the underlying algorithms and code structure, and outline implementation details for several specific architectures. We show selected accuracy and performance results from some of the largest high resolution cosmological simulations so far performed, including benchmarks evolving more than 3.6 trillion particles.

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Large-scale structure formation with massive neutrinos and dynamical dark energy

Cited by 57 publications

References 81 publications

The Mira-Titan Universe. II. Matter Power Spectrum Emulation

The Mira-Titan Universe. II. Matter Power Spectrum Emulation

Large-scale dark matter simulations

HACC: Simulating sky surveys on state-of-the-art supercomputing architectures

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