Kinematic Morphology of Large-Scale Structure: Evolution From Potential to Rotational Flow

Wang, Xin; Szalay, Alexander S.; Aragón-Calvo, M. A.; Neyrinck, Mark C.; Eyink, Gregory L.

doi:10.1088/0004-637x/793/1/58

Cited by 33 publications

(47 citation statements)

References 50 publications

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“…After defining the rotational invariants of tensor A ij , which essentially combines both potential and rotational information of A ij , Wang et al (2014) demonstrated that the distinct correlation between vorticity generation and cosmic web structure could be phenomenologically explained by a stochastic process that drives the transition from potential to rotational flow in their parameter space. To some extent, this generalized dynamics has a similar underlying philosophy to the approach of the effective field theory (EFT) of the large-scale structure (Baumann et al 2012;Carrasco et al 2012;Pajer & Zaldarriaga 2013;Hertzberg 2014;Mercolli & Pajer 2014), where new operators that are compatible with the symmetries of the problem were introduced to effectively describe the evolution of large-scale modes.…”

Section: Stochasticity and Effective Fluid Elementsmentioning

confidence: 99%

Statistical Decoupling of a Lagrangian Fluid Parcel in Newtonian Cosmology

Wang

Szalay

2016

ApJ

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The Lagrangian dynamics of a single fluid element within a self-gravitational matter field is intrinsically non-local due to the presence of the tidal force. This complicates the theoretical investigation of the nonlinear evolution of various cosmic objects, e.g., dark matter halos, in the context of Lagrangian fluid dynamics, since fluid parcels with given initial density and shape may evolve differently depending on their environments. In this paper, we provide a statistical solution that could decouple this environmental dependence. After deriving the evolution equation for the probability distribution of the matter field, our method produces a set of closed ordinary differential equations whose solution is uniquely determined by the initial condition of the fluid element. Mathematically, it corresponds to the projected characteristic curve of the transport equation of the density-weighted probability density function (ρPDF). Consequently it is guaranteed that the one-point ρPDF would be preserved by evolving these local, yet nonlinear, curves with the same set of initial data as the real system. Physically, these trajectories describe the mean evolution averaged over all environments by substituting the tidal tensor with its conditional average. For Gaussian distributed dynamical variables, this mean tidal tensor is simply proportional to the velocity shear tensor, and the dynamical system would recover the prediction of the Zel'dovich approximation (ZA) with the further assumption of the linearized continuity equation. For a weakly non-Gaussian field, the averaged tidal tensor could be expanded perturbatively as a function of all relevant dynamical variables whose coefficients are determined by the statistics of the field.

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Section: Stochasticity and Effective Fluid Elementsmentioning

confidence: 99%

Statistical Decoupling of a Lagrangian Fluid Parcel in Newtonian Cosmology

Wang

Szalay

2016

ApJ

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“…Therefore, as time progresses, vorticity is produced on ever larger scales. It is difficult to study analytically the production of vorticity and many works have used dedicated N -body simulations in order to obtain its magnitude and time/scale dependence [18,19,20]. In particular, the results of [19,20] show how vorticity is correlated with the density contrast and that it becomes important (as compared to the velocity divergence) at small scales and/or at early times.…”

Section: Discussionmentioning

confidence: 99%

“…For ν = 0 the system of equations (18)(19)(20)(21)(22)(23) reduces to the standard case of an uncoupled quintessence field with exponential potential. In particular, if λ 2 < 3 there is a stable (accelerated for λ 2 < 2) attractor with Ω φ = 1 and w φ = w eff = −1 + λ 2 3 (scalar field-dominated solution); and, if λ 2 > 3, a stable attractor with Ω φ = 3 λ 2 and w φ = w eff = 0 (scaling solution).…”

Section: Limiting Casesmentioning

confidence: 99%

Coupling dark energy to dark matter inhomogeneities

Marra

2016

Physics of the Dark Universe

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We propose that dark energy in the form of a scalar field could effectively couple to dark matter inhomogeneities. Through this coupling energy could be transferred to/from the scalar field, which could possibly enter an accelerated regime. Though phenomenological, this scenario is interesting as it provides a natural trigger for the onset of the acceleration of the universe, since dark energy starts driving the expansion of the universe when matter inhomogeneities become sufficiently strong. Here we study a possible realization of this idea by coupling dark energy to dark matter via the linear growth function of matter perturbations. The numerical results show that it is indeed possible to obtain a viable cosmology with the expected series of radiation, matter and dark-energy dominated eras. In particular, the current density of dark energy is given by the value of the coupling parameters rather than by very special initial conditions for the scalar field. In other words, this model - unlike standard models of cosmic late acceleration - does not suffer from the so-called "coincidence problem" and its related fine tuning of initial conditions.Comment: 12 pages, 2 figures; revised and expanded discussion of proposed interaction and figures; matches version accepted for publication in Physics of the Dark Univers

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“…1. Illustration of structure type classification in Lagrangian invariants space, according to the lich procedure (see also figure 3 in Wang et al ., 2014). We show the s3 − s2 plane for s1 < 0 (left panel) and s1 > 0 (right panel).…”

Section: Lichmentioning

confidence: 99%

The phase-space structure of nearby dark matter as constrained by the SDSS

Leclercq

Jasche

Lavaux

et al. 2017

J. Cosmol. Astropart. Phys.

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Previous studies using numerical simulations have demonstrated that the shape of the cosmic web can be described by studying the Lagrangian displacement field. We extend these analyses, showing that it is now possible to perform a Lagrangian description of cosmic structure in the nearby Universe based on large-scale structure observations. Building upon recent Bayesian large-scale inference of initial conditions, we present a cosmographic analysis of the dark matter distribution and its evolution, referred to as the dark matter phase-space sheet, in the nearby universe as probed by the Sloan Digital Sky Survey main galaxy sample. We consider its stretchings and foldings using a tetrahedral tessellation of the Lagrangian lattice. The method provides extremely accurate estimates of nearby density and velocity fields, even in regions of low galaxy density. It also measures the number of matter streams, and the deformation and parity reversals of fluid elements, which were previously thought inaccessible using observations. We illustrate the approach by showing the phase-space structure of known objects of the nearby Universe such as the Sloan Great Wall, the Coma cluster and the Boötes void. We dissect cosmic structures into four distinct components (voids, sheets, filaments, and clusters), using the Lagrangian classifiers diva, origami, and a new scheme which we introduce and call lich. Because these classifiers use information other than the sheer local density, identified structures explicitly carry physical information about their formation history. Accessing the phase-space structure of dark matter in galaxy surveys opens the way for new confrontations of observational data and theoretical models. We have made our data products publicly available.

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Kinematic Morphology of Large-Scale Structure: Evolution From Potential to Rotational Flow

Cited by 33 publications

References 50 publications

Statistical Decoupling of a Lagrangian Fluid Parcel in Newtonian Cosmology

Statistical Decoupling of a Lagrangian Fluid Parcel in Newtonian Cosmology

Coupling dark energy to dark matter inhomogeneities

The phase-space structure of nearby dark matter as constrained by the SDSS

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