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We present N-body simulations of unstable spiral modes in a dynamically cool collisionless disc. We show that spiral modes grow in a thin collisionless disk in accordance with the analytical perturbation theory. We use the particle-mesh…

Astrophysics · Physics 2009-11-13 A. V. Khoperskov , A. Just , V. I. Korchagin , M. A. Jalali

We describe in detail the general methodology and numerical implementation of consistent N-body simulations for coupled scalar field cosmological models, including the background cosmology and the generation of initial conditions (with the…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 Baojiu Li , John D. Barrow

Kinetic equations model the position-velocity distribution of particles subject to transport and collision effects. Under a diffusive scaling, these combined effects converge to a diffusion equation for the position density in the limit of…

Numerical Analysis · Mathematics 2023-07-26 Emil Løvbak , Giovanni Samaey

I review the evolution of binary supermassive black holes and focus on the stellar-dynamical mechanisms that may help to overcome the final-parsec problem - the possible stalling of the binary at a separation much larger than is required…

Astrophysics of Galaxies · Physics 2017-04-24 Eugene Vasiliev

We build a field level emulator for cosmic structure formation that is accurate in the nonlinear regime. Our emulator consists of two convolutional neural networks trained to output the nonlinear displacements and velocities of N-body…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-02 Drew Jamieson , Yin Li , Renan Alves de Oliveira , Francisco Villaescusa-Navarro , Shirley Ho , David N. Spergel

In this article, we propose a Frozen Gaussian Sampling (FGS) algorithm for simulating nonadiabatic quantum dynamics at metal surfaces with a continuous spectrum. This method consists of a Monte-Carlo algorithm for sampling the initial wave…

Computational Physics · Physics 2022-11-30 Zhen Huang , Limin Xu , Zhennan Zhou

The Millennium N-body simulation and the Sloan Digital Sky Survey seventh data release (SDSS DR7) galaxy and galaxy group catalogues are compared to study the properties of galaxy groups and the distribution of galaxies in groups. We…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-29 P. Nurmi , P. Heinämäki , T. Sepp , E. Tago , E. Saar , M. Gramann , M. Einasto , E. Tempel , J. Einasto

We apply and test a field-level emulator for non-linear cosmic structure formation in a volume matching next-generation surveys. Inferring the cosmological parameters and initial conditions from which the particular galaxy distribution of…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-20 Matthew T. Scoggins , Matthew Ho , Francisco Villaescusa-Navarro , Drew Jamieson , Ludvig Doeser , Greg L. Bryan

We revisit a method to incorporate the Vainshtein screening mechanism in N-body simulations proposed by R. Scoccimarro in~\cite{Scoccimarro:2009eu}. We further extend this method to cover a subset of Horndeski theories that evade the bound…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-28 Guilherme Brando , Kazuya Koyama , Hans A. Winther

Fixed-node diffusion Monte Carlo (FNDMC) is a stochastic quantum many-body method that has a great potential in electronic structure theory. We examine how FNDMC satisfies exact constraints, linearity and derivative discontinuity of total…

Chemical Physics · Physics 2019-10-16 Matej Ditte , Matus Dubecky

We propose a method to estimate non-Gaussian error bars on the matter power spectrum from galaxy surveys in the presence of non-trivial survey selection functions. The estimators are often obtained from formalisms like FKP and PKL, which…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Joachim Harnois-Deraps , Ue-Li Pen

We present a new, simple, fast algorithm to numerically evolve disks of inelastically colliding particles surrounding a central star. Our algorithm adds negligible computational cost to the fastest existing collisionless N-body codes, and…

Astrophysics · Physics 2008-11-26 Yoram Lithwick , Eugene Chiang

In this work we establish and test methods for implementing dynamical friction for massive black hole pairs that form in large volume cosmological hydrodynamical simulations which include galaxy formation and black hole growth. We verify…

Astrophysics of Galaxies · Physics 2021-12-08 Nianyi Chen , Yueying Ni , Michael Tremmel , Tiziana Di Matteo , Simeon Bird , Colin DeGraf , Yu Feng

The microphysical properties of the DM particle can, in principle, be constrained by the properties and abundance of substructures in DM halos, as measured through strong gravitational lensing. Unfortunately, there is a lack of accurate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Raul E. Angulo , Ruizhu Chen , Stefan Hilbert , Tom Abel

Fuzzy dark matter (FDM) made of ultra-light bosonic particles is a viable alternative to cold dark matter (CDM) with clearly distinguishable small-scale features in collapsed structures. On large scales, it behaves gravitationally like CDM…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-11 Bodo Schwabe , Jens C. Niemeyer

The class of $\alpha$-stable distributions enjoys multiple practical applications in signal processing, finance, biology and other areas because it allows to describe interesting and complex data patterns, such as asymmetry or heavy tails,…

Methodology · Statistics 2016-06-03 Eugenia Koblents , Joaquin Miguez , Marco A. Rodriguez , Alexandra M. Schmidt

We consider some aspects of a standard model employed in studies of many-body localization: interacting spinless fermions with quenched disorder, for non-zero filling fraction, here on $d$-dimensional lattices. The model may be recast as an…

Strongly Correlated Electrons · Physics 2019-01-10 Staszek Welsh , David E. Logan

Using N-body simulations and galaxy formation models, we study the galaxy stellar mass correlation and the two-point auto-correlation. The simulations are run with cosmological parameters from the WMAP first, third and seven year results,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 X. Kang , M. Li , W. P. Lin , P. J. Elahi

The modeling of out-of-equilibrium many-body systems requires to go beyond the low-energy physics and local densities of states. Many-body localization, presence or lack of thermalization and quantum chaos are examples of phenomena in which…

Statistical Mechanics · Physics 2023-06-21 Rémi Lefèvre , Krissia Zawadzki , Grégoire Ithier

Simulation based inference has seen increasing interest in the past few years as a promising approach to model the non linear scales of galaxy clustering. The common approach using Gaussian process is to train an emulator over the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Tyann Dumerchat , Julian Bautista