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Cosmological $N$-body simulations are typically purely run with particles using Newtonian equations of motion. However, such simulations can be made fully consistent with general relativity using a well-defined prescription. Here, we extend…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-20 Thomas Tram , Jacob Brandbyge , Jeppe Dakin , Steen Hannestad

The signature left in quasar spectra by the presence of neutral hydrogen in the Universe allows one to constrain the sum of the neutrino masses with improved sensitivity, with respect to laboratory experiments, and may shed a new light on…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-05 Graziano Rossi , Nathalie Palanque-Delabrouille , Arnaud Borde , Matteo Viel , Christophe Yeche , James S. Bolton , James Rich , Jean-Marc Le Goff

Providing an accurate modeling of neutrino physics in dense astrophysical environments such as binary neutron star mergers presents a challenge for hydrodynamic simulations. Nevertheless, understanding how flavor transformation can occur…

High Energy Astrophysical Phenomena · Physics 2025-01-15 Julien Froustey , Sherwood Richers , Evan Grohs , Samuel Flynn , Francois Foucart , James P. Kneller , Gail C. McLaughlin

Nonuniform neutron-rich matter present in both core-collapse supernovae and neutron-star crusts is described in terms of a semiclassical model that reproduces nuclear-matter properties and includes long-range Coulomb interactions. The…

Astrophysics · Physics 2009-11-10 C. J. Horowitz , M. A. Perez-Garcia , J. Carriere , D. K. Berry , J. Piekarewicz

We propose a new method for calculating spectra and luminosities for (anti)neutrinos produced in the pre-supernova environment by weak processes with hot nuclei. It is based on the thermal quasiparticle random phase approximation (TQRPA),…

Nuclear Theory · Physics 2023-12-14 A. A. Dzhioev , A. V. Yudin , N. V. Dunina-Barkovskaya , A. I. Vdovin

Velocity dispersion of the massive neutrinos presents a daunting challenge for non-linear cosmological perturbation theory. We consider the neutrino population as a collection of non-linear fluids, each with uniform initial momentum,…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-18 Joe Zhiyu Chen , Amol Upadhye , Yvonne Y. Y. Wong

N-body simulations are essential for understanding the formation and evolution of structure in the Universe. However, the discrete nature of these simulations affects their accuracy when modelling collisionless systems. We introduce a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Oliver Hahn , Raul E. Angulo

We develop a highly accurate analytic approximation for small-scale non-cold relic perturbations by solving the collisionless Boltzmann equation in the quasi-stationary regime. The approximation is implemented in CLASSIER (CLASS Integral…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-20 Nanoom Lee , Yacine Ali-Haïmoud , Marc Kamionkowski

We discuss the cold dark matter plus massive neutrinos simulations of the MillenniumTNG (MTNG) project, which aim to improve understanding of how well ongoing and future large-scale galaxy surveys will measure neutrino masses. Our largest…

This work presents a hybrid modeling approach to data-driven learning and representation of unknown physical processes and closure parameterizations. These hybrid models are suitable for situations where the mechanistic description of…

Computational Physics · Physics 2021-08-17 Suraj Pawar , Omer San , Adil Rasheed , Ionel M. Navon

In the last years, chiral effective field theory has been successfully developed for and applied to systems with few nucleons. Here, I present a new approach for ab initio calculations of nuclei that combines these precise and systematic…

Nuclear Theory · Physics 2015-05-27 Ulf-G. Meißner

Future large scale structure observations are expected to be sensitive to small neutrino masses, of the order of 0.05 eV or more. However, forecasts are based on the assumption that by the time at which these datasets will be available, the…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-05 J. Lesgourgues , S. Matarrese , M. Pietroni , A. Riotto

Simulating the distribution of cosmological neutral hydrogen (HI) during the epoch of reionization requires a high dynamic range and is hence computationally expensive. The size of the simulation is dictated by the largest scales one aims…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-24 Ankur Barsode , Tirthankar Roy Choudhury

We present a novel scattering emulator utilizing the complex scaling method to enhance nuclear reaction analysis. This approach leverages a single set of reduced bases, allowing for efficient and simultaneous emulation across multiple…

Nuclear Theory · Physics 2024-10-24 Junzhe Liu , Jin Lei , Zhongzhou Ren

Cosmological neutrinos strongly affect the evolution of the largest structures in the Universe, i.e. galaxies and galaxy clusters. We use large box-size full hydrodynamic simulations to investigate the non-linear effects that massive…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-16 Federico Marulli , Carmelita Carbone , Matteo Viel , Lauro Moscardini , Andrea Cimatti

Predictive simulations of complex systems are essential for applications ranging from weather forecasting to drug design. The veracity of these predictions hinges on their capacity to capture the effective system dynamics. Massively…

Computational Physics · Physics 2021-10-20 Pantelis R. Vlachas , Georgios Arampatzis , Caroline Uhler , Petros Koumoutsakos

The non-trivial phase-space distribution of relic neutrinos is responsible for the erasure of primordial density perturbations on small scales, which is one of the main cosmological signatures of neutrino mass. In this paper, we present a…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-07 Willem Elbers

We report a Vlasov simulation of cosmic relic neutrinos combined with N-body simulation of cold dark matter in the context of large-scale structure formation in the Universe performed on Fugaku supercomputer. Gravitational dynamics of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-01 Kohji Yoshikawa , Satoshi Tanaka , Naoki Yoshida

We propose an algorithm, deployable on a highly-parallelized graph computing architecture, to perform rapid reconstruction of charged-particle trajectories in the high energy collisions at the Large Hadron Collider and future colliders. We…

Instrumentation and Detectors · Physics 2020-01-22 Ashutosh V. Kotwal

The standard numerical tools for studying non-linear collapse of matter are Newtonian $N$-body simulations. Previous work has shown that these simulations are in accordance with General Relativity (GR) up to first order in perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-07 Christian Fidler , Thomas Tram , Cornelius Rampf , Robert Crittenden , Kazuya Koyama , David Wands