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N-body algorithms for long-range unscreened interactions like gravity belong to a class of highly irregular problems whose optimal solution is a challenging task for present-day massively parallel computers. In this paper we describe a…

Computational Physics · Physics 2009-10-30 U. Becciani , R. Ansaloni , V. Antonuccio-Delogu , G. Erbacci , M. Gambera , A. Pagliaro , -

Cosmological large scale structure $N$-body simulations are computation-light, memory-heavy problems in supercomputing. The considerable amount of memory is usually dominated by an inefficient way of storing more than sufficient phase space…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-31 Hao-Ran Yu , Ue-Li Pen , Xin Wang

A particle-in-cell algorithm is derived with a canonical Poisson structure in the formalism of finite element exterior calculus. The resulting method belongs to the class of gauge-compatible splitting algorithms, which exactly preserve…

Plasma Physics · Physics 2022-05-05 Alexander S. Glasser , Hong Qin

We present a new N-body and gas dynamics code, called Nyx, for large-scale cosmological simulations. Nyx follows the temporal evolution of a system of discrete dark matter particles gravitationally coupled to an inviscid ideal fluid in an…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 Ann Almgren , John Bell , Mike Lijewski , Zarija Lukić , Ethan Van Andel

We present an algorithm to simulate the many-body depletion interaction between anisotropic colloids in an implicit way, integrating out the degrees of freedom of the depletants, which we treat as an ideal gas. Because the depletant…

Soft Condensed Matter · Physics 2015-08-31 Jens Glaser , Andrew S. Karas , Sharon C. Glotzer

We present a low-space overhead simulation algorithm based on the truncated Dyson series for time-dependent quantum dynamics. This algorithm is applied to simulating time-independent Hamiltonians by transitioning to the interaction picture,…

Quantum Physics · Physics 2019-06-07 Guang Hao Low , Nathan Wiebe

Splitting schemes are numerical integrators for Hamiltonian problems that may advantageously replace the St\"ormer-Verlet method within Hamiltonian Monte Carlo (HMC) methodology. However, HMC performance is very sensitive to the step size…

Numerical Analysis · Mathematics 2022-12-02 F. Diele , C. Marangi , C. Tamborrino , C. Tarantino

We study a graph partitioning problem motivated by the simulation of the physical movement of multi-body systems on an atomistic level, where the forces are calculated from a quantum mechanical description of the electrons. Several advanced…

Hamiltonian systems such as the gravitational N-body problem have time-reversal symmetry. However, all numerical N-body integration schemes, including symplectic ones, respect this property only approximately. In this paper, we present the…

Instrumentation and Methods for Astrophysics · Physics 2017-11-29 Hanno Rein , Daniel Tamayo

Phase-space representations are a family of methods for dynamics of both bosonic and fermionic systems, that work by mapping the system's density matrix to a quasi-probability density and the Liouville-von Neumann equation of the…

Quantum Gases · Physics 2023-04-24 F. Rousse , O. Eriksson , M. Ogren

Time integration of ODEs or time-dependent PDEs with required resolution of the fastest time scales of the system, can be very costly if the system exhibits multiple time scales of different magnitudes. If the different time scales are…

Numerical Analysis · Mathematics 2012-05-15 Anders Logg

Simulating the evolution of the gravitational N-body problem becomes extremely computationally expensive as N increases since the problem complexity scales quadratically with the number of bodies. We study the use of Artificial Neural…

Earth and Planetary Astrophysics · Physics 2023-11-01 Veronica Saz Ulibarrena , Philipp Horn , Simon Portegies Zwart , Elena Sellentin , Barry Koren , Maxwell X. Cai

We generalize a recently developed method for accelerated Monte Carlo calculation of path integrals to the physically relevant case of generic many-body systems. This is done by developing an analytic procedure for constructing a hierarchy…

Statistical Mechanics · Physics 2011-08-08 Aleksandar Bogojevic , Ivana Vidanovic , Antun Balaz , Aleksandar Belic

We introduce a new approach for the robust control of quantum dynamics of strongly interacting many-body systems. Our approach involves the design of periodic global control pulse sequences to engineer desired target Hamiltonians that are…

Quantum Physics · Physics 2020-07-08 Joonhee Choi , Hengyun Zhou , Helena S. Knowles , Renate Landig , Soonwon Choi , Mikhail D. Lukin

A systolic algorithm rhythmically computes and passes data through a network of processors. We investigate the performance of systolic algorithms for implementing the gravitational N-body problem on distributed-memory computers. Systolic…

Astrophysics · Physics 2009-11-07 E. N. Dorband , Marc Hemsendorf , David Merritt

We present a method for efficient differentiable simulation of articulated bodies. This enables integration of articulated body dynamics into deep learning frameworks, and gradient-based optimization of neural networks that operate on…

Machine Learning · Computer Science 2021-09-17 Yi-Ling Qiao , Junbang Liang , Vladlen Koltun , Ming C. Lin

The code we describe (FLY) is a newly written code (using the tree N-body method), for three-dimensional self-gravitating collisionless systems evolution. FLY is a fully parallel code based on the tree Barnes-Hut algorithm and periodical…

Astrophysics · Physics 2009-11-06 U. Becciani , V. Antonuccio-Delogu

Gas-poor galaxies can be modelled as composite collisionless stellar systems, with a dark matter halo and one or more stellar components, representing different stellar populations. The dynamical evolution of such composite systems is often…

Astrophysics of Galaxies · Physics 2021-03-24 Carlo Nipoti , Giacomo Cherchi , Giuliano Iorio , Francesco Calura

An improved implementation of an N-body code for simulating collisionless cosmological dynamics is presented. TPM (Tree-Particle-Mesh) combines the PM method on large scales with a tree code to handle particle-particle interactions at small…

Astrophysics · Physics 2009-11-07 Paul Bode , Jeremiah P. Ostriker

We present a new approach to describe the dynamics of an isolated, gravitationally bound astronomical $N$-body system in the weak field and slow-motion approximation of the general theory of relativity. Celestial bodies are described using…

General Relativity and Quantum Cosmology · Physics 2015-03-30 Slava G. Turyshev , Viktor T. Toth