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We introduce our new binary tree code for neighbour search and gravitational force calculations in an N-particle system. The tree is built in a "top-down" fashion by "recursive coordinate bisection" where on each tree level we split the…

Instrumentation and Methods for Astrophysics · Physics 2011-11-24 Emanuel Gafton , Stephan Rosswog

Miller and Reif's FOCS'85 classic and fundamental tree contraction algorithm is a broadly applicable technique for the parallel solution of a large number of tree problems. Additionally it is also used as an algorithmic design technique for…

Data Structures and Algorithms · Computer Science 2021-11-04 MohammadTaghi Hajiaghayi , Marina Knittel , Hamed Saleh , Hsin-Hao Su

We present a hybrid technique of N-body simulation to deal with collisionless stellar systems having an inhomogeneous global structure. We combine a treecode and a self-consistent field code such that each of the codes model a different…

Astrophysics · Physics 2009-10-30 S. Vine , S. Sigurdsson

Cosmological N-Body simulations are used for a variety of applications. Indeed progress in the study of large scale structures and galaxy formation would have been very limited without this tool. For nearly twenty years the limitations…

Astrophysics · Physics 2010-05-07 J. S. Bagla , Nishikanta Khandai

We consider a machine learning algorithm to detect and identify strong gravitational lenses on sky images. First, we simulate different artificial but very close to reality images of galaxies, stars and strong lenses, using six different…

Instrumentation and Methods for Astrophysics · Physics 2021-04-06 H. G. Khachatryan

Magnetic fields play an important role in many astrophysical systems and a detailed understanding of their impact on the gas dynamics requires robust numerical simulations. Here we present a new method to evolve the ideal…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Philip Mocz , Mark Vogelsberger , Lars Hernquist

The dynamics of physical systems is often constrained to lower dimensional sub-spaces due to the presence of conserved quantities. Here we propose a method to learn and exploit such symmetry constraints building upon Hamiltonian Neural…

Machine Learning · Computer Science 2021-04-30 Marc Syvaeri , Sven Krippendorf

Cartesian tree matching is the problem of finding all substrings of a given text which have the same Cartesian trees as that of a given pattern. So far there is one linear-time solution for Cartesian tree matching, which is based on the KMP…

Data Structures and Algorithms · Computer Science 2019-08-15 Siwoo Song , Cheol Ryu , Simone Faro , Thierry Lecroq , Kunsoo Park

(A) The momentum density conjugate to a bosonic quantum field splits naturally into the sum of a classical component and a nonclassical component. It is shown that the field and the nonclassical component of the momentum density satisfy…

High Energy Physics - Theory · Physics 2007-05-23 Michael J. W. Hall , Kailash Kumar , Marcel Reginatto

Gyrokinetic theory is arguably the most important tool for numerical studies of transport physics in magnetized plasmas. However, exact local energy-momentum conservation law for the electromagnetic gyrokinetic system has not been found…

Plasma Physics · Physics 2021-09-22 Peifeng Fan , Hong Qin , Jianyuan Xiao

Various adaptive abilities are required for robots interacting with humans in daily life. It is difficult to design adaptive algorithms manually; however, by using end-to-end machine learning, labor can be saved during the design process.…

Robotics · Computer Science 2019-09-20 Kazuki Fujimoto , Sho Sakaino , Toshiaki Tsuji

Binary systems with neutron stars and double degenerate systems are crucial objects to test current stellar evolution models and Einstein's general relativity. In this study, we present angular momentum loss mechanism via gravitational…

Solar and Stellar Astrophysics · Physics 2016-03-15 T. İçli , K. Yakut

The recent gravitational wave observations provide insight into the extreme gravity regime of coalescing binaries, where gravity is strong, dynamical and non-linear. The interpretation of these observations relies on the comparison of the…

General Relativity and Quantum Cosmology · Physics 2018-12-19 Alexander Saffer , Nicolas Yunes

In many so-called "beyond-mean-field" many-body methods, one creates symmetry-breaking states and then projects out states with good quantum number(s); the most important example is angular momentum. Motivated by the computational intensity…

Nuclear Theory · Physics 2018-12-05 Calvin W. Johnson , Changfeng Jiao

Recent progress on deep learning relies heavily on the quality and efficiency of training algorithms. In this paper, we develop a fast training method motivated by the nonlinear Conjugate Gradient (CG) framework. We propose the Conjugate…

Machine Learning · Computer Science 2021-07-28 Zhiyong Hao , Yixuan Jiang , Huihua Yu , Hsiao-Dong Chiang

Simulations at the atomic scale provide a direct and effective way to understand the mechanical properties of materials. In the regime of classical mechanics, simulations for the thermodynamic properties of metals and alloys can be done by…

Computational Physics · Physics 2019-11-05 Ka-Ming Tam , Nicholas Walker , Samuel Kellar , Mark Jarrell

We have proposed new algorithms for the numerical integration of the equations of motion for classical spin systems. In close analogy to symplectic integrators for Hamiltonian equations of motion used in Molecular Dynamics these algorithms…

Statistical Mechanics · Physics 2009-10-31 M. Krech , Alex Bunker , D. P. Landau

In the present study, we consider general form of the Lagrangian $ f(R, \phi^{I}, X) $, that is a function of the Ricci scalar, multiple scalar fields and non-canonical kinetic terms. We obtain the effective Newton's constant deep inside…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Habib Abedi , Amir M. Abbassi

Following a comprehensive analysis of the historical literature, we model the geometry of the Stern$\unicode{x2013}$Gerlach experiment to numerically calculate the magnetic field using the finite-element method. Using this calculated field…

Computational Physics · Physics 2024-08-28 Faraz Mostafaeipour , S. Suleyman Kahraman , Kelvin Titimbo , Yixuan Tan , Lihong V. Wang

We develop a tensor network technique that can solve universal reversible classical computational problems, formulated as vertex models on a square lattice [Nat. Commun. 8, 15303 (2017)]. By encoding the truth table of each vertex…

Statistical Mechanics · Physics 2018-03-09 Zhi-Cheng Yang , Stefanos Kourtis , Claudio Chamon , Eduardo R. Mucciolo , Andrei E. Ruckenstein