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A new computationally efficient method has been introduced to treat self-gravity in mesh based hydrodynamical simulations. It is applied simply by slightly modifying the Poisson equation into an inhomogeneous wave equation. This roughly…

Instrumentation and Methods for Astrophysics · Physics 2016-04-20 Ryosuke Hirai , Hiroki Nagakura , Hirotada Okawa , Kotaro Fujisawa

The Bethe-Salpeter approach allows for quantum-field-theoretic descriptions of relativistic bound states; its inherent complexity, however, usually prevents to find its exact solutions. Under suitable simplifying assumptions about the…

High Energy Physics - Phenomenology · Physics 2013-05-30 Wolfgang Lucha , Franz F. Schoberl

With the aim of identifying universal trends, we compare fully self-consistent electronic spectra and total energies obtained from the GW approximation with those from an extended GWGamma scheme that includes a nontrivial vertex function…

Materials Science · Physics 2007-05-23 Arno Schindlmayr , Thomas J. Pollehn , R. W. Godby

Ground State Energy Estimation (GSEE) is a central problem in quantum chemistry and condensed matter physics, demanding efficient algorithms to solve complex electronic structure calculations. This work introduces a structured benchmarking…

Higher order fluctuation expansions for stochastic heat equations (SHE) with nonlinear, non-conservative and conservative noise are obtained. These Edgeworth-type expansions describe the asymptotic behavior of solutions in suitable joint…

Probability · Mathematics 2024-06-27 Benjamin Gess , Zhengyan Wu , Rangrang Zhang

We introduce a method for solving a self consistent electronic calculation within localized atomic orbitals, that allows us to converge to the complete basis set (CBS) limit in a stable, controlled, and systematic way. We compare our…

Strongly Correlated Electrons · Physics 2015-05-19 S. Azadi , C. Cavazzoni , S. Sorella

We study the dynamical generation of resonances in isospin singlet channels with mixing between two- and four-quark states. To this end we generalise a Bethe-Salpeter approach to four-quark states employed previously \cite{Heupel:2012ua} to…

High Energy Physics - Phenomenology · Physics 2020-09-18 Nico Santowsky , Gernot Eichmann , Christian S. Fischer , Paul C. Wallbott , Richard Williams

The high-order accurate continuous Galerkin finite element method offers attractive computational efficiency for computational fluid dynamics. A challenge is however spurious oscillations which result for convection dominated flows over…

Numerical Analysis · Mathematics 2023-11-10 Arnaud G. Malan , Jan Nordstrom

The dependence of ab initio many-body perturbation theory within the $GW$ approximation on the eigensystem used in calculating quasiparticle corrections limits this method's predictive power. Here, we investigate the accuracy of the…

In this work we show the advantages of using the Coulomb-hole plus screened-exchange (COHSEX) approach in the calculation of potential energy surfaces. In particular, we demonstrate that, unlike perturbative $GW$ and partial self-consistent…

Chemical Physics · Physics 2021-06-14 J. Arjan Berger , Pierre-François Loos , Pina Romaniello

To expand the QUEST database of highly-accurate vertical transition energies, we consider a series of large organic chromogens ubiquitous in dye chemistry, such as anthraquinone, azobenzene, BODIPY, and naphthalimide. We compute, at the CC3…

PET requires accurate, precise, and efficient scatter correction techniques. Conventional scatter estimation typically relies on tail-fitted single-scatter simulation (SSS) strategy. However, the accuracy of tail-fitted SSS is limited, for…

We introduce the stochastic Boltzmann equation (SBE) as an approach for exploring the spin dynamics of magnetic molecules coupled to a stochastic environment. The SBE is a time-evolution equation for the probability density of the spin…

Materials Science · Physics 2016-03-15 Daniel M. Packwood , Helmut G. Katzgraber , Winfried Teizer

We present quasiparticle (QP) energies from fully self-consistent $GW$ (sc$GW$) calculations for a set of prototypical semiconductors and insulators within the framework of the projector-augmented wave methodology. To obtain converged…

Materials Science · Physics 2018-10-31 Manuel Grumet , Peitao Liu , Merzuk Kaltak , Jiří Klimeš , Georg Kresse

We present an approach to calculate the electronic structure for a range of materials using the quasiparticle self-consistent GW method with vertex corrections included in the screened Coulomb interaction W. This is achieved by solving the…

Materials Science · Physics 2023-10-10 Brian Cunningham , Myrta Gruening , Dimitar Pashov , Mark van Schilfgaarde

We investigate the dynamics of an effectively one-dimensional Bose-Einstein condensate (BEC) with scattering length $a$ subjected to a spatially periodic modulation, $a=a(x)=a(x+L)$. This "collisionally inhomogeneous" BEC is described by a…

Pattern Formation and Solitons · Physics 2009-11-11 Mason A. Porter , P. G. Kevrekidis , Boris A. Malomed , D. J. Frantzeskakis

The periodic standing wave (PSW) method for the binary inspiral of black holes and neutron stars computes exact numerical solutions for periodic standing wave spacetimes and then extracts approximate solutions of the physical problem, with…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Benjamin Bromley , Robert Owen , Richard H. Price

We introduce numerical solvers for the steady-state Boltzmann equation based on the symmetric Gauss-Seidel (SGS) method. Due to the quadratic collision operator in the Boltzmann equation, the SGS method requires solving a nonlinear system…

Computational Physics · Physics 2023-11-27 Tianai Yin , Zhenning Cai , Yanli Wang

Gaussian processes are the model of choice in Bayesian optimization and active learning. Yet, they are highly dependent on cleverly chosen hyperparameters to reach their full potential, and little effort is devoted to finding good…

Machine Learning · Computer Science 2024-02-16 Carl Hvarfner , Erik Hellsten , Frank Hutter , Luigi Nardi

We develop a method for finding the time evolution of exactly solvable models by Bethe ansatz. The dynamical Bethe wavefunction takes the same form as the stationary Bethe wavefunction except for time varying Bethe parameters and a complex…

Quantum Physics · Physics 2020-03-04 Igor Ermakov , Tim Byrnes