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The Method of Invariant Grid (MIG) is a model reduction technique based on the concept of slow invariant manifold (SIM), which approximates the SIM by a set of nodes in the concentration space (invariant grid). In the present work, the MIG…

Statistical Mechanics · Physics 2007-12-17 E. Chiavazzo , I. V. Karlin , C. E. Frouzakis , K. B. Boulouchos

The diagrammatic Monte Carlo (Diag-MC) method is a numerical technique which samples the entire diagrammatic series of the Green's function in quantum many-body systems. In this work, we incorporate the flat histogram principle in the…

Statistical Mechanics · Physics 2015-06-16 Nikolaos G. Diamantis , Efstratios Manousakis

Modelling the interaction between ionizing photons emitted from massive stars and their environment is essential to further our understanding of galactic ecosystems. We present a hybrid Radiation-Hydrodynamics (RHD) scheme that couples an…

Instrumentation and Methods for Astrophysics · Physics 2024-04-29 Cheryl S. C. Lau , Maya A. Petkova , Ian A. Bonnell

Cosmological hydrogen recombination has recently been the subject of renewed attention because of its importance for predicting the power spectrum of cosmic microwave background anisotropies. It has become clear that it is necessary to…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 Yacine Ali-Haïmoud , Christopher M. Hirata

We propose a new algorithm which works effectively in global updates in Monte Carlo study. We apply it to the quantum spin chain with next-nearest-neighbor interactions. We observe that Monte Carlo results are in excellent agreement with…

Condensed Matter · Physics 2017-02-01 Tomo Munehisa , Yasuko Munehisa

In this paper, a novel multigrid method based on Newton iteration is proposed to solve nonlinear eigenvalue problems. Instead of handling the eigenvalue $\lambda$ and eigenfunction $u$ separately, we treat the eigenpair $(\lambda, u)$ as…

Numerical Analysis · Mathematics 2024-04-30 Fei Xu , Manting Xie , Meiling Yue

We present a study of hydrogen at pressures higher than molecular dissociation using the Coupled Electron-Ion Monte Carlo method. These calculations use the accurate Reptation Quantum Monte Carlo method to estimate the electronic energy and…

Materials Science · Physics 2013-05-29 Miguel A. Morales , Carlo Pierleoni , David Ceperley

Monte-Carlo methods for zero energy quantum scattering are developed. Starting from path integral representations for scattering observables, we present results of numerical calculations for potential scattering and scattering off a…

Nuclear Theory · Physics 2009-10-28 Stefan Lenz , Hubertus Mall

In this paper, the high-order compact gas-kinetic scheme (CGKS) on three-dimensional hybrid unstructured mesh is further developed with the p-multigrid technique for steady-state solution acceleration. The p-multigrid strategy is a…

Computational Physics · Physics 2021-09-22 Xing Ji , Wei Shyy , Kun Xu

In this work, we introduce a simple modification of the Monte Carlo algorithm, which we call step Monte Carlo (sMC). The sMC approach allows to simulate processes far from equilibrium and obtain information about the dynamic properties of…

Other Condensed Matter · Physics 2023-12-15 Dariusz Sztenkiel

A cascadic multigrid method is proposed for eigenvalue problems based on the multilevel correction scheme. With this new scheme, an eigenvalue problem on the finest space can be solved by smoothing steps on a series of multilevel finite…

Numerical Analysis · Mathematics 2014-09-11 XIaole Han , Hehu Xie

We develop a classical Monte Carlo algorithm based on a quasi-classical approximation for a pseudospin S=1 Hamiltonian in real space to construct a phase diagram of a model cuprate with a high Tc. A model description takes into account both…

Strongly Correlated Electrons · Physics 2021-10-25 Yu. D. Panov , A. S. Moskvin , A. A. Chikov , V. A. Ulitko

We give an introduction to the calculation of path integrals on a lattice, with the quantum harmonic oscillator as an example. In addition to providing an explicit computational setup and corresponding pseudocode, we pay particular…

Computational Physics · Physics 2018-04-03 Marise J. E. Westbroek , Peter R. King , Dimitri D. Vvedensky , Stephan Durr

The trace of a matrix function f(A), most notably of the matrix inverse, can be estimated stochastically using samples< x,f(A)x> if the components of the random vectors x obey an appropriate probability distribution. However such a…

Numerical Analysis · Mathematics 2021-08-26 Andreas Frommer , Mostafa Nasr Khalil , Gustavo Ramirez-Hidalgo

Quantum Monte Carlo coupled with neural network wavefunctions has shown success in computing ground states of quantum many-body systems. Existing optimization approaches compute the energy by sampling local energy from an explicit…

Computational Physics · Physics 2023-05-29 Xuan Zhang , Shenglong Xu , Shuiwang Ji

We introduce a Monte Carlo algorithm to efficiently compute transport properties of chaotic dynamical systems. Our method exploits the importance sampling technique that favors trajectories in the tail of the distribution of displacements,…

Statistical Mechanics · Physics 2018-05-25 Diego Tapias , David P. Sanders , Eduardo G. Altmann

We introduce an efficient scheme for the molecular dynamics of electronic systems by means of quantum Monte Carlo. The evaluation of the (Born-Oppenheimer) forces acting on the ionic positions is achieved by two main ingredients: i) the…

Strongly Correlated Electrons · Physics 2009-11-13 Claudio Attaccalite , Sandro Sorella

Multi-dimensional density of states provides a useful description of complex frustrated systems. Recent advances in Monte Carlo methods enable efficient calculation of the density of states and related quantities, which renew the interest…

Disordered Systems and Neural Networks · Physics 2009-11-10 Yukito Iba , Hisanao Takahashi

We introduce an efficient scheme for the molecular dynamics of electronic systems by means of quantum Monte Carlo. The evaluation of the (Born-Oppenheimer) forces acting on the ionic positions is achieved by two main ingredients: i) the…

Strongly Correlated Electrons · Physics 2007-05-23 Sandro Sorella , Claudio Attaccalite

Recurrence relations of perturbation theory for hydrogen ground state are obtained. With their aid polarizabilities in constant perpendicular electric and magnetic fields are computed up to 80th order. The high orders asymptotic is compared…

Atomic Physics · Physics 2015-08-06 V. A. Gani , V. M. Weinberg