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We present a new analytical method that systematically improves the convergence of path integrals of a generic $N$-fold discretized theory. Using it we calculate the effective actions $S^{(p)}$ for $p\le 9$ which lead to the same continuum…

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

This paper introduces quantum computing methods for Monte Carlo simulations in power systems which are expected to be exponentially faster than their classical computing counterparts. Monte Carlo simulations is a fundamental method, widely…

Quantum Physics · Physics 2023-10-02 Emilie Jong , Brynjar Sævarsson , Hjörtur Jóhannsson , Spyros Chatzivasileiadis

We analyze a new Monte Carlo method which uses transition matrix in the space of energy. This method gives an efficient reweighting technique. The associated artificial dynamics is a constrained random walk in energy, producing the result…

Statistical Mechanics · Physics 2009-10-31 Jian-Sheng Wang

We compute quasi-exact \emph{ab initio} path-integral Monte Carlo results for the Matsubara Green's function of the uniform electron gas (UEG) at finite temperature over a broad range of coupling strengths ($r_s=1,\dots,10)$. This allows us…

Quantum Gases · Physics 2026-01-22 Paul Hamann , Michael Bonitz , Jan Vorberger , Tobias Dornheim

In a recent paper, Lucco Castello et al. [arXiv:2107.03537] provided an accurate parametrization of classical one-component plasma bridge functions that was embedded in a novel dielectric scheme for strongly coupled electron liquids. Here,…

Statistical Mechanics · Physics 2021-10-11 P. Tolias , F. Lucco Castello , T. Dornheim

We propose a new method for calculating total energies of systems of interacting electrons, which requires little more computational resources than standard density-functional theories. The total energy is calculated within the framework of…

Condensed Matter · Physics 2009-10-31 Paula Sanchez-Friera , R. W. Godby

The discrete time path integral Monte Carlo (PIMC) with a one-particle density matrix approximation is applied to study the quantum phase transition in the coupled double-well chain. To improve the convergence properties, the exact action…

Statistical Mechanics · Physics 2015-06-25 Dong-Hee Kim , Yu-Cheng Lin , Heiko Rieger

Over the past decade, experimental microscopy and spectroscopy have made significant progress in the study of the morphological, optical, electronic and transport properties of materials. These developments include higher spatial…

Materials Science · Physics 2025-02-12 Simone Taioli , Maurizio Dapor

We carry out highly accurate \emph{ab initio} path integral Monte Carlo (PIMC) simulations to directly estimate the free energy of various warm dense matter systems including the uniform electron gas and hydrogen without any nodal…

Quantum Gases · Physics 2024-07-02 Tobias Dornheim , Zhandos Moldabekov , Sebastian Schwalbe , Jan Vorberger

The Feynman path integral approach for computing equilibrium isotope effects and isotope fractionation corrects the approximations made in standard methods, although at significantly increased computational cost. We describe an accelerated…

Quantum Physics · Physics 2017-05-10 Marcin Buchowiecki , Jiri Vanicek

In the design of stellarators, energetic particle confinement is a critical point of concern which remains challenging to study from a numerical point of view. Standard Monte Carlo analyses are highly expensive because a large number of…

Plasma Physics · Physics 2022-05-18 Frederick Law , Antoine Cerfon , Benjamin Peherstorfer

Markov chain Monte Carlo methods are primarily used for sampling from a given probability distribution and estimating multi-dimensional integrals based on the information contained in the generated samples. Whenever it is possible, more…

Statistical Mechanics · Physics 2017-05-22 Manuel Athènes , Pierre Terrier

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

We present a formalism of the transition matrix Monte Carlo method. A stochastic matrix in the space of energy can be estimated from Monte Carlo simulation. This matrix is used to compute the density of states, as well as to construct…

Statistical Mechanics · Physics 2011-12-30 Jian-Sheng Wang , Robert H. Swendsen

We present a Monte Carlo model for degradation of 1-10,000 eV electrons in an atmosphere of methane. The electron impact cross sections for CH4 are compiled and analytical representations of these cross sections are used as input to the…

Space Physics · Physics 2015-05-27 Anil Bhardwaj , Vrinda Mukundan

Energy-transfer efficiency is an important quantity in plasma-wakefield acceleration, especially for applications that demand high average power. Conventionally, the efficiency is measured using an electron spectrometer; an invasive method…

We demonstrate an efficient numerical method to calculate three-tangle of general mixed states. We construct a "energy function" (target function) for the three-tangle of the mixed state under certain constrains. The "energy function"…

Quantum Physics · Physics 2015-05-14 Kun Cao , Zheng-Wei Zhou , Guang-Can Guo , Lixin He

In order to find the equilibrium geometries of molecules and solids and to perform ab initio molecular dynamics, it is necessary to calculate the forces on the nuclei. We present a correlated sampling method to efficiently calculate…

Condensed Matter · Physics 2009-10-31 Claudia Filippi , C. J. Umrigar

Use of explicit integration methods for power electronic circuits with ideal switch models significantly improves simulation speed. The PLECS package [1] has effectively used this idea; however, the implementation details involved in PLECS…

Computational Engineering, Finance, and Science · Computer Science 2024-06-19 Mahesh B. Patil

We present a new Monte Carlo algorithm that produces results of high accuracy with reduced simulational effort. Independent random walks are performed (concurrently or serially) in different, restricted ranges of energy, and the resultant…

Statistical Mechanics · Physics 2009-10-31 Fugao Wang , D. P. Landau