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The quark spin effects are introduced for the first time in the string fragmentation routine of the Pythia 8 Monte Carlo event generator for the simulation of $e^+e^-$ annihilation to hadrons. To describe the spin effects the…

High Energy Physics - Phenomenology · Physics 2023-12-29 A. Kerbizi , L. Lönnblad , A. Martin

We use Monte Carlo approach to study the energetics of electrons accelerated in a pulsar polar gap. As energy-loss mechanisms we consider magnetic Compton scattering of thermal X-ray photons and curvature radiation. The results are compared…

Astrophysics · Physics 2007-05-23 J. Dyks , B. Rudak

Resonant positron annihilation on atomic electrons provides a powerful method to search for light new particles coupled to $e^+e^-$. Reliable estimates of production rates require a detailed characterization of electron momentum…

High Energy Physics - Phenomenology · Physics 2024-10-11 Fernando Arias-Aragón , Luc Darmé , Giovanni Grilli di Cortona , Enrico Nardi

The diffusion quantum Monte Carlo method is extended to solve the old theoretical physics problem of many-electron atoms and ions in intense magnetic fields. The feature of our approach is the use of adiabatic approximation wave functions…

Quantum Physics · Physics 2009-11-13 S. Bucheler , D. Engel , J. Main , G. Wunner

In this work we develop tools that enable the study of non-adiabatic effects with variational and diffusion Monte Carlo methods. We introduce a highly accurate wave function ansatz for electron-ion systems that can involve a combination of…

Chemical Physics · Physics 2014-10-29 Norm M. Tubman , Ilkka Kylänpää , Sharon Hammes-Schiffer , David M. Ceperley

Path integral Monte Carlo (PIMC) simulations are used to calculate the momentum distribution of the homogeneous electron gas at finite temperature. This is done by calculating the off-diagonal elements of the real-space density matrix,…

Statistical Mechanics · Physics 2007-05-23 B. Militzer , E. L. Pollock , D. M. Ceperley

The measurement of the hadronic cross-section in $e^+ e^-$ annihilation at high luminosity factories using the radiative return method is motivated and discussed. A Monte Carlo generator which simulates the radiative process $e^+ e^- \to…

High Energy Physics - Phenomenology · Physics 2007-05-23 German Rodrigo

The two-photon annihilation of a positron with an electron bound in the 1s state of a H-like ion is calculated within the fully relativistic QED framework. The interaction with the nucleus is treated nonperturbatively, thus allowing the…

Atomic Physics · Physics 2022-06-22 Z. A. Mandrykina , V. A. Zaytsev , V. A. Yerokhin , V. M. Shabaev

The energies of $^{3}H$, $^{3}He$, and $^{4}He$ ground states, the ${\frac{3}{2}}^{-}$ and ${\frac{1}{2}}^{-}$ scattering states of $^{5}He$, the ground states of $^{6}He$, $^{6}Li$, and $^{6}Be$ and the $3^{+}$ and $0^{+}$ excited states…

Nuclear Theory · Physics 2016-09-08 B. S. Pudliner , V. R. Pandharipande , J. Carlson , R. B. Wiringa

We report on the general purpose numerical program MERCUTIO, which can be used to calculate any infrared safe four-jet quantity in electron-positron annihilation at next-to-leading order. The program is based on the dipole formalism and…

High Energy Physics - Phenomenology · Physics 2008-11-26 Stefan Weinzierl , David A. Kosower

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 present a method for estimating the probabilities of outcomes of a quantum circuit using Monte Carlo sampling techniques applied to a quasiprobability representation. Our estimate converges to the true quantum probability at a rate…

Quantum Physics · Physics 2015-08-12 Hakop Pashayan , Joel J. Wallman , Stephen D. Bartlett

We present a numerical method and computer code to calculate the radiative transfer and excitation of molecular lines. Formulating the Monte Carlo method from the viewpoint of cells rather than photons allows us to separate local and…

Astrophysics · Physics 2007-05-23 Michiel R. Hogerheijde , Floris F. S. van der Tak

We present an efficient Monte Carlo method to simulate reaction-diffusion processes with spatially varying particle annihilation or transformation rates as it occurs for instance in the context of motor-driven intracellular transport. Like…

Statistical Mechanics · Physics 2013-05-20 Karsten Schwarz , Heiko Rieger

Electron--positron annihilation into hadrons plus an energetic photon from initial-state radiation allows the hadronic cross-section to be measured over a wide range of energies at high luminosity meson factories. Weighted integrals over…

High Energy Physics - Phenomenology · Physics 2009-11-07 German Rodrigo , Henryk Czyz , Johann H. Kuhn

The computational cost of a Monte Carlo algorithm can only be meaningfully discussed when taking into account the magnitude of the resulting statistical error. Aiming for a fixed error per particle, we study the scaling behavior of the…

Computational Physics · Physics 2010-02-11 Norbert Nemec

The cross sections of the Higgs production and the corresponding backgrounds of $e^+e^-$ annihilations at the CEPC (Circular Electron and Positron Collider) are calculated by a Monte-Carlo method, and the beamstruhlung effect at the CEPC is…

High Energy Physics - Experiment · Physics 2016-01-08 Xin Mo , Gang Li , Manqi Ruan , Xinchou Lou

We investigate positron annihilation in electron liquid as a case study for many-body theory, in particular the optimized Fermi Hypernetted Chain (FHNC-EL) method. We examine several approximation schemes and show that one has to go up to…

Condensed Matter · Physics 2010-09-24 V. Apaja , S. Denk , E. Krotscheck

Positron annihilation spectroscopy is often used to analyze the local electronic structure of materials of technological interest. Reliable theoretical tools are crucial to interpret the measured spectra. Here, we propose a parameter-free…

Materials Science · Physics 2015-04-15 Bernardo Barbiellini , Jan Kuriplach

Monte Carlo simulations are widely used in many areas including particle accelerators. In this lecture, after a short introduction and reviewing of some statistical backgrounds, we will discuss methods such as direct inversion, rejection…

Computational Physics · Physics 2020-06-19 Ji Qiang