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Early-time electron-positron correlation in vacuum pair-production in an external field is investigated. The entangled electron and positron wave functions are obtained analytically in the configuration and momentum spaces. It is shown…

Quantum Physics · Physics 2015-06-17 Suo Tang , Bai-Song Xie , Hong-Yu Wang , Jie Liu , Li-Bin Fu , M. Y. Yu

Understanding the dynamics of positron cooling in gases, including the fraction of positrons surviving to thermalisation, is critical for accurate interpretation of positron lifetime spectra, for the development of efficient positron…

Atomic Physics · Physics 2017-11-22 D. G. Green

Quantum Monte Carlo calculations of the relaxation energy, pair-correlation function, and annihilating-pair momentum density are presented for a positron immersed in a homogeneous electron gas. We find smaller relaxation energies and…

Statistical Mechanics · Physics 2011-11-09 N. D. Drummond , P. Lopez Rios , C. J. Pickard , R. J. Needs

In this work we define single-particle potentials for a positron and a positronium atom interacting with light atoms (H, He, Li and Be) by inverting a single-particle Schr\"odinger equation. For this purpose, we use accurate energies and…

Atomic and Molecular Clusters · Physics 2014-05-21 A. Zubiaga , F. Tuomisto , M. Puska

We develop a microscopic description of an electron-doped two-dimensional semiconductor embedded in a microcavity. Specifically, we investigate the interactions between exciton-polaritons and electrons for the case where the interactions…

Mesoscale and Nanoscale Physics · Physics 2021-05-19 Guangyao Li , Olivier Bleu , Jesper Levinsen , Meera M. Parish

The aim of this work is to identify the mechanisms responsible for very large rates and other peculiarities observed in low-energy positron annihilation on molecules. The two mechanisms considered are: (i) Direct annihilation of the…

Atomic Physics · Physics 2009-10-31 G. F. Gribakin

Several first-principles calculations of positron-annihilation characteristics in solids have added gradient corrections to the local-density approximation within the theory by Arponen and Pajanne [Ann. Phys. (N.Y.) 121, 343 (1979)] since…

Materials Science · Physics 2014-07-16 Jan Kuriplach , Bernardo Barbiellini

The effect of confinement on the self-annihilation rate of positronium is studied in three levels of approximation. Artificial restriction of the electron-positron separation leads to an increase in the annihilation rate over its vacuum…

Atomic Physics · Physics 2021-08-05 A. R. Swann , D. G. Green , G. F. Gribakin

This chapter reviews the following items: 1. Energy deposition and track structure of fast positrons: ionization slowing down, number of ion-electron pairs, typical sizes, thermalization, electrostatic interaction between e+ and its blob,…

Positron binding in parabenzoquinone is studied using \textit{ab initio} many-body theory. The effects of electron-positron correlations including polarization, virtual positronium formation and positron-hole repulsion, as well as those of…

Chemical Physics · Physics 2025-02-17 S. K. Gregg , J. Hofierka , B. Cunningham , D. G. Green

The role of local electron-vibration and electron-electron interactions on the thermoelectric properties of molecular junctions is theoretically analyzed focusing on devices based on fullerene molecules. A self-consistent adiabatic approach…

Mesoscale and Nanoscale Physics · Physics 2019-08-08 C. A. Perroni , V. Cataudella

Measuring the Doppler broadening of the positron annihilation radiation or the angular correlation between the two annihilation gamma quanta reflects the momentum distribution of electrons seen by positrons in the material.Vacancy-type…

Materials Science · Physics 2007-05-23 I. Makkonen , M. Hakala , M. J. Puska

We investigate the modeling of positronium (Ps) states and their pick-off annihilation trapped at open volumes pockets in condensed molecular matter. Our starting point is the interacting many-body system of Ps and a He atom because it is…

Atomic and Molecular Clusters · Physics 2014-10-20 A. Zubiaga , F. Tuomisto , M. Puska

A simultaneous analysis of high-resolution directional Compton profiles and two-dimensional angular correlation of positron annihilation experimental data has been performed by studying both a directional anisotropy of measured spectra and…

We investigate energy correlators in semi-inclusive electron-positron annihilation as precision probes of parton hadronization dynamics. Using soft-collinear effective theory, we analyze the correlation patterns between the examined hadron…

High Energy Physics - Phenomenology · Physics 2026-01-21 Yu Jiao Zhu

We report a computational first-principles study of positron trapping at vacancy defects in metals and semiconductors. The main emphasis is on the energetics of the trapping process including the interplay between the positron state and the…

Materials Science · Physics 2007-08-19 I. Makkonen , M. J. Puska

The response of liquid xenon to various types of ionizing radiation has been extensively studied theoretically and experimentally. Recent progress in direct detection dark matter experiments highlights the significance of composite events,…

The formulation of a suitable nonlocal model potential for electron exchange is presented, checked with electron-hydrogen and electron-helium scattering, and applied to the study of elastic and inelastic scattering and ionization of ortho…

Atomic and Molecular Clusters · Physics 2016-09-08 P. K. Biswas , Sadhan K. Adhikari

We investigated the specific electronic energy deposition by protons and He ions with keV energies in different transition metal nitrides of technological interest. Data were obtained from two different time-of-flight ion scattering setups…

A model-potential approach has been developed to study positron interactions with molecules. Binding energies and annihilation rates are calculated for positron bound states with a range of alkane molecules, including rings and isomers. The…

Atomic Physics · Physics 2019-09-17 A. R. Swann , G. F. Gribakin