Work

Impact of positrons on electrical conductivity of hot and dense astrophysical plasma

Year: 2026

Type: article

Abstract: We study the influence of positrons on the outer crusts of neutron stars and the interiors of white dwarfs, introducing them as a novel component in both the composition of matter and in transport processes. We solve a system of coupled Boltzmann kinetic equations for the electron and positron distribution functions in the relaxation-time approximation, taking into account electron-ion, positron-ion, and electron-positron collisions. The relevant scattering matrix elements are calculated from one-plasmon exchange diagrams, with in-medium polarization tensors derived within hard-thermal-loop effective theory. Numerical results are obtained for matter composed of carbon nuclei. We find that the conductivity rises with temperature, following a power law sigma proportional to the 4th power of T in the semi-degenerate regime and sigma proportional to T in the nondegenerate regime, due to the intense creation of thermal electron-positron pairs and the resulting collisions among them. These results highlight the importance of including positrons in the transport properties of heated, dense astrophysical plasmas.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/vmjv-9822

Authors: Tigran Petrosyan, Arus Harutyunyan, Armen Sedrakian

Institutions: Yerevan State University, Byurakan Astrophysical Observatory, University of Wrocław, Frankfurt Institute for Advanced Studies

Language: English

Topic: Dust and Plasma Wave Phenomena

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Deutsche Forschungsgemeinschaft, Narodowe Centrum Nauki

Awards: G177065167, G6253508833