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Oleg A. Goglichidze

Publications and source records attributed to Oleg A. Goglichidze.

3 recordsLinked to original sources

Neutron contribution to the force on a proton vortex in superconducting neutron-star matter

We investigate the forces acting on a proton vortex in superconducting neutron-star matter composed of neutrons, protons, and electrons, accounting for Fermi-liquid interactions in the neutron-proton subsystem. While the force arising from electron scattering by the vortex magnetic field is well known, we demonstrate that normal neutrons also exert a force on proton vortices due to Fermi-liquid coupling with superconducting protons. Using a kinetic approach based on Landau Fermi-liquid theory, we show that neutron quasiparticles scatter off a proton vortex through the spatially varying condensate momentum, giving rise to a longitudinal force proportional to the relative neutron-vortex velocity. In contrast to the electron contribution, this force has no transverse component and vanishes in the absence of neutron-proton Fermi-liquid interaction. Within a simple model, we analyze the main properties of this force and provide physically motivated estimates of its magnitude.

astro-ph.HE↗

Non-purely transverse Magnus force in superconducting neutron stars

The force acting on a proton vortex in extreme type-II superconducting neutron star matter is studied in the limit of vanishing temperature. A detailed analysis is presented on how momentum is transferred from length scales on the order of the London penetration depth to the vortex core. To examine the momentum flux, expressions for proton and electron currents are derived for arbitrary distances from the vortex line. It is shown that, in the regime of a large electron mean free path, the only force acting directly on the vortex core is the Magnus force. Notably, the correction to the proton current near the vortex core generates a component of the Magnus force aligned with the incident current measured far from the vortex. This contribution, responsible for longitudinal force, is usually overlooked in the literature. The results obtained in this work for a relatively simple problem concerning the force on a vortex in cold matter of neutron stars may also be relevant to other superconducting systems.

astro-ph.HE↗

Diffusion in superfluid Fermi mixtures: General formalism

With neutron star applications in mind, we developed a theory of diffusion in mixtures of superfluid, strongly interacting Fermi liquids. By employing the Landau theory of Fermi liquids, we determined matrices that relate the currents of different particle species, their momentum densities, and the partial entropy currents to each other. Using these results, and applying the quasiclassical kinetic equation for the Bogoliubov excitations, we derived general expressions for the diffusion coefficients, which properly incorporate all the Fermi liquid effects and depend on the momentum transfer rates between different particle species. The developed framework can be used as a starting point for systematic calculations of the diffusion coefficients (as well as other kinetic coefficients) in superfluid Fermi mixtures, particularly, in superfluid neutron stars.

astro-ph.HE↗