22–26 Jun 2026
Physics Department, University of Coimbra
Europe/Lisbon timezone

Josephson currents in neutron stars

25 Jun 2026, 17:05
25m
Physics Department, University of Coimbra

Physics Department, University of Coimbra

Rua Larga, 3004-516 - Coimbra - Portugal

Speaker

Armen Sedrakian (University of Wroclaw and FIAS)

Description

We demonstrate that the interface between S-wave and P-wave paired
superfluids in neutron stars induces a neutron supercurrent, a
charge-neutral analog of the Josephson junction effect in electronic
superconductors. The proton supercurrent entrainment by the neutron
superfluid generates, in addition to the neutral supercurrent, a
charged current across the interface. Beyond this stationary effect,
the motion of the neutron vortex lines responding to secular changes in
the neutron star's rotation rate induces a time-dependent oscillating
Josephson current across this interface when proton flux tubes are
dragged along with them. We show that such motion produces radiation
from the interface once clusters of proton flux tubes intersect the
interface. The power of radiation exceeds by orders of magnitude the
Ohmic dissipation of currents in neutron stars. This effect appears to
be phenomenologically significant enough to heat the star and alter its
cooling rate during the photon cooling era.

Author

Armen Sedrakian (University of Wroclaw and FIAS)

Presentation materials

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