arXiv subjects

J. A. Gil Granados

Publications and source records attributed to J. A. Gil Granados.

3 recordsLinked to original sources

arXiv2025

Half-vortex states in the rotating outer core of neutron stars

We probe the superfluid-superconductor dynamics of the rotating outer core of neutron stars through half-vortex states. By means of a generalized hydrodynamic model, where proton and neutron fluids are coupled by both dynamic entrainment and Skyrme SLy4 nucleon-nucleon interactions, we analyze single flux tubes in the proton-superconductor component of the system that thread proton vortices located faraway from neutron vortices. It is shown how they give rise to hydrodynamic perturbations in the coexisting neutron superfluid, and its structure remains unaltered for varying rotation rates and magnetic fields within ranges of observational values.

nucl-th↗

arXiv2020

Roton instabilities in the superfluid outer core of neutron stars

We study the superfluid dynamics of the outer core of neutron stars by means of a hydrodynamic model made of a neutronic superfluid and a protonic superconductor, coupled by both the dynamic entrainment and the Skyrme SLy4 nucleon-nucleon interactions. The resulting nonlinear equations of motion are probed in the search for dynamical instabilities triggered by the relative motion of the superfluids that could be related to observed timing anomalies in pulsars. Through linear analysis, the origin and expected growth of the instabilities is explored for varying nuclear-matter density. Differently from previous findings, the dispersion of linear excitations in our model shows rotonic structures below the pair-breaking energy threshold, which lies at the origin of the dynamical instabilities, and could eventually lead to emergent vorticity along with modulations of the superfluid density.

nucl-th↗

arXiv2019

Transverse Josephson vortices and localized states in stacked Bose-Einstein condensates

The stacks of Bose-Einstein condensates coupled by long Josephson junctions present a rich phenomenology feasible to experimental realization and specially suitable for technological applications as the nonlinear-optics and superconducting analogues have already proved. Among this, we show that transverse Bloch waves excited in arrays of one-dimensional coupled condensates can carry tunneling superflows whose dynamical stability depends on the quasimomentum. Across the stacks with periodic boundary conditions, forming closed ring-shaped systems, such Bloch states yield transverse Josephson vortices with a generic non-integer circulation in units of $h/m$. Additionally, the superpositions of degenerate linear Bloch waves can suppress the supercurrents and give rise to families of nonlinear standing-wave states with strong (transverse) spatial localization. Stable states of this type can also be found in finite size systems.

cond-mat.quant-gas↗