arXiv subjects

Ricardo Gabriel Elias

Publications and source records attributed to Ricardo Gabriel Elias.

6 recordsLinked to original sources

arXiv2020

Oscillations of skyrmion clusters in Co/Pt multilayer nanodots

In this work we study the oscillations of the skyrmion cores in a multilayer nanodot as a function of the number of skyrmions hosted in the system. When all the skyrmions in the nanodot have the same core radius, and after applying a perpendicular spin-polarized current, a relaxation process takes place towards an equilibrium configuration that is accompanied by coherent damped oscillations of the skyrmion cores, whose frequency depends on the number of skyrmions present in the nanodot. Additionally, we found that the oscillation frequency is directly related to the total energy of the system.

physics.app-ph↗

arXiv2019

Thermal state entanglement entropy on a quantum graph

A particle jumps between the nodes of a graph interacting with local spins. We show that the entanglement entropy of the particle with the spin network is related to the length of the minimum cycle basis. The structure of the thermal state is reminiscent to the string-net of spin liquids.

quant-ph↗

arXiv2018

Entanglement and interaction in a topological quantum walk

We study the quantum walk of two interacting particles on a line with an interface separating two topologically distinct regions. The interaction induces a localization-delocalization transition of the edge state at the interface. We characterize the transition through the entanglement between the two particles.

quant-ph↗

arXiv2018

Parametric Resonance in Quantum Electrodynamics Vacuum Birefringence

Vacuum magnetic birefringence is one of the most interesting non-linear phenomena in quantum electrodynamics because it is a pure photon-photon result of the theory and it directly signalizes the violation of the classical superposition principle of electromagnetic fields in the full quantum theory. We perform analytical and numerical calculations when an electromagnetic wave interacts with an oscillating external magnetic field. We find that in an ideal cavity, when the external field frequency is around the electromagnetic wave frequency, the normal and parallel components of the wave suffer parametric resonance at different rates, producing a vacuum birefringence effect growing in time. We also study the case where there is no cavity and the oscillating magnetic field is spatially localized in a region of length $L$. In both cases we find also a rotation of the elliptical axis.

hep-ph↗

arXiv2014

Topological changes of two-dimensional magnetic textures

We investigate the interaction of magnetic vortices and skyrmions with a spin-polarized current. In a square lattice, fixed classical spins and quantum itinerant electrons, evolve according to the coupled Landau-Lifshitz and Schrödinger equations. Changes in the topology occur at microscopic time and length scales, and are shown to be triggered by the nucleation of a nontrivial electron-spin structure at the vortex core.

cond-mat.mes-hall↗

arXiv2010

Magnetization structure of a Bloch point singularity

Switching of magnetic vortex cores involves a topological transition characterized by the presence of a magnetization singularity, a point where the magnetization vanishes (Bloch point). We analytically derive the shape of the Bloch point that is an extremum of the free energy with exchange, dipole and the Landau terms for the determination of the local value of the magnetization modulus.

cond-mat.mes-hall↗