Rúben A. Alves

SPaCe-GEM: solver of the Einstein equations using GPUs under the gravitoelectromagnetic approximation

Under specific conditions, there is a formal analogy between the fundamental equations of electromagnetism and relativistic gravitation, described by the Einstein field equations of general relativity. In this paper, we report on how we have used this analogy to implement a solver of the Einstein equations adapting algorithms initially developed for electromagnetism, combined with methods of heterogeneous supercomputing, in GPU that can achieve fast computing and exhibit good performance. We also present the results of the simulations used to validate our solver.

Development of a quantum particle in cell algorithm in GPU for solving Maxwell-Bloch equations

In this paper we report on the development of a numerical solver for Vlasov equations based on heterogeneous supercomputing using GPGPUs. The solver adapts techniques from many-body simulation, namely the particlein-cell approach, to describe the interaction between the electromagnetic field and atomic gas whose internal state can be described by the multilevel Bloch equations. We also present the benchmark and performance analysis of the code. We investigate the interaction between two coherent light beams, as a case of study to demonstrate the validation of the code.

Quantum wires as sensors of the electric field: A model into quantum plasmonics

This paper presents a study for a fibre optic sensor based on quantum wires to detect and measure the amplitude and direction of a static electric field. This study is supported by the analogy of the fluid equations describing the free electrons in the quantum wires and the Madelung formalism of Quantum Mechanics. In this context, it is possible to construct a diatomic plasmonic molecule whose energy levels can be Stark shifted by an external electric field and readout using a light beam tuned to the Rabi oscillations of these levels. Choosing the adequate design parameters it is possible to estimate a sensitivity of 100nm/NC−1.

Solving the multi-level Maxwell-Bloch equations using GPGPU computing for the simulation of nonlinear optics in atomic gases

We present a numerical implementation of a solver for the Maxwell-Bloch equations to calculate the propagation of a light pulse in a nonlinear medium composed of an atomic gas in one, two and three dimensional systems. This implementation solves the wave equation of light using a finite difference method in the time domain scheme, while the Bloch equations for the atomic population in each point of the simulation domain are integrated using splitting methods. We present numerical simulations of atomic-gas systems and performance benchmarks.

Tunable light fluids using quantum atomic optical systems

The realization of tabletop optical analogue experiments of superfluidity relies on the engineering of suitable optical media, with tailored optical properties. This work shows how quantum atomic optical systems can be used to develop highly tunable optical media, with localized control of both linear and nonlinear susceptibility. Introducing the hydrodynamic description of light, the superfluidity of light in these atomic media is investigated through GPU-enhanced numerical simulations, with the numeric observation of the superfluidic signature of suppressed scattering through a defect.

The analogue quantum mechanical of plasmonic atoms

Localized plasmons in metallic nanostructures present strong analogies with Quantum Mechanical problems of particles trapped in potential wells. In this paper we take this analogy further using the Madelung Formalism of Quantum Mechanics to express the fluid equations describing the charge density of the conduction electrons and corresponding interaction with light in terms of an effective generalized Non-linear Schr¨odinger equations. Within this context, it is possible to develop the analogy of a plasmonic atom and molecule that exhibits Rabi oscillations, Stark effect, among other Quantum Mechanical effects.

Dissipative solitons in 4-level atomic optical systems

In this work we develop a theoretical model to describe the propagation of an optical pulse in a 4-level atomic system. We investigate the existence of dissipative soliton solutions and analyze the stability of these solitary waves, comparing the analytical results with computational simulations based on the effective (1+1)-dimensional model derived from the Maxwell-Bloch equation under the slowly-varying envelope approximation.

Fast physical ray-tracing method for gravitational lensing using heterogeneous supercomputing in GPGPU

In this work we address the development of a fast solver of the ray-tracing equations based on heterogeneous supercomputing using PyOpenCL. We apply this solver to the study of gravitational lensing and light propagation in optical systems.

Physical ray-tracing method for anisotropic optical media in GPGPU

In this paper we discuss the development of a fast ray-tracing solver for complex anisotropic uniaxial optical media based on heterogeneous supercomputing in GPGPU using PyOpenCl. This solver simulates both the propagation of ordinary and extraordinary rays, while taking into account the polarization rotation introduced by position dependent modulations of the optical axis of the medium. We demonstrate the application of this solver by simulating the generation of polarization caustics in random uniaxial optical media.

Doppler broadening effects in plasmonic quantum dots

In this paper we analyse the effects of the Doppler shift on the optical response of a nanoplasmonic system. Through the development of a simplified model based on the Hydrodynamic Drude model we analyse the response of a quantum dot embed in a moving fluid, predicting the Doppler broadening and the shift of the spectral line.