134 research outputs found
Late time cosmological approach in mimetic gravity
In this paper, we investigate the late-time cosmic acceleration in mimetic
gravity with Lagrange multiplier and potential in a Universe
containing, besides radiation and dark energy, a self-interacting (collisional)
matter. We obtain through the modified Friedmann equations, the main equation
that can describe the cosmological evolution and with several models from
and the well known particular model , we perform an analysis of
the late-time evolution. We examine the behavior of the Hubble parameter, the
dark energy equation of state and the total effective equation of state and we
compare in each case the resulting picture with the non-collisional matter
(assumed as dust) and also with the collisional matter in mimetic
gravity. The results obtained are in good agreement with the observational data
and show that in presence of the collisional matter the dark energy
oscillations in mimetic f(R, T) gravity can be damped.Comment: 18 pages, 2 figure
Late time cosmological approach in mimetic gravity
In this paper, we investigate the late-time cosmic acceleration in mimetic
gravity with Lagrange multiplier and potential in a Universe
containing, besides radiation and dark energy, a self-interacting (collisional)
matter. We obtain through the modified Friedmann equations, the main equation
that can describe the cosmological evolution and with several models from
and the well known particular model , we perform an analysis of
the late-time evolution. We examine the behavior of the Hubble parameter, the
dark energy equation of state and the total effective equation of state and we
compare in each case the resulting picture with the non-collisional matter
(assumed as dust) and also with the collisional matter in mimetic
gravity. The results obtained are in good agreement with the observational data
and show that in presence of the collisional matter the dark energy
oscillations in mimetic f(R, T) gravity can be damped.Comment: 18 pages, 2 figure
Mathematical analysis of plasmonic nanoparticles: the scalar case
Localized surface plasmons are charge density oscillations confined to metallic nanoparticles. Excitation of localized surface plasmons by an electromagnetic field at an incident wavelength where resonance occurs results in a strong light scattering and an enhancement of the local electromagnetic fields. This paper is devoted to the mathematical modeling of plasmonic nanoparticles. Its aim is threefold: (i) to mathematically define the notion of plasmonic resonance and to analyze the shift and broadening of the plasmon resonance with changes in size and shape of the nanoparticles; (ii) to study the scattering and absorption enhancements by plasmon resonant nanoparticles and express them in terms of the polarization tensor of the nanoparticle. Optimal bounds on the enhancement factors are also derived; (iii) to show, by analyzing the imaginary part of the Green function, that one can achieve super-resolution and super-focusing using plasmonic nanoparticles. For simplicity, the Helmholtz equation is used to model electromagnetic wave propagation
Ultrasensitive Optical Shape Characterization of Gold Nanoantennas Using Second Harmonic Generation
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