124 research outputs found
Cosmology in the Universe with distance dependent Lorentz-violating bakground
We consider a cosmological setup with the inflaton field in the presence of a
redshift dependent Lorentz-violating time-like background to address the
inflationary regime and other phases of the Universe. We also show that the
regime of dark energy at large distances (low redshifts) is essentially
dominated by the presence of the Lorentz-violating background.Comment: 8 pages, no figure, Latex, to appear in AHE
Lorentz-violating dimension-five operator contribution to the black body radiation
We investigate the thermodynamics of a photon gas in an effective field
theory model that describes Lorentz violations through dimension-five operators
and Horava-Lifshitz theory. We explore the electrodynamics of the model which
includes higher order derivatives in the Lagrangian that can modify the
dispersion relation for the propagation of the photons. We shall focus on the
deformed black body radiation spectrum and modified Stefan-Boltzmann law to
address the allowed bounds on the Lorentz-violating parameter.Comment: 8 pages, 6 figures. Version published in PL
Absorption, scattering and shadow by a noncommutative black hole with global monopole
In this paper, we investigate the process of massless scalar wave scattering
due to a noncommutative black hole with a global monopole through the partial
wave method. We computed the cross section of differential scattering and
absorption at the low frequency limit. We also calculated, at the high
frequency limit, the absorption and the shadow radius by the null geodesic
method. We showed that noncommutativity causes a reduction in the differential
scattering/absorption cross section and shadow radius, while the presence of
the global monopole has the effect of increasing the value of such quantities.
In the limit of the null mass parameter, we verify that the cross section of
differential scattering, absorption and shadow ray approach to a non-zero value
proportional to a minimum mass.Comment: 20 pages, 14 figure
- …