2,119 research outputs found
Casimir Effect in the Rainbow Einstein's Universe
In the present paper we investigate the effects caused by the modification of
the dispersion relation obtained by solving the Klein-Gordon equation in the
closed Einstein's universe in the context of rainbow's gravity models. Thus, we
analyse how the quantum vacuum fluctuations of the scalar field are modified
when compared with the results obtained in the usual General Relativity
scenario. The regularization, and consequently the renormalization, of the
vacuum energy is performed adopting the Epstein-Hurwitz and Riemann's zeta
functions.Comment: 15 pages, 1 figure. To appear in Europhysics Letter
Efeito da densidade de plantio sobre o crescimento e a produção de cajueiro anão precoce irrigado.
bitstream/CNPAT-2010/5598/1/Pa-030.pd
Vacuum Polarization for a Massless Spin-1/2 Field in the Global Monopole Spacetime at Nonzero Temperature
In this paper we present the effects produced by the temperature in the
renormalized vacuum expectation value of the zero-zero component of the
energy-momentum tensor associated with massless left-handed spinor field in the
pointlike global monopole spacetime. In order to develop this calculation we
had to obtain the Euclidean thermal Green function in this background. Because
the expression obtained for the thermal energy density cannot be expressed in a
closed form, its explicit dependence on the temperature is not completely
evident. So, in order to obtain concrete information about its thermal
behavior, we develop a numerical analysis of our result in the high-temperature
limit for specific values of the parameter which codify the presence
of the monopole.Comment: 22 pages, LaTex format, 5 figure
Vacuum Polarization by a Magnetic Flux Tube at Finite Temperature in the Cosmic String Spacetime
In this paper we analyse the effect produced by the temperature in the vacuum
polarization associated with charged massless scalar field in the presence of
magnetic flux tube in the cosmic string spacetime. Three different
configurations of magnetic fields are taken into account: a homogeneous
field inside the tube, a field proportional to and a
cylindrical shell with -function. In these three cases, the axis of the
infinitely long tube of radius coincides with the cosmic string. Because
the complexity of this analysis in the region inside the tube, we consider the
thermal effect in the region outside. In order to develop this analysis, we
construct the thermal Green function associated with this system for the three
above mentioned situations considering points in the region outside the tube.
We explicitly calculate in the high-temperature limit, the thermal average of
the field square and the energy-momentum tensor.Comment: 16 pages, 1 figur
Produção de alpĂnia em cultivo protegido na regiĂŁo litorânea do estado do Ceará.
bitstream/item/33803/1/Ct-137.pd
- …