2,933 research outputs found
On aether terms in a space-time with a compact extra dimension
In this paper, for the CPT-even and CPT-odd extensions of the QED, we
explicitly obtain the aether-like corrections for the electromagnetic field in
the case when the space-time involves an extra compact spatial dimension
besides of usual four dimensions. Our methodology is based on an explicit
summation over the Kaluza-Klein tower of fields which is no more difficult than
the finite-temperature calculations. The quantum corrections turn out to be
large as the extra dimension is small. We demonstrate that in the CPT-even
case, the extra dimension manifests itself through a new scalar particle.Comment: 9 page
The Godel metric in the Chern-Simons modified gravity
We discuss the consistency of the Godel metric within the Chern-Simons
modified gravity, both for external and dynamical Chern-Simons coefficients.Comment: 6 pages; to be published in the Proceedings of 5th International
Workshop on Astronomy and Relativistic Astrophysics (IWARA 2011), matches the
accepted versio
Gravitational Geometric Phase in the Presence of Torsion
We investigate the relativistic and non-relativistic quantum dynamics of a
neutral spin-1/2 particle submitted an external electromagnetic field in the
presence of a cosmic dislocation. We analyze the explicit contribution of the
torsion in the geometric phase acquired in the dynamic of this neutral
spinorial particle. We discuss the influence of the torsion in the relativistic
geometric phase. Using the Foldy-Wouthuysen approximation, the non-relativistic
quantum dynamics are studied and the influence of the torsion in the
Aharonov-Casher and He-McKellar-Wilkens effects are discussed.Comment: 14 pages, no figur
Teste de avaliação do metabolismo espermático em ovinos.
Apresenta técnicas adotadas para avaliação da qualidade do sêmen, uma que seja de alta precisão, de simples adoção e que não requeira treinamento especializado, favorecendo as atividades de veterinários e de criadores de ovinos.bitstream/CNPC/20247/1/cot71.pd
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