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  1.  66
    The Nonlinear Essence of Gravitational Waves.R. Aldrovandi, J. G. Pereira & K. H. Vu - 2007 - Foundations of Physics 37 (10):1503-1517.
    A critical review of gravitational wave theory is made. It is pointed out that the usual linear approach to the gravitational wave theory is neither conceptually consistent nor mathematically justified. Relying upon that analysis it is argued that—analogously to a Yang-Mills propagating field, which must be nonlinear to carry its gauge charge—a gravitational wave must necessarily be nonlinear to transport its own charge—that is, energy-momentum.
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  2.  66
    Kinematics of a Spacetime with an Infinite Cosmological Constant.R. Aldrovandi, A. L. Barbosa, M. Calçada & J. G. Pereira - 2003 - Foundations of Physics 33 (4):613-624.
    A solution of the sourceless Einstein's equation with an infinite value for the cosmological constant Λ is discussed by using Inönü–Wigner contractions of the de Sitter groups and spaces. When Λ→∞, spacetime becomes a four-dimensional cone, dual to Minkowski space by a spacetime inversion. This inversion relates the four-cone vertex to the infinity of Minkowski space, and the four-cone infinity to the Minkowski light-cone. The non-relativistic limit c→∞ is further considered, the kinematical group in this case being a modified Galilei (...)
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  3.  72
    The Equivalence Principle Revisited.R. Aldrovandi, P. B. Barros & J. G. Pereira - 2003 - Foundations of Physics 33 (4):545-575.
    A precise fomulation of the strong Equivalence Principle is essential to the understanding of the relationship between gravitation and quantum mechanics. The relevant aspects are reviewed in a context including General Relativity but allowing for the presence of torsion. For the sake of brevity, a concise statement is proposed for the Principle: An ideal observer immersed in a gravitational field can choose a reference frame in which gravitation goes unnoticed. This statement is given a clear mathematical meaning through an accurate (...)
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  4.  58
    Spin-2 Fields and Helicity.H. I. Arcos, C. S. O. Mayor, G. Otalora & J. G. Pereira - 2012 - Foundations of Physics 42 (10):1339-1349.
    By considering the irreducible representations of the Lorentz group, an analysis of the different spin-2 waves is presented. In particular, the question of the helicity is discussed. It is concluded that, although from the point of view of representation theory there are no compelling reasons to choose between spin-2 waves with helicity σ=±1 or σ=±2, consistency arguments of the ensuing field theories favor waves with helicity σ=±1.
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  5. Studies in Brain and Mind, Volume 12.Inês Hipólito, J. Gonçalves & J. G. Pereira (eds.) - 2018 - Springer.
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  6.  52
    De Sitter Relativity: a New Road to Quantum Gravity? [REVIEW]R. Aldrovandi & J. G. Pereira - 2009 - Foundations of Physics 39 (1):1-19.
    The Poincaré group generalizes the Galilei group for high-velocity kinematics. The de Sitter group is assumed to go one step further, generalizing Poincaré as the group governing high-energy kinematics. In other words, ordinary special relativity is here replaced by de Sitter relativity. In this theory, the cosmological constant Λ is no longer a free parameter, and can be determined in terms of other quantities. When applied to the whole universe, it is able to predict the value of Λ and to (...)
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