AT1 - Extended Theories of Gravity and Quantum Cosmology |
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Speaker |
Vieira Lobato, Ronaldo |
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Coauthors |
Lobato, R.V.; Carvalho, G. A.; Martins, A. G.; Moraes, P. H. R. S. |
| Talk Title |
Energy Nonconservation as a Link Between $f(R,T)$ Gravity and Noncommutative Quantum Theory |
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Abstract |
$f(R,T)$ gravity was proposed as an extension of the $f(R)$ theories, containing not just geometrical correction terms to the General Relativity equations, but also material correction terms, dependent on the trace of the energy-momentum tensor $T$. These material extra terms prevent the energy-momentum tensor of the theory to be conserved, even in a flat background. Energy nonconservation is a prediction of quantum theory with time-space noncommutativity. If time is considered as an operator and there are compact coordinates which do not commute with the time, then the time evolution gets quantized and energy conservation can be violated. In the present work we construct a model in a 5-dimensional flat spacetime consisting of 3 commutative spatial dimensions and 1 compact spatial dimension whose coordinate does not commute with time. We show that the energy flows from the 3-dimensional commutative slice into the compact extra dimension (and vice-versa), so that conservation of energy is restored. In this model the energy flux is proportional to the energy density of the matter content, leading to a differential equation for $f(R,T)$, and thus providing a physical criterium to restrict the functional form of $f(R,T)$. We solve this equation and analyse the behaviour of its solution. |
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