Talk detail

Participant	Vieira Lobato, Ronaldo
Institution	Instituto Tecnológico de Aeronáutica and ICRANet - Marechal Eduardo Gomes - São José dos Campos - São Paulo - Brazil

Session	AT1	Accepted	Yes	Order	4	Time	15:45	15'
Talk	Oral abstract	Title	Energy Nonconservation as a Link Between $f(R,T)$ Gravity and Noncommutative Quantum Theory
Coauthors	Lobato, R.V.; Carvalho, G. A.; Martins, A. G.; Moraes, P. H. R. S.
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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Session	WD2	Accepted	Yes	Order	6	Time	18:05	15' + 5'
Talk	Oral abstract	Title	On the Electromagnetic Emission of SGRs/AXPs as White Dwarf and Neutron Star Pulsars
Coauthors	Rueda, Jorge A.; Coelho, Jaziel G.; Otoniel, Edson; Malheiro, M.
Abstract	In this work, we discuss white dwarf pulsars found recently making also reference of the possibility of some soft $\gamma$ repeaters (SGRs) and anomalous X-ray pulsars (AXPs) being part of this class of pulsars. We also investigate nine of these sources that can also be rotation power neutron star pulsars considering a self-consistent calculation taking in account the mass, star radius and momentum of inertia obtained by several neutron star equations of state for the respective rotational period of these sources. The death lines for the electromagnetic radiation obtained for each emission model, above which the sources can emit in radio, are presented for SGRs/AXPs described as white dwarf or neutron star pulsars.
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