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N. Dias

Publications and source records attributed to N. Dias.

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Noncommutative Graphene

We consider a noncommutative description of graphene. This description consists of a Dirac equation for massless Dirac fermions plus noncommutative corrections, which are treated in the presence of an external magnetic field. We argue that, being a two-dimensional Dirac system, graphene is particularly interesting to test noncommutativity. We find that momentum noncommutativity affects the energy levels of graphene, but that it does not entail any kind of correction to the Hall conductivity.

hep-th

Noncommutative Quantum Cosmology

One presents a phase-space noncommutative extension of Quantum Cosmology in the context of a Kantowski-Sachs (KS) minisuperspace model. We obtain the Wheeler-DeWitt (WDW) equation for the noncommutative system through the ADM formalism and a suitable Seiberg-Witten map. The resulting WDW equation explicitly depends on the phase-space noncommutative parameters, $θ$ and $η$. Numerical solutions of the noncommutative WDW equation are found and, interestingly, also bounds on the values of the noncommutative parameters. Moreover, we conclude that the noncommutativity in the momenta sector leads to a damped wave function implying that this type of noncommutativity can be relevant for a selection of possible initial states for the universe.

hep-th