engleski

Regular solutions in f(T)-Yang-Mills theory

We consider extended covariant teleparallel (f(T)) gravity whose action is analytic in the torsion scalar and which is sourced by an su(2) valued Yang-Mills field. Specifically, we search for regular solutions to the coupled f(T)-Yang-Mills system. For f(T)=T, not surprisingly, the Bartnik-McKinnon solitons of Einstein Yang-Mills theory are recovered. However, interesting effects are discovered with the addition of terms in the action which are nonlinear in the torsion scalar, which are specifically studied up to cubic order. With the addition of the nonlinear terms the number of regular solutions becomes finite. As well, beyond critical values of the coupling constants it is found that there exist no regular solutions. These behaviors are asymmetric with respect to the sign of the nonlinear coupling constants and the elimination of regular solutions turns out to be extremely sensitive to the presence of the cubic coupling. It may be possible, therefore, that with sufficiently high powers of torsion in the action, there may be no regular Yang-Mills static solutions.

Extended theory of gravity ; Yang-Mills systems

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