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تسجيل مستخدم جديدVacuum polarisation of Dirac fermions in the cosmological de Sitter-global monopole spacetime
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We study the vacuum polarisation effects of the Dirac fermionic field induced by a pointlike global monopole located in the cosmological de Sitter spacetime. First we derive the four orthonormal Dirac modes in this background. Using these modes, we then compute the fermionic condensate, $langle 0| overline{Psi} Psi | 0rangle$, as well as the vacuum expectation value of the energy-momentum tensor for a massive Dirac field. We have used the Abel-Plana summation formula in order to extract the pure global monopole contribution to these quantities and have investigated their variations numerically with respect to suitable parameters. Also in particular, by taking the massless limit for the components of the energy-momentum tensor we show that the global monopole cannot induce any contribution to the trace anomaly.
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