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dc.contributor.authorBallardini, Mario
dc.date.accessioned2022-12-05T10:44:48Z
dc.date.available2022-12-05T10:44:48Z
dc.date.issued2019
dc.identifier.citationBallardini, Mario & Braglia, M. & Finelli, F. & Marozzi, G. & Starobinsky, Alexei. (2019). Energy-momentum tensor and helicity for gauge fields coupled to a pseudo-scalar inflation.en_US
dc.identifier.issn2470-0010
dc.identifier.urihttp://hdl.handle.net/10566/8206
dc.description.abstractWe study the energy-momentum tensor and helicity of gauge fields coupled through $g \phi F \tilde{F}/4$ to a pseudo-scalar field $\phi$ driving inflation. Under the assumption of a constant time derivative of the background inflaton, we compute analitically divergent and finite terms of the energy density and helicity of gauge fields for any value of the coupling $g$. We introduce a suitable adiabatic expansion for mode functions of physical states of the gauge fields which correctly reproduces ultraviolet divergences in average quantities and identify corresponding counterterms. Our calculations shed light on the accuracy and the range of validity of approximated analytic estimates of the energy density and helicity terms previously existed in the literature in the strongly coupled regime only, i.e. for $g \dot \phi/(2H) \gg 1$. We discuss the implications of our analytic calculations for the backreaction of quantum fluctuations onto the inflaton evolution.en_US
dc.language.isoen_USen_US
dc.publisherUniversity of the Western Capeen_US
dc.subjectHelicity integralen_US
dc.subjectadiabatic regularization methoden_US
dc.subjectENERGY DENSITYen_US
dc.subjectpseudoscalar inflatonen_US
dc.subjectEnergy-momentum tensoren_US
dc.titleEnergy-momentum tensor and helicity for gauge fields coupled to a pseudoscalar inflatonen_US
dc.typeArticleen_US


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