Berlin 2015 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 7: Cosmology

GR 7.1: Talk

Tuesday, March 17, 2015, 15:20–15:40, H 2013

The question of quantum equivalence between Jordan and Einstein frames in cosmology — •Christian F. Steinwachs¹ and Alexander Yu. Kamenshchik^2,3 — ¹Physikalisches Institut, Albert-Ludwigs-Universität, Freiburg, Germany — ²Dipartimento di Fisica e Astronomia and INFN, Bologna, Italy — ³L. D. Landau Institute for Theoretical Physics of the Russian Academy of Sciences, Moscow, Russia

We investigate the equivalence between two different parametrizations of fields in cosmology – the so-called Jordan frame and Einstein frame – in the framework of a general scalar-tensor theory. While it is clear that both parametrizations are mathematically equivalent at the level of the classical action, the question about their mathematical equivalence at the quantum level as well as their physical equivalence is still a matter of debate in cosmology. We analyze whether the mathematical equivalence still holds when the first quantum corrections are taken into account. We explicitly calculate the one-loop divergences in both parametrizations by using the generalized Schwinger-DeWitt algorithm and find that quantum corrections induce an off-shell dependence on the parametrization. An explanation of the origin and a possible resolution of this quantum ambiguity is suggested to be found within a geometric field theoretical approach. Finally, we discuss the physical implications of this analysis and its consequences for cosmology.