  Understanding the radiative-dynamical coupling between upper photosphere and
deeper atmosphere is a key in understanding the abnormal large radii of hot
Jupiters. One needs very long integration times of 3D general circulation
models (GCMs) with self consistent radiative transfer to achieve a better
understanding of the feedback process between dynamics and radiation. We here
present the longest 3D non-gray GCM study (86000 d) of an ultra hot Jupiter
(WASP-76 b) published to this date that reached a final converged state.
Furthermore, we present a method that can be used to accelerate the path
towards temperature convergence in the deep atmospheric layers. We find that
the final converged temperature profile is cold in the deep atmospheric layers,
lacking any sign of vertical transport of potential temperature by large scale
atmospheric motions. We thus conclude that the coupling between radiation and
dynamics alone is not sufficient to explain the abnormal large radii of
inflated hot gas giants.
