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<div>Dear C&G group,</div>
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<div>please save the date for the next Theory WG meeting. Tomorrow at 13:15 in Nordita 132:028. See below.</div>
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<div>Cheers,</div>
<div>Martina</div>
<div>---------</div>
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<div>The next OKC Theory Working Group seminar is on:</div>
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<div>Date: Thursday Dec 14, at 13.15</div>
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<div>Place: Nordita 132:028</div>
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<div>Speaker: Sadra Jazayeri (Institute for Theoretical Physics, Utrecht & IPM,</div>
<div> Tehran)</div>
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<div>Title: Systematics of Adiabatic Modes in Cosmology</div>
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<div>Abstract: Adiabatic modes (ADMs) play an essential role in derivation of </div>
<div>soft theorems in Cosmology. They also give us non-trivial solutions to the </div>
<div>Einstein perturbed equations that are almost independent from the matter </div>
<div>content of the universe. They are defined as the physical perturbations </div>
<div>(on the top of a fixed FRW universe), that can be locally removed by a </div>
<div>local coordinate transformation. In this work we systematically construct </div>
<div>the adiabatic modes and find new time-dependent ones. In the light of a </div>
<div>new time dependent ADM for graviton, we show that alternative theories to </div>
<div>inflation enjoy asymptotic symmetries associated with soft gravitons. We </div>
<div>point out adiabaticity of vector perturbations and mention the relevance </div>
<div>of this finding to primordial magnetogenesis. New ADMs, possess </div>
<div>interesting features. In particular, they can be either mixed or pure in </div>
<div>terms of scalar-vector-tensor decomposition. The long mode of the tensor </div>
<div>perturbation is able to have quantum behavior even on large scales. </div>
<div>Moreover, we figure out that some ADMs can not be monochromatic but </div>
<div>instead they will be continued into spherical waves.</div>
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<div>------------------------------------------------------------------</div>
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<div>Best regards,</div>
<div>Fawad</div>
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