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Copernicus Webinar and Colloquium Series

9 July 2020 to 31 January 2025
Europe/Zurich timezone

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Dear colleagues,
 
We would like to invite you to take part in the upcoming 168th Copernicus Webinar.
 
Time:               30th April, Tuesday, at 10am CEST (4 pm Beijing, 5pm JST, 4 am EDT). 
                        (*Please take note of the unusual starting hour!*)
 
Speaker:          Anamaria Hell (Kavli IPMU, the University of Tokyo)
 
Title: Who ordered the disformal coupling for the Proca field?
 
Abstract: In this talk, we will study the massless limits of two cases of Proca theory -- in the presence of self-interactions, and with non-minimal coupling to gravity. In contrast to its massless counterpart, this theory propagates an additional longitudinal mode in flat spacetime. Due to this, conventional methods indicate that the perturbative series is singular in mass. In the presence of self-interactions, we will confirm that the longitudinal mode becomes strongly coupled at the Vainshtein scale, and decouples from the remaining transverse modes beyond it, which in turn remain weakly coupled. In the case of non-minimal coupling to gravity, however, the longitudinal mode will cause the strong coupling of the tensor modes, leading to a surprising inconsistency. We will show that this can be solved by the introduction of the disformal couplings, and discuss further implications to the cosmological backgrounds.  
 
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Zoom link:
Meeting ID: 421 480 1692
Passcode: cosmology
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Europe/Zurich

This series is co-organised by the cosmology groups in the following institutions (in alphabetical order): 

Harvard University, Hong Kong University of Science and Technology, Institut d'Astrophysique de Paris, Institute of Physics of the Czech Academy of Science, Jagiellonian University, Kyoto University, Leiden University, Ludwig Maximilians University, McGill University, Perimeter Institute, Polish Society on Relativity, The Pennsylvania State University, The University of Tokyo, Tsinghua University, University of Geneva, University of Groningen, University of Science and Technology of China, University of Waterloo.

Science Organising Committee members (in alphabetical order):

Niayesh Afshordi, Robert Brandenberger, Yifu Cai, Xingang Chen, Ema Dimastrogiovanni, Ruth Durrer, Ghazal Geshnizjani, Chunshan Lin, Jerome Martin, Jakub Mielczarek, Viatcheslav Mukhanov, Shinji Mukohyama, Subodh Patil, Misao Sasaki, Sarah Shandera, Wei Song, Alexander Vikman, Yi Wang, Zhong-Zhi Xianyu

 
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