July 9, 2020 to January 31, 2025
Europe/Zurich timezone
Dear colleagues,
We would like to invite you to take part in the upcoming 178th Copernicus Webinar (the last one before the summer break).
Time:              16th July, Tuesday, at 3pm CEST (9 pm Beijing, 10pm JST, 9 am EDT). 
Speaker:        Hassan Firouzjahi (Institute for Research in Fundamental Sciences)

Title: Upper bounds on the mass of fields from vacuum zero point energy fluctuations during inflation 
Abstract: We study the fluctuations in the vacuum zero point energy associated to quantum fields and their statistical distributions during inflation. We show that the perturbations in the vacuum zero point energy  have large amplitudes and are highly non-Gaussian. The effects of vacuum zero point fluctuations can be interpreted as the loop corrections in primordial power spectrum and bispectrum. Requiring that the primordial curvature perturbation to remain nearly scale-invariant and  Gaussian imposes strong upper bounds on the mass of fundamental fields during inflation. We show that the fundamental fields can not be much heavier than the Hubble scale during inflation, otherwise their vacuum zero point fluctuations  induce large non-Gaussianities and scale-dependence in primordial perturbations. Imposing the observational upper bound on tensor to scalar ratio, we conclude that all fundamental fields are lighter than $10^{14}$ GeV.
Zoom link:
Meeting ID: 421 480 1692
Passcode: cosmology

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