Samenvatting
The field of cosmology deals with the properties and evolution of the universe as a whole, and tries to answer questions such as 'What did the universe look like in the past?', 'How did it evolve into its current state?' and 'What will it look like in the future?'.
In this thesis we investigated several formal aspects of cosmological models that are intended to describe the accelerated expansion of the very early universe (also called inflation) and that of the current universe.
Firstly we have examined under which conditions one can avoid particular unwanted instabilities that often appear in models with socalled higher derivatives. Our findings led us to introduce a classification of models that are free of such instabilities.
We have also investigated particular mathematical properties of socalled nonlinear realisations of spacetime symmetries. Such nonlinear realisations occur naturally whenever spacetime symmetries of a model get spontaneously broken. Lastly, based on particular broken spacetime symmetries, we have introduced new inflationary models that can be tested in the near future with the newest generation of satellite experiments.
In this thesis we investigated several formal aspects of cosmological models that are intended to describe the accelerated expansion of the very early universe (also called inflation) and that of the current universe.
Firstly we have examined under which conditions one can avoid particular unwanted instabilities that often appear in models with socalled higher derivatives. Our findings led us to introduce a classification of models that are free of such instabilities.
We have also investigated particular mathematical properties of socalled nonlinear realisations of spacetime symmetries. Such nonlinear realisations occur naturally whenever spacetime symmetries of a model get spontaneously broken. Lastly, based on particular broken spacetime symmetries, we have introduced new inflationary models that can be tested in the near future with the newest generation of satellite experiments.
Originele taal2  English 

Kwalificatie  Doctor of Philosophy 
Toekennende instantie 

Begeleider(s)/adviseur 

Datum van toekenning  13dec2018 
Plaats van publicatie  [Groningen] 
Uitgever  
Gedrukte ISBN's  9789403412429 
Elektronische ISBN's  9789403412412 
Status  Published  2018 