Theory Seminar (High Energy/Cosmology)
Events on Friday, April 5th, 2019
- Large Field Ranges from Aligned and Misaligned Winding
- Time: 2:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Andreas Schachner, Heidelberg University
- Abstract: One of the most prominent aspects of the landscape-swampland program is the quest for large field ranges in string compactifications. One reason for this is the interest in large-field inflation. Another is the hope for a deeper understanding of general quantum gravity constraints and therefore of quantum gravity itself. In the present talk, I focus on large axionic field ranges summarizing work done in collaboration with A. Hebecker and D. Junghans (arXiv: 1812.05626). More specifically, I explain our attempt to construct effective axions with parametrically large decay constants in type IIB string models. I argue that such axions can be realised as long winding trajectories in complex-structure moduli space by an appropriate flux choice. The main findings are: The simplest models with aligned winding in a 2-axion field space fail due to a general no-go theorem. However, equally simple models with misaligned winding, where the effective axion is not close to any of the fundamental axions, appear to work to the best of the present understanding. These models have large decay constants but no large monotonic regions in the potential, making them unsuitable for large-field inflation. I also show that the no-go theorem can be avoided by aligning three or more axions. Contrary to misaligned models, such models can in principle have both large decay constants and large monotonic regions in the potential. These results may be used to argue against the refined Swampland Distance Conjecture and strong forms of the axionic Weak Gravity Conjecture. After stabilizing Kähler moduli, it becomes apparent, however, that realizing inflation is by far harder than just producing a light field with large periodicity.