Large field inflation from axion mixing

Journal of High Energy Physics 2015.6 (2015): 026 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)We study the general multi-axion systems, focusing on the possibility of large field inflation driven by axions. We find that through axion mixing from a non-diagonal metric on the moduli space and/or from Stuckelberg coupling to a U(1) gauge field, an effectively super-Planckian decay constant can be generated without the need of "alignment" in the axion decay constants. We also investigate the consistency conditions related to the gauge symmetries in the multi-axion systems, such as vanishing gauge anomalies and the potential presence of generalized Chern-Simons terms. Our scenario applies generally to field theory models whose axion periodicities are intrinsically sub-Planckian, but it is most naturally realized in string theory. The types of axion mixings invoked in our scenario appear quite commonly in D-brane models, and we present its implementation in type II superstring theory. Explicit stringy models exhibiting all the characteristics of our ideas are constructed within the frameworks of Type IIA intersecting D6-brane models on T6/ΩR and Type IIB intersecting D7-brane models on Swiss-Cheese Calabi-Yau orientifoldsWe would like to thank Kiwoon Choi, Michele Cicoli, Daniel Junghans, Luis Ibáñez, Fernando Marchesano, Francisco Pedro, Jan Rosseel, Pablo Soler and Angel Uranga for useful discussions and suggestions. G.S. and F.Y. are supported in part by the DOE grant DE-FG-02-95ER40896 and the HKRGC grants HUKST4/CRF/13G, 604231 and 16304414. W.S. was initially supported by the Cluster of Excellence ‘Precision Physics, Fundamental Interactions and Structure of Matter’ (PRISMA) DGF no. EXC 1098 and the DFG research grant HO 4166/2-1, but is now supported by the ERC Advanced Grant SPLE under contract ERC-2012-ADG-20120216-320421, by the grant FPA2012-32828 from the MINECO, and the grant SEV-2012-0249 of the “Centro de Excelencia Severo Ochoa” Programme. W.S. would also like to thank the European COST action MP1210 “The String Theory Universe” for a Short Term Scientific Mission Gran