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Advances in High Energy Physics
Volume 2015, Article ID 397410, 12 pages
Research Article

Helical Phase Inflation and Monodromy in Supergravity Theory

1State Key Laboratory of Theoretical Physics and Kavli Institute for Theoretical Physics China (KITPC), Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
2School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
3George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
4Astroparticle Physics Group, Houston Advanced Research Center (HARC), Mitchell Campus, The Woodlands, TX 77381, USA
5Division of Natural Sciences, Academy of Athens, 28 Panepistimiou Avenue, 10679 Athens, Greece

Received 3 July 2015; Accepted 17 November 2015

Academic Editor: Ignatios Antoniadis

Copyright © 2015 Tianjun Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3.


We study helical phase inflation which realizes “monodromy inflation” in supergravity theory. In the model, inflation is driven by the phase component of a complex field whose potential possesses helicoid structure. We construct phase monodromy based on explicitly breaking global symmetry in the superpotential. By integrating out heavy fields, the phase monodromy from single complex scalar field is realized and the model fulfills natural inflation. The phase-axion alignment is achieved from explicitly symmetry breaking and gives super-Planckian phase decay constant. The -term scalar potential provides strong field stabilization for all the scalars except inflaton, which is protected by the approximate global symmetry. Besides, we show that helical phase inflation can be naturally realized in no-scale supergravity with symmetry since the supergravity setup needed for phase monodromy is automatically provided in the no-scale Kähler potential. We also demonstrate that helical phase inflation can be reduced to another well-known supergravity inflation model with shift symmetry. Helical phase inflation is free from the UV-sensitivity problem although there is super-Planckian field excursion, and it suggests that inflation can be effectively studied based on supersymmetric field theory while a UV-completed framework is not prerequisite.