12 - 7 - 2012 DBI Inflation in N = 1 Supergravity

It was recently demonstrated that, when coupled to N = 1 supergravity, the Dirac-Born-Infeld (DBI) action constructed from a single chiral superfield has the property that when the higher-derivative terms become important, the potential becomes negative. Thus, DBI inflation cannot occur in its most interesting, relativistic regime. In this paper, it is shown how to overcome this problem by coupling the model to one or more additional chiral supermultiplets. In this way, one obtains effective single real scalar field DBI models with arbitrary positive potentials, as well as multiple real scalar field DBI inflation models with hybrid potentials. Disciplines Physical Sciences and Mathematics | Physics Comments Koehn, M., Lehners, J., & Ovrut, B. A. (2012). DBI Inflation in N = 1 Supergravity. Physical Review D, 86(12), 123510. doi: 10.1103/PhysRevD.86.123510 © 2012 American Physical Society This journal article is available at ScholarlyCommons: http://repository.upenn.edu/physics_papers/268 DBI inflation inN 1⁄4 1 supergravity Michael Koehn,* Jean-Luc Lehners, and Burt A. Ovrut Max-Planck-Institute for Gravitational Physics, Albert Einstein Institute, 14476 Golm, Germany Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA (Received 9 August 2012; published 7 December 2012) It was recently demonstrated that, when coupled to N 1⁄4 1 supergravity, the Dirac-Born-Infeld (DBI) action constructed from a single chiral superfield has the property that when the higher-derivative terms become important, the potential becomes negative. Thus, DBI inflation cannot occur in its most interesting, relativistic regime. In this paper, it is shown how to overcome this problem by coupling the model to one or more additional chiral supermultiplets. In this way, one obtains effective single real scalar field DBI models with arbitrary positive potentials, as well as multiple real scalar field DBI inflation models with hybrid potentials. DOI: 10.1103/PhysRevD.86.123510 PACS numbers: 98.80.Cq