Ghost Condensate in N = 1 Supergravity

We present the theory of a supersymmetric ghost condensate coupled to N=1 supergravity. This is accomplished using a general formalism for constructing locally supersymmetric higher-derivative chiral superfield actions. The theory admits a ghost condensate vacuum in de Sitter spacetime. Expanded around this vacuum, the scalar sector of the theory is shown to be ghost-free with no spatial gradient instabilities. By direct calculation, the fermion sector is found to consist of a massless chiral fermion and a massless gravitino. By analyzing the supersymmetry transformations, we find that the chiral fermion transforms inhomogeneously, indicating that the ghost condensate vacuum spontaneously breaks local supersymmetry with this field as the Goldstone fermion. Although potentially able to get a mass through the super-Higgs effect, the vanishing superpotential in the ghost condensate theory renders the gravitino massless. Thus local supersymmetry is broken without the super-Higgs effect taking place. This is in agreement with, and gives an explanation for, the direct calculation. Disciplines Physical Sciences and Mathematics | Physics Comments Koehhn, M., Lehners, J. & Ovrut, B. (2013). Ghost condensate in N=1 supergravity. Physical Review D, 87(6), 065022. doi: 10.1103/PhysRevD.87.065022 © 2013 American Physical Society This journal article is available at ScholarlyCommons: http://repository.upenn.edu/physics_papers/287 Ghost condensate inN1⁄4 1 supergravity Michael Koehn,* Jean-Luc Lehners, and Burt Ovrut Max Planck Institute for Gravitational Physics (Albert Einstein Institute), 14476 Potsdam, Germany Department of Physics, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6395, USA (Received 14 January 2013; published 26 March 2013) We present the theory of a supersymmetric ghost condensate coupled to N 1⁄4 1 supergravity. This is accomplished using a general formalism for constructing locally supersymmetric higher-derivative chiral superfield actions. The theory admits a ghost condensate vacuum in de Sitter spacetime. Expanded around this vacuum, the scalar sector of the theory is shown to be ghost-free with no spatial gradient instabilities. By direct calculation, the fermion sector is found to consist of a massless chiral fermion and a massless gravitino. By analyzing the supersymmetry transformations, we find that the chiral fermion transforms inhomogeneously, indicating that the ghost condensate vacuum spontaneously breaks local supersymmetry with this field as the Goldstone fermion. Although potentially able to get a mass through the superHiggs effect, the vanishing superpotential in the ghost condensate theory renders the gravitino massless. Thus local supersymmetry is broken without the super-Higgs effect taking place. This is in agreement with, and gives an explanation for, the direct calculation. DOI: 10.1103/PhysRevD.87.065022 PACS numbers: 04.65.+e, 98.80.Cq