M-flation: inflation from matrix valued scalar fields

Abstract

We propose an inflationary scenario, M-flation , in which inflation is driven by three N N hermitian matrices. The inflation potential of our model, which is strongly motivated from string theory, is constructed from and their commutators. We show that one can consistently restrict the classical dynamics to a sector in which the are proportional to the irreducible representations of SU(2). In this sector our model effectively behaves as an N-flation model with 3 N 2 number of fields and the effective inflaton field has a super-Planckian field value. Furthermore, the fine-tunings associated with unnaturally small couplings in the chaotic type inflationary scenarios are removed. Due to the matrix nature of the inflaton fields there are 3 N 2 extra scalar fields in the dynamics. These have the observational effects such as production of iso-curvature perturbations on cosmic microwave background. Moreover, the existence of these extra scalars provides us with a natural preheating mechanism and exit from inflation. As the effective inflaton field can traverse super-Planckian distances in the field space, the model is capable of producing a considerable amount of gravity waves that can be probed by future CMB polarization experiments such as PLANCK, QUIET and CMBPOL.