Inflation and cosmological constant

Abstract In construction of an inflationary model, one usually assumes that the matter sector gravitational action is minimally coupled to background. It means (inflaton) part with same metric part. We elaborate on this assumption and investigate some consequences. assume inflaton sectors belong different units (or conformal frames). show coupling can convert a single-field model into two-field mixed kinetic term. The energy-momentum tensor therefore non-conserved due interaction factor. This allows energy exchange between two fields provides us mechanism for reduction large effective cosmological constant during inflation.