Post-Newtonian Feasibility of the Closed String Massless Sector

Abstract

We perform post-Newtonian analysis of double field theory as a test of string theory in gravitational sector against observations. We identify the Eddington-Robertson-Schiff parameters beta(PPN), gamma(PPN) with the charges of electric H flux and dilaton respectively, and further relate them to stress-energy tensor. We show beta(PPN) = 1 from weak energy condition and argue that the observation of gamma(PPN) similar or equal to 1 signifies the ultrarelativistic equation of state in baryons, or the suppression of gluon condensate.