Post-Newtonian Feasibility of the Closed String Massless Sector

TL;DR

This paper investigates the compatibility of Double Field Theory's gravitational sector with observations using post-Newtonian analysis, linking theoretical parameters to physical charges and stress-energy conditions.

Contribution

It establishes a connection between string theory parameters and observable gravitational parameters, providing a test of string theory in the weak-field regime.

Findings

eta_{PPN} = 1 from weak energy condition

mma_{PPN}  1 indicates ultrarelativistic baryon matter or suppressed gluon condensate

The analysis supports the feasibility of string theory's massless sector in gravitational observations.

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 $\beta_{{{\rm{PPN}}}}$, $\gamma_{{{\rm{PPN}}}}$ with the charges of electric $H$-flux and dilaton respectively, and further relate them to stress-energy tensor. We show ${\beta_{{{\rm{PPN}}}}=1}$ from weak energy condition and argue that the observation of $\gamma_{{{\rm{PPN}}}}\simeq 1$ signifies the ultrarelativistic equation of state in baryons, or the suppression of gluon condensate.