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

中文翻译：

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闭弦无质量扇区的后牛顿可行性

我们对双场理论进行后牛顿分析，作为引力扇区中弦理论对观测的检验。我们确定 Eddington-Robertson-Schiff 参数${\beta }_{\mathrm{PPN}}$,${\gamma }_{\mathrm{PPN}}$带电$H$分别为通量和膨胀子，并进一步将它们与应力-能量张量联系起来。我们展示${\beta }_{\mathrm{PPN}}=1$从弱能量条件，并认为观察${\gamma }_{\mathrm{PPN}}\simeq 1$表示重子中的超相对论状态方程，或胶子凝聚体的抑制。