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arXiv · hep-th/9112044

$O(d,d)$-Covariant String Cosmology

M. Gasperini·G. Veneziano
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Abstract

The recently discovered $O(d,d)$ symmetry of the space of slowly varying cosmological string vacua in $d+1$ dimensions is shown to be preserved in the presence of bulk string matter. The existence of $O(d,d)$ conserved currents allows all the equations of string cosmology to be reduced to first-order differential equations. The perfect-fluid approximation is not $O(d,d)$-invariant, implying that stringy fluids possess in general a non-vanishing viscosity.

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M. Gasperini, G. Veneziano. 1991-12-17. $O(d,d)$-Covariant String Cosmology. https://doi.org/10.1016/0370-2693(92)90744-o

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