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arXiv · hep-th/9503142

A new class of spatially homogeneous 4D string backgrounds

Nikolaos A. Batakis
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Abstract

A new class of spatially homogeneous 4D string backgrounds, the $X(d\rightarrow)$ according to a recent classification, is presented and shown to contain only five generic types. In contrast to the case of $X(d\uparrow)$ (which contains as a subclass all possible FRW backgrounds), exact $SO(3)$ isotropy is always broken in the $X(d\rightarrow)$ class. This is due to the $H$-field, whose dual is necessarily along a principal direction of anisotropy. Nevertheless, FRW symmetry can be attained asymptotically for Bianchi-types $I$ and $VII_0$ in a rather appealing physical context. Other aspects of the solutions found for types $X=I,II,III,VI_{-1}$, and of the $VII_0$ case are briefly discussed.

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Nikolaos A. Batakis. 1995-03-21. A new class of spatially homogeneous 4D string backgrounds. https://doi.org/10.1016/0370-2693(95)00632-u

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