Relaxing unimodularity for Yang-Baxter deformed strings

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Authors	HRONEK Stanislav WULFF Jörgen Linus
Year of publication	2020
Type	Article in Periodical
Magazine / Source	Journal of High Energy Physics
MU Faculty or unit	Faculty of Science
Citation
Web	https://doi.org/10.1007/JHEP10(2020)065
Doi	http://dx.doi.org/10.1007/JHEP10(2020)065
Keywords	Bosonic Strings; Conformal Field Models in String Theory; String Duality
Description	We consider so-called Yang-Baxter deformations of bosonic string sigma- models, based on an R-matrix solving the (modified) classical Yang-Baxter equation. It is known that a unimodularity condition on R is sufficient for Weyl invariance at least to two loops (first order in alpha (')). Here we ask what the necessary condition is. We find that in cases where the matrix (G + B)(mn), constructed from the metric and B-field of the undeformed background, is degenerate the unimodularity condition arising at one loop can be replaced by weaker conditions. We further show that for non-unimodular deformations satisfying the one-loop conditions the Weyl invariance extends at least to two loops (first order in alpha (')). The calculations are simplified by working in an O(D, D)-covariant doubled formulation.
Related projects:	Integrable deformations