Browsing by Author "Gray, James"

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    Free quotients of favorable Calabi-Yau manifolds
    Gray, James; Wang, Juntao (2022-07-19)
    Non-simply connected Calabi-Yau threefolds play a central role in the study of string compactifications. Such manifolds are usually described by quotienting a simply connected Calabi-Yau variety by a freely acting discrete symmetry. For the Calabi-Yau threefolds described as complete intersections in products of projective spaces, a classification of such symmetries descending from linear actions on the ambient spaces of the varieties has been given in [16]. However, which symmetries can be described in this manner depends upon the description that is being used to represent the manifold. In [24] new, favorable, descriptions were given of this data set of Calabi-Yau threefolds. In this paper, we perform a classification of cyclic symmetries that descend from linear actions on the ambient spaces of these new favorable descriptions. We present a list of 129 symmetries/non-simply connected Calabi-Yau threefolds. Of these, at least 33, and potentially many more, are topologically new varieties.
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    Future Farmers of Virginia Chapter Chats September 1971
    Atwood, John; Myers, John W.; Truitt, Howard; Reavis, Howard; Gilliam, C. M.; Gray, James; Houff, Ken; Mitchell, A. W.; Lehmann, Dan; Powell, Jr., Earnest E.; Gibson, D. V.; Smith, Robert G.; Brubaker, Lewis M.; Simmons, Roland; Roller, O. B.; Eades, Larry; Kell, E. H.; Spence, Steven; Gardner, J. T. (The Future Farmers of Virginia, 1971-09)
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    Twisted Fibrations in M/F-theory
    Anderson, Lara B.; Gray, James; Oehlmann, Paul-Konstantin (2024-01-04)
    In this work we investigate 5-dimensional theories obtained from M-theory on genus one fibered threefolds which exhibit twisted algebras in their fibers. We provide a base-independent algebraic description of the threefolds and compute light 5D BPS states charged under finite sub-algebras of the twisted algebras. We further construct the Jacobian fibrations that are associated to 6-dimensional F-theory lifts, where the twisted algebra is absent. These 6/5-dimensional theories are compared via twisted circle reductions of F-theory to M-theory. In the 5-dimensional theories we discuss several geometric transitions that connect twisted with untwisted fibrations. We present detailed discussions of 𝔢(2)6,𝔰𝔬(3)8 and 𝔰𝔲(2)3 twisted fibers and provide several explicit example threefolds via toric constructions. Finally, limits are considered in which gravity is decoupled, including Little String Theories for which we match 2-group symmetries across twisted T-dual theories.