3,264 research outputs found
Charge and the topology of spacetime
A new class of electrically charged wormholes is described in which the outer 2-sphere is not spanned by a compact, co-orientable hypersurface, These wormholes can therefore display net electric charge from the source-free Maxwell equations. This extends the work of Sorkin on non-space-orientable manifolds, to spacetimes which do not admit a time orientation. The work is motivated by the suggestion that quantum theory can be explained by modelling elementary particles as regions of spacetime with non-trivial causal structure. The simplest example of an electrically charged spacetime carries a spherical symmetry
Symplectomorphism group relations and degenerations of Landau-Ginzburg models
In this paper, we describe explicit relations in the symplectomorphism groups
of toric hypersurfaces. To define the elements involved, we construct a proper
stack of toric hypersurfaces with compactifying boundary representing toric
hypersurface degenerations. Our relations arise through the study of the one
dimensional strata of this stack. The results are then examined from the
perspective of homological mirror symmetry where we view sequences of relations
as maximal degenerations of Landau-Ginzburg models. We then study the B-model
mirror to these degenerations, which gives a new mirror symmetry approach to
the minimal model program.Comment: 100 pages, 24 figure
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