Abstract

A large number of examples of compact G2 manifolds, relevant to supersymmetric compactifications of M-Theory to four dimensions, can be constructed by forming a twisted connected sum of two building blocks times a circle. These building blocks, which are appropriate K3-fibred threefolds, are shown to have a natural and elegant construction in terms of tops, which parallels the construction of Calabi-Yau manifolds via reflexive polytopes. In particular, this enables us to prove combinatorial formulas for the Hodge numbers and other relevant topological data.

Highlights

  • Given the central position of M-Theory in the web of string dualities, a better understanding of M-Theory compactifications is expected to tie together supersymmetric compactifications of all of the weakly coupled string theories

  • The first constructions [1, 2] were non-compact examples which are asymptotically conical, see [3, 4] for more examples. These can be thought of as smoothed versions of singular cones, which is very interesting from the point of view of physics: in compactifications of M-Theory on manifolds of G2 holonomy, non-abelian gauge groups and matter arise from singularities of the compactification geometry and interesting singularities can be constructed from such conical manifolds

  • The construction of G2 manifolds as twisted connected sums [6,7,8] starts from K3-fibred threefolds Z which are called building blocks

Read more

Summary

Introduction

Given the central position of M-Theory in the web of string dualities, a better understanding of M-Theory compactifications is expected to tie together supersymmetric compactifications of all of the weakly coupled string theories. (the singular versions of) these manifolds do not support interesting singularities on their own and their toroidal origin renders them locally flat This prevents to cut and paste the interesting singular non-compact examples studied in the literature as these are not asymptotically flat. As first discussed by Kovalev [6] and further elaborated on in [7, 8], one may construct compact manifolds of G2 holonomy by forming a twisted connected sum (TCS) of two appropriate ‘building blocks’ times a circle. These building blocks can be thought of as K3 fibrations over a P1 base. As the relevant theorems and constructions from [6,7,8] are nicely reviewed in the physics literature in [23], the discussion is limited to a minimum

Building blocks
Gluing building blocks to G2 manifolds
Tops as building blocks
Tops and fibred Calabi-Yau manifolds
Formal construction
Normal fans of tops
Vertical and non-vertical faces
Topological properties of building blocks
The stratification associated with a refinement of the normal fan
Computing Hodge numbers from stratification
Hodge numbers of building blocks
The lattices N and K
Summary
Relation to construction via semi-Fano threefolds
Examples
Building blocks with a quartic K3 fibre
Building blocks with a K3 fibre of degree 2
Discussion and outlook
Lattices
Lattice polarized K3 surfaces and mirror symmetry
K3 surfaces from reflexive polyhedra
Mirror symmetry and reflexive three-dimensional polyhedra
B Toric Calabi-Yau hypersurfaces and toric stratification
Hodge numbers of toric Calabi-Yau hypersurfaces
Topology of divisors
C Degenerating an elliptic K3 surface into a pair of rational elliptic surfaces

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.