An analytic invariant of G_2 manifolds

Fuente: arXiv
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Main Authors: Crowley, Diarmuid, Goette, Sebastian, Nordström, Johannes
Format: Preprint
Published: 2015
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author Crowley, Diarmuid
Goette, Sebastian
Nordström, Johannes
author_facet Crowley, Diarmuid
Goette, Sebastian
Nordström, Johannes
contents We prove that the moduli space of holonomy G_2-metrics on a closed 7-manifold is in general disconnected by presenting a number of explicit examples. We detect different connected components of the G_2-moduli space by defining an integer-valued analytic refinement of the nu-invariant, a Z/48-valued defect invariant of G_2-structures on a closed 7-manifold introduced by the first and third authors. The refined invariant is defined using eta invariants and Mathai-Quillen currents on the 7-manifold and we compute it for twisted connected sums à la Kovalev, Corti-Haskins-Nordström-Pacini and extra-twisted connected sums as constructed by the second and third authors. In particular, we find examples of G_2-holonomy metrics in different components of the moduli space where the associated G_2-structures are homotopic and other examples where they are not.
format Preprint
id arxiv_https___arxiv_org_abs_1505_02734
institution arXiv
publishDate 2015
record_format arxiv
spellingShingle An analytic invariant of G_2 manifolds
Crowley, Diarmuid
Goette, Sebastian
Nordström, Johannes
Geometric Topology
Differential Geometry
57R20 (Primary) 53C29, 58J28 (Secondary)
We prove that the moduli space of holonomy G_2-metrics on a closed 7-manifold is in general disconnected by presenting a number of explicit examples. We detect different connected components of the G_2-moduli space by defining an integer-valued analytic refinement of the nu-invariant, a Z/48-valued defect invariant of G_2-structures on a closed 7-manifold introduced by the first and third authors. The refined invariant is defined using eta invariants and Mathai-Quillen currents on the 7-manifold and we compute it for twisted connected sums à la Kovalev, Corti-Haskins-Nordström-Pacini and extra-twisted connected sums as constructed by the second and third authors. In particular, we find examples of G_2-holonomy metrics in different components of the moduli space where the associated G_2-structures are homotopic and other examples where they are not.
title An analytic invariant of G_2 manifolds
topic Geometric Topology
Differential Geometry
57R20 (Primary) 53C29, 58J28 (Secondary)
url https://arxiv.org/abs/1505.02734