### Abstract

We consider geometric and analytical aspects of M-theory on a manifold with boundary Y11. The partition function of the C-field requires summing over harmonic forms. When Y11 is closed, Hodge theory gives a unique harmonic form in each de Rham cohomology class, while in the presence of a boundary the Hodge-Morrey-Friedrichs decomposition should be used. This leads us to study the boundary conditions for the C-field. The dynamics and the presence of the dual to the C-field gives rise to a mixing of boundary conditions with one being Dirichlet and the other being Neumann. We describe the mixing between the corresponding absolute and relative cohomology classes via Poincaré duality angles, which we also illustrate for the M5-brane as a tubular neighborhood. Several global aspects are then considered. We provide a systematic study of the extension of the E8 bundle and characterize obstructions. Considering Y11 as a fiber bundle, we describe how the phase looks like on the base, hence providing dimensional reduction in the boundary case via the adiabatic limit of the eta invariant. The general use of the index theorem leads to a new effect given by a gravitational Chern-Simons term CS11 on Y11 whose restriction to the boundary would be a generalized WZW model. This suggests that holographic models of M-theory can be viewed as a sector within this index-theoretic approach.

Original language | English (US) |
---|---|

Pages (from-to) | 1284-1297 |

Number of pages | 14 |

Journal | Journal of Geometry and Physics |

Volume | 62 |

Issue number | 5 |

DOIs | |

State | Published - May 1 2012 |

### Fingerprint

### Keywords

- Chern-Simons invariants
- Dirichlet-to-Neumann map
- Eta invariants
- Gauge theory on manifold with boundary
- Hodge theory
- M-theory on manifold with boundary

### ASJC Scopus subject areas

- Mathematical Physics
- Physics and Astronomy(all)
- Geometry and Topology

### Cite this

*Journal of Geometry and Physics*,

*62*(5), 1284-1297. https://doi.org/10.1016/j.geomphys.2011.11.012

**Duality and cohomology in M-theory with boundary.** / Sati, Hisham.

Research output: Contribution to journal › Article

*Journal of Geometry and Physics*, vol. 62, no. 5, pp. 1284-1297. https://doi.org/10.1016/j.geomphys.2011.11.012

}

TY - JOUR

T1 - Duality and cohomology in M-theory with boundary

AU - Sati, Hisham

PY - 2012/5/1

Y1 - 2012/5/1

N2 - We consider geometric and analytical aspects of M-theory on a manifold with boundary Y11. The partition function of the C-field requires summing over harmonic forms. When Y11 is closed, Hodge theory gives a unique harmonic form in each de Rham cohomology class, while in the presence of a boundary the Hodge-Morrey-Friedrichs decomposition should be used. This leads us to study the boundary conditions for the C-field. The dynamics and the presence of the dual to the C-field gives rise to a mixing of boundary conditions with one being Dirichlet and the other being Neumann. We describe the mixing between the corresponding absolute and relative cohomology classes via Poincaré duality angles, which we also illustrate for the M5-brane as a tubular neighborhood. Several global aspects are then considered. We provide a systematic study of the extension of the E8 bundle and characterize obstructions. Considering Y11 as a fiber bundle, we describe how the phase looks like on the base, hence providing dimensional reduction in the boundary case via the adiabatic limit of the eta invariant. The general use of the index theorem leads to a new effect given by a gravitational Chern-Simons term CS11 on Y11 whose restriction to the boundary would be a generalized WZW model. This suggests that holographic models of M-theory can be viewed as a sector within this index-theoretic approach.

AB - We consider geometric and analytical aspects of M-theory on a manifold with boundary Y11. The partition function of the C-field requires summing over harmonic forms. When Y11 is closed, Hodge theory gives a unique harmonic form in each de Rham cohomology class, while in the presence of a boundary the Hodge-Morrey-Friedrichs decomposition should be used. This leads us to study the boundary conditions for the C-field. The dynamics and the presence of the dual to the C-field gives rise to a mixing of boundary conditions with one being Dirichlet and the other being Neumann. We describe the mixing between the corresponding absolute and relative cohomology classes via Poincaré duality angles, which we also illustrate for the M5-brane as a tubular neighborhood. Several global aspects are then considered. We provide a systematic study of the extension of the E8 bundle and characterize obstructions. Considering Y11 as a fiber bundle, we describe how the phase looks like on the base, hence providing dimensional reduction in the boundary case via the adiabatic limit of the eta invariant. The general use of the index theorem leads to a new effect given by a gravitational Chern-Simons term CS11 on Y11 whose restriction to the boundary would be a generalized WZW model. This suggests that holographic models of M-theory can be viewed as a sector within this index-theoretic approach.

KW - Chern-Simons invariants

KW - Dirichlet-to-Neumann map

KW - Eta invariants

KW - Gauge theory on manifold with boundary

KW - Hodge theory

KW - M-theory on manifold with boundary

UR - http://www.scopus.com/inward/record.url?scp=84858004391&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84858004391&partnerID=8YFLogxK

U2 - 10.1016/j.geomphys.2011.11.012

DO - 10.1016/j.geomphys.2011.11.012

M3 - Article

VL - 62

SP - 1284

EP - 1297

JO - Journal of Geometry and Physics

JF - Journal of Geometry and Physics

SN - 0393-0440

IS - 5

ER -