© 2002 by London Mathematical Society
© The London Mathematical Society
A Topological Criterion for the Existence of Half-Bound States
Département de Mathématiques, UMR 6629, Université de Nantes 2 rue de la Houssinière, F-44322 Nantes Cedex 03, France, gilles.carron{at}math.univ-nantes.fr
Received 1 October 1999. Revision received 10 July 2001.
The following theorem is proved: if (M4n+1,g) is a complete Riemannian manifold and
M is an oriented hypersurface partitioning M and with non-zero signature, then the spectrum of the HodgedeRham Laplacian is [0,
]. This result is obtained by a new Callias-type index. This new formula links half-bound harmonic forms (that is, nearly L2 but not in L2) with the signature of
.