Revisiting the Cohen-Jones-Segal construction in Morse-Bott theory

TL;DR

This paper rigorously constructs the stable homotopy type associated with Morse-Bott Floer homology, confirming it recovers the manifold's suspension spectrum and extends to Thom spectra with KO-theory classes.

Contribution

It provides a rigorous construction of stable normal framings in Morse-Bott theory and demonstrates their role in recovering known spectra, extending the Cohen-Jones-Segal framework.

Findings

Constructed stable normal framings for Morse-Bott flows.

Proved the stable homotopy type recovers the suspension spectrum of M.

Extended the framework to Thom spectra for KO-theory classes.

Abstract

In 1995, Cohen, Jones and Segal proposed a method of upgrading any given Floer homology to a stable homotopy-valued invariant. For a generic pseudo-gradient Morse-Bott flow on a closed smooth manifold $M$, we rigorously construct the alleged stable normal framings, which are an essential ingredient in their construction, and give a rigorous proof that the resulting stable homotopy type recovers $\Sigma^\infty_+ M$. We further show that other systems of compatible stable normal framings recover Thom spectra $M^E$, for all reduced $KO$-theory classes $E$ on $M$. Our paper also includes a construction of the smooth corner structure on compactified moduli spaces of broken flow lines with free endpoint, a formal construction of Piunikhin-Salamon-Schwarz type continuation maps, and a way to relax the stable normal framing condition to orientability in orthogonal spectra.